3.2 Monster Engine
 

I plan on rebuilding my 85 3.2 Carrera engine. Since this will be a dedicated track car, I wanted to know if anybody had any configuration options in building a "monster" GT class engine. I'm hearing stories of some racers have 500+ NA engines on the track. Not sure how true this is. Wayne I've read your book a while back, when I first got it, but from what I remember you seem to talk mostly of the older engines (3.0 back). In the 3.2 section there is mostly talk of the programmable chips.

Henry Schmidt posted a very cool MFI 3.5 (3.2 based) in another thread on this forum a couple of days ago. I believe it's under "thoughts on different engine configurations". that engine is a pretty beefy 3.2 based N/A engine.

Check out rdanes 3.4 SC. The 98mm Mahle P&Cs with 23mm wristpins should be a direct bolt on upgrade for your 3.2 Carrera without going to twin ignition. You already have the Motronic fuel delivery and better heads than even the early SCs had. This would be a really awesome upgrade/rebuild option.

3.2->3.4 FAQ

some different engine configs

Search for '3.4' from posts from user 'rdane' and stay tuned for upcoming dyno results after he breaks his engine in.

100 HP per liter is pretty much the limit to achieve any configuration that could possibly be driven on the street. So, a 3.5 would max out around 350 HP before turbos or superchargers. A hot rod short-stroke 3.2 like the one featured in the book would probably output about 275 or so.

All the Porsche engines are very similar from 1965 thru 1989. See the end of Chapter Four for some performance configs...

-Wayne

First, if you are going to go club racing, make sure you check the rule book to see what you can do. A big bruising engine may put you in a class that even with a ton of power will render you uncompetitive.

I'm in the initial stages of going 3.5L from 3.2L using 100mm Mahle's, twin-plug and Motronic. Will be in the 260-265 range using pathetic 91 octane and will be smog legal (live in CA). It is a street motor that may see a few DE events.

For a street motor using the Motronic, that is about the power you will get. Changing to carbs for competition or for offshore customers, we did 3.5L motors in the 325-350 range while at Andial in the late 80's/early 90's. Razor sharp throttle response, awesome sound and you can watch the gas guage move from full to empty almost as fast as the tach moves (okay, I'm embellishing a bit).

If you stick with single plug and Motronic, use the stock style wedge dome piston because of the "pooling" effect that this piston provides. If you are going to twin-plug (regardless of the injection you use) than I would use the hemi-style piston (carb specification) with the valve pockets as it will work at least as well if not better with the Motronic than the wedge dome piston and will allow you to only have to change cams rather than p's and c's if you ever decide to discard the Motronic.

Ralph

Thanks for all the input guys.
Wayne, I'll look through the book more cloesly. But like I said this will not be a street car it will be strickly track.
Ralph, I still need to look deeper into the rules. But as far as I can tell from the rule book it states that a GT class car only needs a Porsche engine block all else is free. Of course I still have to talk with officials to get an official interpertation of the word "free".
Andy, I was looking at Henry configuration and seriously considering it. I am also weighing my options.

Again, thanks all.

No problem, Armando. I think Henry's MFI 3.5 is very nice, and apparently very powerful, and he is very knowledgeable. Definitely double check your rules!

A good benchmark to look at is the Porsche factory racing team. See what they got out of limited displacement, and you could probably do the same with an unlimited budget...

-Wayne

so true.

100mm cylinders, boat-tailed case, super-light & strong rods, custom made lightweight pistons (~10.8:1 CR or such), slide-valve throttle bodies, maximum ported double-plugged heads, titanium retainers and springs, wild cams, Alpha-N Autronic/Haltech/Whatever ECU and equal length custom bent headers with nothing but megaphones would be a good start ;-)

We built a 3.4 that made 375 hp, it had all the bells and whistles, Tec2 etc...

You could make a nice 300+ hp 3.2, but make sure to bring your checkbook

When I was at Andial, we built a 3.5L twin-plug with slide valves for a customer in Mexico City. If I remember, it was also in the 350-375 range. Unfortunately with slide valve injection, they are very expensive (even the Andial repro kits) and are on-off. Wouldn't want them for the street (this customer did) but they sure look trick!

Ralph