[nailer335]

I am getting ready to do a big service, and would like to know if there are ways out there to better support more than twice the boost the car was made for... and before I go for my glory runs this winter, I want to make sure the car is completely healthy before I dump MS109 in it and set the meth adder to 45 :-) 18psi target boost, IIRC. should get me into the high 11s I'm hoping.

Its been about 8k miles since my last oil change, the car isn't misfiring but the plugs are past due for sure, and I've never had the transmission fluid changed either.

I have an e92 AT 335xi at 63XXX miles now, and will be doing the following:

1) oil change
2) spark plugs
3) transmission fluid flush + new filter + sealing sleeve
4) transfer case fluid?
5) diff fluid?

Going to stick with OEM plugs, and will probably put in Pensotin ATF1 fluid, slightly overfilled (thanks to some good advice) but other than that, does anyone have any other ideas as to what to do to tune things up for much higher output, maintenance or otherwise? Clean stock IC? seafoam? that crap actually make any significant difference?

[Doyle]

It seems like for these cars the engine is pretty stout, but the driveline is the weak point. There are a few 500+ whp guys that haven't done much outside of fluids for the engine.

As far as the driveline, there aren't really any high power xi's to know where the weak points are. If I were you, I'd handle it in stages based on power levels.

Stage 1 <400whp:
-change all fluids to the good stuff (motul 300v for engine & diffs, atf for tranny, mocool+distilled water for radiator, BMW for transfer case, brake fluid)
-spark plugs
-occ if you want...but do research first

Stage 2 400-475whp:
-transmission and transfer case coolers (for added fluid and better temp control)

Stage 3 475+whp:
-Level 10 or similar transmission upgrade
-potentially half shafts/axles over 500whp, but there is a lack of sample size to see
-maybe WPC coat the diffs or transfer case clutches

At least thats the plan I will follow. I really don't think I'll shoot for over 475/475 at the wheels, since the transmission upgrade is mucho dineros.

[nailer335]

Thanks Doyle.

I'll be shopping around for those. Will I want to stay to spec on the amount of fluid in each? Ie another source recommended slightly overfilling the transmission fluid- that kind of thing. Also, if it isn't too much trouble, how much of each will I need for each "stage 1" job, or maybe a link to where I can find this out myself.

Appreciate the good feedback. Not every response is as worthwhile.

[Doyle]

Here you go:

http://www.e90post.com/forums/showpo...10&postcount=4

As for overfilling, I have no idea. I know that for all of these parts (tranny, tc, diffs) heat is the enemy. More fluid = more difficult to heat up. The better the temp, the better it lubricates.