GM 8.1L Tuning

Hello, I am a new member getting ready for my first tune. I am a professional technician ASE Master Tech. I fully understand how VE and Fuel trims work. I am attempting to tune an 2001 GMC Yukon 8.1L
The engine is just built. It has many modifications. I have a 540 block, Raylar CNC Heads, BP-202 cam. 90 MM Throttle body, Marine injectors, and shorty headers I calculated the new CID at 9.5L. It is currently tuned by a local tuner. I recently added a Whipple 2.9 L Supercharger. I am going to try and tune it to accommodate the Supercharger. I am installing lamda sensors with duel gauge inside for each bank, also a 3 in 1 gauge for boost, fuel pressure and exhaust gas temp. The Supercharger eliminates the EGR and Air Injection.


I am open to any and all advise, opinions and cautions. I have a Dyno in my shop, but it isn?t a performance HP measuring dyno. Just an emissions dyno that I can apply a load to and drive the truck while monitoring my laptop.
Thanks for your time.

Did the whipple come with a 2 bar or 3 bar MAP sensor?

Do you know if the computer you are running can do a 2 bar or 3 bar operating system upgrade under the OS tab?

It would need to do that in order to calibrate the VE beyond 1 bar. With what you said I can we assume that the MAF is no longer in the picture and that it's going to be a speed density tune with a separate IAT sensor??

I will check the MAP tomorrow. I just got the Supercharger installed. It does have an IAT and harness with the kit.
I will get back to you with these answers.
Thanks for your time

So, I am trying to connect to the Yukon. I installed the program but it will not connect. I am using windows 7, a friend of mine said he uses it and it works. I can open the program, but is will not connect to the vehicle?? any advice would be appreciated.

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Originally Posted by Jameyt

So, I am trying to connect to the Yukon. I installed the program but it will not connect. I am using windows 7, a friend of mine said he uses it and it works. I can open the program, but is will not connect to the vehicle?? any advice would be appreciated.

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Forget all that, I figured it out.... operator error.

As to your questions (5FDP) I have a 1 bar map and I still need to connect the IAT into the wiring at the MAF. The OS tab reads speed density and 1 BAR MAF.

If the OS tab doesn't have at least a 2 bar speed density OS, you won't be able to calibrate the VE table correctly for boost. Perhaps the whipple kits are thinking that the stock MAF sensor is still going to be used.

I'm not up on my 8.1 calibration files but I'd be curious if there are 2 bar OS's on the same year trucks or 2002 model years.

Sorry it has taken me a while to get back to you on the Yukon. I finally got my Lamda gauges installed. I am running at 10:1 fuel ratio at the moment. I would like to lean it out a bit. What should I do first. I need to turn off my AIS and EGR. I found where I can do that. I’m just not sure how to go about reducing my fuel delivery. Appreciate any tips.

Post up your tune if you can.

I want to see what it is commanding first, then think of changes from there. You just have to remember that what you command is a set value and that shouldn't be altered unless you have a reason for it. You should be making the commanded match the actual.

Your fueling tables are the airflow tables, those being the MAF curve and VE. If you lower the numbers in those, you reduce the fuel it gives. Where you do that all depends on what your logs show. The lambda gauge you bought can be logged in the scanner against the commanded AFR/Lambda. The error value between the two will let you know where to add/remove fuel.

Could you post up the tune ?

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Originally Posted by EFIBigBlock

Could you post up the tune ?

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It has been a while since I had this Yukon here. I attached the last file I had.