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

[Andyrew]

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..

[stownsen914]

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 (IMG:style_emoticons/default/smile.gif). For trans, I'd switch to a 915 and use custom gearing to get the RPM range where I want.

[Andyrew]

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 (IMG:style_emoticons/default/smile.gif). For trans, I'd switch to a 915 and use custom gearing to get the RPM range where I want.

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.