[NY337]

So I put the car on the dyno last Wednesday. Not too satisfied with the numbers. On this same dyno I baselined at 287 which is the RED plot below.

The second run in BLUE was after the car was running for a bit while it was getting strapped down and set up. They forgot to turn the fan on too.

Finally, the last run was after the car sitting for 20 minutes so I can swap out coil packs that apparently did not work too well and switched back to the originals. This is the GREEN. That was with the peak at 320 WHP. Kinda sad when I started at 287.

So, after checking the AFR levels I was really worried that I am really lean. Especially since my stock tune was richer all the way through compared to the last run. I checked my fuel pressure and it sits at 65 psi and peaks at 75 when I goose the throttle. Changed the fuel filter and still the same pressure. I checked my bentley it it specified that my pressure should be 72.5 psi +- 2.9, but at what engine condition? Idle, revs, what?

The only time my AFR dips below 12 is right before redline, isn't this bad? I have read some other SS plots and noticed that after about 5k RPM the AFR sits at around 11.8 or so. Any ideas folks? The only other thing that I can think of is maybe a bad fpr? If so, would an adjustable fpr be a smart move? Don't know of any companies that make one for the M3.

Oh yea, and I hooked up a boost gauge about an hour ago and found that I build boost right around 4k rpm holding at 3-4 psi and peaking at 5 psi. I guess I should be boosting just fine considering my AFR. Anyway, this is a long thread but here's the plot below:



Here's the HP and Torque:

[swc]

Tail pipe reading is always higher than gauge reading(closer to the block). My gauge is always showing 10.5~11.8 but it was 11.5~12.5 on the dyno with sniffer. It could be something else like retarded timing etc.

[NY337]

This is true, but after 5k I am at 13 to 12.5. And I have noticed that after the kit the motor has definitely been running a bit hotter. I am also thinking that a little more fuel might increase my gain a bit, no?

[swc]

Normally lean out gives you more power but motor will be running hot and dangerous if it's too lean then the ecu pulls timing few degrees for safety. That results in less power. I think you need to send your DME with dyno plot to VF and have them retune it.

[NY337]

Yes, thats definitely an option I should consider. I was also thinking of a custom tune but its $$$$

[AirFrcd]

oh no...

[RaceMX-M3]

Dyno Dynamics reads much lower than Dynojet. Personally I hate dynos. 60-130 times rule. http://www.m3forum.net/m3forum/showthread.php?t=189369

[NY337]

This was the reason why I baselined on the same dyno just so I can see the gain. The base seemed pretty high so I figured that my new number would be higher. What could have changed on the dyno between now and the time I baselined? New to the whole dyno thing and don't know the different variables that can be changed. I tried to keep everything else the same. Same gas, same heavy ass LM's, same gear pull, etc. More importantly though is what can i do about these lean AFR's? I guess the only thing I can do is retune?

[MaleChimp]

I would be calling OE tuning, best of luck.

[ccsykes]

Originally Posted by NY337

So I put the car on the dyno last Wednesday.

How were you taking your AFR readings? If from a tail pipe sniffer, your going to read leaner.. your cats will burn off excess fuel.

My car did 328 HP and 254 TQ. Here was my review http://www.m3forum.net/m3forum/showthread.php?t=293873

I'm now running a Stage II kit and my AFR's are right where they should be and I'm making 500 HP on 104.

As for performance gains, your not going to find some 50 HP increase for $5,000 anywhere else.. so I wouldn't be too disappointed.