Turbocharging a type 4 Options

[jd74914]

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.

[mepstein]

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

[Mueller]

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.

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?

[stownsen914]

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.

No limits, at least not in the rulebook (IMG:style_emoticons/default/smile.gif) I don't have a bottomless wallet, but I would plan to use a quality engine management system if I do this project.

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?

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 (IMG:style_emoticons/default/smile.gif). 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.

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

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!

[zig-n-zag]

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

[stownsen914]

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

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 ...

[ThePaintedMan]

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

[zig-n-zag]

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.

[Zimms]

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.

[stownsen914]

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...

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?

[McMark]

Twin spark for:

1. High compression
2. Big bore

[HAM Inc]

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...

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?

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.

[Andyrew]

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.

[Mueller]

Twin spark for:

1. High compression
2. Big bore

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

[McMark]

Twin spark for:

1. High compression
2. Big bore

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

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

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

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.

[stownsen914]

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.

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.

[stownsen914]

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.

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.

[Andyrew]

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.

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.

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.

[Mueller]

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

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

[jd74914]

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.

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.

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.