95greense

if peak HP is at 5600 wouldn't it make sense to go a little past that so that the next gear would be in the powerband? I'm obviously no race expert but that's what i heard
By the way, while i was testing out my air box mod i tried manually shifting from first the second at 4500 and the tranny still shifted at close to redline. maybe i did it wrong but i'll try again later.

JimW

First of all, you cannot say track times aren't reliable as there are too many variables, at least I think that you can't. This entire thread is about how to lower your et's. I am simply giving people advice as to how I did it. Being that I probably have more experience at racing an auto Max than many people on this BBS.
As far as 5000 being the best rpm to shift at. Let me explain. It's been a while since I've had the Max, so I may have forgotten a few things, but I'll be as accurate as my memory will allow. As I'm sure you know, a vehicle will accelerate most rapidly when the engine is kept as close as possible to it's torque peak. Since the VQ engine makes peak torque at close to 4000 (IIRC) you want the engine to stay as close as possible to that rpm when you change gears. Now, I also believe that the VQ makes its 190 Hp at something like 5500 rpm, perhaps less so. I have also told you (and many others) that the engine (with a stock exhaust and intake) seems to run out of breath in the high rpm ranges. If the redline is 6500, but the power peak is at 5500, running the engine past the HP peak is just wasting your time. You'd be better off shifting into 2nd gear, as the VQ's gearing is pretty optimal for standing start acceleration. Each upshift at 5500 rpm will put you just below 4000, I believe. Right where you want to be, in the meat of the powerband. Now, in preparation for the 2-3 upshift (automatics here) you'll be running close to 70 mph in 2nd gear (if memory serves me correctly, I remember with my ECU and the extra rpms it allowed, I would be at 80mph still in 2nd gear). Now you have an engine that is past it HP peak, trying to accelerate a vehicle and punch a large hole in the air. It's torque is going to do a better job than the falling HP (remember HP=TQ @ 5252 rpm, after that point, one or the other is falling rapidly) of accelerating the vehicle. You shift 3rd, and you're right back in the meat of the torque curve again, 4000 rpm.

Now, in my car, moving the shifter at 5000rpm would get me a 5500 rpm upshift, right at the HP peak, not spinning the motor faster than it needed to make power. It also landed me right back at 4000rpm, for maximum acceleration in the next gear. That method rewarded me with the best et's and trap speeds.
When I added a Y-pipe and Intake, I found that I could rev the engine to 6000 rpm before shifting (which gave me a 6500rpm shift point) Why? Because the engine made more HP in the higher range, and it pulled hard all the way to 6000rpm. I found this through trial and error, and the method described was quicker.
Now, as far as HP&TQ, take a look at JULIAN's post. He has the Y-pipe and ECU that I had in my car. He also has a 95 auto, Fed. emissioned. His car is as close to mine as you'll find. Even the same color.

JimW

In my case the numbers worked out a little on the low side. It said that I should be running 14.2's based upon my trap speed and et. It also said that I should be putting out 265hp, which sounds a little low to me. 4100 lbs of car running 95 mph in the 1/4 sounds like closer to 275 to me.

xHypex

iTrader: (1)

Since we're talking about 1/4mi and ETs did you ever run slicks Jim? Right now I'm riding on a set of 18"s, but I do have a set of 16" SE wheels with Nitto NT555R Drag slicks on them. I was going to try to go to the track tomorrow, but I was somewhat reserved about actually running the slicks. I have a 5spd. so it's probably not as bad for my transmission, but not many people have actually run slicks. I'll probably run them anyway, but I try not to abuse my car too much
-hype

JimW

I had the opportunity to run them, but I was too busy frying my tranny to try them out I have a quicktime movie of me doing a burnout on my street tires (which were inflated to 20 psi) to gain some traction. I did gain traction, but at the expense of a tranny. After I had the tranny re-built for light duty racing, I always ran on street tires with low pressure. I wanted to be sure that I would blow away the tires rather than hook up hard and blow the tranny. I still managed to kill that tranny one night while trying one of my "14's or bust" runs. After that, I just decided to give up alltogether, as it was getting very expensive.
Jeff K ran slicks and he ran a 14.3's in his 5spd with intake, exhaust and Y-pipe.

95greense

hey jim w, thanks again for the advice. last time at the track i made most of my runs racing with my buddy who has a 325is and we were pretty much dead even. but he just got gears installed so his car should be hella fast now. I'm hoping that new plugs, air box mod, and your tips on launch and shift rpm will at least keep me close. do you think the brake torqueing (?) or the burn outs killed your tranny? just wondering when i should expect the tranny to go.

JimW

If you've got 70k on it now, and you haven't been too abusive on it, it should last you another 30k or so. Just remember this, if you are going to be hard on it, add an external tranny fluid cooler. Until then, let the motor idle for a few minutes after a pass down the track. Let the fluid cool off. When the coolant temp gauge has dropped to the low side, then your tranny fluid should have cooled enough also. I didn't do many burnouts at all, just the one I did was enough to finish off my tranny. (I had made 2-3 passes down the strip that night, and was anxious to get another run in before the track closed. I had no traction, so I tried a small burnout) Nothing too abusive, just set the parking brake, and punched the throttle open in 1st gear (this was on dry ground) spun the tires enough for some smoke, and they were good and sticky. I staged and launched, launched hard (had the revs at about 1500) It was cold, the tires hooked, then spun a few feet. I backpedalled a little, and the tires hooked with a SLAM!! I thought I broke a motor mount, but instead, the tranny let go. I still had 3rd and 4th and reverse. But 1st and 2nd went south for the winter.
There are a few guys that have run 15.4's with nothing but an intake. Eben (DC) does it on a regular basis. Not too many guys run faster than that with autos though.
Good Luck