Tuning a Classic FAST

[Chevman2448]

So if I understand you correctly....My INJ DC was so high because that is what it took to run the engine at those VE tables. But now that I dropped the INJ DC the VE tables all have to be increased 30%? Am I going to have to go through the entire VE table and increase all of the numbers in the table just as I did in the idle circuit?

Also Im not seeing a file in the C-Com programming for the stage 2 program you mentioned earlier.

 

[pacecarta]

the inj delay was high (why i cant imagine) which had the inj flowing more because it was told the injector was slow so it adds the delay figure to the pulse width and the old ve at idle are had been adjusted for that
you lowered the delay to what it should be and that will require the ve to be bumped up at idle , as you get off idle the additional .5 ms you removed wont have as great a percentage on the overall fueling as it did at idle when the injector pulse width is generally very low . the ve table near idle might need slight tweaking but it wont be much and probably wont even be noticeable

in the c-com download from fast there is a gct folder , in that youll find the "demo. gct " which is from a stage2 race gas setup , so dont use the af/spark tables as those will be unsafe for pump gas

 

[Chevman2448]

I found the demo.gct I wish there was an easy way to copy and paste it, but oh well. If it were that easy everyone could do it.
Your help is MUCH appreciated!

 

[Chevman2448]

It runs pretty good with my settings. When I rev it though the 02 correction % goes to zero.

 

[Chevman2448]

3 bar map is ordered. Not that I needed it but I did just in case the PSI settings are over 15 psi. I have all winter to play around with it so Ill figure out where I need to be on the tune then.

 

[Chevman2448]

What is the best location for the air temp sensor. I thought about putting it in the turbo pipe just after the turbo of course, but I would have to weld in a bung. Im also contemplating putting it in my upper intake plenum. If I put it in the lower intake I would have to remove the intake from the engine and I dont really want to do that. I figure the upper plenum would be the easiest choice since I can easily take that off the engine. I dont exactly want to drill a hole in the intake but if its required for the FAST to operate properly then I have to do it.

 

[pacecarta]

i put nmine in the plenum driverside , if you do driverside the wire can be sliced out of the tape and reach without needing an extension harness

 

[Chevman2448]

Have a picture of how you did it?

 

[Chevman2448]

Some tuning

 

[Chevman2448]

I am going to put the air temp sensor on the passenger side of the upper intake. Figured there is too much stuff going on on the DS with the throttle. My wires are long enough to put it there as well.

I also figure that all my tuning is futile without the Air temp reading the air temp going into the engine.

 

[Lance]

I am going to put the air temp sensor on the passenger side of the upper intake. Figured there is too much stuff going on on the DS with the throttle. My wires are long enough to put it there as well.

I also figure that all my tuning is futile without the Air temp reading the air temp going into the engine.

Good call...

 

[Chevman2448]

Pretty certain that is an indication of a vacuum leak. (no, Not the RJC plate) The oil soaked gasket and the fact that there is oil pooling on my lower intake.

 

[Chevman2448]

All back together!! Idles a lot better (though I think im going to go back to the UR5 plugs. the car seemed to idle better for some odd reason with them). It idles down to 800 and is pretty smooth with very little idle surge. Now I need to mess with the VE tables.

On a bad note the rear bolt hole for the doghouse seems partially stripped. So I may be needing a lower intake at some point. Ive tried all those thread fixes and they dont seem to work all that well. Guess I could heli-coil it though. With its EXTENSIVE port work that might be a good thing to upgrade at some point anyways.

 

[pacecarta]

just get a longer bolt , or stud it

 

[Chevman2448]

Alright....it starts and idles GREAT! I can smell the difference just on start up from the exhaust. Now I need to figure out where to start on the rest of the fueling table. Im guessing that i am going to be messing with the base VE table or am I going to be looking at the closed loop A/F tables? As soon as I hit the throttle it falls on its face. Its definitely lean. The backfires/popping is in the intake. My other option is to take it to a dyno tuning shop but Id rather do it myself. Lastly..and ultimately more important where would I start? Where to increase and where to leave it alone? I guess it would be hard to figure out since the cam specs arent known and its a lot easier to tune this stuff in person.

 

[Chevman2448]

So I was having issues when the fan was kicking on with the car wanting to die. It did it when I put the car in gear as well. I adjusted the A/F ratio from the 13.1 to 12.1 now it doesnt do that. Now I cant get the "gross correction" to go down. The number is green on the dash. Any suggestions on how to make that go back to zero? Or does it even really matter? Aft corr goes down to zero and stays there when the car gets up to temp so its still going into closed loop.

 

[pacecarta]

gross correct includes battery correction for voltage , if voltage is low then youll have correction

if you want to work on off idle you really want it in gear so there is load
dont really need to mess with the AF table
you could work the ve table , watch the bubble on the ve table and add a little wher it goes while watching the AF
, better fix is go to AE vs tps position (this was really wrong on the gct you posted) . basically it replicates an adjustable power enrichment valve on a carb. put it in gear foot on brake and give it a little throttle and see where the a/f goes ... raise the line to add fuel ..because of your smaller injector size youll need proportionally more injector % coming in than was in demo program

 

[Chevman2448]

Im not using the base file that was in the fast when I got the car. I found another one on this site. All I did was adjust the parameters, AFR's and the VE table and it has been running a whole lot better.
I got rid of the gross correct. I opened the throttle with the Idle air screw and the correction went to 0. I was chasing my tail for a while but.....I figured out when the fan kicked on the gross corr was there at a .8 number and that is where it stayed. The ECU was also adding fuel at this point as well. So here I am trying to adjust this and that only to go back to what it was when it got to operating temp before the fan kicked on. So I adjusted the Idle/Air screw and left it alone so that the IAC operated within its parameters and its been fine since.
I had to adjust the target A/F ratio down to 12.5 to get rid of the stalling in gear or the adjustment the FAST made when the fan kicked on. Based on what I read in the "Unofficial FAST" info posted on this topic it said they saw as rich as 11.5 AFR's to get rid of the stalling.
Also with the Injector DC it will not go down to 1.0 ms. Every time I change it the engine dies. I know 56# injectors are large enough to do what I need but if tuning this thing is going to be easier with larger injectors bigger ones will be in order. I have no problem spending the money if Idle quality and tuning becomes easier. Im sure 80# injectors are a pretty penny but overall if its going to help the process along might as well do it and get it over with. Reading a couple threads maybe 120 injectors will be in order.

 

[Chevman2448]

I modified this one to fit my car. I found it off this site. Idle is better all the targets are spot on with where I was directed.

 

[Chevman2448]

I cant go to the 13.1 afr at idle. The car wants to die every time the fan kicks on because of the volt surge. Maybe my LT1 alternator cant keep up at the lower engine speed?
I also adjusted the AE vs Tps fueling up from the tune program I posted in my last post. Didnt seem to change much. No matter what I couldnt get that little bubble on the AE vs TPS to bounce off the line.