After doing some research I found that gen 2 3.1 and 3100 pistons are
-26cc pistons. 3.4 pistons are a -7cc piston. So, can I put the 3.1 piston in my 3.4? (i think they are the same bore) How much would this lower compression? I'm thinking of doing a 3.4 turbo project. How much boost can this engines stock rotating assembly take? Will I have to modify my ECM to use a turbo if I'm only going to use 5-6psi of boost?

 

Wrong bore size. The 3.4 is esentially a bored 3.1 with smaller dished pistons for higher compression.

Turbo your 3.4 as is, it will be fine.

If you want some real power, forget the 3.4 heads and get yourself a set of 3500 heads and you can keep the 3.4 pistons (11.5:1 SCR) *or* use a set of 3400 pistons and 3500 heads to yeild a 9.1:1 SCR and be a perfect candidate of high boost situations.

There is a little more to it then bolting the heads to your engine, but we have a lot of discussion about it in the V6 section.

I happen to have a shop that deals primarily with 60* V6's, and would be glad to help you with your goals. I stock 3100, 3400, and 3500 parts just ask.

#x00 motors are just the FWD counterparts of the RWD 2.8/3.1/3.4's.


BTW: Welcome to TGO

-john

 

Thanks firstfirebird!
This is my only my second 60* v6 car. well, the first one I am modifying for performance. Anyways, isnt the 3.4 CR already like 9.5-1? How high can this motor go in stock form? I cant really afford to use 3500 or even 3400 top end. Nor do I want to have to swap the pistons yet. Maybe in the future though. Will a 3400 or 3100 intake swap to the 3.4 w/ no mods? I hear the 3.4 intake is incredibly restrictive. I am looking forward to the future turbo mod but will I have to tune the ECM if I use 5-6psi of boost?

 

Yes you should tune for boost.

If you can't afford an aluminum top end, how are you going to afford a turbo?

IIRC the 3.4 is just over 9:1, so you are probably correct there.

Yes the intake is one of the worst designs GM ever made and falls flat on it's face at about 4500RPM (motor can handle about 7k).

3x00 parts do not interchange with the iron heads. Top end has to stay together.

I'm currently building an 11.5:1SCR 3500/3.4 hybrid and it will have a little boost added. Then 3400 pistons are taking the place of the 3.4 pistons and high boost is going to be accomplished (perhaps by 2 turbos, no solid decision yet).