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S4 NA rotors under boost and 3mm Apex seals in a street build FD engine

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S4 NA rotors under boost and 3mm Apex seals in a street build FD engine

Old 11-24-18, 01:35 PM
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BC S4 NA rotors under boost and 3mm Apex seals in a street build FD engine

So, in the process of trying to clearance my stock REW rotors to accept 2mm oversize apex seals I goofed and opened the rotors up too wide, ruining them. Since then, I've decided to try and find the most optimal rotors for a roughly 400-450whp single turbo REW and came across a set of '84 13B N/A rotors with 3mm apex slots, so my questions are these;

1) Would the '84 GSL-SE 13B (series 4..?) rotors work at all in my REW motor with a T04S single turbo setup and achieve the power I want?

2) Would 3mm apex seals work well on the street doing normal speeds? I've heard they're only really any good for racing as they're not good with compression at lower RPM
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Old 11-24-18, 03:29 PM
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1. GSL-SE is an S3, you had better make sure what you have! the 74-85 13B rotors are 12lbs so they are WAY heavier than the 89+ rotors (about 9.5lbs) you MUST use the 74-85 counterwieghts. the older rotors also do not have as many dowel pins holding the gear in, so they tend to come out at high rpm, which is bad.

2. the 3mm seals are stronger, but they seal worse and are heavier so basically they are worse everywhere.

keep shopping
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Old 11-24-18, 06:33 PM
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The 3mm seals suck unless you are a fan of low RPM and wrecked rotor housings. Taking Mazda 3mm seals over 8000rpm usually leads to a bad time, and they are not as chrome friendly as 2mm seals.

I've heard good things about high compression rotors in turbo applications that are geared for drivability and response rather than all-out power.

That said one of the most ridiculously responsive turbo engines I ever experienced (piston) had 10:1 compression, so I can believe it.
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