Went to test & tune in the Camaro with mixed results tonight. I messed with the chassis and killed my 60' times. Dropped from 1.267 last week to 1.387 this week. Next week I'll undo what I just did (rear ride height adjustment that modified the instant center). But I also modified the air fuel ratio on the alcohol injection system. Leaned it out a bit and picked up some mph on the top end. So the new milestone is........... 142.45 MPH First run for me in the 140's. (actually, that was my 2nd run in the 140's. Half an hour earlier I ran 140.71 MPH) What's this mean for the SRT crowd? Tune youe AFR with trap speed. Measure your trap speed. Adjust richer. If your trap speed goes up, keep adding fuel until your trap speed starts to drop. If your trap speed goes down, start subtracting fuel and watch your trap speeds go back up. Once your trap speeds maximize and start to drop, go back a step and you're done. That's what I was doing tonight, and I was glad to pick up 3.35 mph over my prior best.
Can't tell if it's broke until you adjust and see if it goes quicker or slower. Next week I'll drop the rear end back where I started just to make sure it was suspension that made the difference and not a transmission issue. I don't think it can be motor related, or I wouldn't have had the ability to go 142+. So it's either chassis, or maybe a trans issue off the line. I should know next Thursday though. LOL.
Sweet congrats Matt! Now, with the tuning SRT thing, I find that my first 2 runs at the track are always the best...even if I ice the intake for half an hour. Once it's hot, I just can't seem to improve my times. I'm not patient enough to wait more than 45 min to an hour.
alright, just keep adjusting and you will find out what works best. keep up the good work. ah yes, 140's bring back some good memories, lol
Oh - no issues. I just didn't know if there was more to be had in the chassis or not. 1.267 is nice, but in theory this car has done 60' times in the 1.21-1.24 second range. I clearly went the wrong way on my first guess for adjustment. I'm going back where I started, and then maybe even drop it 1/16th to 1/8th inch. E.T.s were bad due to the slow 60' times. 9.397 seconds @ 142.45 MPH.
Thanks man. It's all about the rewards of using the old noggin to tune the engine and tune the chassis and see how you do. Obvious mixed results tonight. Try again next week. See if I cant get the chassis working better again, along with the HP tuning hopefully I can keep the MPH and drop the time again. I think I can ultimately hit 9.0x with nothing more than tuning. We'll see though.
So why would too much fuel slow you down? wet plugs? too cold? You're limited on the amount of O2 you can get in there. Wouldn't the excess fuel just go out the pipes? Not like you got to worry about burning out your cats, lol. Is there any reason you'd want different AFR in different rpm ranges?
Nope. Not even a full car scale to make sure what I assume my total weight to be is correct. Can you believe the scales at Indianapolis Raceway Park don't even work? There's always an AFR that provides maximum horsepower. The point at which if you go leaner or richer you'll lose HP. The method outlined above is the generally accepted method for finding that point on the curve where you maximize your HP. In my case, as I suspected, the previous owner had left the car set up a bit fat (rich).
