RPM 7000+ How?

[nando]

I'm not trying to start a war here (I think we're looking at this from 2 different view points) so please don't take this post that way; but I wouldn't call what I did here a slapped together setup; as stated my E30 was purchased with track use in mind; the plan was and still is to eventually take the car racing I was looking at BMWCCA prepared rules (KP is a decent play ground for E30's) which basically limit you to the mods I had on the car, so I picked out the parts I put on the motor with these limitations in mind not just cobbled something together. Also I never said there weren't gains; there were just nothing at an RPM point that the average person on this forum would ever find useful; at a track secnario where minimum engine speeds are about 3.5-4k the cam did wake up the motor (at the cost of torque below that point) so for someone that doesn't use there car in these scenarios its not really a good idea to spend there.

but to get back on topic you can rev the M20 to 7k with a cam, valve springs and chip but don't expect the vavle train to be very stable at those speeds (heck M/S50/52's have stability issues over 6800) so sustained RPM is going to break parts (OE rockers 1st) so I'd turn the rev's down and just try not to money shift the car; if you really want to rev the piss out of your motor research an S54 or Euro S50 swap they have the valve train to handle that type of sustained RPM levels

no war intended, it's just annoying when people ask about a motor other than an M50 and there's always at least one post that says "$500 m50 swap dood!" it's not helpful and we all know about the M50 swap.

as far as being unstable above 7k, that hasn't been my experience, but maybe I've just been lucky.

[digger]

it doesn't make sense to go past 7k on any motor with a pretty much standard intake manifold. You can cam the shit out of it but even that won't help that much.

A stroker is less likely to need to be revved to 7k as it is more likely to make peak power a bit lower rpm than the stock engine. If you made a M20B20 and tuned like you would a stroker it i bet you could make peak power into the 7k band pretty easily but what would be the point.

In 1st and probably 2nd gear it makes sense to rev it to around 7k if the limiter allows it but in the others the power drop is too large when you look at the fact that the revs drop less with each gear chnage as you get into the higher gears.

You'll want to make sure the valve springs, and rockers are in good order if you start raising the revlimiter. There is a video of a 2.8L that gets its tits revved off when going to 240km/h even it sounds like it wants to explode.

[bear]

rocker arms, always the first thing to go when I fuck with my redline on both m20's and 3.5's, seems like the factory bottom end is tough as nails on every bmw I've owned, don't blow your money on any cam, these aren't chevy 350's from the old days where the aftermarket had more tuning expertise than the make did, your dealing with SMALL engines that have as much useable horsepower as any stock v8 from the 70's (just minus the torque). Save your money and time, pull your head, have it serviced, put it back on with arp head bolts and a good head gasket, then turbo it, leave your redline intact, you'll have lotsa fun. No sense in trying to reinvent the wheel leave that for the top fuel and formula 1 guys, who cares. once that is done drive the fuck out of it, buy a wrecked car cheap with a good motor, have it ready to swap when you grenade your old motor, pure grass roots cheap fun. be sure to put all your cam money into a spec dual friction clutch, and then clutch it like its a dirtbike. Now you've bypassed all the modification snobbery.

[akinswonder]

I will disagree with this, the longer the stroke the lower the revs. kind of like putting bigger tires on a car. My stroker motor I am turning 3 seconds a lap faster at most tracks while turning 1000 less RPM then my built 2.5. I generally by 6100 now, where I was shifting at 7000 before.

Can give the specs on your stroker motor and what crank are you using?

[jahnaboi]

More info here: http://www.e30tech.com/forum/showthre...
E30 with naturally aspirated but highly modified M20 engine does 0-240km/h on the Haapsalu old Soviet army airfield. Was recorded on the event One Mile Challange. Real thing - without any tricks. In case of any doubts - look my other videos.



bmw e30 325i, M20 2,8 stroker, naturally aspirated, in dyno 08.05.2009. Measured 224hp (164,4kw) and 292,3nm. Sorry for bad sound quality...

Dynapack dyno numbers are so retardedly high. Bet you anything he's putting less than what is already stated.

[digger]

Dynapack dyno numbers are so retardedly high. Bet you anything he's putting less than what is already stated.

torque is a bit of a give away.......go's like stink because its 2200lbs