Alright with Tbirds Mini and the Sol thread has led me to ask the question .

How much hp can a 4th gen fbody really handle and still handle (without having to back pedal or get into changing all the susp)?

I know the drag racers go 700+hp and go 9seconds.

But it seems that 700+hp would be a little hassle to control in autoX and road racing with a near stock chassis (even with the GC setup).



I know its an open ended question because of use of throttle and even more open ended when compared to a small tight low speed autoX verses an open road race.

Interested to see how the regulars reply to this but my hunch is that its a non-issue.

Obviously a newbie jumping into a 700hp f-body on a road course has a high chance of dying, but with the proper tires/suspension and gearing and respect for the accelerator I don't see any HP level automatically being a barrier.

A lot would depend on where that 700hp comes in too. If the car is a tq beast then yeah its going to be hard to modulate the throttle, but that's where the right gearset comes in.

My target number is 650 but it won't be stock suspension.

GC, stiffer springs, stiffer bars, panhard lowered, brake ducts. And this year I'll probably run race tires for the first time too...

One advantage of the higher hp, for me with my auto tranny (if it holds up), is less shifting. Which should actually help the tranny live longer. I can tweak the shift tables so it won't downshift unless I'm just going at crawl speed.

This car is an experiment in a tri-athlete - street, drag, and road racing/autocross.

Learning to barely tweak the throttle will be key.

I for one would like as much HP as I could have and then worry about the handling aspects that might arise.

Big HP can make up for a lot of bad setup and driving.

more hp = need BIGGER BRAKES

obviously hp doesn't change the handling characteristics of the car, it's just driveability. With no suspension changes the car will still corner at the same speed, it's just that you get to the corner faster. Of course the other thing is that you have to be more careful coming out of the corners since with more hp you are more likely to throttle oversteer, but unless you upgrade the diff the inside rear wheel will just spin faster with the extra hp and you won't go anywhere anyways. If you can manage to not throttle oversteer the car then it shouldn't be a problem, just remember the throttle isn't an on/off switch and it should be fine.

Big horsepower that's all or nothing would be a problem. There's a local guy with a C4 who is in exactly that situation. He has a very aggressive cam, and the throttle is basically a light switch. It seems to be a bear to control.

As long as you can modulate the throttle, the next question is going to be how much power you can get to the ground coming out of a turn (how much can you USE?). The original question did specify no suspension changes for the extra power, but didn't specify the starting point for the suspension before the power was increased

Getting power down out of a turn (and from a straight launch) is something the UE decoupled torque arm does extremely well. And yes, I've compared the very same wheel and tire set on two different cars on the same site

You aren't qualified to offer your opinion on that. Perhaps we need to swap cars again this next year. I'd like to see what the UE torque arm would do. Or perhaps not-I'd fall in love and have to buy it.


To answer the original question it depends on the car's setup. You'd have the max useable power when you could spin the tires at the exit of a tight hairpin and all the way down the longest straight. However, I suspect you would see dimishing returns before you actually got to this point. It would be fun though wouldn't it?

Imagine that 700 hp engine in a 6-speed car with stock suspension (or even a AX/RR suspension ) and Nitto's at the drag strip. Now imagine it with ET Streets slicks or whatever (I'm ignorant), a stalled 350 or 400, and a drag oriented suspension.

On an autocross course you can't even begin to use all the stock LT1/LS1 HP until you have an ESP suspension setup and a proper diff. That's why I waited to do headers after my T2R.

I've always liked the way Mark Donahue put it, "If you can spin the wheels at the end of the longest straightaway in top gear, then you have enough power."

My car makes a little over 500 at the rear tires. I find myself using part throttle alot on some local mountain roads unless I am on V700's or Hoosiers. I run 315/35/17's on the rear for daily driving and the car will blow them off at anything less than 85 mph under full throttle while banging gears. I had a 337 Golf give me a wake up call about three months ago. The guy stayed right on my tail the first half of the mountain because of my heavy foot and spinning tires.I quickly adjusted my lead foot and was able to run off from him.

The car is a different beast with some sticky tires on it.Feels like being strapped to a train.

I'd say its a non-issue with proper suspension setup. I have more than 400 at the tires in my SM autox car and that hooks up very well even on 1st gear autox courses (still on the 3:42's). On the street (275 MX's) it only just spins the tires above ~4500 in 1st. This is all of course with my "stiff" rear springs and a UE TA and a preloaded T2.

In a properly setup road race car I'd say that 700 certainly isn't too much...

Jason S.

Now that I have a fresh 2.97 T56, controlled experiments are no longer possible [edit: but you're welcome to try it]. I'm curious to see how it copes with the stronger gearing.

I think you'll like the way the UETA launches Instead of feathering the gas after launch or short-shifting to control the wheelspin, you can just ignore the wheelspin, go quickly to full throttle, and it will just hook up all on it's own

I'm in the same boat... a little over 500 rwhp, and I would say that it's pretty much border line for those that consider driving it on the street.
It's fun to have that extra hoomph, but controls are more sensitive too.
Also, I would never get that much power before I would get bigger brakes, suspension setup, chassis stiffning (rollbar/cage) and rear-end.

Over 600 to the wheels.
On a softer compound street tire (295/35/18) there is very little traction, it's actually blown the tires off going through the traps at our local quarter mile track at 130+ mph.
That was eye opening .

Nitto r2s (305/35/18) are much better from a roll but still let go pretty easy under 65mph.

I'm looking at the racelogic traction control setup and/or the UETA as I'm going up another 150 or so rwhp.

When the car was around 400rwhp it was much nicer to drive, I had more confidence in my ability to put the car exactly where it needed to be.
Now it needs alot of respect, it can get you into trouble in a hurry. Small errors in judgement become large, life threatening errors very quickly indeed.

Thanks for the replies . Some good reading.

Interesting and good quote from Mark D (summed it all up).

Also interesting to read about the street handling with 500+ hp.

I'd like to add how the 2 red colored F1 drivers have the throttle pedal throws setup. One has a very short throw with almost instant full throttle and the other has a long throw for a large/long throttle response. As you may have guessed Ruebens runs the long throw and MS runs an instant full throttle pedal throw (it even is said he drives like in a kart).