amount of power loss from lower compression?

[Dyncaus]

alright, i am getting the 6-bolt swap done next week, i do have a few questions though first. Since the compression in the 6-bolt is 7.8:1, and the 2g is 8.5:1, then what kind of power loss will i experience from this? Also, will i still be able to use my t-25 with the 6-bolt? because i know the 1g's had the 14b and it uses a different manifold. one more, will my 97 pistons from my crankwalked engine go into the 6-bolt or do they have to be 95 pistons? i am prob gonna just go ahead and do the whole longblock swap because everyone seems to be saying that the 1g head is better than the 2g anyways. any help would be great, i can't wait to get my 6-bolt put in.

 

[peregrine]

any loss in power from lower compression can be made up by turning up the boost a little. it all evens out pretty much. little more lag but mo more top end. thats been my experience anyway.

 

[Wizard]

The 1g 6 bolt motor is far more powerful than the 2g. Even with the lower compression. It is not uncommon for a 1g to turn 300hp at the flywheel with the 14b on stock internals. While the 2g pistons are a slight upgrade for the 1g motor, the rest of the 1g motor is excellent.

The exhaust manifolds are virtually identical and can be swapped. In fact, the 2g manifold is slightly better mostly because is it less prone to cracking and flows a bit better. So use the 2g manifold and also the 2g O2 housing as it flows better too. But use the 14b if it is still in good shape.

As for the pistons, yes they will fit the 1g rods with mods. But usually when you press the pistons from the rods, they are damaged, so you'd be better off buying new 2g pistons. About $140-160 for all 4. Plus $120 for rings.

Wiz

 

[candela]

Usually the lower compression will sort of open a larger window for tuners to screw around in, enabling you to run a little bit more boost or screw up a little more. I think the ideal setup in your situation would be to use the 6 bolt, rebuild it with your pistons(depending on shape, new ones are like 200$ for the set), use your TB elbow and use your manifold and use everything else from the 6 bolt longblock including the 14b... We share basically the same manifold and the t25 will bolt to it but youll need basically an install kit to run it. I suggest just using the 14b that it came with

 

[igs]

The important thing to remember is boost. Lower compression will let you run higher boost, but before the boost builds your car will be a dog. It will make the lag and on/off power characteristic even worse.