I'm curious about the opinion of others who actually own and drive high HP cars on this issue.

First, let's forget about drag racing and dedicated autocross cars. I'm talking about a car that is street driven at least 99% of the time.

It seems to me that traction starts becoming a real issue at about 400WHP or so. And while the usable limit can be raised with better and larger tires and a superior suspension, there comes a point where additional power only has value in bragging rights (which I want to leave out of the equation entirely).

So, given a street driven daily driver with appropriately sized tires, at about what level does additional power become moot or unusable?

 

how much $$$$$ are you willing to spend??

 

385whp, realistically.

 

Ive been in cars nearing 500 rwhp that seemed more than fine as daily drivers (which they were), and that is taking into account poor conditions which we get a ton of down here.

 

440whp was very usable. I'll be going 500whp and 295s in the rear when built.

 

400 is enough for anything. Anything past that and it's fun for highway pulls etc.

 

You also have to take into account torque and how linear the power is. If you have a big turbo car that has all the power at the top end, that's not very streetable. You could have a 500whp car with good torque down low and linear hp that would be a great daily driver, but a similar 500whp car with no low end and all high that would drive like crap. Take a Z06, 500 crank hp and very easy to drive around town. Take a big turbo drift car with 500 crank hp, a nightmare to drive(unless you drift everywhere you go).

 

Also, your suspension and wheel/rim set up is part of the equation. 450 whp w/ a solid TT setup for steady power should be streetable w/ the proper suspension/brakes and 285-305's in the rear..but of course I am just guesstimating.

It is starting to look like I will be delaying my FI plans because I have the 10 K right now for the TT, but I don't have the other 10K I need to make the power safe.

 

It depends on how much torque you have and where it comes in. My Stillen does not make a ton of Hp but has a lot of torque down low. If it had any more from 2000-3000rpm it would be a total waste.

As far as Hp you can have a 600whp car with a good power band and use it all on the street from time to time. I think for my use I would be happy with 380-400whp. Plus that way you are not required to build your engine. You may need to at some point if it goes on you but there are a lot of G's and Z's around that mark with quite a few miles on them.

 

The power you're looking at running is completely safe (under 380whp), even with stock rims and tires. Just don't drive like a maniac and you'll be fine. Believe me, it's not like all of the sudden the car is uncontrollable, you'll only notice the TT when you get on it and then it's really linear power.

 

So, you think that my 245 rear 225 fronts will be sufficient? I have the performance tire/rim package and I really like the rims. I want to keep them for at least 12 K miles.

Also, if I TT now w/ low boost, I will have the engine pulled. How much will I save by installing TT and building bottom (short block) at the same time?

I have decided to eventually do the engine build, especially since I am only 40 minutes away from one of the best VQ3.5 shops in the country (SGP)

 

I did the engine build first also, what is the use of having that much power and being able to get it to the ground if you engine blows first.

I would think 500rwhp is streetable if the torque is not around 500 also... lets say 400ish would be good, again this is all a guess so far.

 

Yes, I'd start out with your stock tire/rim setup and see how they do. I'm sure you'll be fine. You could even go a little wider on the stock rims.

If you're considering building (which I would do first if you can afford to), you will save a lot of money. If you wait until she blows, figure in a lot more in parts and labor. At least an additional $5K or more than if you would of done it originally with your TT install. Labor alone for pulling the motor, reinstalling the motor and retuning would be around $3-4K. If you do it the right way, with an APS TT, forged pistons and rods, you can get away with it for around $16-18K total. It's going to cost me $23-25K total after it's all said and done! I wish I would of started this way

You'll get used to the 380whp pretty quick and will want more. If you can't do it now, I'd wait until you're financially ready to do it all at once.

 

Thanks Brian, sounds like good advice.