Over this summer and fall I am going to bridge my 12a. I cant really see why I would rev past 9.5k rpms, but I dont think the stock steel seals will have much fun up there. But I want to run at least a 100 shot and probably a 150 shot



So it is a simple question, I 've heard carbon seals are terrible with FI. Is it that they are too brittle for pre-ign and detonation? If it is detonation that kills the seals I dont thnik I will have much of a problem, I plan on running alky and jetting up a few pills to run a little fatter than normal on the kit to give me a small margin of error.



BTW great section fellows, keep up the good work https://www.nopistons.com/forums/pub...IR#>/bigok.gif

Pineapple has told me (FWIW) that carbon seals can take a properly tuned 150 shot

carbon seals are like the inside of a pencil, they are light but brittle. any detonation is gonna kill em.



the good news is that if and when you break a carbon seal, it most likely wont damage anything else

so its just the detonation that is the problem(other than the sealing issue)



I mean realistacially I'd love to stick with the stock iron seals to give me a bigger saftey net but I know they start to chatter ~8500rpms, kind of defeating the advantage of the bridge port. cermaics are way outta my price range.



also how important are hardened gears, and comp rotor bearings if I keep it around 9k max. I havent really heard a definate answer on these and would rather not spend unnecessary money.

Detonation on an na and detonation on a boosted engine are quite different.



A buddy of mine ran all day on a 12ABP with sidedrafts and a s4 turbo. Towards the end of the day the Carbon seals finally bit the dust. But they took a hell of a beating considering he is using a locked disributor. He just ran the bp that day becuse his ohther engine was down and this one was ready to pop anyway and would not be reused. It was an open track day and he beat the **** out of it for an extended period of time. Also the plates and housings were pretty shot to begin with when he built this experimentla bp.



He also had a stationary gear warp. Cant remember if it was on this engine but this guy has a thing for revving the crap out of stuff. If you can afford hardend get them otherwise get youself a scatter blanket https://www.nopistons.com/forums/pub...1047683473.gif



Gregory

um if you verify the clearances, start out with really nice set of gears, and dont stay at 9k for long periods of time it will be 'ok'



the hardened gears are for people like lynn hannover who are at 9k for hours, not seconds.



still the chance of failure is a lot lower with hardened gears

well Im building the car for open track days(no class) and local autox so I might be at 8.5k+ for a bit, hence the bride port. so looks like I'll get the gears.



what will I need the race bearings with the extra clearance?. and wouldn't I have to shim the pump to raise the pressure to make a thicker oil sleeve?