Conflicting ring gap suggestions?

[87'GTstang]

I have been told by many different people various gaps and now it is confusing me. For the record, the engine is a 304 sporting about 8.8:1 compression, forged 4032 SRP aluminum pistons, Speed pro plasma moly rings, and aluminum heads. The engine itself is roughly a 325hp engine, but with (key words) moderate boost (roughly 8-10 psi tops but not frequently in boost), around 425-450.

Now I have been told as follows (top gap/2nd gap) 17/18, 18/20, 20/22, and 24/26. I have been debating about this quite a bit but just cannot figure which one to run with. Can anyone reccommend a solid answer as to which gap or where at all to gap the rings at?

 

[vristang]

Personally I would just use what your ring company suggested. They know the material properties of their rings better than anyone else.

Basically, you want enough gap to let some pressure get behind the ring to help it seal, and to prevent the ring ends from butting together when things get hot and expand. Too much gap will result in excessive blow by, and hence lower compression. Since conditions vary between applications, there will be a million answers to your question. For example a low compression n/a street motor will not produce as much combustion heat as a heavily boosted race motor. Hence boost applications need more gap.

Another thing that I have been burned on is ring tension. If you haven't done so already make sure that the part numbers you get are approprate for your application. Just takes a few minutes to look up the numbers.

Good Luck with the build
jason

 

[87'GTstang]

They are standard tension rings. Speed pro recommends for supercharged 24-26 for both the top and bottom and (top/2nd ring) 16-18/20-22 for street performance. JE recommends 20/22 for moderate boost and 18/20 for high performance/street-strip. This I forget to mention in the first post - hence the confusion is still kind of there.