9000RPM!

[Onz]

I have heard stories of modified E30's that can rev to 9000 RPM! What do you guys think? Is it possible?

[march109]

What engine, I reckon the S14 or M42 would me more suited to scream mor than say an M20!

Though on e30tech.com some m20's have been modded to run very high RPMs, it can be done but doubt its cheap and I doubt it would last long it would be so highly strung.

[e30bmlover]

anything is possible my friend im sure achem schnitzer could do it!!!

[Onz]

well this was for a FI M20, I was told 9000 is easily attainable but then how does the head cope? I am sure that at that speed the head would just go pop!

[HairyScreech]

or just about anyone with some forged rods, light pistons and a custom forged crank.

[Jhonno]

why on earth would the head go pop?!

[munky30]

anything is possible with enough magic fairy dust.

[march109]

why on earth would the head go pop?!

because it was made from a weasel and thats what they do

[HairyScreech]

why on earth would the head go pop?!

because it was made from a weasel and thats what they do

clasic, the head would only go pop if you exceeded the maximum mean effective presure it could hold, the increase in revs will just meen the stress it put on it at a higher frequency. (more explosions per second but not any bigger explosions.)

[Onz]

wont it overheat at higher revs?

[march109]

wont it overheat at higher revs?

Why? If your building a screamer likely to over heat you would compensate for it. But why would it be likely to overheat if it was running at higher than normal revs in normal use, even allowing for track use and alike you would never be cruising for minutes or more on end at full throttle.

[HairyScreech]

as long as you have adaquite flow through the cooling system then no.

[--alpina--]

A question guys!! to make a car rev high like stated above, how can you do it? what takes it that high? i know its a stupid question it something ive never thought about to search on..

I know maybe a performance chip helps, but if over revved wont it cause damage and also to have that kind of revs without damage then whats the trick...


cheers

j

[dimebag_from_hell]

Mine revs straight through the red, im sure it must be doing my sport some damage....

[Ziggy]

I know maybe a performance chip helps, but if over revved wont it cause damage and also to have that kind of revs without damage then whats the trick...

Replace the things that would break at high revs, with stronger ones.

[HairyScreech]

i theory an engine would rev untill it either couldnt get any more air in, or couldnt get any more fuel in.

in practice either the rev limiter cuts in and cut the fuel/spark, the valves begin to bounce and the timing goes to shit or the engine flyes to bits.

to get higher revs you prevent the three things above from happening.

[CustomX]

Higher revs is usually done with lighter internals and cams / ECU's that take advantage of this.

Lightweight pistons, con-rods etc so they go up and down quicker.

Because they're light, they need to be made strong. This is done by forging (rather than casting) and sometimes using materials like titanium.

[CustomX]

I thought!

[march109]

As HairyScreech and Ziggy have said

To get it to rev higher you'll need to remove the rev limiter or move it further up the rev range, also a suitable cam, and a combination of uprated parts either strengthened or lightened to help the enigne not fly to bits and maintain the high revs.

The chips the zone shop sells raises the rev limit by 200rpm iirc! Someone else could confirm though.

[march109]

Higher revs is usually done with lighter internals and cams / ECU's that take advantage of this.

Lightweight pistons, con-rods etc so they go up and down quicker.

Because they're light, they need to be made strong. This is done by forging (rather than casting) and sometimes using materials like titanium.

Lightning the parts also makes sure as they move they have less momentum (mass * velocity) and thus the stresses placed upon them when changing direction is less and the energy required to change their direction of velocity is lowered too.

[lenny-d]

i chipped my car and it'll rev 2 8000rpm but i hit the limiter once and didn't like it

was waiting for the bang and 12 bonnet vents appearing

[march109]

I really don't know why you would want to do it, a good m20 makes all its usefull power much lower down the rev range, if you want to go fast you need to time your changes up with the point just after here your car makes peak power.

Its also not fanny tastic for the engine and I wouldn't do it on an M20, especially as most of them are a bit tired these days.

[agreen]

especially as most of them are a bit tired these days.

thats about the tip of it

to do this you gotta have a rebuilt engine in the first place

lets be honest these engine are like 15-16 years old most over due for a rebuild anyway

[march109]

especially as most of them are a bit tired these days.

thats about the tip of it

to do this you gotta have a rebuilt engine in the first place

lets be honest these engine are like 15-16 years old most over due for a rebuild anyway

If you have £3300 you can get a 'new' one from BMW, don't thinkthey are actually new though, just reconditioned I would expect, but rebuilt and tested by BMW with warranty its almost worth it, especially with £600 cash back for your old engine.

[HairyScreech]

or you can do what i just did and blow £300 on the bit you need and do it yourself.

[e21Jason]

Hi

More reves = more air = more power, thats why bike engines of 1200 make more than 120bhp/litre. A full race m10 runs to about 9k, but of course this is an engine which has been designed to make peak power and have a narrow powerband.

M20 rockers are the first pioint of failure in an m20 that revs hard or has suffered a mishift as they are alloy cast often pourous, before upraded ones were avilable you paid to have them x-rayed + shot & peened to up the strenght. After market rockers will take you to 9k with an uprated 324td crank, forged rods light pistons etc.

Above 9k unless you do major headwork you will start to get valve float, and again FI can cuase valve float at lower revs.

Jason

[march109]

or you can do what i just did and blow £300 on the bit you need and do it yourself.

£300 for the parts for a rebuild?

[oakey]

or you can do what i just did and blow £300 on the bit you need and do it yourself.

Any chance of a list of those bits mate?

[appletree]

Not a BMW but heres a nice berg cup style V-dub revving to 10krpm



It would be hard to or pointless to make an engine rev to 9k if you want it to be FI aswell as you're asking for different things from the engine! if its FI you could spec it to get peak boost and power by 6krpm and probly get more power any way IMHO

[HairyScreech]

suplied at trade price from the engine recon shop around the corner, iirc they would be over £500 at normal price.

all the shells,
main, rod and head bolts,
head, sump, rocker inlet and exhaust gaskets
cam, valve stem and crank seals,
timing belt and tensioner,
throttle boot,
pistons and bores were within spec,
oil pump was new anyway.
bundle of odds and sods like breather tube seals and thermostat gaskets.

and not pikey kit either the bearings are Federal-mogul and the gaskets and seals are elring.
http://www.federal-mogul.com/en/Afterma ... -Bearings/
http://www.elringparts.co.uk/


{edit} infact i lied it was about £350.

[Colonel Sanders]

you need the right cam that will still make power at so high revs, stiffer valve springs, good valves, and billet rockers, and a fi m20 will rev maybe over 9500rpm.
i have the cam and valves and stiffer springs in my 325 turbo, but not gonna bother with the billet rockers as oem ones are so cheap to replase, il only be setting my revlimiter at 8200rpm anyway...

[HairyScreech]

theres some forged steel rockers for sale on here if thats any help, better than billet ones will ever be.

[Colonel Sanders]

i have looked into it alot, and they would be good, but if anything is gonna let go in my engine i would rather the rockers go as they are cheap an easy...

[HairyScreech]

unless a lump of rocker goes under the cam and slams through the head.

[Colonel Sanders]

true, i got advised it wasnt worth it on ppf forum. mine aint gonna be balls out all the time though...