Weird dip in curves and low output on dyno!

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Nov 25, 2007 | 06:21 PM

#31

joedr

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From: Puerto Rico

Here they are:

Quote:

Originally Posted by DTM

Could you take a pic of your engine bay and post it. Close ups of the BOV and piping would be preferred.

Also Mellon, why did you make the comment about richer AFR and more timing? Richer mixtures do not always tend to allow more lead. I found that comment very interesting.

Nov 25, 2007 | 07:19 PM

#32

joedr

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From: Puerto Rico

Freaking Boost Limit Tables! I swapped the main bin for the Tephra one (NLTS, Valet and Knock SES) and forgot to update the Boost Limit Tables. I thought that I transfered all my settings but for some reason that was the ONLY table that I did not update. What are the chances haaaa?

It is late, but most likely will test it while going to work tomorrow morning!

Nov 25, 2007 | 07:21 PM

#33

EvoBroMA

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From: MA

well that'll get rid of the boost cut you had circled in your graph. is your boost leak issue solved?

Nov 25, 2007 | 07:23 PM

#34

tephra

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From: Melbourne, Australia

lol

Nov 25, 2007 | 07:28 PM

#35

Mellon Racing

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From: Virginia Beach, Virginia

lol oh well shame on all of us for not suggesting the obvious

Nov 25, 2007 | 07:58 PM

#36

joedr

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From: Puerto Rico

LOL! Well... I will test it again in the morning and post the results.

BTW... adjusting the preload helped the losing boost pass 5500 RPMs. I can see the slope to stay on the positive side moving towards the rev lim. I can see less fluctuation as well.

Nov 26, 2007 | 04:26 AM

#37

DTM

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From: Dulles, VA 20166

Quote:

Originally Posted by Mellon

It's been my experience that 12.0 + AFR is a bit too lean for 93 octane...yes you can make good power like that but I found that the gains made from leaning it out from say 11.5 to 12.0 are minuscule.

staying the 11's allows for more timing/boost and typically more power.

For certain 12.+ on a 4g 63 is extremely lean IMHO. Regardless of the fuel used.
Increasing boost, fuel and timing lead can be just as dangerous. As you know VE, charge density and flame speed should dictate timing lead. All three characteristics I mention are greatly affected when increasing boost, fuel and timing.
Just a thought. Sorry to jack to the thread.

Im glad you found your problem.

Nov 28, 2007 | 05:43 PM

#38

joedr

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From: Puerto Rico

Update run!

Well... I went today for another pull and you can notice the improvement on the boost curve and smother spikes/dips. Again, adjusting the preload changed the boost characteristic and behavior substantially.

I will be adjusting the timing and AFR. I think that I can advanced the timing to 7 degrees with an 11.4-11.5 target AFR passed 5500 RPMs. Any suggestions? Any recommendations? Would like to hear your inputs!