TheOtherEric

Guys this was a trick question. The car with the supercharger will lose because his engine will heat soak at lap 12 and his belt will break at lap 15.

Rassel

So many posts..
*Ugh*

Anyway, Mark is right about HP vs. Torque (I didn't read it thoroughly, but it looks so)

Regarding the quicker car. Only one person mentioned a very very important factor.
Professor Helmüt Tester: Area Under the curve

For those who don't believe it. Go speak with the team engineer. If you still go for " Max the Engine Torque vs. HP" - I'd love to see you working for a rival team one day

mark kibort

thats what I always hope for with my racing with the S2000 with the blower.
so far,its defied logic! still running strong and pissing me off at 400rwhp out of a 2.2Liter
mk

Greg Smith

See post #51, the one that's before post #73 .

mark kibort

Thanks!

Also, as a side note to your point, thats why I always go a little deeper with the term, "HP-seconds" that ecompasses. Its better than area under the curve, because along the curve you spend different time in different HP ranges. This is much more accurate than just "Area under the curve". MY very first post mentioned this! (post 18)

mk

POST 18
Ok, if you havent had enough of this, Ill break it down into its very simple elements.

Torque means absolutely nothing without a speed attached to it. And guys, we are talking ENGINE torque.
Torque that causes acceleration at ANY vehicle speed, will be generated by Power (HP). (i.e HP is the rate of doing work. unit measure of measure of work might be something like HP-seconds, like the kilowatt hours on your power meter at home) It is HP that determines the torque at the rear wheels, not some level of ENGINE torque. Engine torque is one of two factors of HP.

Now, follow me here

Acceleration = power/(mass x velocity)

what this Newtonian identity tells us, is that acceleration is directly proportional to power and inversely proportioal to vehicle speed.

Why is this important?

Because if you are comparing two vehicles, all you need to do, is find out how much hp is made at any vehicle speed and you will know its comparable acceleration potential. (all other things being equal, like aero, weight, etc)

the main question you need answered is what is the average HP that the car will be producing between its gear shifts. in otherwords, what does the shape of the HP curve look like. the flatter the better, as your average or area under the HP curve, becomes higher.

It doestn matter what your peak torque values are on the engine. GT3RS engines can make 440rwhp and have less than 275rw torque. peak torque is flat and the peak could be anywhere! who cares? It matters on what the rear wheel torque is and that is determined by the HP. The HP curve can be looked at in HP-seconds between gear shifts through all the speed ranges. This determines the acceleration rates of any two cars with the same HP.
If one of those cars HP curve is peakier than the other, than the flatter HP curve'd car will acceleratate better off turns. if both have the same shaped HP curve, yet one has 1/2 the torque as the other, BOTH cars will accelerate exactly the same at ANY vehicle speed.

mk

mark kibort

sorry, post 18 is before post 51

mk

onefastviking

So if I took two identical cars but put some oxygenated fuel in one of the cars increasing the torque at the exact same engine speed would it be faster/quicker ?

mark kibort

Then the HP at that exact same speed would be greater, so it would have more acceleration forces. (ie more torque to the rear wheels).

what you have created with that example, is two cars that have different shaped hp curves. (assuming you only use the oxygenation injection for a few hundred rpms). now, if you inject this power boost til redline, then you would not be comparing two cars with similar HP, defeating the point of the entire argument here.

Study the Viper vs GT3 HP curve comparison graph. It has all the extreme posibilities right there. I just wish I could have found a viper graph with a max hp of the same 438rwhp vs the 455rwhp im using. hopefully, ill stumble on one soon as it will make the points even clearer.

anyway, there was talk about the controlability of the Audi R10 vs the higher reving low torque prototypes. I was actaully able to get a humours response from Dorcey schrader from Speed, as they were continually saying that the R10s had all this "torque" off the corners. They would have no more or less torque off the corners than any other prototype with the same HP. (which is what they have). If all the prototypes are 550hp, it doesnt matter than the R10 has 800ft-lbs of torque, as the torque off the turn is exactly the same at the rear wheels!!!! If you plot out the curves for the R10 and R8 or high reving prototypes, you can see that with the closer gear ratios, that the high reving engines would have no problem having the same HP at any speed around a road course. Sure, there is a little more shifting going on, (5 speed vs 6 speed) but, in the end, with sequential shifting, thats really not an issue. Ironically, it was the short courses where the lower engine torqued proto's actually beat the R10s. In the the end, the heavier R10s actually had a better average HP overall vs the small engined protos. But, it was fairly equal and thats why we saw some great racing. heck, even the porsche P2 was able to churn out the same lap time at laguna as the R10, and it was a class behind!
In the end, they stopped raving about the "torque" of the R10 and gave me a few subliminal jabs about it on the TV show.

mk

Veloce Raptor

The perfect example of a (relatively) high TQ high RPM motor is that in the current Z06. For its displacement (7 liters) it makes its peak HP way way up in the RPM range, but also has a lot of area under the turque curve from relatively down low. And again, gearing plays a huge part of the usability of both IMO.

Veloce Raptor

I am sorry Mark, but irrespective of your theoretical exercises here, in the REAL WORLD on a road course, my point was correct.

Veloce Raptor

You missed the point, respectfully. Two cars with 400 hp, same weight same handling, give me the one with the higher torque any day for road course use. Which is exactly what the OP asked.

mark kibort

No really. Hard for you to believe, but you are not correct. Let me give you a real life race where this is not the case (again). daytona 24hours. porsche high reving flat 6 vs V8. v8 had a lot more power and was at WORST the same as the V8 in any "off corner " area. Why??? for the reasons Ive run the "theoretical exercises" about. Want more proof, and a much better comparison? Have you ever seen the Vipers vs the porsches coming off turns at VIR, Long Beach, Laguna, Sears point and other tracks with slow or fast , literally any type of turn. Ive seen the Porsche with a great driver or sloppy driver come off the turns and beat or be equal to the vipers in all aspects of acceleration. why???? for the reasons i note here on this thread.

Let me also make your point for you, because I know exactly what you are trying to say and holding on to. I run a 365rwhp car against a high reving 400rwhp 2.2 liter supercharged S2000. You have probably seen my videos. why is it i can pull him off the start, off turns (sometimes) and down the straights?
Its because of the exact point that you are trying to make. SOMETIMES a high torque engine can have a very flat HP curve. Meaning, its average HP will be greater than the competiting equal hp, high reving, peaky hp, low torque racer.
This is absolutely a real world case. However, for everyone of those type competitors, Ill come accoss one (like a cup car) that will go gear for gear with me, and only have the same HP and I will have NO advantage anywhereon the track. This is the point and follows to the Tee exactly what i have tried to message here.

Open your mind, if you want to be someone that can help folks understand these very important racing concepts related to race cars power plants.

Mk

Veloce Raptor

Mark, you are comparing apples to ashtrays. Porsche 911s come out of corners better than Vipers ANYWAY because most of the weight of the car is over the drive wheels. Has zero to do with HP or TQ or RPM. That is one of their primary advantages over front engined cars.

I cannot believe that I actually have to explain this to you.

mark kibort

Absolutely, positively, wrong.

Do you really need me to spell it out to you?

look at the dyno runs (real world) that i posted. They show an interesting comparison of capabilities.

Lets say we have two 400hp cars. I can have a flatter HP curve with less peak torque very easily. This happens all the time with high reving engines vs low reving engines. I could have 275rwt vs 400rwt and have more REAR wheel torque at every point on any track, excpect at maybe max HP where one might have it lower or higher in the MPH scale than the other.

There are plenty of 400ft-lb 400hp engines that cant hold a candle to a restricted 996GT3RS engine. Or, just take my graph above and put a rev limiter at 400rwhp. go find a 400rwhp viper and match redlines. the viper still will have much more torque and yet, it will be deficient in at every speed on a road course..

so, you stay very vague with your prefernce below. Two 400hp cars, one with more torque, you take the higher torque car. You will get spanked all day util tuesday if that is your only qualifier. You should know better than that if you have any " real world experience".

You have to look no farther than the engines HP curve and the area under the curve, or more accurately said, look at the HP seconds over a road course. the one with the most will win, all things being equal. AND this can happen with a car with an engine with a very low torque value. BUT, remember, HP determines REAR WHEEL TORQUE, which is the force that determines acceleration.

Stop fighting it!

mk

Veloce Raptor

Reread post #103 and then get back to me on who is "wrong" here, Mark.

Again, the theoretical exercises & the graphs and charts are really neat and all, but in the real world, on a racetrack, we're just gonna have to agree to disagree.