Stock redline or raise it?

[pokeybritches]

Most tuning companies offer the option of raising the stock 8k rpm redline, while others don't recommend it. I understand the high piston speed of the undersquared S54, but many cars in race applications run higher-than stock redlines for extended periods in track conditions. I'm wondering 1.) what the ultimate limit of the stock engine is without the risk of significant catastrophic failure... and 2.) if the engine does ever grenade and the car is still under warranty, is there a way to reset the max revs without the dealership knowing, or does the fault code permanently store the rpm at which the engine blew up.

I plan on getting a 4.10 diff later on down the road, so the extra rpm would be useful, but I'm hesitant to raise the stock redline because of the potential catastrophic consequences and warranty concerns. I don't want the dealership telling me that because I ran the car up to 8150 rpm my warranty is no longer valid.

Edit: One reason BMW may have left the stock redline at "only" 8k rpm is because so many owners fail to let their cars warm up to normal operating temperatures prior to getting on it.

[Z4-VILLA]

i would leve it alone, just a 410 diff

[NickyC]

Originally Posted by pokeybritches

2.) if the engine does ever grenade and the car is still under warranty, is there a way to reset the max revs without the dealership knowing

Stay classy.

[Diokaef]

I will be using mine at 8.5K on mine with the 4.10 LSD. is on you, any mods comes with risks.

[pokeybritches]

Originally Posted by NickyC

Stay classy.

I meant more as a manufacturer's defect, unrelated to the raised redline. I'd be dishonest if I ran the car up to 8800 rpm, it blew up, and I tried to get BMW to fix it under warranty. However, when BMW has cars destroying themselves at idle from the cam bolts shearing, and they refuse to do anything about it... I wouldn't put it past them to try and deny any warranty-related work because of a 200 rpm over-rev.

Regardless, I ended up deciding to raise the limiter to 8200 rpm. I don't plan on going there very often, but it's nice to have those extra revs if I miss my 8000 rpm shift point.