Boosted ring gaps
Some of the people on this forum are completely worthless and unwilling to help and I really don't get why. Why bother posting if you don't want to help, were you just born knowing everything there is to know about building a motor... **** no someone helped you and taught you, you should do the same share what was taught to you to other people to make them more knowledgable.
And to the guy that said read the instructions that come with the rings. If your reusing stock rings there are no instructions.
And to the guy that said read the instructions that come with the rings. If your reusing stock rings there are no instructions.
Last edited by MY_2K_Z; Jun 16, 2016 at 10:54 PM.
Most of these questions have been answered many times over... even in this thread if you look.
Fuel used? boost/power level desired? SCR/DCR? RPM? IC? all those play a roll. Then there's the tune itself.
I've never butted an OEM ring with a .022 top ring on E85, intercooled, with water/meth on small bore stuff. Pinged 30lbs a few times too... Usually the ring gaps are around that anyway on a 100k+ mile motor. I've seen a few tight ones though.
As long as the bottom ring is .002 or so larger than the top, I don't mess with it.
Fuel used? boost/power level desired? SCR/DCR? RPM? IC? all those play a roll. Then there's the tune itself.
I've never butted an OEM ring with a .022 top ring on E85, intercooled, with water/meth on small bore stuff. Pinged 30lbs a few times too... Usually the ring gaps are around that anyway on a 100k+ mile motor. I've seen a few tight ones though.
As long as the bottom ring is .002 or so larger than the top, I don't mess with it.
Last edited by Forcefed86; Jun 17, 2016 at 09:42 AM.
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Verdad Gallardo They are naturally looser on the second ring from the factory. I’ve never seen a bottom ring tighter than the top on a used LS and I’ve never seen a lower ring as tight as .018. I’ve opened up quite a few and were all right around .022 top and around .024 or so on the bottom ring. Some tops as tight as .016. Usually thrown in randomly with a bunch of .022 on the other pistons. Assuming they never seated properly on break in. Could have been a new piston/ring install, but didn’t look like it.
And for further information it's a gen3 4.8 gen4 internals on e85 dual walbro 450s, 243 heads and probably 20-25 psi on kill and 15 otherwise. Factory ecu in a 2000 fbody with a 4l80e
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Forcefed86 knows my setup, but for the others here its.
4.030 forged piston. New Steel rings. LQ4, 317 heads, dual 044 pumps to 80lb DEKA injectors. S482 turbo.
PSI is unknown right now. But I would assume about 7-9psi on the street and low 20's on the track. Pump gas for street, race gas if needed for track, A2W IC, Meth injected at higher boost levels when needed.
As for the gap, the bore doesn't seem to effect it a whole lot from the calculations. So the difference between a stock bore and .070 over less than .0005 at .006 per inch of bore. So its .024 with a 4" bore and .02442 on a 4.070 and with this I would just stay at .024
I actually told my machinist to be .026 top and .028 second. I am playing it safe. Its a race engine so I don't mind it being a little loose.
4.030 forged piston. New Steel rings. LQ4, 317 heads, dual 044 pumps to 80lb DEKA injectors. S482 turbo.
PSI is unknown right now. But I would assume about 7-9psi on the street and low 20's on the track. Pump gas for street, race gas if needed for track, A2W IC, Meth injected at higher boost levels when needed.
As for the gap, the bore doesn't seem to effect it a whole lot from the calculations. So the difference between a stock bore and .070 over less than .0005 at .006 per inch of bore. So its .024 with a 4" bore and .02442 on a 4.070 and with this I would just stay at .024
I actually told my machinist to be .026 top and .028 second. I am playing it safe. Its a race engine so I don't mind it being a little loose.