How much horsepower is too much?, for a road car.... Options

[tadink]

Hey all -

I've been looking at options for increased HP and have run across some crazy stuff, and that got me thinking about "how much is too much"?

This would be an occasional track car, AX often, mostly street, preferably reliable.

I've seen recently, in no particular order: 3.2L pretty stock, 3.3L race prepped turbo, 2.7 or 2.8 race prepped, v-8 twin turbo (IMG:style_emoticons/default/confused24.gif) , and other various mixes of suby-turbo, McMark's turbo 1.7L project, etc etc.

so, for you high HP guys out there - when does the car get just too silly to be practical on the street? 300bhp? 400bhp? 600bhp? 900bhp?

and what makes it not so enjoyable to drive around 'normally'? One guy described his 2.7 race engine as just too high strung for the street - - - so that means that you have to get into higher revs to get the power from the cam? (IMG:style_emoticons/default/confused24.gif)

edumacate me pls......

td

[rick 918-S]

350+ doesn't seen to ben an issue... (IMG:style_emoticons/default/assimilate.gif)

[iamchappy]

I think 400 is fine, takes a little getting used too, but is very streetable. (IMG:style_emoticons/default/driving.gif)

[GeorgeRud]

As Mark Donahue stated, "when I can spin the tires in top gear at the end of the straight"!

Actually, it's more fun to pull away from "muscle" cars through the twisty bits. Just about anyone can plant their foot on an accelerator.

[Mike Bellis]

Autocrossing with big HP in a small car is a challenge. Big torque is an even bigger challenge. I have had from 250hp up to 500hp in a 914. The 250-325hp seemed to be the sweet spot for a mild conversion. If you go much higher, you will need flares, big tires, big brakes, stiffening, etc...

Here is a video of Andyrew drifting his 383ci V8 914 around a parking lot. With a big torque motor, this is what happens at an autocross. This is fun but not a way to get a competitive time.


https://www.youtube.com/watch?v=tOJf7PpP4l0


I am building my conversion to be in the 325-350hp range right now. I'm keeping the factory ECU flashed for big injectors and turbo. The plan is to make it totally streetable with plenty of mods to take to the track. (IMG:style_emoticons/default/shades.gif)

.

[euro911]

Shit, I'm happy with 125 (IMG:style_emoticons/default/biggrin.gif) ...











... but 200 would be nice (IMG:style_emoticons/default/aktion035.gif)

[TheCabinetmaker]

Richard Fisher has about600 in his car. I've ridden in it, and drove behind him in the twisties.
He has no trouble with either of them. I had my foot in my 4 hard just to keep up with him on talimena drive. Too much hp? Not!

[ConeDodger]

225HP is very fun and streetable... Idles well, handles traffic without complaint.

[carr914]

Depends on the car & what the Induction is. I've driven 600+HP cars on the Street - No Problem. I've been around 250HP cars at the Track that I wouldn't set a foot into.

Then there is the Driver Equation! The fact that Car Companies make 600+HP cars that the Average Schmo can buy is a recipe for disaster!

[iamchappy]

When i built up my car i did it because i wanted to do it, and had wanted to do it ever since they built the 911 turbo, but another reason was to make it run away from the Porsche owners cars that have always looked down their noses at us 914's...
Of course there are plenty of built up Porsche's out there that will out run my car, but i would still give those a respectable fight......

Overview - a torqued out 220 hp car or a 300 hp 3.6 would satisfy just about any of us 914 owners...

[JmuRiz]

Just my thoughts...I'll have more insight later this year...but I think a hot 2.7 to a stock-ish 3.2 will be great in a skinny fender car. Up to 3.6 with flares and the associated tires. I'm hoping for ~180 with my engine, it should feel like a rocket compared to my previous ~100 /4

[messix]

imho
it's how the power is made. a high strung small ci 150hp engine that makes it's power in a narrow power band would be a bitch to drive around in traffic.

then if you had a large ci engine that makes monster torque low in the rpm range would be a handful trying to drive on the streets.

if you had a balance of a well mannered engine that made reasonable torque and power in the low end and then progressively more power in high rpm to 400, 500, 600, hp as long as it would be progressive and predictable.

with modern engine management systems including turbo's it is possible to have a very high hp engine that will behave and well mannered to drive around like a Honda accord when needed.

like Jake says "it's all in the combo"

[Dave_Darling]

I think the answer to "how much power do you need" is always "a little bit more than you have now". (IMG:style_emoticons/default/wink.gif)

--DD

[Spoke]

282HP is enough to get me pulled over by the PA State Police at over 140MPH.

They couldn't keep up with me to get a speed so I got off with just a warning. (IMG:style_emoticons/default/beer.gif)

[McMark]

I think 175-225 is the sweet spot. More than that is fun, but you get into diminishing returns after 200, IMHO.

[Madswede]

imho
it's how the power is made. a high strung small ci 150hp engine that makes it's power in a narrow power band would be a bitch to drive around in traffic.
...
if you had a balance of a well mannered engine that made reasonable torque and power in the low end and then progressively more power in high rpm to 400, 500, 600, hp as long as it would be progressive and predictable.

with modern engine management systems including turbo's it is possible to have a very high hp engine that will behave and well mannered to drive around like a Honda accord when needed.

(IMG:style_emoticons/default/agree.gif) I'm breaking in my 3.2L twin-plug, big cam, 10.5:1, PMO ITB, Megasquirt setup right now and I can say (though I'm at a mile high altitude) that it's an utter joy to drive and can be driven around town with ease.

In fact, my setup idles so low and can be so polite, it's a bit of a problem. I forget easily what really lurks behind me in that engine bay. I'm surprising people (including myself) with how quick she can be. How quick she always WANTS to be! If it were more aggressive, I think it would be like a crack-crazed kitten rather than the fun but still kinda wild puppy that it's like now.

This is really a question that can only be answered by you, the driver and owner, and the amount of $ you want to can spend. There is always going to be someone with more power and money and huevos/insanity than myself out there, so I went a certain way down that path and am not regretting it at all. So there's my $0.02 worth.

Oh, and my car has not be dyno'd yet, but it's probably around 285hp at sea level, says O'Brien.

[Andyrew]

Autox? You wont get much benefit from over 250hp given good tires. Track? Depends on the track and the suspension setup, but the chassis doesnt take over 500hp very well.

I think 300-400 is a really good range.

The problem on the street is to much torque, As you can see in the video above you never even heard the engine in the video as I never got much over 1/4 throttle... But keep in mind that was on concrete. The car looks very similar to that at an autox with full throttle, but also keep in mind its built to drift at a whim as thats how I like to drive. The video above is of the car with about 300hp and 380lbs of torque.

I dont think over 300lbs of torque is really advisable, the real fun here is horsepower with a nice torque curve that lets you get on the gas predictably.

I think that this chassis really benefits from a large displacement v6 or a medium displacement 4 cylinder turbo that revs high (think 7.5k) and has enough torque to pull strong from 2500+. Examples being a porsche 3.6 or a modern 1.8-2L medium sized turbo.

[Cap'n Krusty]

Hmmmmmm. A wise and admired driver once said something like: "If you can burn rubber from the exit of one turn until you have to brake for the next one, you have enough horsepower". He said nothing, however, about too much horsepower. IMO, having too much HP is like having too much garlic; It can't happen.

The Cap'n

[messix]

"if everything seems in control, you're just not going fast enough!" Mario Andretti

[SirAndy]

"how much is too much"?

I've been in a (street legal) 914 with over 1000hp.

"Too much" doesn't even begin to describe how i felt about the car.

If you like a full body workout while 100% concentrating on not losing control the whole time all the time instead of enjoying to drive, then by all means, go for it.
(IMG:style_emoticons/default/huh.gif)