I have some 81.5mm forged pistons I can't seem to sell and I want to run about 10:1 compression. The pistons look like they're around 11-12:1, like a dome larger than a ITR piston but smaller than CTR. Would it be possible to just mill the dome off the pistons to make them flat like a GSR piston? Is that too risky?

My goal is to build a GSR turbo motor running about 10:1 compression, around 8-10lbs of boost on a Turbonetics T3/T4 I'm planning on running Crome on a P72 ECU and street tuning it until I get more money and can get a dyno tune. The car will be daily driven, so reliability is very important.

 

I wouldnt do it if you are looking for reliablity, you will end up creating hot spots on the pistons. your better off buying the proper pistons.

 

i used to have a similar set, i believe they were +5cc domed. youre probably better off just buying a new set, milling them down, smoothing edges, and getting them all weighed properly might cost close to just as much.

 

Pistons are designed with proper quench areas and are more high tech than just metal slugs. Buy a new set and avoid potential problems.

 

reliable?


why not, get a belt sander a go to work

 

If he's only having the domes milled down by a precise amount, and then re-matching for weight, why would it cause any problems? Quench areas shouldn't be affected if these are truly "domes."

 

...found an issue. These are forged where the dome is the same thickness at the inside as the outside. Removing anything would make them uber thin... and one has a cracked ring land...

 

Oooops, there's the answer to my question!

Oh well. I used to do it with my old forged V-8 pistons Heh heh. . .