Drag Strip...crappy times and tune way off.

[exploder]

I went to the track today to get some times. Mod list is Heads, Cam, Supercharged, Meth injection 60lb. motrons....yada yada. I have never been able to do a log from 1st to 4th, but I got it today. The car feels noticeably slower on the track than on the street. I looked at some of my old logs and in 3rd and 4th gear logs a:f stays in the 11.3-11.8 range with timing in the 21-22 range. Today in the log af was 10.1-10.5 range with the timing around 13 degrees. I just don't understand the dissparity between it feeling so strong from a 3rd gear pull and so bad when going through 1st-4th. The only thing I can think of is that the belt is slipping and I am not getting the airflow that is expected and hence running overly rich. Also looking at the timing it looks like it somehow switched to the low octane map. Should I copy my high and lows to be the same? I need help. Attached will be a 3-4 log with good afrs and timing and my run today. I will also attach my tune.

[exploder]

anybody??

[S2H]

what method was used to tune?
it looks tome like a 1 bar tune...on a 2 bar car??
and then all the fueling is being winged in the PE table??
which will lead to very inconsistent fueling
plus teh wrong value in your IFR table for Motron 60's

you've got some pretty hefty spark removal based on higher IAT's


not knocking anything you've done...but if you dot have a 2 bar MAP sensor and a 2 bar Tune going on...then its always going to be inconsistent

[exploder]

It is a Maf tune. No SD or 1 bar OS enhanced. I never did the original tune, but I am trying to correct things that were done wrong. I guess now my main questions are:

1. Should I set my HO and LO tables to be the same?
2. How high is too high for IAT's you mentioned? I guess I need to turn the meth up more to help lower the IAT's?
3. What should be the proper value for the IFR table based on 60lb. motrons with boost referenced regulator running 58psi base FP?
4. Am I still wrong in thinking that I am getting belt slippage due to the crazy low afrs when doing a 1-4 run and not a 3-4 roll run?

[Russ K]

Use my Maf config file. Just insert your brand of wideband in place of my FJO in the table display. Then the histograms will work to tune the Maf.

Get your IFR table set right, it shouldn't be a flat line unless you have a vacuum referenced fuel regulator & a return line to the tank. Set the open loop table to 1.00 at operating temps. Then set the PE to were you want it and adjust the Maf table using the Maf AFR% Error histogram. Your Maf table is still stock, so you will be able to increase it by 15% at the 12000 hz cell if needed.

Depending how much boost your making, you may max the Maf. If not by too much, you could raise the PE ratio at the higher rpms were the Maf is maxed. This isn't the best way, but first scan the car using my config file so I can see how much air your motor is taking in. You may need to upgade to a 2 bar sd.

Russ Kemp

[exploder]

Thank you very much Mr. Kemp. I have made my setup to run a return style with a vacuum referenced regulator. I am pretty sure I will max out the maf pretty quickly, I am running around 11psi. So do I need to change the open loop to 1.0 before I log or after you look at it? Also, how exactly do I change the error histogram...copy paste special?

[exploder]

I just realized it would probably help if I posted my config..... here it is.

[exploder]

Ok, I just went out and made some logs using the wb02 config. that you guys supplied me. I went in and changed how much timing the car was pulling at higher iat's and that has helped tremendously. I know my afrs are still way rich, but it feels like it is pulling pretty hard up top. Please give me some advice on what I should change next.

[caliswangin916]

i couldn't read your log for some reason. i'm having a similar problem on a dry shot and noticed that my logs of runs at the track from a stop is different from say 40,50,60 roll going to about 90 on the freeway. i've done 5,10,20 rolls to 70-80 on the street but never from a complete stop to the end of a 1/4 mile on the streets which i think will give you very different data than from a roll to 90.
i've done complete stops to 60 and it has different characteristics than from a 5mph roll. the other difference is the condition of the track vs. the streets which i think is a factor to consider. outside temp at the track was also hotter than my street logs so that probably makes a difference too.
my timing is also using the low octane table. good luck, i'll check back if i find what the problems are.

[Russ K]

exploder,

Try this tune, it is based on the one you posted. Disable closed loop first, then rescale the Maf table to get the actual AFR to match the commanded. I set the PE to 12.0 AFR till 5200 rpm. Then you can set the PE vs RPM to get the AFR to 12.0.

I would first get the open loop part throttle AFR right up to 7500 HZ. Next, with the car in 3rd at 1000 rpm, go wot till your red line. This will help prevent tire spin and to increase the resolution of the scan log.

Could you post your stock tune?

Russ Kemp