rolling road fail

[slipstream 1985]

so took my e46 m3 to the local rolling road and it recorded 308bhp at fly at 6350 rpm. I asked why it never went to 7900ish and the operators said that if the front wheels arn't moving the car won't rev past that limit they had had it before with manual m3s (smg were ok though). For one i wish i'd known about that before hand. However is there a way to extrapolate the final likely power figure from the remaining 1500 or so revs seeing as that is where the power really hits home.

[stevesingo]

How does everyone else dyno manual E46 M3s? There are plenty of places do so without issue.

[TheAngryDog]

You need to pull the abs fuse if I remember rightly.

[Paul_M3]

There is a 'Dyno mode' that can be selected when the appropriate diagnostic equipment is connected.

Alternatively, it is said to be possible to do it via buttons. I just had to look this up to remind myself:

"Some have asked me to put up a post on how to put an E46 M3 into Dyno mode without specialists tools.
Manual or SMG and even 2004 onwards including CS and CSL.

so here we go.

As many are away the M3 will only rev to 6500rpm unless you put it into dyno mode.

1. Switch on ignition (position 2)
2. Hold down DSC Button for 8-10seconds but no more than 10 seconds.
3. Only DSC Light should come on not ABS or H/Brake light. If they come on you have done it incorrectly
and you will have to wait 5mins for vehicle to reset, if it is built after 2004.

4. Press Sports button and start car.

5. You can run car now upto 7900rpm or more, if rev limiter has been increased."

I have copied that from another forum, and cannot confirm for definite whether it actually works or not.

[Vixpy1]

done 100's of them, if it does it simply turn the car back off and on again and they then usually rev through.

[Polarbert]

Sounds like the rolling road people were a bit st then.

[E65Ross]

I'm guessing you don't mean another 1500rpm if they revved it to 7900? I thought these revved to 8k or 8250?

[Crackie]

E65Ross said:

I'm guessing you don't mean another 1500rpm if they revved it to 7900? I thought these revved to 8k or 8250?

OP said his car made 308HP at 6350rpm and wondered if there might be a way to determine the likely power at approx. 1500 higher........

Google images dyno plots for various standard E46s show them making 325-328HP max and about 310HP at 6500. Your 308 at 6350rpm looks fairly healthy to me.

These plots are from Evolve but there are many other sources if you search; Vixpy1 has a good reputation and might comment on the realistic max he sees on the 100s he's done. http://forums.m3cutters.co.uk/showthread.php?t=184...

Edited by Crackie on Tuesday 5th April 11:02

[Evolved]

I wouldn't worry, based on the figures it seems on par with where it needs to be. Not really worth re running as you'll not gain anything other than a higher figure.

My CSL made 355 when it was dynod, didn't need any fuse pulling or any special mode selecting so perhaps the Alpha N map allows this mode as standard? God knows, sounded good though even though it was a 200sx day with lots of wishing turbos and dump valves.

[slipstream 1985]

Evolved said:

I wouldn't worry, based on the figures it seems on par with where it needs to be. Not really worth re running as you'll not gain anything other than a higher figure.

My CSL made 355 when it was dynod, didn't need any fuse pulling or any special mode selecting so perhaps the Alpha N map allows this mode as standard? God knows, sounded good though even though it was a 200sx day with lots of wishing turbos and dump valves.

aparantly not an issue on the semi box.