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      08-31-2012, 10:37 PM   #1
ajw45
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Running rich up top? (dyno included)

Hey Everyone,
I went over to New England Dyno (http://nedyno.com) to get a few baseline runs in before I apply the Evolve tune which I'm still waiting to get back from Sal. Everything went great and other than the brake and ABS lights coming on the dash, there was no problem running up to redline for the dyno runs (no dyno mode needed or fuses to pull).
The one thing we were surprised to see is that on all the runs the car starts dumping fuel in at high RPMs and really running rich. Anyone have any idea why this might happen? As the car got hotter it seemed to dump even earlier in the rpm range so we're thinking it could be heat related?

TIA!
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      09-01-2012, 07:35 AM   #2
Beedub
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sniffer backed out the exhaust???
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      09-01-2012, 09:52 AM   #3
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Could be a fuel dump dictated by ecu to protect the catalysts from getting too hot/lean. This is a issue when using load based Dyno's like a mustang or dyno dynamics. The shops you used has a dynojet, not load baring, so I'm not sure if this hold weight.
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      09-01-2012, 02:00 PM   #4
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Quote:
Originally Posted by sabbanick View Post
Could be a fuel dump dictated by ecu to protect the catalysts from getting too hot/lean. This is a issue when using load based Dyno's like a mustang or dyno dynamics. The shops you used has a dynojet, not load baring, so I'm not sure if this hold weight.
Cats get burned up from too rich a condition, rather than too lean. Ask me how I know! Cats on a track car don't last near as long.
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      09-01-2012, 03:20 PM   #5
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Looks a bit similar to my dyno results:

http://www.zpost.com/forums/showthread.php?t=713140

Read the description in the first post for what I got from Sal at Evolve. Hopefully later this month I'll be able to get the "after Evolve tune" dyno done.
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      09-01-2012, 11:34 PM   #6
ajw45
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Quote:
Originally Posted by gferil View Post
Looks a bit similar to my dyno results:

http://www.zpost.com/forums/showthread.php?t=713140

Read the description in the first post for what I got from Sal at Evolve. Hopefully later this month I'll be able to get the "after Evolve tune" dyno done.
Interesting. I'll dyno again with the tune and see if that sorts that the rich problem. FWIW, we also did one run without an air filter and there was pretty much no difference in power.

Also, here's a comparison dyno of my e28 M5 (no cats, fresh engine build) run a few years ago on the same dyno. Interesting how the S38 had a little more max torque but way peakier torque curve to the S54.
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