Last post on Oct 24, 2006 at 4:56 PM
You are in the Speed Shop Tuning and Modification
What is this discussion about?
Dodge Viper, Porsche Carrera GT, Chevrolet Corvette, Ford Mustang SVT Cobra, Performance Mods
#14 of 22 Re: Horsepower to Weight Ratio [subygt]
Oct 06, 2006 (4:08 pm)
It's also not street legal, and there are plans to attempt to make it so. If they did, it would undoubtedly weigh a lot more, anyway (bumpers, airbags side impact protection beams, etc.).
#15 of 22 Re: Horsepower to Weight Ratio [wideglide]
Oct 06, 2006 (4:23 pm)
I didn't see that as a criteria for being in the discussion. As far as street legal goes, you can register and get plates for almost any car you can drive in almost any state. You can get parade plates or special purpose plates...... thats what most people do they when import cars or build kit cars "IE: super seven", All you have to do is add a VIN to it, issued from the state you live in a , get a ins company and a license plate..... bang, now its street legal.
Just takes some doing by the person purchasing the car, its not for everyone, but people who have the will to drive something very different can find legal ways to do it... they also assume all the risks associated with it and most do, thats why it is possible but difficult.
I personally know people who have built kits and imported cars with a much lower build quality that the DP1 that have had zero problems getting the car thru the local DMV.
It all depends on how bad someone wants to do it. I see no problem with it as long as people know what they are doing....
#16 of 22 Re: Horsepower to Weight Ratio [subygt]
by steve_ HOST
Oct 06, 2006 (6:40 pm)
Bill Gates' 1988 Porsche 959 was impounded for ten years before he finally got it licensed for street use.
#17 of 22 Re: Horsepower to Weight Ratio [steve_]
Oct 06, 2006 (6:57 pm)
That car was impounded because it was a widely mass produced car that they refused to crash test, so the U.S. decided to make an example of them and hold up a very high profile customer and car manufacturer.
Many a Lotus elise made it into the U.S. with not a second look by DMV. Along with another 20 or so specialty cars.... IE: Ariel Atom, Seven, Westfield, Different TVR's... Etc,
#18 of 22 Re: Horsepower to Weight Ratio [subygt]
by steve_ HOST
Oct 06, 2006 (8:21 pm)
I heard that fewer than 200 "street legal" 959s were made. The Ariel Atom looks like it may be a bigger hoot to drive, and for a lot less dough too. I thought the Top Gear review of it was hilarious.
No matter, my vision and reflexes wouldn't do any of these supercars justice.
#19 of 22 Re: Horsepower to Weight Ratio [steve_]
Oct 07, 2006 (5:01 pm)
Low wt/HP cars are not just a hoot on the street. I see many trailered into HPDE track events that don't have plates and not all of them are driven at the limits, for that matter neither are the street legal ones. Last weekend I got to watch a 70-72? Pantera with a 351 Cleveland engine, best sounding machine I've heard lately, go around Buttonwillow Raceway. It was formerly a race car owned by Bob Woodhouse, still in World Challenge, and had been updated after sitting for over a decade. Probably 450+ HP for a package that should have been under 3000 lbs. The guy was very conservative on track, not a replaceable car.
#20 of 22 torque and gearing
Oct 21, 2006 (7:34 pm)
Steve, torque really is just torque and is the same once it gets to the wheels whether it comes from the engine or tranny. Non-inertial chassis dynos (those that apply a constant/braking load and can hold a car at a particular RPM) can show *REAL* torque output at the wheels. When you choose that option, you'll see high revving I4 cars making something like 250hp and 800 lb-ft.
Now if you're wondering then how does that work out with the equation of HP = Tq * RPM / 5252, you have to measure the RPM where you measure the torque. So the HP works out because RPM is not the engine rpm, but rather the wheels (or equivalently dyno rollers).
I think a good way to think of torque is the ability gain HP faster.
#21 of 22 hp / weight
Oct 21, 2006 (7:47 pm)
While I agree that having higher hp / weight ratio is more ideal.. I think one has to also consider that hp / weight is not static, meaning that when most quote hp/weight, they are really stating the *peak* hp/weight ratio.
As an extreme example, try putting an F1 engine in a Hummer.. yes, the (peak) hp/weight fiqure will improve a great deal, but I bet it'll actually be slower in most cases! We can talk about the subject of torque, but we can omit the term "torque" entirely to simplify things and simply speak of HP, but now include RPMs.
So to truely determine the potential performance from hp/weight figures, we need to also consider hp/weight across all RPMs. But if we were to settle on "single" figure that's indicative of such across the board performance, perhaps *average* HP / weight would be it. Popular Hotrodding magazine for exmaple, scores participants' engines based on average HP in their annual EngineMasters contest.
Going back to the F1 example, it reminds me of a Motortrend article I read a few years ago where the author had his first experience driving an Forumla car. He stated that it was like learning how to drive a manual tranny all over again.. because clutching in at 4000+ rpms, still stalls the car!! Although I guess that's to be expected because that was close to where his car idled. I've read of more recent cars idling even higher..
Another example is Edmunds' own review of the Subie WRX wagon with automatic tranny: http://www.edmunds.com/insideline/do/Drives/Followup/articleId=48462
Accelerating right off idle resulted in 0-60 of 8.7 seconds. Brake launching at 3000 rpms, spooling the turbos up results in a 0-60 of 6.7 seconds. I should say though that the performance of turbocharged cars are even harder to model because not only does HP vary by RPM, but there is a transient effect varying HP at the same point of waiting for the turbos to spool up, if not already.
Another in similar vien was a C&D comparison of various cars. The S2000 faired significantly worse doing 5-60 (high 8's) than 0-60 (slipping the clutch in at nearly 5000 rpm; 6.1 if I recall). And again, I think we can predict or model these outcomes if we look at power delivery instead of only peak output.
#22 of 22 Re: Horsepower to Weight Ratio [subygt]
Oct 24, 2006 (4:56 pm)
I am missing something here Subygt?????????
You compare these cars to a 2007.
It is 2006 and they are selling 2007 Corvettes!
I agree that the weight to horsepower ratio does mean something but why are you talking about ancient history??? But your comparisons are meaningless. Why don't you compare a 2007 Porsche to a 1958 Corvette? That would be a real valid comparison wouldn't it!
The 2007 Corvette coupes and convertibles and the 2007 ZO6 are all street legal cars that are great sports cars!
It is pretty obvious that you don't own any of the 3!