Best all around engine for a street car is a 3.6 IMHO. Very tractable, but crazy fast when you call on it.
But I wouldn't go that way without serious suspension work. And of course that applies to any major HP transplant.
Full Version: How much horsepower is too much?
Great discussion - thanks for all who have contributed -
Here's why I asked the original question - there was a car for sale in SF CL that was advertised at "900 HP". I was interested since the build since the parts used seemed first class, and the the engine pedigree was top notch (Keith Black - race engine builder). Turbo V8.
I went to look at it and drive it - and, well, it was as advertised but was in need of serious sorting out. What I found was that the race engine combined with a ZF trans and race pedal cluster meant that it was nearly impossible to drive! The clutch pedal throw was maybe 2 inches, and the lack of low end torque meant that you could hardly launch.
Once you were on the gas and rolling - watch out - went like the hounds from hell. But in between - lack of low end grunt, lightweight flywheel, huge clutch, no throw, etc. made the car completely ridiculous for common drive around town comfort.
Perhaps with some sorting and some clutch pedal work the thing might have been more workable - but the race bred high revving engine was a poor match for the rest of the build.
so, I'll answer my own question, if you are driving in normal around-town-traffic, too much horsepower is probably possible if the build is not well matched to the engine.
I believe the engine torque curve in this instance is probably right for the track (maybe), but starting out on a hill in SF in traffic would be nearly impossible.
I'm now thinking - as result of much of this discussion - that a 3.2 would be just about the perfect powerplant for a semi-practical all around car - some street, able to get thru SF, and decent AX and track beast.
Great discussion - thanks again!
td
Here's why I asked the original question - there was a car for sale in SF CL that was advertised at "900 HP". I was interested since the build since the parts used seemed first class, and the the engine pedigree was top notch (Keith Black - race engine builder). Turbo V8.
I went to look at it and drive it - and, well, it was as advertised but was in need of serious sorting out. What I found was that the race engine combined with a ZF trans and race pedal cluster meant that it was nearly impossible to drive! The clutch pedal throw was maybe 2 inches, and the lack of low end torque meant that you could hardly launch.
Once you were on the gas and rolling - watch out - went like the hounds from hell. But in between - lack of low end grunt, lightweight flywheel, huge clutch, no throw, etc. made the car completely ridiculous for common drive around town comfort.
Perhaps with some sorting and some clutch pedal work the thing might have been more workable - but the race bred high revving engine was a poor match for the rest of the build.
so, I'll answer my own question, if you are driving in normal around-town-traffic, too much horsepower is probably possible if the build is not well matched to the engine.
I believe the engine torque curve in this instance is probably right for the track (maybe), but starting out on a hill in SF in traffic would be nearly impossible.
I'm now thinking - as result of much of this discussion - that a 3.2 would be just about the perfect powerplant for a semi-practical all around car - some street, able to get thru SF, and decent AX and track beast.
Great discussion - thanks again!
td
What color was it, anything you can describe about it? Its very possible some of us might know of the car.
QUOTE(Andyrew @ Apr 23 2013, 09:07 PM) 
What color was it, anything you can describe about it? Its very possible some of us might know of the car.
It has been kicking around the Bay Area for awhile - white with a fg 'fiero kit' installed years ago. the guy has been building it since the 80's, has a 'miami vice' look about it.
The break-up value exceeds what he is asking for it - on CL for $12k. The pantera transaxel is probably worth $6k, and he's got Fox coilover suspension on all 4 corners. the turbo v8 looks a little cobbled together - think mad scientist.
clearly an interesting source for some really nice parts....but the guy is a bit of a nutter, seriously went off on me when I did not buy the car. lol
may be an interesting ride - but as I said it needs serious sorting out. damn, I did not think to get the vin number for the db....ratz.
td
The 2.7L in the shitbox was good AX motor......10.5:1 compression and Solex cams....pretty mild. It was also a fine street motor with good low end grunt/midrange & peak power at around 6400 rpms....but would pull just fine to 7200. No need of light switch clutches & all.....a stock 911 unit.
With a lot of tire, there is usable power.....AND it always ran. It's tough to develop a car that is broke down 50% of the time. Hp is only a part of the overall need of any car and is over emphasized.
Inertia in the from of cornering forces/directional changes was what I wrote about.
The flat motor keeps the CG down low.....ever seen a fast V-8 AX 914?....me neither.Want one? Buy a Z06. You can spend multi-thousands trying to match their capabilities.....and still come up short.
10 :1 weight/hp is a good number......provided you have enough tire. Drop below that and you'll find yourself "into" tire research.....more money spent on black holes.
Ignore the above if you're into "bragging rights".
With a lot of tire, there is usable power.....AND it always ran. It's tough to develop a car that is broke down 50% of the time. Hp is only a part of the overall need of any car and is over emphasized.
Inertia in the from of cornering forces/directional changes was what I wrote about.
The flat motor keeps the CG down low.....ever seen a fast V-8 AX 914?....me neither.Want one? Buy a Z06. You can spend multi-thousands trying to match their capabilities.....and still come up short.
10 :1 weight/hp is a good number......provided you have enough tire. Drop below that and you'll find yourself "into" tire research.....more money spent on black holes.
Ignore the above if you're into "bragging rights".
My variation on the question is what tire, brakes, suspension set up works best for what HP range. The set up values are just a wild guess, please post suggestions based on your experience.
Tires are max performance summer street tires or better.
100-150 HP - 205 tires, stock brakes, 100 lb springs, stock torsion bars, stock shocks
150-200 HP - 225 tires, M calipers, 140-165 springs, 21 mm torsion bars, bilstein HDs or konis, flares required, engman kit
200-250 HP - 245 tires, A, S, brembo calipers, etc...
You all get the idea...now please fill this in with the right values.
I know that I have spun my tires shifting into 3rd gear when on it hard with 205 tires and 175 hp 4 banger.
John
To much is when you things start to break.....
Great perspective, John! 
More clearly states what I was trying to get at. Above a certain HP it starts costing more and more in suspension, brakes, chassis stiffening, etc.
I like your list, and would love to see people's input on those designations.
More clearly states what I was trying to get at. Above a certain HP it starts costing more and more in suspension, brakes, chassis stiffening, etc.
I like your list, and would love to see people's input on those designations.
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