Bill00Formula

iTrader: (4)

I was always told that you tune in fourth gear (manual).

Based on my logs it seems like the AFR in third gear is more lean than 4th gear. Is it better maybe to do an average of third and fourth gear?

I know that I shouldn't use first and second gear because you go through them so quickly that the accuracy of the data isn't very good.

Thanks

redtan

iTrader: (5)

Seeing as how most dyno tunes are done in the 1:1 gear, I'd assume that that's where you'd want the proper air/fuel ratio and let the rest be what they are.

Me being a more conservative guy I went a little richer in that gear (12.4-12.6) which also subsequently made the previous gear in the 12.7-12.9 range. That is still considered safe fueling and given it's in a lower gear should be fine.

As long as there's no knock in the earlier gears then I wouldn't worry too much if 4th gear is properly fueled.

redbird555

iTrader: (14)

exactly 4th gear is about the most load the engine gets put through so as long as thats in the good range the other gears are just fine

jimmyblue

iTrader: (11)

In lower gears your RPM can more outrun the air mass
measurement (MAF is pretty slow, even SD has some
time domain filtering applied) and so air mass will always
be a little late and fuel a little short. So these gears
may be more ping-prone. You need to check that out
and stay safe. But the majority of your time on the
1/4 track is spent in 3rd (A4 anyway) and so there is
value in optimizing AFR there for power (ET and MPH)
provided you don't blow the motor before you get to
3rd.

You have ditches on either side, to stay out of.

RonSSNova

iTrader: (3)

MAF only I could never get the fueling quite right in low gear on my A4.
No doubt due to the slow response as was mentioned by Jimmyblue.
I actually used the PE settings to cheat it.
2nd and third fell in line pretty well.
Eventually I'll swap to a 2002 OS for the single VE table and see how the perf compares.
Mine is a 2000 with the secondary VE which drives me nuts.,,,
Ron

JakeFusion

iTrader: (7)

Ron, upgrade to a custom OS? Wouldn't that help?

As for gearing - what I'd do is tune for all gears. Data log a run through all three gears and look at the histogram for the run and apply the percent difference to the VE table in SD mode. Rinse, repeat until you're pretty damn close. If you did that 8-10 times on a given night, you'd be set. You'd end up running WOT through the three gears 8-10 times for 24-30 points of data.

Set your histogram up for your MAF as well. Disable it and tune the VE, but apply the changes there and it'll be pretty close for WOT too (depending on where you set your RPM blending).

The pinging comes from too much timing. The dyno and the street/track show a difference. Set it for something like 24 degrees and add a degree each run until you see KR (wouldn't go past 27 or 28 to be honest) or until you notice your MPH level out or start to decrease. Something in the 24-26 range will probably work out fine for you.

RonSSNova

iTrader: (3)

Jake,
If a custom OS would allow the MAF to still function, I'd do that.
But it's not clear that is the case.
I suppose I could try it.
That would solve the VIN number issue I'll have by switching to a later OS.

Eventually I'd like to run blended.

My engine likes 20 deg timing at 5000-5500 and ramp to 25 above that. I'll get KR if I try 22 across the board.
Small cam, 11:1 CR and our fine 92 octane.....

joecar

Are you using HPT or EFIlive (whover is considering running a COS)...?

If you need to know more about the EFILive COS, I can explain the details.

JakeFusion

iTrader: (7)

Ron, if you're running HPT, the Custom SD tune still allows for MAF. I now have my MAF working again as it helps. It doesn't disable it - just allows for more tuning options in SD mode.

I found out the 100mm MAF I have actually works pretty well.

RonSSNova

iTrader: (3)

Cool. Thanks.
Later this summer I'll give it a try.

Ron