E30 M3’S

M3Nally wrote: So why did they not build the Evo Sport with high compression pistons like evo2 to get nearer 250bhp. After all 18bhp with 48mm TB's is not alot more than my evo2 at 220bhp with only 2.3l engine. Was there a power restriction for racing as well as engine size in DTM at the time?

What is quoted by the manufacturers is the static compression ratio which has little relevance to the engine when it is running.

See HERE for more details

Steve

Toby,

Cheers, which Dave is that then and what is his number?

PM please if don't want to give details on here.


Kevin

I run my E46 on Optimax only. If I get really desperate I'll go with BP Ultimate, but find a definate difference if I use anything less than that.

Uwe - the informationmeister...

thanks for that - always stayed clear of early cars because i thought unleaded would be a problem - infact i bottled out and bought an evo sport so i was certain it would be a late one...

UweM3 wrote: Coasting, you engine has a knock sensor fitted which senses the quality of fuel used and adapts the ignition accordingly. Our old bangers don't do this. So if you fill it up with lower Oktan petrol than mapped it goes BANG! BTW that BP stuff is crap. It burns faster than I can fill the tank up! And smells funny.

Exactly the reason why I had mine mapped on std unleaded, as I couldn't be certain that I would always be able to get the high octane stuff.

what about my cecotto what does that supposed to use , i just stick normal unleaded in

ill have a look  soon , is the ecu under the glovebox or on the drivers side on the m3 (cant remember) normal e30s its above the s/column, i used to be a vauxhall mech years ago & they had a simelar thing of an octane pug which you simply turned over ,one side for 95ron & the other for 98ron they were colour coded too for different models  

Here's a pic from Uwe's posting on another thread. The green arrow points to a black block, but it's the connecter, the same shap as the blue one just above/behind it.



This will give you some idea.

HTH's

Rob L wrote: So does this apply to my Sport Evo, should i always run super U 98 (optimax normally) Is it ok to run 95 standard stuff now and then when you cant get any super U? Will it have this plug you mentioned to switch between the grades?

Yes it does. I find my Sport Evo runs best with both connectors connecter (98 RON Map) but running on 95 RON unleaded. Smoother idle, more responsive on part throttle and will still hit the limiter in top even with the front/rear spoilers in position 2/3 respectivly. The standard MAPs are quite consevative I think that running this way is closer to the optimum when using good quality fuels.

Steve

Edited by stevesingo

Ok again.
DO NOT RUN 95 OKTAN fuel with the 98 Oktan map!!!!!!!!
Have a guess why this map is called 98 Oktan map?
The better response is coming from the "sharper" ignition timing. But this could only be done because 98 Oktan is used. Anything less will cause pinking --> destruction! I can put you in touch with a fellow M3 owner blowing his engine up that way.
The danger lies in the high speed pinking at WOT. You cant hear it, but this does the most damage.