Thread: Strange Dyno Graph..Dip + Missing WHP (Updated: ECUTALK logs)

Did you hold the throttle open during the testing. You might want to remove all the plugs to get a faster crank going from the starter. You need to hold the throttle wide open during cranking.

Dets usually make around 150 to 160 from what ive seen. With s4 cams you will be slightly lower maybe 140 to 155 or so. As long as your numbers are consistent and close you shouldnt be worried again as long as the compression isnt too low. Redo the test if you feel there is a problem. From those number I think your alright especially if you had the throttle closed.

Ya I asked my friend if he did WOT after I got home and was reading about compression tests, I really doubt it as it was the first time we did the test and both of us didn't quite know the correct procedure. We may do the compression test again this week, but ya I agree, it's good to see numbers are consistent so at least 1 cylinder isn't dead.

-G

Just got off the phone w/JWT. I was told that for the MAF voltage the tune is seeing, the duty cycle is pretty accurate for 92%. I have sent them my logs and also the dyno graph. I'm interested to see if they find anything that could be related to the tune, but so far it appears the tune is fine. I'm still going to try and get those A/F numbers off the wideband. I'll report back when I have new info.

-G

Which mark was the crank pulley on? Can't tell from the pic, and yes a/f is very useful on the dyno sheet.

lol, stop using your cell phone to look at the internets. It's at 0*. If you look close(or use a real monitor) you can see where the pin is pointing. It's a B14 crank pulley if that's why you were confused.

Are we crazy to think that maybe you're actually driving them that hard, and you're running exceptionally rich? Taking away some fuel would liven up the power and stop stressing the injectors? Do we have AFR readings? Edit: I see we're waiting on those.

Just FYI that double hump with a dip in torque around that rpm is exactly how the stock DE torque curve looks like.

My cell phone browsing the net has nothing to do with the fact that your picture doesn't clearly show the timing needle. I'm no photog, but I do have a digital camera capable of taking suitable pictures; and yes you can see the needle if you look closely, bit you shouldn't have to.
P.S. No, I will continue to omit random letters from words and have my iPhone auto-correct words improperly.

My A/F ratio was about 11.1-11.4 from what I saw during the runs. I actually had my fuel pressure decreased to about 56psi at no vaccum during the runs. JWT at 58psi runs under 11.0 A/F or 11.0 flat. I had my fuel pressure decreased even more for a few months prior and saw my A/F around 11.5-11.8 most of the time. That was at like 54psi or so. That 92% duty cycle was done when I had the fuel pressure much lower. I turned it up for the dyno to be closer to the tune. I didn't think a few points lower on the A/F would have made much difference in my numbers.

Specifically during 4.5k-5.5k where the flat line occurs I'm not sure, I can't look at RPM and A/F at the same time. Friend in the car will help this week.



hmm, that's strange. Most dyno graphs I've seen (at least of turbo motors) are pretty linear and no flat spots. Do they see a flat line in hp as well? In my graph hp flat lines for a couple hundred RPM.

This guy has a similar setup to mine and I see he flat lines as well. Makes me think it might be the tune not compenstating for the addition of the S4 cams:
http://www.sr20-forum.com/tuning/10391-most-powerful-engines-thread-dyno-thread-powerful-cars-tuners-2.html#post287780

every car/motor/tune is diffrent. ditch the jwt

Yah turbo motors or even decently modded N/A motors don't have that double hump to the torque graph. I believe it is mostly a stock ECU thing.