tweaking m30

[rowanhol 0]

so you guys have destroyed my hopes and dreams regarding forced induction on my car...

what options do i have to get some power out of my m30 without spending bulk?

ive spoken to someone locally about putting a chip in my car, $1000 for 18hp increase..not too sure if its really worth it so had a look at bmwe34.net and they recomended jim conforti chips which are $250US, although most of the chips over there are programed to run better on 91 octane i think..so just wondering if it'l be much of a hp increase running performance chip on lower octane fuel compared to standard chip on 95 octane, or would the performance chip be fine with 95octane??

what abouts cams? shrick cams are around $500US but itd be alot of work installing and setting up, they also recomend running stiffer valve springs.

extractors?? where do i even get a set?

port and polish head?maybe even get it skimmed but then i'll have to run octane boosters if the compression is too high correct??

apparently the intake manifold doesnt match the head nicely so porting there can help..and the standard afm is quite restrictive, will the air flow meter from a m50b25 be too small?

[kiwi535 538]

chip cam and "blueprint".Maybe extractors but the steering box gets in the way of most "mass produced" ones.The chip has to match our dirty engines.Most E 34 markets had cats and oxygen sensors,ours didnt.To get the best results out of a chip you need higher octane fuel.Dont forgetthe yanks use a different octane rating than we do.Their 91 would be at least 95

[rxsumo 33]

Sorry if I'm about to burst your NA tuning aspirations...but.....

Before buying a chip, get a copy of the dyno sheets for the chip for a euro spec car with no other modfications.

I think you will find that while they may gain some HP in the mid range the overall gain in HP is FA....probably in the range of 5-6 HP, and the gain you want to see in the mid range is probably torque and not necessarily HP.

A lot of chips only dump more gas in, and raise the redline, effectively shortening engine life. So you want to do a lot of research, with a chip that you can get fitted and supported in NZ, with a written warranty that you will actually get the gains claimed.

The 18 HP gain is a really big ask from just a chip.

To give you some idea on realistic HP gains, from one of my old Total BMW mags, they ran an article on a race E12 M535i. With a blueprinted engine, knife-edged crank, a Schrick 300 degree cam, extractors and a gas flowed head, running adjustable pressure L-Jet, the engine ran approx 238 BHP....which is a gain of 20BHP on stock.

The Schrick sports cam will cost around $NZ800, the valve springs will cost you another $600, extractors will cost you at least $1000, as they will need to be custom built or imported from the UK (or another RHD market), and I would suggest that the actual gains from the tubular exhaust may be minimal because of the restrictions created by the steering box...by the time you get the rest of the exhaust done, and maybe some head work done, you would end up spending lots.

Suggest if you want to gain HP per KG, sell the E34 and buy an E28 M535i, the other alternative is to put the dosh you would spend doing up the M30 in th bank, and start looking for an E34 M5 or a 540.

Edited June 4, 2007 by rxsumo

[rowanhol 0]

hmm sounds like im going to have to live with what i've got for now..

have done a bit of research on the chip thing and apparently makes a fair bit of difference to the m30, don't think bmw spent alot of time tuning this engine so a chip leans it out a bit and advances timing, and yeah some up the rev limiter by 400rpm. from what i've heard it just gives it alot more throttle response.might give it ago and keep you guys posted, cant be all bad if it leans out a little atleast i'll save coin on fuel haha it's an investment..

[Gus 5]

yep...leave the m30..enjoy it for what it is and save up for a decent car/engine...