Are Naturally Aspirated cars faster than Turboed cars?

[NewyorkKopter]

Hey, I was wondering. What if you took two of same exact car, with the same horsepower, weight, torque, weight distribution, but one made its power naturally through the engine, and the other through Twin Turbos. Which one would be faster on a Circuit. My impression is that the n/a will be faster because of the powerband and no lag

[Black Lotus]

And you would probably be correct.

[2.2 Straight six]

not necassairily true, you get turbos now with just about zero lag, with the right setup size etc.. besides with turbo as they spool up the power is accesible earlier, an you could tind that you get better acceleration, im not sure though

[drdisque]

with the same power and torque, it would be very close

lots of high power NA cars have much peakier powerbands than turbo cars. It would probably depend alot on the track and where you would be in the powerband of each car on most of it.

[sracing]

Originally Posted by NewyorkKopter

Hey, I was wondering. What if you took two of same exact car, with the same horsepower, weight, torque, weight distribution, but one made its power naturally through the engine, and the other through Twin Turbos. Which one would be faster on a Circuit. My impression is that the n/a will be faster because of the powerband and no lag

Tough call. Assuming they were geared properly for each one, lag on a road race car is not much of an issue anymore. So they would probably be pretty close iniitally. However the turbo car has a heat problem. While both cars may dyno out very close initially. The turbo car will start dropping HP every lap until it reaches some stable point.

We built two NASA Mustangs here. One with a NA 4.6 Cobra getting about 350 to the rear wheels. One a ATI Procharger and intercooled blown 4.2 GT 4.6 getting about 350 to the rear wheels. The NA car could do dyno run after dyno run and get 350 every time. The blown car dropped to under 330 HP after 2 or 3 runs and continued to drop slightly every run.

Thats the only problem with a "forced" engine. They make great street cars and drag cars, but for road racing, you have to be prepared for the large heat losses.

Jim
SR Racing Inc

[TheSilentChamber]

depends on the track and the useable part of the powerband on both.

[NewyorkKopter]

say like Sarthe in France. U kno the LeMans track. Its built with local roads, and bits a pieces of other racing circuits

[curtis73]

It all depends on the area under the TQ and HP curves. If they are identical then they should act the same. The chances are slim that they will be the same, and even so, dyno results are only at WOT. Races take place at all throttle settings.

In a drag race, they should be equal.

[NewyorkKopter]

but doesn't a n/a car have a smoother powerband, than a turbo??

[curtis73]

Not necessarily. In the case of some turbos, they can make peak boost from just off idle all the way to redline, meaning the chances are that the turboed example would have the smoother powerband. If its a poorly designed turbo (like almost any from the factory except porsche) it would be peaky and tend to make peak boost early and be very inefficient at higher RPMs.

But, even if the dyno charts were 100% identical for both engines (equal areas under the curves) they still might be different at Laguna Seca since the naturally asprirated engine would probably have more part throttle power than the turboed engine.

[sracing]

Originally Posted by curtis73

But, even if the dyno charts were 100% identical for both engines (equal areas under the curves) they still might be different at Laguna Seca since the naturally asprirated engine would probably have more part throttle power than the turboed engine.

Curtis, Not really. On most road courses you are either at WOT or on the hard on the brakes. (sometimes both). If one car had less HP at 1/2 throttle than the other one did (in a long sweeper for example), he could just add the throtte he needed. So.. WOT HP is all one is ever worried about. (assuming all else is equal.) And.. as I pointed out earlier, the forced car will drop HP. Even in a 1 mile long straight. So that has to be taken into account.

Jim
SR Racing

[NewyorkKopter]

There was a Top Gear episode where the Zonda C12S 7.3 with its naturaly aspirated AMG V12 550 hp engine, and weight of 2700 lbs posted a lap time of 1:23.8, while in a diffrent episode a Koenigsegg CC 8S with its Carbon Fiber Monoque chassis, Supercharged V8, 655 hp(over 100 more horses than the Zonda) and weight of 2500 lbs did the lap in 1:23.9. It was just a tenth off, but still don't you think a car with more power and less weight would completley rip the Zonda's time into peices? Same thing with the straightaway test. They took the Zonda out onto their straight and floored it until they couldn't go any faster w/out damaging the car. The Zonda managed 170 mph, and it does the quarter mile in like 11.8 Then they did the same with the Koenigsegg CC. It did 174 mph. No doubt it beat the Zonda but still I was expecting it to do like 190 if the Zonda does 170. The Koenigesegg supposedly does the quarter mile in 10.8!!!!! Nearly a second faster. And I would think it would keep on accelerating that hard until it approached its Top Speed of 240 mph. So then what caused the Koenigsegg to be slower and not to amazing in either test. My impression is that it was because that the Koenigsegg uses forced induction. Like some one said before, the Turboed car was losing hp, and in general superchargers make more heat. May be the Koenigsegg lost its peak of 655 during the tests, while the Zonda stayed constant at 550 with that natural V12

[amanichen]

Originally Posted by NewyorkKopter

There was a Top Gear episode where the Zonda C12S 7.3 with its naturaly aspirated AMG V12 550 hp engine, and weight of 2700 lbs posted a lap time of 1:23.8, while in a diffrent episode a Koenigsegg CC 8S with its Carbon Fiber Monoque chassis, Supercharged V8, 655 hp(over 100 more horses than the Zonda) and weight of 2500 lbs did the lap in 1:23.9. It was just a tenth off, but still don't you think a car with more power and less weight would completley rip the Zonda's time into peices? Same thing with the straightaway test. They took the Zonda out onto their straight and floored it until they couldn't go any faster w/out damaging the car. The Zonda managed 170 mph, and it does the quarter mile in like 11.8 Then they did the same with the Koenigsegg CC. It did 174 mph. No doubt it beat the Zonda but still I was expecting it to do like 190 if the Zonda does 170. The Koenigesegg supposedly does the quarter mile in 10.8!!!!! Nearly a second faster. And I would think it would keep on accelerating that hard until it approached its Top Speed of 240 mph. So then what caused the Koenigsegg to be slower and not to amazing in either test. My impression is that it was because that the Koenigsegg uses forced induction. Like some one said before, the Turboed car was losing hp, and in general superchargers make more heat. May be the Koenigsegg lost its peak of 655 during the tests, while the Zonda stayed constant at 550 with that natural V12

You can't compare a drag race, to a circuit with many turns. A drag race shows a car's accelerating ability (and torque performance), while a top speed test shows its power and aerodynamic efficiency. A circuit with lots of turns is a blend of all of these charactertisitcs in addition to HANDLING. The performance of a car in a turn does account for much of the performance around the Top Gear Track. The Top Gear track is setup so that it tends to level cars together. Get a track with a 5 mile straight, and the Koenigsegg might win, while give a series of chicanes and the Zonda might pull ahead.

[NewyorkKopter]

if the segg cant beat a Zonda on a track with a 5 Mile straight, now thatd be pathetic. I was just saying I expected the Koenigsegg to be much faster, like completley destroy the Zonda

[beef_bourito]

the thing about forced induction is that you can get more power out of an engine of the same dimentions without stressing it as much. if you had a 2L engine putting out 350hp NA, it would probably be reving high enough for it not to be a comfortable daily driver and really stressed whereas if it was turboed it would be streetable and might not be stressed as much. also, you can get more power out of that 2L, the max on the turbo car might be 100hp, 200hp, or more over that of the na car. unless certain limitations in competitions prevent you from using forced induction or there are penalties (such as added weight) for using it, there's really no point in building a na engine.