Running too lean?

G37Sam · 12-09-2009, 05:53 PM

I already have a CAI, test pipes and a true dual catback. That's a lot more flow than OEM, I am also planning on getting some long tube headers sometime soon. My fear is that my engine might start running too lean which from what I read, know isn't good (can cause detonation??).

Quote:

A lean fuel mixture, more air than fuel in the combustion charge, is another known detonation culprit. The lean mixture burns hotter and absorbs less heat in the process, hence EGTs rise when the mix goes lean and adding fuel drops temps. This heat can rise to where the mixture starts burning out of sequence with timing events and bam you have detonation.

How lean can I go before I start getting worried? Do I NEED a tune? I'm staying away from that for now as the only solution out there for me to get a tune would be to get chipped or get a standalone (not going to happen anytime soon).

I do plan on getting a few dyno pulls once the headers are in to get exact AF numbers

Your input is muchos appreciated

Cheers,

NYBladeZ · 12-09-2009, 05:56 PM

I know you stated you didn't want to get a tune right now but I think that's your best bet. I know some vendors are having a sale on the Cobb accessport might wanna take a look.

G37Sam · 12-09-2009, 06:00 PM

Quote:

Originally Posted by NYBladeZ

I know you stated you didn't want to get a tune right now but I think that's your best bet. I know some vendors are having a sale on the Cobb accessport might wanna take a look.

Yes I did state that, and here's why

Quote:

Originally Posted by G37Sam

I'm staying away from that for now as the only solution out there for me to get a tune would be to get chipped or get a standalone (not going to happen anytime soon).

Cobb APs don't work on non US spec G37s as they don't recognize our ECM numbers or so

corbin09 · 12-10-2009, 10:45 AM

one of my friends got the Cobb AP and said it was a PITA and you couldnt even really adjust much.

G37Sam · 12-10-2009, 11:09 AM

So I've heard too, AAM seems to think otherwise though. It's not an option I would/can consider anyways

Sharif@Forged · 12-10-2009, 12:24 PM

There is only one way to find out. Get the car to a dyno or install a wideband gauge. The G37 uses closed loop lambda feedback, so it will make adjustments to AF ratio at WOT in attempts to maintain a safe AF ratio. That said, if the intake causes a distruption or unusual flow across the MAF sensor, then you may end up running lean or rich regardless.

If you are indeed running lean, then we could send you a custom UpRev e-Tune to correct the condition.

G37Sam · 12-10-2009, 04:26 PM

Would your UpRev e-tune work on my Gulf Spec car?

Sharif@Forged · 12-10-2009, 10:25 PM

Quote:

Originally Posted by G37Sam

Would your UpRev e-tune work on my Gulf Spec car?

Do you, or someone you know, happen to have a Cipher cable? I need your ECU ROM number to determine if I can flash it for you.

spearfish25 · 12-26-2009, 07:34 PM

So is running lean something everyone should worry about if they have a cbe and hfcs with or without a cold air intake?

I have a catback and want to add some high flow cats (no intake for now), but I don't need any problems with lean mixtures. I just don't know enough not to worry about it.

G37Sam · 12-26-2009, 07:45 PM

Quote:

Originally Posted by Sharif@Forged

Do you, or someone you know, happen to have a Cipher cable? I need your ECU ROM number to determine if I can flash it for you.

Not that I know off, but I am going on a dyno when my headers come in for sure.

What's the most accurate way to measure A/F numbers? Would using sniffers in the tailpipe be enough?

Chris@FsP · 12-26-2009, 08:51 PM

Quote:

Originally Posted by G37Sam

Not that I know off, but I am going on a dyno when my headers come in for sure.

What's the most accurate way to measure A/F numbers? Would using sniffers in the tailpipe be enough?

IMO the most accurate way to measure a/f is from a wideband sensor in the test pipe or high flow cat. If putting them in the cat, make sure the sensor is ahead the actual catalyst.

G37Sam · 12-26-2009, 08:54 PM

Quote:

Originally Posted by FailsafePerf

IMO the most accurate way to measure a/f is from a wideband sensor in the test pipe or high flow cat. If putting them in the cat, make sure the sensor is ahead the actual catalyst.

Thing is, my FI test pipes have a J-shaped bung to fool the sensor in some way as to not trip the CEL, so that will require me doing custom work which I don't think would be worth it.. or would it?

Are sniffers completely off? Seen a few local Turbo Z's do it.

SilverBullet · 12-26-2009, 08:54 PM

Sniffers are set on the tailpipe. How do you place the wideband sensors?

Chris@FsP · 12-27-2009, 12:15 AM

Quote:

Originally Posted by G37Sam

Thing is, my FI test pipes have a J-shaped bung to fool the sensor in some way as to not trip the CEL, so that will require me doing custom work which I don't think would be worth it.. or would it?

Are sniffers completely off? Seen a few local Turbo Z's do it.

From my experience, tailpipe sniffers seem to be fairly accurate at WOT, when gas velocities are the highest. Trying to tune idle/cruise/light load though, they tend to read a little lean.

I was doing some pulls on a Dynojet last month, and the tailpipe readout on the dyno's software consistently read about 1-1.5 points leaner than my Haltech widebands mounted in the downpipes.

Chris@FsP · 12-27-2009, 12:21 AM

Quote:

Originally Posted by SilverBullet

Sniffers are set on the tailpipe. How do you place the wideband sensors?

If it's just for a tuning session, we temporarily remove one of the factory o2 sensors and replace it with our calibrated wideband sensor.

12-09-2009, 05:56 PM	#2 (permalink)
NYBladeZ A True Z Fanatic Join Date: Apr 2009 Location: New York Posts: 2,158 Drives: Lotus Exige S Rep Power: 20	I know you stated you didn't want to get a tune right now but I think that's your best bet. I know some vendors are having a sale on the Cobb accessport might wanna take a look. __________________ 2009 Carbon Fiber/Red 370z aka Trish: Sports Package, Meisterschaft full catback, Fast Intentions Longtube Headers, Injen Long Tube Intakes, UpRev Tune: Sold 2008 Lotus Exige S Club Racer aka Bella, always leaves me smiling

12-10-2009, 11:09 AM	#5 (permalink)
G37Sam A True Z Fanatic Join Date: Dec 2008 Location: Dubai, UAE Posts: 1,507 Drives: RB'd G37 Rep Power: 20	So I've heard too, AAM seems to think otherwise though. It's not an option I would/can consider anyways __________________ '14 Viper GTS '08 RB'd G37S - Sold

12-10-2009, 12:24 PM	#6 (permalink)
Sharif@Forged The370Z.com Sponsor Join Date: Dec 2008 Location: Marietta, GA Posts: 840 Drives: 2009 GT-R, 2010 370Z Rep Power: 17	There is only one way to find out. Get the car to a dyno or install a wideband gauge. The G37 uses closed loop lambda feedback, so it will make adjustments to AF ratio at WOT in attempts to maintain a safe AF ratio. That said, if the intake causes a distruption or unusual flow across the MAF sensor, then you may end up running lean or rich regardless. If you are indeed running lean, then we could send you a custom UpRev e-Tune to correct the condition. __________________ Sharif@Forgedperformance.com General Manager/Certified Tuner/NASA-PCA-BMWCAA Instructor JRZ RS1's Available NOW...PM me Cobb ProTuner, Uprev ECU Flash, FCON Vpro, Haltech, Motec Certified

12-10-2009, 04:26 PM	#7 (permalink)
G37Sam A True Z Fanatic Join Date: Dec 2008 Location: Dubai, UAE Posts: 1,507 Drives: RB'd G37 Rep Power: 20	Would your UpRev e-tune work on my Gulf Spec car? __________________ '14 Viper GTS '08 RB'd G37S - Sold

12-26-2009, 07:34 PM	#9 (permalink)
spearfish25 A True Z Fanatic Join Date: Mar 2009 Location: Naples, FL Posts: 4,117 Drives: to work Rep Power: 1856	So is running lean something everyone should worry about if they have a cbe and hfcs with or without a cold air intake? I have a catback and want to add some high flow cats (no intake for now), but I don't need any problems with lean mixtures. I just don't know enough not to worry about it. __________________ 2013 Cadillac V-Wagon, RIP Z

12-10-2009, 10:45 AM	#4 (permalink)
corbin09 Track Member Join Date: Jun 2009 Location: Dallas tx Posts: 665 Drives: 370z Rep Power: 280	one of my friends got the Cobb AP and said it was a PITA and you couldnt even really adjust much.

12-26-2009, 08:54 PM	#13 (permalink)
SilverBullet Track Member Join Date: Dec 2009 Location: California Posts: 873 Drives: 2008 G37 Rep Power: 16	Sniffers are set on the tailpipe. How do you place the wideband sensors?

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