Shadow....Tony is right. MAximum acceleration occurs at peak Tq...always. If you start off in first gear at idle in a manual transmission car....and mash the gas....your acceleration RATE will mimic that of the Tq curve you would see on a dyno print out. On your avaerage NA v8 for instance you would have peak TQ in a mid rpm at say....4000 rpm. At that very point you are under the greatest acceleration.. If max accell was at peak HP it would be glaringly apparent by the seat of the pants meter since ther is hardly any HP made in the lower RPMs of most NA engines. However...some Tq monsters like the L98 will KICK you in the pants at 2500 rpm...even though they are barely making any significant HP at that point.

If you need direct measurable proof.....look at some dyno runs and plot it against time. See where tha max acceleration takes place....it will clearly be where the TQ peaks.

I was just looking at my last dyno run on the Dynojet runviewer. It has some neat options on it where you can select different info to be displayed. I just set it up to show time vs rpm. If I need to I will do a "print screen" with the info if you would like to see. Anyways...if i select a window of one second to view exactly how many rpm the engine accelerated during that second....you can get that info easily.
If I select...on my dyno run the one second period that equals peak TQ from 5 seconds into the run to 6...you will see that I went from 5210 rpm to 5780 rpm in that one second span. Thats a gain of 570 rpm in one second at peak TQ of around 440 ft/lbs and HP was approx 430 rwhp. If you compare this to seconds 8 through 9 where I was making roughly 510 rwhp but less than 400 TQ you will see that I only gained 430 rpm during the time of peak HP.

Again...during exactly one second of peak TQ I gained 570 rpm...during 1 second of peak HP...i gained 430 rpm. Peak TQ accelerates the car faster than peak HP.

I almost never look at HP figures when trying to determine how fast a car will be and how it will behave under acceleration through the gears.

I think people get fixed on the notion that TQ is low end grunt. It is not. Low end grunt is ALOT of TQ in the lower RPMs. Big HP is alot of TQ in the higher RPMS. ITS ALL TQ. You just need to look at WHERE in the rpm range you are making that TQ. If you want to do the math to figure HP then thats fine. But the TQ line is the easiest way to see what an engine combo will do....atleast for me.

Now to gearing and why that may be important..and how it relates to high rpm TQ (HP), shift points and rear wheel TQ.

So for now...forget the HP numbers....to me they are nearly useless. Concentrate on that TQ graph. Again thats going to determine where everything happens.

SO if peak TQ is max accel...why dont we set up our shift points to go just beyond peak TQ as we look at our dyno graphs and shift then. We would be right back in our MAX accel point wouldnt we?
Usually no!

Max acceleration at peak TQ is only true for THAT GEAR YOU ARE IN. Once you shift...its a completely different calculation taking into acct the next gear multiplier you just shifted into and you obviously cannot compare one gear to another. Yes the peak acceleration in first gear will happen the same rpm as peak acceleration in second. But acceleration in the higher rpm...well after peak TQ in first will usually result in more TQ applied at the rear wheels and thus better acceleration than the acceleration rate even at peak TQ in second. You will always accelerate progressivley slower as your gear multiplier decreases. So unless your motor just DIES big time up top (makes no TQ in upper rpm range and falls of sharply) its usally better to shift around peak HP than peak TQ. Thats where the misnomer comes in that HP is more important than TQ....because you willl accelerate slower once you shift gears...even though you may be closer to peak TQ after the shift...and where closer to peak HP before the shift.

This still doesnt take into acct Tq converters and stall speeds, boosted cars, nitrous. It also doesnt fully take into account usable rpm range and ways to broaden it...and then gear accordingly.

Although alot of you guys did remember the first gear issue and how that affects ET.


This is all just my opinion on what I have seen so far. Some may not be exact thats for sure. Its just a very good topic that really gives the melon a workout when you try to take ALL of this crap into acct and what is best.

Cam selection, cubic inches, stroke and piston speed, Rod to stroke ratio, valvtrain and spring selection, intake design, gearing, Tq converter, power adder setup, tranny type will all play into the "best possible" setup. And its damn mind boggling