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

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.

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

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.

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.

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

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.

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.

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

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.ph...97&start=30

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

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

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.

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 ...

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...

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.

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.

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


Click to view attachment

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

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.ph...37&t=141797

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.

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.

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.

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

Yes to the Type I exhaust ports.

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

Fixed that for you.

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

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

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.

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!)

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.

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.

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-...ged-flat-fours/

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.

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

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.

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.

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!

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

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.

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

This is so much easier.

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).

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?

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.

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.

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.

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 ...

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.

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

Click to view attachment

Cool pic.