[Saclsick6]

Hello guys,

Had my first outing with my new set up, read sig, this weekend at Thunderhill, road racing.At about 90ish mph-135mph, top speeds on track, AFR's lean out about .3. Goes from 12.5/12.6's to 12.8-12.9's. about 4500rpm-6100rpm.
I did not have this issue on the dyno a day before the event. Environmental conditions were relatively the same, ambient temp, elevation, humidity. Only variance was dyno end on pump 91 and driven at track on Sunoco 260GT 100 octane fuel.

I added some MAF, half a %, above 4.2V which is my 4500-redline area. Didn't seem to help out, added another half % and it was a little better.

Question is, should I work the maf numbers for this or work on the O/L multiplayer VS MPH.

On dyno things are spot on, in real life it's a tad off.

Thank you

[markedforlife]

Good possibilty your out of injector or pump, 30 lb injectors are not that big on your setup
and if your injectors go static the afr will be erratic. What kind of pulsewidths did you see in
your logs? What was your fuel pressure at?

[Saclsick6]

FP is set to factory 39.

I was not runing data log on track. I need to come up with a secure solution for mounting a lap top in car that will pass tech.

I also was afraid I could be on the top side of the injectors.

On the dyno injectors are in the safe zone. But the dyno can not replicate the added load of 130mph drag CoE.

Thanks for the input.

[LeadHead]

Just try a 0-80 acceleration run on the highway (assuming this thing is still street legal)? As long as you don't have wheel spin, the load up high should be pretty much the same.

If your dutycycle is ~80-85% doing that, you should still have plenty of head room on the track.

[EDS50]

Have you tried setting your FP to 42 with the vac. line off? I would try that and adjusting the wot multiplier in the upper rpms.

[decipha]

Your engine should be making around 350 them 30s should be good for 385ish so u shud be cool

are u sure you were able to reach that mafv on the dyno?

Half a % ain't gonna do much

12.9/12.6 = 1.02 %

the wot multiplier does not dial in fuel it just multiplies lambse

[EDS50]

WOT multiplier will give you that extra bit of fuel you need if you dont want to mess with the hi slope. You can set it to be active rpm specific. So for example if your leaning out a lil above 5000 rpm you can start by setting the multiplier to .950 and the added fuel will show up on your wideband afr. And yes, this is one of many ways to help dial in your fuel. Not a be all end all but a tool for sure. Its all I needed to tweak on one of my cars on the dyno. Dyno showed my 6400 rpm afr to be .3 afr from where I wanted it. Instead of jacking with the hi slope or the maf xfer since everything else was spot on a simple tweak of the WOT multiplier took care of things.

[decipha]

The high slope nor the wot multiplier is capable of dialing in the maf??

the ONLY way to fix his issue is to kick up the maf flow, there is no other option capable

[Saclsick6]

Thanks for the input guys.


I was getting high 4.5v on dyno.

354.8rwhp @ 5100
396.1rwtq @ 3750


I know it's not in sig but I still have factory "cat back" exhaust. I'm sure between the
Cobra intake and factory exhaust I am neutering this motor.

[EDS50]

The high slope nor the wot multiplier is capable of dialing in the maf??

the ONLY way to fix his issue is to kick up the maf flow, there is no other option capable

HUH?? Where was that said?? Do you actually read responses or just skim through things?

And NO, that is not the only way to fix his issue. The OP clearly stated adding a little to maf didn't really change things. If the fuel system is up to par then add a lil fuel to her and be done with it. There is more than one way to do it. He only needs it at a certain rpm. If the rest of the curve is spot on according to the OP why mess with it?

[Vortech347]

I open track my car as well. What is your WOT multiplayer at? Dyno's are great but usually it takes open track time/logging. I put my laptop under my passenger floor mat and run 4-5 laps. That usually gives me enough data without I heating the lappy. Also. Is the car running at a different temp than what you tuned with?

[EDS50]

I open track my car as well. What is your WOT multiplayer at? Dyno's are great but usually it takes open track time/logging. I put my laptop under my passenger floor mat and run 4-5 laps. That usually gives me enough data without I heating the lappy. Also. Is the car running at a different temp than what you tuned with?

With my air and fuel dialed in this is what my fn303 looks like:

16384 0.945
6000 0.969
4400 1.000
3800 1.000
3200 1.000
2400 1.000
1600 1.000
0 1.000