Advice For Tune

[livedsm4g63]

I just started to tune my dsm and I was wondering what you guys thought of my log. The beginning of the log is a 3rd gear pull. Any help would be nice. Im thinking that my timing is a little messed up and im not sure what i should do to it in the timing map. It seems a little rich from 4500-5500 so i pulled a little bit of fuel out, but the numbers seemed to stay around 10.6ish. thanks for the help

 

[snowborder714]

Do you happen to have any more logs? I can't view any of your settings in the one you posted.

 

[Detective Coating]

You should go get another log and datalog ltft and stft.

 

[snowborder714]

Make sure you get all 3 LTFT's - Lo, Mid, and Hi.

You also need to adjust your TPS sensor. And it seems like that throttle wasn't a WOT pull, because your TPS didn't read above 90% and seemed to fall over the pull duration.

 

[livedsm4g63]

ok i will go do another log and log 3 LTFT's - Lo, Mid, and Hi with everything else. i will also check out the tps.

 

[big_d]

I'm just curious...What do you use to view .dat files?

 

[snowborder714]

DSMlink

 

[JayRolla]

Do you have a wbo2? If so tune to 10.9 afr and that will give a little more power. Also timing looks pretty good but with a 16g I would stop at around 18* max timing. At 5600 rpms and up I would pull 2* all the way through the rpm band.

After that add boost untill you see knock and you can either pull some boost back out or pull more timing. I would pull timing myself. I would run 10.9 afr, 16* max timing and as much boost as possible. If you can get more timing than that with 24-26psi then that would be good.

 

[livedsm4g63]

heres a couple of logs. i looked at my tps and i logged it with the car on and off. it said 0% then i pressed the pedal all the way down and i got 100%. i think that there is something blocking the pedal from getting all the way to the floor. i checked it at the TB as well. Im starting to see some knock up top though. im thinking of pulling a degree or 2 of timing.

 

[JayRolla]

How much boost are you running? Do you have a wbo2, and if so whats the AFR. I would pull 2* from 5600rpms like I stated.

 

[livedsm4g63]

How much boost are you running? Do you have a wbo2, and if so whats the AFR. I would pull 2* from 5600rpms like I stated.

im around 17-18 psi. and as far as anything else you want to see. when you open up dsmlink go to display->Values. and put up pretty much anything you want to see. like my afr's

 

[Detective Coating]

Your logs aren't loading for me.

 

[livedsm4g63]

any advice for the last log?

 

[LandoAWD]

BoostEST is way low if you're at 17-18lbs....

 

[1992awdlaser]

BoostEST is way low if you're at 17-18lbs....

Agreed

You have a leak between the maf and the turbo. Fix that and all other leaks then make another log.

 

[LandoAWD]

See, I can conceptualize, just not "do".

 

[livedsm4g63]

Why do you say its between the maf and turbo?

 

[1992awdlaser]

I will try to explain.

This is for a maf in the stock location.

We are talking about when the car is in boost.

Engine is running, pulling in air. The maf is reading lets say 100cfm of airflow. So the ecu thinks your engine is getting 100cfm. This is where the boostest value come from. If there is a hole in the intake pipe after the maf but before the turbo or a clamp is loose, air will be getting in that hole(let's say 50cfm). The air getting in the hole is NOT able to be read by the maf since it is entering after the maf. So now you actually have 150cfm of air entering the engine but the ecu only knows about 100 of it.

So you have 150cfm of air (boost gauge reading) in the engine but it only knows about 100cfm(boostest reading).

This is not possible with a gm maf in a blow through setup since every pipe after it will be under pressure. So you can only blow out air to cause boostest to go off with a blow through setup.



This one goes for a blow through setup or a stock setup.

Still talking about when the car is in boost.

The engine is pulling in 100cfm again. All this air is being metered by the maf and the signal sent to the ecu. There are no leaks between the maf and turbo, so every bit of air entering the engine is taken account for by the maf. Now there is a leak in the pressurized part(intercooler, intercooler pipes, couplers,etc) of the intake system(also known as a boost leak) after the maf. So now air is getting out. Let's say 20cfm is getting out via this leak. So, now since 20cfm is getting out you only have 80cfm going into the engine. The ecu still thinks 100 cfm is entering the engine(boostest reading) but in reality only 80cfm (boost gauge reading) is getting in since there is no way for the maf to know about the 20cfm being lost after it.

So the boostest is going to be higher than actual boost since some air is getting out.


Put simply

A leak between the maf and turbo will cause a boostest lower than actual boost.

A leak in the pressurized part of the intake system after the maf will cause a boostest reading that is higher than actual boost.



Make sense?

 

[livedsm4g63]

Ok. Yeah that makes sense. But I have a question. If the ecu thinks there is less/more air then there really is would it show up through my afr's?

 

[1992awdlaser]

Ok. Yeah that makes sense. But I have a question. If the ecu thinks there is less/more air then there really is would it show up through my afr's?

Absolutely. If there is more air(your situation) it should run leaner. If there is less air(boost leak) it should run richer. You might not see the difference on a wideband though. The stock fuel curve goes into the 9.6:1 range.

 

[livedsm4g63]

Ok. Well it makes sense that it would be right before the turbo because i have been having a problem with my car stalling out after it is warmed up and its sitting at idle. I have a extreme psi intake pipe and i really dont like how the return hole is on it for the bov. It is like a cone shape but the base is bigger then the top. (If that makes sense) So its hard to seal it off with a clamp because if you start tightening it then the clamp will work itself right off. Thanks for all the help