numbingtwitch

Hey guys I'm brand new here so I hope you can be patiant with me and the many questions I have. I WILL search the archives, don't worry, but if anyone feels so inclined to give their 2 cents I would appreciate it alot.



My biggest question is about low compression rotors. I'm in the process of shopping for a third gen 7, and once I start modding, I want to be able to squeeze as much power out as I can. I plan on a twin turbo upgrade, and running high amounts of boost. I have been told that ceramic apex seals are a must, and more specifically I have been told by a local rotary nut, that 5mm ceramics are a sure shot, but 3mm is the largest I can find on the web. I know the cost to rebuild the motor will be alot, but I'm more concerned with getting it right the first time, and not needing to replace or rebuild the motor numerous times. Anybody got anything for me?

j9fd3s

the 87-88 rotors are low compression (8.5:1 instead of 9:1), this will let you boost a little higher, especially on pump gas. they are a different balance than the fd rotors so they arent a drop in, unless you use the FC couterweights



are you sure he said 5mm? 3mm is the biggest ive heard of...

dpf22

Never heard of 5mm apex seals. I had my s4TII rotors lightened and balanced to fd rotor spec.

I also use 2mm seals and they do the job just as well. Honestly larger apex seals usually lead to high rpm seal chatter and they aren't necessarilly any more robust than 2mm. Stay away from ceramic unless you have an extremely good tuner because they are brittle and break with lower levels of detonation than standard seals. There is tons of info in the engine building forum. Read it all, take what you need, and leave the rest.

Good luck!