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Posted by: stownsen914 Oct 12 2016, 02:04 PM

I have heard the conventional wisdom that "you can't turbocharge a type 4 successfully." Is it just difficult, or can it really not be done well? I'm tossing around the crazy idea of turbo'ing a type 4 for PCA club racing, to put in the chassis in my avatar. My 6 in its current configuration is not competitive, so I can put a bunch of money in that, or do something different. I like a challenge, so why wouldn't the following work?

- 1.8 or 2.0 type 4 as a base. I would keep displacement stock or close to it.
- EFI for induction
- Properly sized intercooler and huge oil cooler
- A good aftermarket cooling fan
- Would be dry sumped
- I would work with a knowledgeable builder or shop to build the engine. I am not so familiar with type 4 race modifications, but presumably this would include reinforcing the bottom end, using Carrillo, Pauter, etc. rods
- Obviously the heads would need to be reworked for flow and possibly reliability

If I do the above, could a type 4 be built to withstand 15 psi of boost and make 350 hp reliably?

Scott

Posted by: snakemain Oct 12 2016, 02:44 PM

Here's the thread from when this topic came up a couple weeks ago.

http://www.914world.com/bbs2/index.php?showtopic=295420&hl=turbo

It can be done (turbo a type4, not 350 reliable hp...if you want those numbers go Suby or small block)

Posted by: Jetsetsurfshop Oct 12 2016, 03:37 PM

I like that you posted this here. Should be some more constructive answers then in the Garage.
It seems that if you built the bottom end and valve train to handle the power it would work. I think I remember reading from a credible post that the heads were the problem. I swear i've seen that someone adds head studs. I don't know if that would help or not? I want to build one too.

Posted by: HAM Inc Oct 12 2016, 06:53 PM

It can be done, but the heads are indeed the weak point, specifically, the combustion chambers in the areas positioned directly above the exhaust ports.

Take a look at the way the port cuts directly beneath a significant area of the chamber. That area is very thin. When exposed to high pressure and high heat it droops into the hollow space that forms the port, anywhere from a few thousanths to half a milimeter in extreme cases. It only takes a few thousanths to blow the jug seal.

This droop is a problem on N.A. engines of modest CR's when temps get high enough in the presense of steady high revs at full throttle. The aluminum is pretty soft at the egt's that peak power demand -1225-1250.

Turbo's like high egt's, and they generate a good deal more cylinder pressure than NA engines.

My suggestion for making it work is to keep the bore as small as possible, the stroke as long as possible and the revs as low as possible. Think really low speed torque.

If I were building a turbo T4 I'd look for a pristine pair of 1.7 Q heads and follow the above blueprint, with a max bore of 91mm.

A fellow on here did a pretty good job with his turbo T4 engine. He followed that blueprint. He didn't cook the heads, but he did hurt it with a mechanical overrev.

Posted by: Mueller Oct 12 2016, 11:59 PM

Would the heads benefit from ceramic coatings in this application to help protect the potential soft spot?

Posted by: HAM Inc Oct 13 2016, 07:14 AM

Coatings in chambers and ports definitely help. But they're a band-aid.

Posted by: Andyrew Oct 13 2016, 10:42 AM

I dont see you making 350hp in a type 4 for any less than a 3.6L conversion. And thats pretty close to that...


I would 100% just run a 3.6 instead.

Posted by: HAM Inc Oct 13 2016, 12:07 PM

When the chamber droops it takes the exhaust seat with it. None of our heads have ever suffered a seat failure as a result, but it does lose the valve seal.

You really get a good look at the impact of the droop when you flycut the head and cut the valve seat. This post on our FB site is an excellent example of a head that suffered this issue.

These were new LE200's that were installed on a track car engine and saw very elevated egt's for long, full throttle runs. It developed high leak down around the valves, indicating it lost the valve job. Fortunately the owner stopped running before he blew the head-jug seal, which would have done major damage.

In the pics we're cutting the ex seats. The layout die shows the low side. This one got hot enough to move the intake seats, too. That's some serious warpage!

https://www.facebook.com/HoffmanAutomotiveMachine/photos/pcb.1050307268317778/1050307071651131/?type=3&theater

These were new heads, but only God can make a cylinder head that heat won't hurt!

Posted by: stownsen914 Oct 13 2016, 12:14 PM

Thanks for the thoughts, guys. I'm giving this some thought because I like a challenge and wondering if it's possible if done correctly. Definitely not looking to do a 3.6 conversion, or a Chevy or Suby conversion. I have a 2.7L 911 race motor in the car now that needs a rebuild, and I'm toying with the idea of a turbo 4 instead of putting the $$$ to make a 911 engine competitive in PCA club racing.

I do understand that a type 4 turbo will not be a cheap venture. I am wondering whether it can be done, if done right.

It sounds like the heads are a limitation. I've heard that there are some fresh castings being done these days. Are those heads designed to address the limitation that HAM mentions above?

Posted by: Andyrew Oct 13 2016, 12:45 PM

What are your limitations for your class in PCA racing?

Posted by: stownsen914 Oct 13 2016, 12:50 PM

Looks like I was writing while HAM was posting. I guess the LE200 heads are the ones I asked about.

Posted by: stownsen914 Oct 13 2016, 02:20 PM

My car currently runs in the PCA Club Racing GT4 class (and where I'd like to stay), which is for highly modified cars using a Porsche tub as a base and a Porsche engine and transmission. The engine case needs to be a Porsche (or in this case VW) part. Pretty much every other part of the engine can be from any manufacturer. The GT classes use a sliding scale for displacement to weight, and different Porsche engines have different hp indexes. The aircooled 911 engine has a 110 hp/L index, 911 turbocharged is 210, type 4 is 90, and type 4 turbo is 150. Currently I run a 2.7L 911 motor in GT4. To remain in this class, I can have a turbo type 4 in the 1.8-2.0L range to run at the car's current weight of about 2100 lbs with me in the car. The type 4 has what may be a favorable index, if I can get 150-200 hp per liter, hence my inquiry.

Posted by: Jetsetsurfshop Oct 13 2016, 03:10 PM

Does more boost mean more heat?
Can you run two smaller turbos with less boost?
I don't know much about turbo. Throwing darts here.

I like that Len knows the problem for the turbo idea. How can we solve it?
The ceramic coating idea sounds good to me. What if you took a proactive approach and serviced the heads once a season? Race cars require this kind of service all the time. It's not like your trying to make a daily driver here. But then again, WOT does take its toll.

Posted by: HAM Inc Oct 13 2016, 04:21 PM

All engines that see sustained full throttle (max cylinder pressure) are vulnerable to heat related issues from a poor state of tune.

Aircooled engines are by nature more unforgiving to tuning issues than H2O engines since they have a less effective means of dealing with heat.

Among air cooled heads that I've worked with the T4 has the weakest ex port area as it relates to the chamber.

The twin turbo idea is interesting, but turbo's like heat, so the practical impact on the heads will be the same.

The bottom line is that careful temp monitoring is a must. The track LE200's in my FB post were new and had one weekend on them, which IIRC was 6 sessions. Temps were not monitored.

Nickies and coatings will go a long way to managing heat. Limit the revs and run a small bore.

IMO a 4 banger pushing 175hp/liter will be a tedious beast that will steal the fun from your time at the track, and in the shop. You will likely go through a difficult learning curve that will cause you to pull off track early many times to protect the investment from climbing temps, and then thrash on the piping hot beast back in the paddock to try and make the next session. Not a ticket to an enjoyable track outing, unless you like that sort of thing.

When a state of tune issue arises on a long straightaway at full throttle on a NA engine, I know from experience that things go pear shaped very fast. Throw a turbo on there and that will increase exponentially.

For someone with deep pockets, plenty of patience and very accomplished engine tuning skills it could be made to work, just like any other turbo engine.

The T4 wants the same things any high output engine does, ie perfect spark and perfect fuel mixture, and adequate cooling. The biggest challenge with the T4 is that it is an unforgiving platform when it doesn't get all of those things, in concert with each other.

Posted by: stownsen914 Oct 13 2016, 08:19 PM

Thank you for sharing your thoughts. I guess this must be Len?

The turbo formula is a better known quantity with 911 engines since it's been done so many times for so long. I would think many of the challenges would be the same, and big oil cooler, big intercooler, and sufficient fuel seem to be high on the list (and if you are the Porsche factory, a huge flat cooling fan too). Even without the flat fan, if you get the other stuff right, 250 hp/L is possible. I wonder if some of those who turbo'd type 4 motors didn't take all those steps?

Posted by: stownsen914 Oct 13 2016, 08:23 PM

More boost is definitely more heat and stress on the engine. I understand that the advantage of smaller turbos is faster spool-up when you step on it. I think usually for a smaller motor, like 2.0L, most just use a single turbo.

Maintenance would definitely be frequent on a turbo type 4!

Posted by: Cracker Oct 13 2016, 08:40 PM

This may not be popular, and I do not mean to be a "Debbie downer" but I think it is a disaster waiting to happen. Even under the best scenario (as is modern components and technology) turbo motors on the track are very expensive, tougher to drive, plagued with heat issues, and its tough to achieve reliably. The subies blow like its the fourth of July (on the track) - I've seen it "live" many a time. I'd never run one in anger (and they are light years ahead of a T4)! If you move forward, make sure you do so with the expectation that it will be "long road to hoe" (and expensive). Good luck in whatever you choose.

Tony

Posted by: HAM Inc Oct 13 2016, 08:44 PM

Yes, 250hp/L is definitely possible. Like I always say: "Where there's a wallet, there's a way." And: "If you want to push the envelope, better stuff it with cash."

Road racing is hard on engines, and a very unforgiving environment to tuning mistakes. Don't make any tuning mistakes along the way and you'll be doing better than most. They happen. A 10/10th's turbo T4 will not tolerate them well. A N.A. engine can consume itself in less than a lap around Road Atlanta. Ask me how I know.

Like I said before, all engines want the same things for optimum performance and reliability, 911, 914 or 917, etc.

A massive oil cooler will help with heat soak, but do nothing to combat damage from EGT spikes and detonation.

Keep in mind that on a T4 you're funneling that power through a crank with half the main bearing support/cylinder as a 911. The case and crank will have to have a good bit of attention to handle this. I'm not sure (meaning I don't know one way or the other) if the currently available T4 main bearings are up to this.

Also keep in mind when comparing the 911 to the T4 that the 911 heads are much stronger than the T4 with much better cooling characteristics.

IMO the issues that make the T4 not so great a platform for turbo's are pretty well baked into the design. I think that for a short burst AX car the turbo has some serious potential. For a road race car... I see a lot of $$/hp to make it work.

Len Hoffman

Posted by: stownsen914 Oct 14 2016, 01:20 PM

Thank you again Len and others for sharing your thoughts. A few questions from reviewing other threads and other sources as well:
- I've seen references to a dual-plug option for T4's. I was under the impression that this mod is more for hemispherical combustion chambers. I am curious to know how it helps for a T4.
- What modifications are done to the bottom end of a T4 to make it stronger? Shuffle-pinning is commonly done on 911 motors. Is this done for T4's? Other mods?
- Does anyone do 911-style piston squirters in T4's?
- What options are out there for providing air cooling? I see the RAT sells the DTM setup, and I've seen 911 fan based setups. What works, and what doesn't?
- For 911 turbos, sometimes "Niresist" or interlocking fire rings are used to seal the heads to the cylinders which are considered much more effective than head gaskets. Would this be feasible and desirable for a T4?

Scott

Posted by: Mueller Oct 14 2016, 02:15 PM

Seems like there is potentially a small market for some redesigned coast or billet T4 heads.


Key word...small, which is why I guess nobody has taken on such a venture.

Posted by: jd74914 Oct 14 2016, 02:51 PM

Scott, what limits do you have on engine controls? I'm just wondering if you could extend engine life with some fancier fuel/timing/boost control strategies based on EGTs, knock, etc.

Posted by: mepstein Oct 14 2016, 04:19 PM

I imagine you have to decide if you heart is into the project or the driving.

Posted by: Mueller Oct 14 2016, 05:46 PM

How about water mist cooling like some if the 911 guys have done?

I think is called Coleman water cooling or something like that. Good for 10 to 15 minutes?

Posted by: stownsen914 Oct 15 2016, 04:52 AM

No limits, at least not in the rulebook I don't have a bottomless wallet, but I would plan to use a quality engine management system if I do this project.




I thought of this too. I believe it has been called the Rubbermaid solution for the brand name of the container you put the water in . Popularized by a 914 guy, no less - Grady Clay, RIP. He used it on 911 motors at the track, and I assume on his 914/6 racecar.




Yes, you've got me on that one. If I didn't like a challenge, I would not still be racing the 914. I'd have bought a spec Boxster!

Posted by: zig-n-zag Oct 15 2016, 05:41 AM

Burning alcohol would keep head temps down. Add power too. Is it legal?

Posted by: stownsen914 Oct 15 2016, 09:13 AM

I've wanted to do this for a while on my 911 motor, and would make sense to me for a T4 turbo as well. Unfortunately, not legal at the moment for PCA Club Racing. I looked just yesterday to make this suggestion again, but it seems the period for submitting suggestions for 2017 rules closed in August. I would suggest E85 actually, which gives a more visible flame than straight alky when on fire. I understand that the invisibility of alcohol fires is why some has reservations about its use. Maybe next year ...

Posted by: ThePaintedMan Oct 15 2016, 12:39 PM

These days, anyone racing a turbo pretty much has moved to E85. Makes a ton of sense to me.

Posted by: zig-n-zag Oct 15 2016, 02:23 PM

FAT Performance does install 911 oil piston squirters in Type 4 cases, check with them.
I read somewhere that when using twin-plug ignition, there are more gains in power for smaller bores than with larger bores. It might have been written in the B Anderson 911 Handbook, or maybe in Up-Fixin...going by memory on this...
I bought ARP thru bolts and ARP head studs. Jake recommends the head bolt torque be 24lbs, no mention of the case thru bolts. Gene Berg raised the case torque on Type 1s by spot-facing all the bolt holes and using thicker, hardened washers. An old article about engine builder John Zeitler increased thru bolt torque to 40lbs, perimeters 35lbs.

Posted by: Zimms Oct 16 2016, 07:44 PM

https://www.youtube.com/watch?v=6r1Unv9L39k


There was more detail about this on Jake's Forum. I think the owner said he was getting approx. 300 hp. Sounds sweet.

Posted by: stownsen914 Oct 17 2016, 09:07 AM

You're right about B. Anderson and the twin plug, but I think that was for 911 engines. The dual plugs make a lot of sense on the 911 due to the hemispherical combustion chamber shape, and even more so on high compression 911 motors, since high-domed pistons make the situation even worse.

I thought that dual plug didn't have the same advantages for type 4's since they have flatter combustion chambers and pistons (and like many other engine types that also don't get much benefit from dual plugs). But maybe I'm wrong on that?

Posted by: McMark Oct 17 2016, 12:22 PM

Twin spark for:

1. High compression
2. Big bore

Posted by: HAM Inc Oct 17 2016, 12:26 PM

As for the twin plugs it's the other way around; the extra plug benefits larger bores more than smaller bores.

On 911's the second plug is advantageous because the piston dome interferes with the flame front. Putting a second plug on the opposite side of the chamber cuts down on detonation. This is a typical issue with true hemi chambers.

A second plug on a T4 is a royal PITA to deal with. Gets pretty crowded and hot on the bottom of the engine. The plug wires routing is a challenge.

All of those challenges can be (and have been) overcome, but with a small bore (90-91mm) wedge chamber using a flat top or even dished piston, the second plug will not be needed.

Posted by: Andyrew Oct 17 2016, 01:40 PM

My suggestion for minimizing heat gain from the turbo is to run a larger turbo and run low boost.

I have a pretty big turbo in my audi 1.8L engine and on 10psi it will make about 275hp on good fuel and lots of timing. I run an air to water intercooler and its a pretty solid setup.

You can easily adjust your power level for the track your on by adjusting the boost. My setup is a bit extreme and its a newer motor so its always going to have more potential, but on race gas and high boost (30ish) it'll make over 500hp very easily...

You can also program in an overboost function that will increase your boost for a couple seconds. Many electronic boost controllers have this option. Great little secret weapon for a track car.

Posted by: Mueller Oct 17 2016, 03:46 PM

I would think forcing more into the cylinders via a turbo would be increasing the cylinder pressure just like increasing the compression.

Posted by: McMark Oct 18 2016, 08:46 AM

Yup. I was just correcting his post (Len did a better job).


I'm missing the correlation between big turbo and low boost? I get low boost, but you presented it as if those two work in tandem. My first two thoughts on turbo size relate to 1. what rpm the turbo kicks in and 2. what rpm the turbo starts impeding exhaust flow. But I agree with all your benefits of running low boost.

Most new production cars with turbos are running higher compression, small turbos and lower boost. Giving good off-boost performance and a nice little kick when the turbo spools.

Posted by: stownsen914 Oct 18 2016, 08:53 AM

I'm thinking I'd need to run at least 15 psi for the hp I'd be looking to make (at least 350). At that boost, heat from the turbo is certainly something I'd have to deal with. I would run a large intercooler, and hang it in clean air to cool it. My 914 has very wide bodywork, so I would be able to fit it on the fender well area in front of the rear tire (even extending forward to the door if needed, which also sits much wider on my car) with a large NACA duct or similar feeding incoming air.

Posted by: stownsen914 Oct 18 2016, 11:19 AM

I read his comment to mean that a smaller turbo, when pushed hard, tends to generate more heat than a larger turbo. I would be building this for track use only, so the logic makes sense to me.

Posted by: Andyrew Oct 18 2016, 01:07 PM

PSI is relative to turbo size and plumbing. A small turbo running 15psi on a 2L engine would make say 175hp, medium say 250-275, and a large say 350-375 simply as examples... But the tradeoff there is WHERE they make the power. the 175HP engine might make say 200lbs of torque from 1.5k-5k rpms making it a fantastic responding engine. The 250-275 turbo might make power from 3-6k making it a great street/track engine using all of a typical rev range. the 350-375 turbo might make power from 4.5-7.5k meaning it would need an engine built to rev higher, and would have a very noticeable boost lag.

Its all relative in that remark. Also certain turbo's make much more power when you get above a certain PSI range. For example my big turbo is just starting to wake up around 25psi and is comfortable up to about 35psi. Whereas a stock style turbo wont make much more than 20psi and will fall on its face as the RPM's increase.

There is a LOT of turbo tech out there. Heat and detonation will be your enemy. Adjustable timing, a properly sized turbo, race gas and methanol injection will be your hero's. Your going to need a tuner that REALLY knows their stuff.

Posted by: Mueller Oct 18 2016, 01:18 PM

http://shoptalkforums.com/viewtopic.php?f=3&t=131253

An interesting build thread, a couple different versions and tests done

Posted by: jd74914 Oct 18 2016, 01:34 PM

I would think you'd be shooting for the most efficient spot on the turbine and compressor maps to keep heat generation down and pressure drop across the turbine relatively low. This likely equates to a larger turbo than would generally be selected since low rev drive-ability isn't really a concern for a track car.

Posted by: Andyrew Oct 18 2016, 01:36 PM

Good results from a GT3076. Seems to me those are wheel numbers, which again is pretty impressive for a T4! You could find similar numbers for the Audi 1.8T guys.

Whats equally impressive is the torque curve. There is no boost spike, its straight linear. I cant tell from that first dyno sheet where the turbo makes max spool but Im going to guess its around 4k

Just for reference the GT3076 is about the same size turbo as whats on my Audi 1.8T for those following my setup, and those are numbers I was expecting to hit myself on a much more advanced motor.

Posted by: Andyrew Oct 18 2016, 01:38 PM

Correct

Posted by: Jetsetsurfshop Oct 18 2016, 03:50 PM

Been following this thread intently and want to get back to the heads.
Why do companies like Scat and Pauter have there own performance castings for type 1 and not for us? Isn't there enough of us interested to get some of that love our way?
I dont know this, but does the bug and bus crew like using our engines to make more power? It just seams to me that we have enough customers to make some performance castings, right?

Posted by: falcor75 Oct 19 2016, 03:34 AM

If I was building a turbo setup for a track car I would do it like this.
Which tracks am I driving and whats the lowest revs I will use on track with the current gear /tire ratios. Lowest RPM will determine usable turbo sizes depending on how much you value boost out of those lowest speed corners.

Take this data to the person thats going to tune the car and get their view on turbo size etc. Critical to use someone with ALOT of experience of different setups. A turbo doesnt care if its boosting an aircooled engine or a watercooled engine.

I for one would choose a broad rpm range with boost over peak hp.
An easy to drive car will yield the most consistant laptimes and let you focus on driving.

Not sure it helps any but hopefully you've thought of this already.

Posted by: socal1200r Oct 19 2016, 06:06 AM

What about using a supercharger for the forced induction, vice turbos? From reading thru this thread, it seems that you would have the resources to make an SC engine work just as well as a turbo one? I don't know a whole lot about either method of forced induction, but I would think you wouldn't have as much of a heat issue with an SC as you would with a turbo, and the plumbing wouldn't be anywhere near as complicated?

I'm talking about the accessory-belt driven style SC units like those from Paxton or Magnuson, not the Roots-style ones. As long as there's a belt on the car, like for the alternator, one should be able to fab up a belt-drive system to power an SC.

Just thought I'd chime in with another option...

Posted by: Andyrew Oct 19 2016, 08:35 AM

Superchargers simply can not make the power of a turbo. However there are many people that are using superchargers to spool the turbo similar to how in the old days people would use nitrous to spool the superchargers.

What some have found is that the supercharger becomes a parasite at higher RPM's to the turbo and they put a flapper that dumps the supercharger pressure once the turbo is outboosting the supercharger. Thats just one way of doing it.


Another is twin charging which is simply running both in the same intake track, which I think is the most commonly found method. If sized correctly it can be very potent. I have been considering it for my setup but I simply dont think I can use the power that that setup will make on my engine... I think I prefer to rev my engine out vs the instant torque. We'll see.

Another common method is multiple turbo's. The theory is that its better for spool, and gives you a similar top end as a medium size turbo with two small turbos. But in practice you will find that most high end tuners go to a single turbo application as its far more simple and has just as much if not more power across the board. I believe its so common among manufacturers today because it is more compact than a large turbo.

Finally there is compound turbos. Not something I would recommend in a racing application but BOY is there some power potential there. Unlike twin turbo's compound turbos have a small turbo that feeds directly into a large turbo, essentially spooling it quickly. The issue with a compound turbo is that you overspool the small turbo. This is very similar in practice to the twin charging setup as you have something that gives power down low as well as spooling an incredibly large turbo.



If hes only looking to make 350hp from a turbo 2.0L that wont be that difficult. As shown by Mike a nicely built T4 can easily do it on pump gas within a safe boost range. Decrease the turbo size a little bit, run race gas and lots of timing and you have a very nice setup for the track. For a track car it'll provide plenty of power in the lower register of his gear infact he might find that the torque it produces is going to be problematic for his transmission..

Posted by: HAM Inc Oct 19 2016, 08:45 AM

O.P., can you convert to a T1 engine for your class?

If so find an aluminum Auto Linea case and build from that. There are plenty of new T1 head options out there that are stronger than T4 heads.

Posted by: stownsen914 Oct 19 2016, 08:50 AM

That's a nice build thread from the shoptalk forum. I haven't finished reading it yet, but definitely will.

As for what I can do for my build, I don't want to limit myself to 350 hp if more is reasonably available . For trans, I'd switch to a 915 and use custom gearing to get the RPM range where I want.

Posted by: Mueller Oct 19 2016, 09:10 AM

^ditto... even MOFOCO has brand new cast in the USA heads starting in the $300 each range. ( doing some reading I guess they had some iffy quality issues years ago but current heads supposed to be decent for street motors, not designed for race car applications as is)

I think the solution is water cooled heads like the 934(935?) race cars.

Posted by: Andyrew Oct 19 2016, 09:12 AM

So your basically looking at about 15-20k engine+trans. Right?





I dont think he can run a T1 at PCA events. It needs to be a "Porsche" motor and trans.

Posted by: Mueller Oct 19 2016, 09:13 AM

Might as well do an LS1 if crossbreeding is allowed

I think block needs to be "Porsche" (even if one considers the Type IV a VW motor)

With the block needing to be Porsche even a 924 motor or a Macan motor would be legalish

Posted by: HAM Inc Oct 19 2016, 09:24 AM

Technically, the T4 is a VW. It has VW stamped all over it.

It might be a stretch of the rules, but if they say engines must be of the same manufacturer as originally supplied it might work.

Posted by: ThePaintedMan Oct 19 2016, 09:31 AM

I think for the amount of engineering involved and the very real possibility that a type 4 with that much boost on it may still be a grenade, I would consider another watercooled Porsche engine, as Mike suggested. What about a turbo 944 motor, or even a 928 V8? Those things can make some pretty healthy and reliable HP numbers without nearly as much $ or time as it would take to make the TiV work. All you need is a radiator and some water lines

Posted by: HAM Inc Oct 19 2016, 09:40 AM

That makes more sense (to me) than a roadrace turbo T4.

But I'd love to see a well engineered and deep wallet turbo t4 build for a roadrace car. I'd like to see how it went and what tech was developed along the way.

Been plenty of turbo t4 street engines, but they don't see the abuse a track car does.

Posted by: Mueller Oct 19 2016, 09:49 AM

I think the Macan 90° V6 would be ideal.

It can be found with super low miles in the $4-5K range (I've been told some places would happily take $2K for one since there is no real market)

It is shorter than a straight 4 like from the 944 and the motor is more or less brand new and won't need an expensive rebuild like the old used 944 motor would need and it would still be cheaper than building a turbo Type IV and should be dead nuts reliable unless those motors have some odd issues that we haven't seen pop up yet.

Posted by: Mueller Oct 19 2016, 09:50 AM

Did Jake or you give up on the billet Type IV heads? Too expensive and small of a market I guess?

Posted by: HAM Inc Oct 19 2016, 11:34 AM

Waaay too small a market for a high-end T4 billet head now. The new AMC castings are very nice and meet the needs of 99% of the marketable T4 applications.

When we were doing that development the economy tanked and demand for high-end T4 engines shrank, but demand for modern Porsche engines took off. We saw the writing on the wall.

The T4 head design - with its exhaust outlets positioned between pushrod tubes - presents some baked in application limitations that are a real challenge to overcome. The most practical way to get around them is to move to a T1 style exhaust arrangment, which the Engine Plus heads did very nicely. They were great heads, but they too suffered the market lmitations facing the T4. Last I heard they were NLA.

If someone wants to build an engine that goes to that level, switching to a T1 based platform makes more sense. Plenty of Hi-Perf parts - from blocks to heads - already developed. Of course much of it is Chinese junk now, making it even crazier to try to develop a T4 configured billet head.

Posted by: stownsen914 Oct 19 2016, 11:36 AM

On the engine type, it has to be either Porsche block or an engine type that was supplied in a Porsche. So an Audi/924 engine or a T4/914 qualifies, unfortunately T1 doesn't.

There is an option to do non-traditional engines like Cayenne, Macan, 928, 944, etc., but 2 things about that:
1. Switching engine/chassis type puts you into a different class (GTP) that basically no one runs in.
2. Doing a Cayenne, Macan, etc. probably would be even less economical than a T4, and at the moment those engines are not classified for PCA Club Racing. For those engines I'm not aware of off the shelf performance parts like camshafts, intake manifolds, etc. or that anyone has invested in learning how to extract power out of the heads. Breaking new ground sounds like $$$$ to me. If I could use one of those engines, I'd need it to make ~150 hp/L, which is where the modern engines seem to fall on the hp to weight index for PCA club racing.

Posted by: HAM Inc Oct 19 2016, 11:42 AM

We started massaging Cayenne heads a few years ago. Much potential there.

Posted by: Mueller Oct 19 2016, 11:48 AM

Thanks for the reply.

How funny, I did a search for those Engine Plus heads and came across a thread with Jake showing off his billet heads!

http://www.shoptalkforums.com/viewtopic.php?f=1&t=113797&start=30

So if someone was to redesign some heads for their own use you'd recommend going the Type I exhaust route?

Posted by: Mueller Oct 19 2016, 11:52 AM

Base Macan motors are in the 300+ hp stock with plenty of torque, the S model is 400+ for hp and torque...no need for different cams!

No biggie for me, I'll never have a race car so classification is no big deal

Posted by: Andyrew Oct 19 2016, 11:57 AM

He needs to be in the 1.8 to 2.0L range to run a turbo.

If he went water cooled he could run a vw 2.0L block from a 924. Im not sure if a better designed DOHC head would fit on that block but that would be a killer setup and let you make a ton of potential power.

Posted by: stownsen914 Oct 19 2016, 12:10 PM

Interesting thought on swapping heads. PCA rules DO allow switching heads. Only the block has to be Porsche (or T4 or Audi/924).

I'm probably showing my ignorance of 4 bangers here, but I wonder if a T1 head be massaged to fit on a T4 engine ...

Posted by: ThePaintedMan Oct 19 2016, 12:47 PM

Well if you insist on the Type 4 route, it would probably be easiest to go to Wasserboxer heads then. No way the Type 1 heads would ever fit - dimensions are way different. With the WBX heads you could actually make that thing live, sort of like a 4-cylinder 962 engine...

Posted by: HAM Inc Oct 19 2016, 01:07 PM

If you want to go T4 and can swap to any head, find some Engine Plus heads. They were most popular in Europe.

As for T1 heads, like I said before; where there's a wallet there's a way.

Because of the wider bore center of the T4 you'd want to start with a set of 4 individual heads, like the scats. They would then need major mods to work with the T4 bolt pattern and lifter spacing.

Bring a big pile of $$ and a shovel.

Posted by: Andyrew Oct 19 2016, 02:01 PM

I like the wasserboxer head idea.

Run enough radiator and you can keep the damn thing cool for racing. You'll be generating a lot of heat with a turbo and really longevity is the key to racing.


I dont think you should be shoveling into R+D on anything... Off the shelf parts and standard machining is the key IMHO.

Posted by: Mueller Oct 19 2016, 02:35 PM

Still going to be some work due to the passages that go to and from the block.


Some pictures of someone converting an air cooled cylinder to watercooled (might be oil cooled from another post)

http://www.thesamba.com/vw/forum/viewtopic.php?t=584970

Posted by: HAM Inc Oct 19 2016, 02:44 PM

Hate to spoil the Wasser fun, but... check the bore center. IIRC it's closer to the T1, which is waaay off from the T4. Not to mention the lifter spacing is off.

It will definitely not be an off the shelf deal. Nowhere near plug and play, even if the exhaust ports can be opened enough (and I don't think they can, but could be wrong) to support a 80+% ex/in flow ratio where intakes are moving in the ballpark of 180-200cfm at .5 lift, which I suspect you'll require for 175hp/l

IMO, you need to keep looking.

Len

Posted by: Mueller Oct 19 2016, 03:03 PM

Bummer, reality always getting in the way....

I figured it was too good to be true, I did find someone running those heads on a type I...

http://www.shoptalkforums.com/viewtopic.php?f=37&t=141797

Posted by: Racer Chris Oct 19 2016, 03:04 PM

I used to have pictures of a SCCA GT3 914 engine that was a T4 with watercooled heads.
Someone welded jackets onto a pair of OE heads.

Posted by: HAM Inc Oct 19 2016, 03:13 PM

That would be a hell of a lot easier than adapting something from another engine.

But it too would not be for the faint of wallet, unless one could do the work themselves.

Posted by: Jetsetsurfshop Oct 19 2016, 03:29 PM

Think the Engine Plus heads will handle the heat?
Did they move the exhaust port to the ends?
Were they quality casting?
I'm full of questions.

Posted by: Mueller Oct 19 2016, 03:52 PM

If I read that one post I added correctly, it looks like no longer available new.

Yes to the Type I exhaust ports.

Posted by: Andyrew Oct 19 2016, 03:56 PM

For the cost of a tig welder and some aluminum that would be a killer way of doing it.

Posted by: HAM Inc Oct 19 2016, 04:22 PM

Fixed that for you.

Posted by: Andyrew Oct 19 2016, 04:23 PM

Meh its just aluminum, how much different can it be than steel

Posted by: Mueller Oct 19 2016, 04:55 PM

TIG welder (AC/DC) = check
Machine shop = check
Certified welder (expired) = check

Posted by: HAM Inc Oct 19 2016, 04:59 PM

This is the sort of project that I think would be cool for a highly skilled, well equipped enthusiast. Someone with the know how, the time, and finances to give it a go.
You should give this a try.

Posted by: stownsen914 Oct 20 2016, 05:13 AM

I understand that the water jacket idea had been done before on a 911 too. Might have been Grady Clay? Read about it on the Pelican forum at one point.

And, well, I've done a good but of MIG, but no TIG, so that might be a bit ambitious for me. Very cool idea though (pun intended!)

Posted by: Randal Oct 20 2016, 12:22 PM

How much time do you estimate that job would take you in hours Len? Just like to have a baseline of time and or related cost. Thanks.

Posted by: HAM Inc Oct 20 2016, 02:23 PM

Hi Randal, I have no idea how much time it would take. It's not the sort of job I would be inclined to accept, but if I did it would be quoted on an hourly basis, broken down by categories: design/engineering; fabrication; machine/welding work.

There would be some major packaging hurdles to overcome to make this work.

I think a better approach would be to adapt 911 heads and go OHC. Mounted on top of Nickies with thermal coatings... That could work. Still lots of challenges, but it wouldn't be a big wet bandaid on a pair of ill suited heads.

Posted by: Randal Oct 20 2016, 04:05 PM

That idea sounds like a better approach. And the cams would be reasonably easy to change.

The "competition" to this would be buying one of the new boxster motors (300 or 350 HP/ 2.0 to 2.5 liters respectively) which will be available at a price less than $15K according to a few people I've talked with that will end up dealing with these motors.

But like the 911 heads approach, there would be engineering issues and might require a subframe to work. A 350hp motor in a 914 along with a transmission that would be designed for that HP, would be nice. The water cooling would be an issue and add weight. From what I've read the motors are plus/minus 25# of a fully configured 2.7 (6). http://blog.caranddriver.com/tech-dive-in-depth-with-the-new-porsche-718-boxsters-turbocharged-flat-fours/

Posted by: Randal Oct 20 2016, 08:58 PM

And by the way, that 350hp motor, will eventually be RE'd and able to make HUGE power like the Subi's. But in the mean time, who has 350hp in a 914 autoX car, together with a Porsche motor?

Would sure like that configuration on any NWHA event.

Posted by: Andyrew Oct 20 2016, 10:54 PM

Im looking forward to the new porsche motors/tranis being cheap They'll make great candidates for engine swaps!

Posted by: jd74914 Oct 21 2016, 06:12 AM

IIRC Grady shoots a water mist at cylinder heads and then uses the latent heat loss to water from evaporation to cool the heads. I bet it actually works pretty well with a small amount of water.

Posted by: HAM Inc Oct 21 2016, 08:15 AM

I have a customer who does vintage racing with a NA 914/4 in TX. He regularly runs on track temps exceeding 130F.

He recently reported that he rigged a nozzle that draws water from his cool suit cooler and squirts it in the fan. Says he does it about half way through his 40 minute races when CHT's start creeping up, and a time or two in the second half of the race. Says it uses about a 2 quarts of water and CHT's drop 30* or so.

Posted by: Mueller Oct 21 2016, 09:49 AM

I think this is the best method to keep the motor more or less "air cooled"

The water jacket idea can work but I wouldn't want to spend the time and money on a high dollar build and have something fail or get a hot spot due to inadequate flow and cook a head!

My last crazy idea for this thread.....water cooled valve covers! The idea is that if you can bolt the new aluminum valve covers (easy to machine something like that) to the the heads you can "suck" some of the heat out of them. Of course the cooling is super far away from the combustion chamber and it might take too long to be effective if really on the gas for long periods of time.

Not so crazy after all? ... Found a thread on the Samba about someone mentioning some 356 racers doing this by brazing tubes to the valve covers and running a 12vdc waterpump. Couldn't find pictures


I lied, one more crazy idea, weld more fins to the heads for more surface area....I swear, only sugar and milk in my coffee this morning!

Posted by: Jetsetsurfshop Oct 21 2016, 10:47 AM

What about that Polo motor? You could turbo that right?

Posted by: Mueller Oct 21 2016, 11:06 AM

Unfortunately I would think that would be illegal in his class since not a "Porsche" block since they are brand new castings with a big Polopolus cast on the side of the block

http://www.polomotor.com/

That would be smart move here and while it might cost more than the upcoming 718 watercooled 4 banger Boxster engine combo it will be much much easier since it will not be easy to run that new direct injection motor more or less standalone.

Posted by: stownsen914 Oct 22 2016, 08:42 AM

Correct that the Polo motor would not be legal for PCA Racing. They cost a fortune, too ...

Posted by: iamchappy Oct 22 2016, 05:37 PM

This is so much easier.


Attached image(s)

Posted by: stownsen914 Oct 23 2016, 11:02 AM

I'd love to just turbo my 911 motor, but the hp index for 911 turbos is not advantageous. PCA club racing classifies the 911 turbo as 210 hp/L, while the type 4 turbo is 150 hp/L. To run a 2.0L 911 turbo, I'd have to add 200 lbs to my 914 and still bump up one class. With the type 4, I can do a 1.8 or 2.0L turbo and stay in the same class at my current weight (~2000 lbs with me in the car).

Posted by: stownsen914 Oct 24 2016, 01:42 PM

So if I did this with a T4, I think I understood that it would be better to start with a 1.7 or 1.8. I did some reading over the weekend, and it looks like the 1.7 heads may be sturdy. The carb 1.8 heads have the biggest valves of any T4 (not sure if that matters since I'd probably have to increase valve sizes anyway). And don't use a motor out of a bus since the heads are more likely to be trashed from hard use.

What's the best base T4 motor to start with for a small displacement turbo?

Posted by: HAM Inc Oct 24 2016, 02:34 PM

If you want to follow the small bore (max 91mm) formula then you'll need to start with 1.7 heads with 100mm registers. 1.8 heads are not the same, they have 105mm registers.

Look for a cherry pair of 1.7 heads with a 'Q' suffix. They came on 914's and 411's, but not busses.

Find a 1.7 case from a 411 or 914.

Talk to Charles Navarro at LN Engineering about a Nickies and piston & rings combo.

Posted by: ottox914 Oct 24 2016, 05:28 PM

I'm "that fellow" from Len's post #4. While I can appreciate the energy and enthusiasm of a turbo type IV, as Len stated, bring lots of money. While I enjoyed the challenge of developing the motor, I lost several autocross seasons trying to get it all to work right. See my build threads in my sig. I watched like a hawk the cht/egt/oil pressure and temp gauges, and thought I had a cool running motor. After the infinity shift, I sent the heads to Len, and he indicated they showed signs of heat abuse. As careful as I was just street tuning and autocrossing, and to have some heat damage to the heads, I would expect them to melt like butter in a racing environment.

And while Len does amazing work, he needs to put food on his table at home too. I wouldn't expect his work to come cheap.

So if you had an infinite supply of money and "Q" heads, I'd say go for it. You'll have allot of fun trying to figure it all out, and Len will be able to send his kids to any college they choose. I hear Harvard is nice.

IF I was to do it again: 1.7 Q heads per Len, and as much stroke as the rules would allow. Single plug. I'd go with Chris Foley flat fan, and have him gear the belt drive for as much cooling as I could get. I'd mount the intercooler as I did in my build, but over the engine fan, and use that draw to pull air thru the IC. If this restriction caused higher than expected CHT or EGT then I'd think about air/water intercooling. This will keep your pressure runs shorter than mounting an IC in the fender. Mount the water radiator there instead. Since this would be going in your race car, an old 1980's F1 style air scoop up and over the targa bar to feed either the top mount intercooler if that worked out, or to dump directly into the flat fan if you ended up with air/water. I'd not go with the ITB's, just a single would do. I used them because thats what I had on hand. E85 if the rules would allow. CHT sensors on each head. EGT on each exhaust pipe. Lots of warning lights for EGT/CHT oil temp overage. I'd think about an individual misting nozzle mounted in Chris's engine tin over each cylinder for additional cooling if needed. I'd dry sump it and run allot of oil, front mount radiator, with piston squirters. I'd pull all the trunk flooring out, and have a custom exhaust, possibly Chris again, to mount the turbo opposite the starter. Should make for nice short exhaust and pressure line runs. "Nickies" are not optional. They are a requirement. What ever ECU you use will need to data log all day long. It would be interesting to find a turbo that would provide as much boost to hit your goals with the least amount of heat. I'd think of RPM's staying south of 6k.

Torque powers your car out of the corners. HP gives you top speed at the end of the main straight. I'd not expect this to be a 7-8k rpm motor, if you expect it to live more then 1 session. So you'll need to consider tire size and gearing to work with a relatively low rev-ing more torque biased engine.

I've probably outlined a system that spends your budget 2-3 times. Before you buy dyno time and melt/re-build it all a couple times.

But it would be so awesome.

Posted by: ottox914 Oct 24 2016, 05:42 PM

It'd be interesting to see about the CHT's for each hole- as much as there is not equal cooling via the air from the fan, I'm having a hard time with equal cooling from the water. He's shown it works- But you'd hate to think you were fine, and have one cylinder be a couple hundred degrees over the others.

Does he run a 4 x 4 system with an EGT and CHT for each cylinder? That would be some interesting data to see.

Posted by: stownsen914 Oct 25 2016, 07:53 AM

Thank you, Len. I will probably keep the displacement under 2L, but I am not sure about the configuration yet. Are the 1.7 heads preferable only due to the 100mm registers for staying with a small bore? From some reading I've been doing, it looks like the ports and sparkplug position on the 2.0 heads are better. If I were to go with a 94mm bore, would 2.0 heads be a better start? I am assuming that significant porting and machining will be part of whatever I do ...

Posted by: ottox914 Oct 25 2016, 09:00 AM

Believe your specialists. They have your best interests in mind. The 1.7 Q has the right size register, and more "meat" in the head than any other factory casting. This gives Len room to do his magic and still end up with a head worth using. And he will do magic. Spark plug can be moved to the 2.0 location, valve sizes changed and porting done to your specifications. When he's done the part # and register size will be the only clues that these did not start out as factory 2.0 heads. But they will be much better suited to your plans.

There will be compromise here, between the valve sizes/air flow/register size you think you want, and the volcano of fire and heat you are going to subject these heads to turbo'd and track'd.

Posted by: Mueller Oct 25 2016, 10:30 AM

Hey Len,

Can you point out where on this cross section the head is weakened due to too much heat?

Type4 on left, Type1 on right, pic "borrowed" from thesamba

Posted by: Jetsetsurfshop Oct 25 2016, 10:39 AM

Cool pic.

Posted by: McMark Oct 25 2016, 11:11 AM

I'm wondering if a good staring point might be squareport heads and 91mm Nickies with 105mm OD?

Posted by: Mueller Oct 25 2016, 11:51 AM

Do they have more meat behind the combustion chamber or are stronger?

Posted by: McMark Oct 25 2016, 01:21 PM

http://www.shoptalkforums.com/viewtopic.php?t=74388

Posted by: zig-n-zag Oct 25 2016, 01:41 PM

Mahalo guys, I appreciate all your generous sharing of knowledge. I'm learning a lot.

78.8mm x 91mm = 1997.9cc
69.1mm x 91mm = 1797.6cc

Nickie cylinder O.D. Top = 114.8mm
I.D. Bore = 91mm
Cylinder wall thickness = 11.9mm. Will this work? Thanks again Everyone.

Posted by: HAM Inc Oct 26 2016, 04:46 PM

That's a pretty good idea. 91mm is as small as you can go with Sq Ports chambers but that's what we want. With 105 nickies that's a lot of contact area.

The Sq Port offers more support under the chamber than the oval. It will still be the weak spot, but it will be stronger for sure.

Posted by: stownsen914 Oct 27 2016, 10:34 AM

Were square port heads only on (some of) the 2.0 Type 4's? We were saying before that the 1.7 heads are a good start for a small bore turbo. Just trying to understand ...

Posted by: Mueller Oct 29 2016, 10:36 AM

Had another crazy idea while sitting in traffic...take Type IV head and from the bottom side machine away the combustion chamber and ports, figure something like a 4" diameter hole a few inches deep.

Grab some 6061 billet and rough machine the combustion chamber and ports, press fit into head. The billet alum has a thermal expansion that is slightly more than the cast alum so the fit will be even better once warmed up. (from what I can find online)


cross section of 911 showing more "meat"

Posted by: McMark Oct 31 2016, 07:06 AM

Just the vanagon Type4s had square ports. But oh the joy of having a normal exhaust flange and gasket.

Posted by: HAM Inc Oct 31 2016, 09:21 AM

I like the idea of the sq ports normal flange and the slight increase in chamber strength from the added material in that area.

Ten years ago I did a lot of R&D on sq ports. What I found was that to match the flow of a oval port head with 36mm ex valves, the port wall had to be opened up a fair amount. This wasn't a huge deal, but in the final analysis we determined that the heads would not be a good fit for 38mm valves, so they would not be a good fit for larger engines.

Eventually we stopped working with them for anything but Camper Specials and our stock Blueprint Specials.

For a small bore turbo engine with 40mm intakes and 36mm exhausts they might be worth a revisit, though be prepared for the potential for heat related cracks in the port runners. We saw a lot of that with O.E. heads. Not much air flow around that area, and the runner will have a not so thick cross section.