tuning tips? Data inside.

[Tony 96 Cobra]

Just trying to get an idea of what is going on. I know when I dynoed my car it was a little lean.

My tuner uses SCT so I got one.

I did some data logging mainly looking at WOT info and here is what I got.

STFT goes to .70 on both sides at WOT.
FPDC goes to .45 at WOT
Spark goes to 18 at WOT

can anyone give me an idea if this is good/bad? I know it is probably lean. I have maxed out fuel and spark without the aid of a custom tune. Is the FPDC on showing 45% duty??

TIA.

 

[TorchedCobra]

I think you at least need to figure what your air/fuel ratios are a WOT.

 

[Tony 96 Cobra]

thanks. I don't have a wideband. I was thinking from what I had read that the STFT would give me an idea of A/F. But I need someone to translate these numbers for me. lol

 

[TorchedCobra]

thanks. I don't have a wideband. I was thinking from what I had read that the STFT would give me an idea of A/F. But I need someone to translate these numbers for me. lol

The nice thing about having a wideband is that you can be sure if it is running lean or not in real time. Are you live data logging? I haven't even got to that point. I have an appointment for the dyno in a couple of weeks.

 

[watman02]

Narrow band o2s dont work well at WOT, STFT being only .7 means that it is adding fuel, but not much. If you really want to do this your self get a wide band!!! that way you know for sure what it is doing.

 

[racebronco2]

Just trying to get an idea of what is going on. I know when I dynoed my car it was a little lean.

I did some data logging mainly looking at WOT info and here is what I got.

STFT goes to .70 on both sides at WOT.
FPDC goes to .45 at WOT
Spark goes to 18 at WOT

can anyone give me an idea if this is good/bad? I know it is probably lean. I have maxed out fuel and spark without the aid of a custom tune. Is the FPDC on showing 45% duty??

TIA.

Did you get the car tuned?
Why would your tuner let allow your car to leave when it was running lean?
45%dc =90%dc so you are not maxed out on fuel.
We need more info to even guess if the spark is ok.

 

[01yellercobra]

STFT's mean nothing at WOT. The .70 you're seeing is the commanded A/F. You won't know your actual A/F without a wideband. The reason it's called open loop is because the ECU doesn't use the O2 sensors to control A/F. .70 Lampda is 10.2:1 commanded. Way too rich IMO. You should be around 11.5:1. Which would also lower your FPDC.

 

[leegro1015]

If you had the car dyno tuned, find a new tuner. The only reason he would command that kind of lamda is because he didnt tune you MAF transfer function correctly and is trying to compensate by commanding .70 which may get you close to where you should be 11.5 or soo. If you are seeing. 45 duty cyle on your pumps muliply that by 2 . To help you any further we need to know what your mods are. Are you on stock injectors, maf, do you have a boost a pump? You say its running lean? How do you know? Dyno reading? I would definitely watch the spark you are running if you think its lean. That could be very bad.

 

[Tony 96 Cobra]

Hey guys, thanks for the replies. I have been busy the last few days.

My car has NOT been dyno tuned. My tuner is booked solid right now.

I had the car on the dyno checking it out with my Diablosport tuner and we had the fuel maxed out without putting it on the laptop. My tuner uses SCT so I have recently switched. I put the SCT handheld on the car to see what I could do with it. The SCT is way different than the Diablosport. I am taking it easy on the car until it is properly tuned.

I am on the stock fuel system with stage 5 port, 6# lower, c&L Cai/maf, and killer chiller.

When we had the car on dyno with Diablosport still on it; the a/f was at 12.4:1 and maxed out the tuners adjustability.

I hope this helps some. Thanks again.

 

[01yellercobra]

You might want to consider a BAP at least before you get tuned. But you need to a custom tune.

 

[Tony 96 Cobra]

I am planning Lethals budget system with 60# injectors and SCT MAF this summer.

 

[01yellercobra]

That would work too. I was close to 600 with twin GT pumps, wire upgrade, and 80lb injectors.

 

[mastwolf]

Get a good wide band, and do your self a favor, Datalog everything in Lambda.

Because A/F ratio means nothing if you displaying a calculation done for 14.64 stoich when the fuel your using is 14.1. Lambda cures all this.

 

[Tony 96 Cobra]

Thanks for the info guys. I will post results later.