2.8l stroker thread

[Sean]

~$200

no, didn't have it balanced.. no real need to really. you don't think BMW balances the crank from the factory? the pistons were matched together as a set, as were the rods.. it runs smoothly too :)

That's true - your pistons were balaned. Mine weren't - at least not too well. He did a lot of material removal on my pistons.

So...what's the news on the engine??

[nando]

did the 500 mile oil change yesterday, and fixed a loose TB nut (started making a really strange whistling sound suddenly). also put in a home made clutch stop. it's running great, no problems at all, and it's pretty much broken in. I can't wait for sunday, it will be my car's first autox in 2 months :D

soon I'll swap to a different shift lever, put in a front driveshaft with a lengthened spline section, and maybe then I'll send one of my extra manifolds off for extrude hone and have a TB bored out. then long tube headers, and after that all that will be left is tuning..

[madjurgen]

smt7? maf? youll be making some nice numbers u do all that. maybe a mildly more aggressive p/p too.

no comments on the added power?

[nando]

well, it's got more of it.. but until I do a dyno session or a 1/4 mile time, I won't really know. the old engine/tranny was probably around a 16sec 1/4 mile and 7 second 0-60 (comparing to my friends SHO). I'm probably only 6.5 0-60 right now, but I haven't tried any agressive launches yet. I think I can do a low 6sec 0-60 and a low 15sec 1/4 mile if I drive more agressively. it's only been recently that I've pushed it much past 6,000rpm.

1st and 2nd gear are a blast around town, I can pretty much pull in front of anything, and getting a slight chirp from the rear wheels before the VC transfers torque to the front wheels is great!

5th gear acceleration on the freeway is nuts though, at 70mph I'm right in the sweet spot for the torque band.. I don't need to shift down at all to pass, just step on it and go. I actually don't use 4th for much, except maybe getting on the onramp, but 3rd is usually enough as the speed limit is 70 anyway. 70-120 happens very fast, the old engine/tranny would get pretty slow above 90, this thing pulls like a freight train until about 120, but the intake restriction holds it back at higher rpm.

I have an autox tomorrow, which I'm really looking forward to. hopefully it continues to run smoothly as it has been so far, I think it will be a blast!

[DrMcDave]

yeah and while that 5th gear rocks for passing it really sucks for fuel economy.

[nando]

I dunno, I seem to be getting better fuel economy so far, even though the auto had the lockout torque convertor and a .72 overdrive gear.

[Sean]

I dunno, I seem to be getting better fuel economy so far, even though the auto had the lockout torque convertor and a .72 overdrive gear.

Same here, I seem to be getting pretty good gas mileage too! lol

[DrMcDave]

well i get crappy mileage in mine. probably in need of a tune.

[e304me]

would you mind sharing what the machining costs were? did you have the crank machined for oversized bearings?

[nando]

would you mind sharing what the machining costs were? did you have the crank machined for oversized bearings?

cheap.. about $200. there is no need to machine a BMW crank, and it's actually a bad idea - they are nitride hardened from the factory and machining it will ruin that. a light polish would be all you need, and i didn't even have to do that. I just cleaned it up and put in new standard sized bearings.

[bimmer_adam69]

wow, thanx alot nando, ur info is really informative since this is what ill be doing, i know now what i want, except if that twin screw supercharger goes into production then ill add that to it. is it possible to bore the engine out any more than you did?? thanks adam

[Sean]

wow, thanx alot nando, ur info is really informative since this is what ill be doing, i know now what i want, except if that twin screw supercharger goes into production then ill add that to it. is it possible to bore the engine out any more than you did?? thanks adam

86mm is pretty much the max. And, that's only possible thanks for the design of the Metric Mechanic pistons. Normally, overbore pistons only go to 85mm rather than 86. I think MM are the only ones that go to 86mm?

[e304me]

you wouldnt want it that far with a supercharger anyways

[Sean]

you wouldnt want it that far with a supercharger anyways

Oh yea, for a supercharger?! No way. 86mm will cause the cylinder walls to be quite a bit skinnier and may not handle boost as well.

For boost, I definately wouldn't go past 85mm.

[diegom6]

Oh yea, for a supercharger?! No way. 86mm will cause the cylinder walls to be quite a bit skinnier and may not handle boost as well.

For boost, I definately wouldn't go past 85mm.

Have you even driven a 1mm over bore forced m20?