[986Jim]

Originally Posted by mtch

The Z-28 made gobs of tq but couldn't breath up high. I ran better times short shifting instead of holding to readline. Additionally, I frequently raced a local guy who had a NSX. His car made about 17 more whp than mine, but my tq numbers were much higher (about 75) and power curve much flatter. The race was a driver's race, he won some and I won some, but according to your experiences, his car should have beat mine each time, especially since his car was lighter.
His trap was higher and if we raced farther, he would eventually walk away, but you see how this situation counters your statement.

This is very true of drag racing. What should win all the time doesn't always. What I'm refering to is, that if your driving your car, your best bet drag racing is to shift at redline. Your Z28 would have been faster if it could breathe at the top end. A new intake manifold with shorter runners and larger plenum would have solved that. THe long runners used on the Z28 mani make for huge torque but rob the motor up high. You would have spanked the NSX with only a few minor changes. Also shifting and how you launch are a lot of the equations. We still can't take out the human aspect of racing.

Originally Posted by Mitch

My Acura RSX-s made 174 hp and 140 ft-lbs at the wheels when stock. After modifications it made 213 whp but tq ony increased by 3 ft-lbs. I currently own a Cooper-S used for daily dutuies, which makes 183 hp and 176 ft-lbs at the wheels. The cars have identical 1/4 times. The trap speed of the Acura is higher and on the highway at higher speeds, the higher reving higher hp engine wins, but in auto-x and in the 1/8 and 1/4, the broader power band and responsiveness mades up for the lower peak power.

Drag racing is really my specialty. With drivers and all other being the same, the higher HP Acura should have been faster. What made the difference is likely your skill is better now with more practice, or the Cooper-S is more your style of car so you drive it easier. Also weight is a concern, your Cooper-S is likely lighter than the RSX is as well. So with all other things being equil the higher HP car would have won. BUt not because it can rev higher, just that it has higher HP. Thats pretty easy to understand.

What I'm talking about is the title of this thread. Shift point for Maximum acceleration. You always shift at highest RPM. If your Camero was more setup for drag racing with a short runner manifold shiftinger higher would have made the car faster. You yourself said the downfall of the car, couldn't brethe up top. If you corrected that, what would your camero do to the NSX then? Right, mop the floor with it.

Originally Posted by mitch

The power band is more important than peak power, and for someone who spends time at the track I'm surprised you don't see this. How many 700-800 hp Supras-MKIVs have you seen run slower than 500-600 hp ones. In order to make this much power, the twin turbo is swapped for a single larger one. It makes big power, but takes so long to spool up ( which means a peaky power curve ) that it's too late by the time is really kicks in. The lower hp cars use twin (actually sequential) turbos, which means power from low to high (flatter curve). I have two co-workers with Supras i described above, 550hp vs 920 hp and the lower hp usualy wins. This is also true for the Suby Sti. When modified to make more hp, they sacrifice a flat power band, which means they lose the hole shot and play catch up the rest of the race. This is a fairly common occurance to see at the tracks.
This should clearly illustrate that peak hp does not win races, in wins braggin rights.

I understand what your saying about Supra's but I build and dyno tune those very cars so your entering my world now.



What your talking about is pull the sequential turbo setup and replacing it with a Single unit like the Greddy T78 setup commonly used on these cars.. They don't acctually spool slowly as you can see on this graph. The supra engine is very efficient at moving air so it can spool a large turbo by 4500rpm or so. This graph is 631whp, see where the power starts and how far is goes?

In drag racing they use a two step to spool the turbo during the launch so you leave the line with 10psi or so. There is no spool up for the turbo then, and you never take your foot off the gas even when shifting so the re-spool is almost nothing, the supra powers down the track and runs a good number.

When you get to 800whp or so, you can't do that anymore. The Getrag tranny in the supra (sound familiar?) is quite good, but you can't two step a stock 800whp engine outta the hole nor can you power shift. Plus we all know the real reason for the Supra pehnomon is because they are all dyno queens and none of them really know how to drag race anyway lol...

I build and dyno tune drag cars for a living, I have also been drag racing imports for 10+ years now. My talon is built for that very purpose. I win the Street Import class every year, and took 3rd in the Steet Summit class which is all V8 powered cars last year as well. My dad has been drag racing for 35+ years and built an import to race in my class about 4 years ago.

One thing I do know is how to make a car run fast in a straight line and what wins races. I build cars dyno then then race them at the track many times before the owner of the car does because they want to see how fast the car should go before they drive it for bragging rights or whatever.

Seriously I'm not trying to start a fight, (tho I'm obviously not doing a good job) What I say is from practical experience at the track.

Hope that helps,