It has been stated in various threads countless times that over X power cannot be used on the street. These statements in my opinion are misguided. This is because the amount of power that can be safely used varies greatly with the vehicle and its driveline. A vehicle can only use a certain amount of tractive effort which is mainly a factor of engine torque, overall gearing, vehicle weight and tires. There are other smaller factors such as weight bias, torque converter, suspension, center of gravity height, etc.

As an example a typical mustang street car with a C4 trans and 4.10 gearing will not need much engine torque before most would consider it unmanageable; however this same car with a Powerglide and 3.42 gearing could manage an engine with significantly more torque.

Here is what we need for a good FAQ thread to point people to when they ask this type of question or express the desire to build something unmanageable.

Here are the basics
vehicle type
estimated vehicle weight
engine peak torque
transmission first gear ratio
final drive ratio
tire size and type
converter (loose or tight is fine)
brief description of drivablility
simplified tractive effort (calculate with torque X trans first gear X final gear X 24 / tire diameter)

There are other factors but if we make this too complicated we will not get many people to provide data. I think the data above is enough to provide roughly what is reasonable and what is not.

 

93 Cobra
3200lb
609lb-ft measured at wheels
2.46 first gear
2.73 rear
275/60-15 Nitto drag radials
tight converter
very manageable unless very cold outside
simplified tractive effort = 3506lb

 

Well then you have !000hp cars made for the street , the Bugotti but it has built in traction control and alot of other things but for putting 1000hp under the hood of a regular car is crazy for the street. Hell my Cobra will blow the tires off at 65 on the freeway and in a street race it's really hard to get it to hook, it's the peddle game. I have to turn the boost down to get it to hook.

 

I have a 70 Chevelle with a 496 that makes 1038 rwhp at 16 lbs of boost, on 8 lbs of boost on pump gas it still fries the tires at 60, even with full slicks on it. Just depends on what your willing to live with, and what you consider a "street car".

 

1965 Cobra replica
2450 lbs
600 rwtq
2.84 1st (AOD wide ratio)
2.73 rear
275/17s Nitto NT05R's
2800 stall
1st gear is very snappy but always spins, 2nd hooks 50% of the time depending upon road cond and temps, but a quick throttle modulation will get it to hook.
Video from a 30 mph roll when I had the standard (non wide ratio) gearing with 2.40 1st.

 

Let me add that when I have turned up the boost above 600 rwhp/tq I have trouble with spinning on the freeway, which I don't like. So for my car weight of 2450 lbs, I feel that I am at the edge for what is reasonable on the street. I know another Cobra replica owner running over 800 rwhp/tq, and he has traction problems at anything under 100 mph. Cheers.

 

Stated this many times but I've done quite a few 700+whp street cars. No three speed auto "street cars" either. No gutted tin cans. Has ac, power everything and a nice stereo. My definition of a street car is just that, what most consider a street car I just consider streetable. Streetcar to me is something anyone can drive, gets 20+ mpg and all comforts and will make the trip across country if needed.
ps. Dead hook first gear roll(6 speed) with 1000+whp(1200 all in) on 18" drag radials . Take it bar hopping, swap out to slicks and grudge race at the track

 

Power is adjustable with turbos .

 

Agreed. To that I would add the ability to idle all day in bumper to bumper traffic without overheating and the ability to run on pump gas. What people consider to be a "Street Car" is a totally subjective term. Just because it has mufflers, lights and a license plate doesn't make it a street car in my opinion. I've been down that path before and it SUCKS!!!!!

 

To those who posted general comments. Do you know the data I requested for your vehicles? If so will you post it?