How much horsepower is enough?

z31maniac wrote: Modern 1000cc sportbikes. If you've never ridden one, you wouldn't even believe the way they bend space and time.

Doesn't even have to be the liter bikes anymore. HEll, my 800-ish cc triple makes 115hp and a torque curve like a tractor and warps time. First and last bike I've ridden that will leave a black mark while carrying the front tire. Not some rock hard touring tire either.

Interesting how small the returns can be adding power in autocross. Curiosity sent me to look up a thing.....at a National tour last year Danny Popp designed a course which turned out to be very "Corvette friendly" (lots of straights and open elements). He then turned a combined two day time of 137 seconds in his vicious ZO6.

My point is that the winning CSP combine was 136 seconds (with 150 hp) and the winning SSM time (fairly comparable setup to CSP but with 450 hp on tap) was 131 seconds. Literally triple the hp to achieve a 5 second advantage)

Not sure if any of this is useful, I just found it interesting.

When it overrides the chassis ability to handle it.

Some one may have already said that.

Drove a twin engine kart once. Case in point.

KyAllroad wrote: Interesting how small the returns can be adding power in autocross. Curiosity sent me to look up a thing.....at a National tour last year Danny Popp designed a course which turned out to be very "Corvette friendly" (lots of straights and open elements). He then turned a combined two day time of 137 seconds in his vicious ZO6. My point is that the winning CSP combine was 136 seconds (with 150 hp) and the winning SSM time (fairly comparable setup to CSP but with 450 hp on tap) was 131 seconds. Literally triple the hp to achieve a 5 second advantage) Not sure if any of this is useful, I just found it interesting.

I think a better comparison would be hp:weight vs talking about just straight power. Also aero and other stuff.

z31maniac wrote:

Furious_E wrote: The answer is always more.

So you've driven/ridden something capable of sub-10 sec 1/4 mile passes? That's an insane level of acceleration on the street.

Not even close, mid 12s at best probably. I'm mostly being facetious with that remark.

z31maniac wrote: I think a better comparison would be hp:weight vs talking about just straight power. Also aero and other stuff.

Agreed. My yes-it's-enough was for a 1700-lb/500hp car, so figure 3.5-4 lbs/hp

David S. Wallens wrote: So this thread got me thinking. How much power is enough? If a car has 205 horsepower, we want it to have 206. And if it has 206, why not 207? And why not make it an even 300? Or 400? Have you ever driven a car and thought, Yeah, this is enough?

A car, no, but a bike yes.

It was a prepped for the Texas mile modified class GSX-R 1100.

At 80 in third I whacked the throttle and when I climbed up on the tank to keep from flying off the damn thing and let go of the throttle, the front wheel set down at 140. Most brutal acceleration I have ever been in "control" of.

No yank on the bars, no clutch, just twisted the wrist too quick.

I don't know if he dyno it, but it was more power than I ever wanted ride again.

z31maniac wrote:

Furious_E wrote: The answer is always more.

So you've driven/ridden something capable of sub-10 sec 1/4 mile passes? That's an insane level of acceleration on the street.

Everyone I know with a 9 second car wants to run 8s.

Knurled wrote:

z31maniac wrote:

Furious_E wrote: The answer is always more.

So you've driven/ridden something capable of sub-10 sec 1/4 mile passes? That's an insane level of acceleration on the street.

Everyone I know with a 9 second car wants to run 8s.

Purpose built drag car != something you can buy for less $17k and run 9s without slicks or extra prep.

1000cc bikes will literally do it stock off the showroom floor if you can get off the line well. Over a decade ago I was touching high 10s on my 600c bike.

Motorcycle on the street? 110-130ish hp. Motorcycle on track? 160ish hp.

I rode a modded 1299 Panigale S with over 200whp (thanks Ducati of Seattle) and it's the only time I've experienced acceleration so fierce (in 3rd no less) that I simply said 'no, too much!' and took it back to the dealer. I was daily riding a KTM Super Duke 990R at the time, and it was still a shock.

For cars, I think the power limit on the street is far more subjective. I daily drive a stock 90whp 1.6 miata and I love being able to beat the crap out of it without violating the law (much). I had a 240whp turbo miata a few years ago and it was far less fun simply bc any time you'd hit the gas for a few seconds you'd double the limit. For some reason on a motorcycle this bothers me less.

My WRX was around ~300awhp and that definitely fit the 'more would be better' category. Problem is, as the cars get more refined the easier it is to get used to the power.

In reply to z31maniac:

If you have a good rider and a good track. From observation, somewhere down in the low 10s range, acceleration is more about rider control than power.

Used a be a bunch of Hayabusas would show up at test and tune night at Norwalk. A lot of high 9s at 150-ish MPH. One guy I talked to had a turbo, claimed mid-400s horsepower at the wheel. He ran about 3 tenths quicker but at 190mph. His front tire was hovering over the ground until about the 1/8th mile mark when he shifted into 4th and could finally give it full throttle.

Anyway, we don't need to be moving any goalposts. The question is "enough power?" and a large percentage of people who want more power, have a pathological need for more and no sense of "enough".

KyAllroad wrote: My point is that the winning CSP combine was 136 seconds (with 150 hp) and the winning SSM time (fairly comparable setup to CSP but with 450 hp on tap) was 131 seconds. Literally triple the hp to achieve a 5 second advantage) Not sure if any of this is useful, I just found it interesting.

Open courses usually favor the lower hp cars, where courses with tight corners and some straights favor higher hp cars. Any course that is big and open is where lower hp cars can use their corner speed to minimize their lack of acceleration. It's the opposite of what many people might think.

To the original question, you can have too much, but it varies from car to car. I've driven a 600hp Supra, and it was entirely manageable, as was the several big hp Vipers I've driven. But then there is the C6 Hennessy Corvette with 700hp that was totally unmanageable. Wheel spin in any gear and at most speeds. Totally unusable and not fun at all to drive. A softer setup might have helped.

Depends on what kind of person you are. Anyone will have a big grin on his face the first time they mat it in an overpowered car. Some never tire of that time after time after.....

Others want more - often, like me, in the handling department, so outright power doesn't really do it for us, although it is nice to at least know there is some capability in that direction.

The guys that have that inane grin on their faces every time the rubber starts squealing scare me - and remind me of the rats that give up food and sex to keep on pushing the bar that feeds an impulse into their pleasure centre until they starve to death.

Sane people want what is safe to handle and that varies considerably depending on whether you are talking about street or track.

My street car runs a 1/4 into the 12s but I rarely use it that way - it bores me, I do often drive a winding road in a fashion that I find very satisfying, normally when there is no other traffic to potentially interact with.

I'm going to say that a ratio of around 8 lbs per bhp is sensible given an adequately capable chassis and anything else is great for bragging rights but not much else unless you track the car or do outrageously illegal and dangerous things on the street.

David S. Wallens wrote: Have you ever driven a car and thought, Yeah, this is enough?

Every day...Although it depends greatly on how one chooses to define the word 'enough'.

When battling the mindless mass of congestion on my daily commute, a 117hp Fit (or previously 116hp Miata) is 'enough' to be one of the (mostly) non-offensively fastest cars on the road. While I do enjoy the added punch in the 269hp RAV4, when combined with my enthusiastic driving style in traffic, it becomes all too easy to cross the line into shiny happy person territory.

A 98hp Bandit 1200 was 'enough' to never be short on fun.

I also expect that the 130hp engine in my garage will similarly be 'enough' for a street oriented Locost to plaster a smile on my face.

So apparently "enough" is somewhere south of 150hp.

David S. Wallens wrote: Have you ever driven a car and thought, Yeah, this is enough?

I drove a 450hp 421 SD in a 64 GTO with drum brakes all around and S.L O.W. steering..... that was waaay more than enough.

I like to be able to use all of the loud pedal... and not for milli-seconds, but to mash, and hold... somewhere around 200-225hp per 1000 kilogram is about enough

David S. Wallens wrote: Have you ever driven a car and thought, Yeah, this is enough?

Yes. My daily driver and One Lap car, CLS63 AMG, has 507hp. I've never wished for any more. As is, I rarely ever get above 2500 RPM, and even when I do, it is just for fun and not necessary in any way. In very short seconds the car can be in go-to-jail-now territory, and makes me giggle with the wave of power. Sure, it could have more, but why bother.

One thousand. One thousand HP is enough. Unless you are trying to move a ship, then 50,000 is enough. Unless it is a carrier, then 200,000 is enough.

Oh, and as I recall, Smith said in one of his books something to the effect of "Drivers want enough HP to break the tires loose all the way down the straightaway, then enough tire not to break loose at that much HP, then enough HP to break those loose."

My silverado with the 6.0 came from the factory with 300 hp. A coworker that is an LS fanatic said to me that this mod plus that mod plus some other thing could get me to 500 hp. I said i dont think ive ever had it wide open. Its never felt underpowered when towing or passing, so i guess given the application it has enough.

KyAllroad wrote: Interesting how small the returns can be adding power in autocross. Curiosity sent me to look up a thing.....at a National tour last year Danny Popp designed a course which turned out to be very "Corvette friendly" (lots of straights and open elements). He then turned a combined two day time of 137 seconds in his vicious ZO6. My point is that the winning CSP combine was 136 seconds (with 150 hp) and the winning SSM time (fairly comparable setup to CSP but with 450 hp on tap) was 131 seconds. Literally triple the hp to achieve a 5 second advantage) Not sure if any of this is useful, I just found it interesting.

Yeah, but pro C/SP car. They seem to defy physics.

JG Pasterjak wrote: There is no such thing as "too much power." There is only "not enough tire."

Personally, I believe it more properly goes like this: There is no such thing as "not enough power". There is "not enough talent", and "not enough tire".

Come to think of it, the only car that I've driven that feels like it has enough power is the previous generation Range Rover Supercharged. The chassis just can't cope with much more than 503 HP.

WildScotsRacing wrote:

JG Pasterjak wrote: There is no such thing as "too much power." There is only "not enough tire."

Personally, I believe it more properly goes like this: There is no such thing as "not enough power". There is "not enough talent", and "not enough tire".

Downforce.

I'm surprised noone has mentioned torque in 4 pages. I think that's a huge difference in when/how you 'experience' speed. A lot of people are referencing wheel spin. That's a torque thing. You can have a car that's not that fast but blows the tires off at speed. My 09 challenge car would have run a high 12 on its best day (which was not Challenge day!) but easily spun the tires in 3rd gear on the street (so, up to about 60mph before it would hook) and made me nervous to floor it in 5th because i thought the trans would break. Far from the fastest car mentioned here, but probably one of the fastest 'feeling' unless you were rolling on from extra-legal speeds to begin with.

Another thing is the linearity of the throttle-to-torque relationship. Keith has talked a lot about how well a Miata with small tires can hook up a v8. A lot of that has to do with controllability because the throttle gives you a lot of resolution when you 'request torque', and it doesn't change suddenly as it would in a turbo car of the same torque.

Another scenario: Take two cars of the same power but totally different torque levels. The one with more torque will feel faster at lower speeds and be relatively disappointing when you get to higher speeds because you don't feel the same immediacy of result when the torque comes in. The one with lower torque will feel disappointing at lower speeds but then begin to feel fast when you realize that your 'indicators' of speed (speedo is only one of them) start telling you you're going faster than you expected to be going by now.