Turbocharging a type 4 Options

[stownsen914]

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

[ottox914]

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.