A few question after data logging

[740turbo]

I recently was able to figure out how to record a run using TunerPro RT and after reviewing the data I have a few concerns and questions. First of all I will give you an idea of the truck specs. 91 Sy 51,000 original miles 20,000 on stock rebuilt engine 150 on rebuilt 700r4 w/ PDQ 9/11 2700 rpm non-lockup stall converter. Mods: hardwired high flow ic pump, no cat, 2.5 in exhaust with single 40 series Flow Master muffler (Previous owner I know some people say they are too restrictive), Slightly larger cam, I can't remember the exact specs, but if it is important I can look at the sheet. New NGK plugs PN 2771 gapped to .035, wires, cap, and rotor + oil change w/filter. I also set the timing to 0 degrees with the signal cut to the ecm. I don't know if it is useful information or not but I have my front prop shaft disconnected right now.

So here are the issues:
Boost spikes to almost 20 psi and at the same time i am getting ~7 degrees of retard and a 2000 or so knock count. I have not changed anything having to do with boost so I wonder what could be causing it to go soo high and cause so many problems. I did notice that the silicon/rubber hoses on the turbo controller are original because they still have the crimp style clamps. Also I have not checked to see if the Knock sensor is properly torqued yet.


Thanks,
Greg

 

[740turbo]

Re: A few question after data logging

I would also like to know the steps for downloading the current configuration of my truck, I am guessing that it is running the stock computer, but I would like to review all of its' current tables and compare them using autotuner

 

[Six-is-Enough]

Re: A few question after data logging

I recently was able to figure out how to record a run using TunerPro RT and after reviewing the data I have a few concerns and questions. First of all I will give you an idea of the truck specs. 91 Sy 51,000 original miles 20,000 on stock rebuilt engine 150 on rebuilt 700r4 w/ PDQ 9/11 2700 rpm non-lockup stall converter. Mods: hardwired high flow ic pump, no cat, 2.5 in exhaust with single 40 series Flow Master muffler (Previous owner I know some people say they are too restrictive), Slightly larger cam, I can't remember the exact specs, but if it is important I can look at the sheet. New NGK plugs PN 2771 gapped to .035, wires, cap, and rotor + oil change w/filter. I also set the timing to 0 degrees with the signal cut to the ecm. I don't know if it is useful information or not but I have my front prop shaft disconnected right now.

So here are the issues:
Boost spikes to almost 20 psi and at the same time i am getting ~7 degrees of retard and a 2000 or so knock count. I have not changed anything having to do with boost so I wonder what could be causing it to go soo high and cause so many problems. I did notice that the silicon/rubber hoses on the turbo controller are original because they still have the crimp style clamps. Also I have not checked to see if the Knock sensor is properly torqued yet.


Thanks,
Greg

No catalitic converter is causing the over boost spike and the knock. The stock turbo wastegate is woefully under sized and needs lots of back pressure to control boost. There are some band aids you can do to help control. Do a search.

You can also tune to adjust your wastegate duty cycle to anticpate the spike. Lower % in duty cycle is more open. IE 10% closed versus 95%Closed.

BTW Be very careful until you get this fix or you will be rebuilding the motor again.:2cents:

 

[740turbo]

Re: A few question after data logging

I am surprised that just removing the cat would cause boost to increase by almost 5 psi, but it would make sense. When I removed it on my Volvo I only saw an extra pound maybe two increase in boost pressure."Six-is-Enough" if you have some time, I would like to ask you more questions regarding adjusting wastegate duty cycles via tunerpro rt. I will shoot you a pm.

Thanks,
Greg E