wolverine8490

Was wondering if anyone could give me a hand. Working on my buddies 98 Cobra. He removed the IMRC plates as well as installed a ported intake. The car right now is bogging at full throttle and will backfire when shifting under full load. We data logged the car with his LC-1 and it appears the car is running rich.

We are using special forces. I was wondering if someone could point me in a direction as what I could change in the spark/fuel trims to make the car run better.

I will also attach the logs from his LC-1 to this thread. The logs are a 3rd gear pull from 2000 - 5500 rpm.

Thanks for the help!

cliffyk

I would set the low RPM fuel modifier to +0.4 (maybe +0.6), and set the mid range fuel modifier to +0.4. That should lean it out in lower half of the range you logged.

Going to +0.6 in the low range will help get rid of that initial spike down in to the 11.5:1 territory. Setting +0.4 in the mid range should get that up to 12.5:1. It's probably cold where you are, you may want to pump it up closer to 13.0:1, if so then set low/mid/high at +0.6/+0.6/+0.4--but watch for going much leaner than 13.0:1...

wolverine8490

Awesome thx for the help. Anything I need to do with the spark tables?

cliffyk

What octane fuel are you running?

wolverine8490

I tuned the car and now I have a new issue. We did the following:

93 Octane
Low RPM Fuel +0.6
Mid RPM Fuel +0.4
High RPM Fuel +0.2
Low RPM Spark +1.0
Mid RPM Spark +1.5
High RPM Spark +2.0
Global Spark +2.0

Now when we go to start the car it runs for about 30 seconds at idle. It bounces up and down until the car stalls. It also smokes when it first starts.

The only way now to make the car idle/run is to put the car back to complete stock. I am at a loss as it will not even run if I leave all of the fuel and spark alone.

wolverine8490

It is runnig 93 octane.

cliffyk

The (on top of the 93 octane selection in SF) add +2.0° to the global spark adder, and +1.5° (low range) to +2.0° (mid and high) to the rpm based settings--do this separately and after you get the fueling where you want it, and listen carefully for pinging. If you do get pinging back off immediately and note what rpm range it happened it, cut the timing back 0.5° in that range.

If there is no pinging then add 0.5° to the global. I am running +2.5° globally, and 2.0° in the low and mid rpm based ranges, and +2.5° in the high range, on my '03 GT now thaty the cooler weather is here.

This said however, pushingtiming right to the edge of detonation does not always produce the most power, so do some timed runs somewhere (timed 2500 to 5500 rpm pulls at WOT are better than worrying about distance covered) and play with the timing to get the best performance.

Ehmark

What work was done to the intake?

wolverine8490

The intake was ported and polished by Pauls High Performance. That is about all we know about it as he bought it used.

My biggest concern is pushing the tune to the car right now. No matter what tune I push to it, even when I leave the fuel and spark timings stock (the way it was last week) it smokes when I start it up and stalls at idle unless I push the stock tune back. It did not do this before. I am not sure what the deal is now.

I about about to say the hell with this cobra. I think the car has more tuning to be done than I am capable of. My GT was easy, but this thing is literally pissing me off.....

H0SS302

I dont think you can use special forces to fix the IMRC delete. There are special selections in commando for it however.