Tuning a turbo s197

[Bullitt6301]

So I have been tuning my turbo 3v with a ba5000 maf and 47lb injectors and everything is pretty well tuned below 3000 rpms. The issue I am running into is I have it in forced open loop and I am trying for a WOT run and it will do what I am commanding until the full 9 psi is built but at what seems the same rpm/load the engine will lean out and really lose power. I back out of it as soon as it gets to 12 but it is sudden. I have riched the maf a lot but it still is not responding. I am logging good frp, volts, ect, fpdc. I noticed that in the log that it will build timing as the load increases but as soon as it hits 1.10 or so it pulls timing to 8* and that it about the same time the car leans out and falls on it face. I went back and checked the spark tables and everything is good. I was looking through my tune and I was looking at the vct tables and it was all zeroed out because I forgot that the original tune I was going to run locked timing gears but instead I am running stock vct gears now. I set the table to stock but haven't had a chance to try and see if that would make a difference. Would this be more problem?

 

[BruceH]

Is the maf pegged? Have you logged maf volts?

 

[Bullitt6301]

I have logged maf counts and I am only hitting 560's #/min before it leans out. I have some logs I will post up in a bit.

 

[retfr8flyr]

What's your fuel setup? Are you running out of fuel, what's the log say on pressure? What is the injector duty cycle?

 

[BruceH]

Has your fuel scalar been changed to allow for 1.99 in aircharge wot multiplier and correction for max air charge?

 

[Bullitt6301]

Yes the fuel scalars are correct. I have smoothed the MAF Volts and load the spark tables from a turbonetics tune in the presets. It looked at better. I also reloaded all the VCT info. I am going to load the tune in the car and see how it responds.

Fuel setup is a single 400lph Walbro in the stock lines with FRPP 47lb injectors running 92. This combo was running but had low end flat lean spots so I am writing a tune myself now. Already the car drives better.

I also reloaded the engine displacement to stock because it was setup lower in the base tune.

 

[Bullitt6301]

I will not let me upload the main datalog file so here is a the screen shot for where it goes wrong.

 

[BruceH]

Yes the fuel scalars are correct. I have smoothed the MAF Volts and load the spark tables from a turbonetics tune in the presets. It looked at better. I also reloaded all the VCT info. I am going to load the tune in the car and see how it responds.

Fuel setup is a single 400lph Walbro in the stock lines with FRPP 47lb injectors running 92. This combo was running but had low end flat lean spots so I am writing a tune myself now. Already the car drives better.

I also reloaded the engine displacement to stock because it was setup lower in the base tune.

Was it scaled in the original tune? If you haven't already then check the injector data and manifold volume to see.

 

[Bullitt6301]

I double check and triple checked the injector values from the calibration sheet from Ford Racing. Also the manifold is the stock 10.8999.

I just want to try to understand what does the VCT effect on spark? If say the VCT tables were 0's what in theory would that do? Even if the gears are stock but you did not have it locked out? It sounds like a stupid question just wondering because that was one of the issues so I set it all back to stock values.

 

[one eyed willy]

nvrmd

 

[BruceH]

I double check and triple checked the injector values from the calibration sheet from Ford Racing. Also the manifold is the stock 10.8999.

I just want to try to understand what does the VCT effect on spark? If say the VCT tables were 0's what in theory would that do? Even if the gears are stock but you did not have it locked out? It sounds like a stupid question just wondering because that was one of the issues so I set it all back to stock values.

Stock is 9.81. Do you have cmcv?

 

[Bullitt6301]

No I do not have the cmcv it is plug deletes. And the cmcv is turned off in the tune.

I reloaded the volume cell and it shows 10.8999.

 

[01yellerCobra]

What about the spark tables? Do these processors still go by load and RPM? I had an issue where I had scaled the spark table load for my old blower. The new blower went to a higher load level, but the spark table didn't go high enough. When it hit the max load the car would nose over. I had to rescale the spark tables to read a higher load.

 

[BruceH]

No I do not have the cmcv it is plug deletes. And the cmcv is turned off in the tune.

I reloaded the volume cell and it shows 10.8999.

What software are you using? The 4.6 3v manifold volume is 9.81 liters. With cmcv turned off SCT will use the imrc closed tables so all the open tables need to be moved to the closed tables. The help guide available in the software will tell you this too.

 

[one eyed willy]

i seen your post on SCT forums. you need to fix your maf xfer, its crazy high!@ 1023 i only have 99.871 as my "#/min".......you have 497.61! you need to dial that thing down....a lot!!

EDIT*here is what my maf xfer looks like.

 

[Bullitt6301]

So I rescaled the maf transfer and smoothed the volts. I also redid the vct tables because like previously said it was zero'd out on accident and redid the spark tables and started the car up. It seems to run a lot better but I need to alter the transfer function. More to follow. I am using SCT Pro Racer.

 

[one eyed willy]

you know how to log that stuff and make your corrections right? That's about %95 of the drive ability , also after you make changes, check your "graph" to make sure it looks nice and smooth, it should not have any spikes in it anywhere.

 

[Bullitt6301]

Yeah I know how. I have a copy of Don Lasota's tuning guide also.

 

[Bullitt6301]

So I went out tuning it today and it is responding a lot better. I have the MTF done pretty straight and have got halfway thru WOT before I ran out of time today. After reviewing the logs everything is lining a lot better spark is reaching commanded timing and the car has more power. Thanks for the suggestions and I will let you guys know if I need anything else.

 

[Bullitt6301]

So I have made some signifcant improvements with the MTF. Question, I can get it into full boost of a smooth hill and it will richer up and have a lot of power but when I get to 4250 it will lean out but alot slower than before. I have been making corrections to the MAF by adding more fuel but it seems I keep doing this at 500 RPM at a time... then try again and again and so on kinda frustrating...

I also after reading about the logging of lambda vs. AFR and decided to change over to lambda and setup the formula to be at 14.1 stoich and that has been more helpful when it comes to corrections. I have just been driving around like normal and making corrections as I go. Trying to get the WOT dialed in now and it is being a real pain.

Anybody got any tips that work good for them? Also can somebody post a graph of ther MAF curve. I want to compare the line graph to mine.

Thanks guys!