running lean in 1st and 2nd gear

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Old Aug 8, 2010 | 05:04 PM
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From: schooling kids in ny, usa
Default running lean in 1st and 2nd gear

well ive been driving/tuning boosted hondas for about 7 years now and i cant recall having one that ran this lean in 1st and 2nd gear. i was seeing afrs from mid 13s to like maybe 12.8, then from 3rd gear and up it sits nicely around 11.3. ive got it pretty much settled out by adding fuel in 1st and 2nd in the gear based parameter in neptune (i think my values are 3.5 in 1st and 2nd and 0 3rd,4th,5th)


what would be the specific cause of this? id figure that between higher gear ratio and slight traction at best i wouldnt be loading the motor up as much, not flowing as much air and potentially running a little richer than leaner. just trying to get an idea of the cause so i know for next time
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Old Aug 9, 2010 | 07:35 AM
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From: b00sting my D16s, SoWis, USA
Default Re: running lean in 1st and 2nd gear

Big turbo? It could be spooling a bit slower due to less load, so if you could be hitting a lower boost column you didn't tune enough.
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Old Aug 9, 2010 | 08:22 AM
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From: lubbock
Default Re: running lean in 1st and 2nd gear

run a log, see if 1/2 are hitting different cells that 3/4 normally is.
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Old Aug 9, 2010 | 10:35 AM
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From: schooling kids in ny, usa
Default Re: running lean in 1st and 2nd gear

Originally Posted by HiProfile
Big turbo? It could be spooling a bit slower due to less load, so if you could be hitting a lower boost column you didn't tune enough.
hmmm, very possible. its the same compressor side as the previous tune, with a larger exhaust side. ( t3 60-1, S housing compressor with a .82 exhaust compared to the old one of .63). ive also upgraded to a full ramhorn (peakboost ftw) rather than the lovefab half ramhorn i had previously.



i should do a 2nd gear datalog...maybe tonight if it doesnt thunderstorm

i datalogged a 4th gear 4000-9000 rpm pull the other day and did notice im getting boost creep, even with the tial 44mm. its starting off around 13 psi at vtec crossover (4800) and i saw 15.4 psi at like 8675rpm. i am running only 1.5" piping as a dumptube, so i just ordered some larger piping (i think its 1 7/8) to make a new dumptube (out of my bumper lol)
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Old Aug 9, 2010 | 01:10 PM
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Default Re: running lean in 1st and 2nd gear

I don't think your dump tube is the issue. I bet changing the turbo is... Like wilhem said, I bet you're hitting different cells in 1/2 now. Did you change the wastegate or spring?
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Old Aug 9, 2010 | 04:31 PM
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From: schooling kids in ny, usa
Default Re: running lean in 1st and 2nd gear

same wastegate same spring, .5 bar. im using a turboxs dual stage boost controller
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