spoolin turbo s

consider all things equal driver car weight everything exept for these 2 different powercurves who wins and why? they both make the same peak whp just in different ways

just a curiousity thread more than anything

im really curious to see the responses to this thread

and im talking about a straight line race......and say a race at laguna seca who wins each and what is your reasoning for your answer

tony1

It's really not a debatable topic, or it shouldn't be at least.

Here are the facts.

http://www.yawpower.com/tqvshp.html

TheShodan

iTrader: (14)

Looks like "that's a wrap". good link for people.

96 GSR-T

The first graph is my best friends car........


BTW look at the torque figures, how can you compare a 450tq car to a 350tq car? The First graph is of a 42R setup at like 18psi on an 85x89mm Engine with a Headgames Head, dont know about the other one......

90sedan

Damn good info.

quicksilver1689

kinda weird, good reading non the less, i say weird because jeff evans article had me in a different state of mind when it came to torque and this guy is saying its important that horepower is the determining factor in acceleration.

nowtype

Find the area under the torque curve between shift points. Compare them. That is what matters when you are referring to acceleration. More area = faster acceleration. Now look at your peak horsepower. That is what determines your max speed. So if your car makes tons of torque, but very little horsepower, you may accelerate very quickly in the first 1000ft but not accelerate for the last 320ft due to the fact you cannot overcome air resistance.

**Note, I'm just talking about the engine. I'm ignoring the rest of the car, including the transmission.

tagperformance

If you were to compare the 2 graphs at the top of the thread i would say the second graph would get to the finish line first considering the setup made 460whp 1175rpms sooner. talk about a laggy setup in the first graph..

turbociv910

no 1/4 mile times have a tq input;.. meaning that it has nothing to do with acceleration..

tony' s link is right

96 GSR-T

For a Divided GT42R on an undivided manifold, I think it spools pretty well, not to mention it holds torque far better than the second graph, which looks like a GT30R on the ragged edge, look at the graph torque drops 125ft/lb in 3k rpm....

I have seen far more T67 graphs that look way laggier than the top graph..........

tony413

a drag strip car DOESNT make a good circuit car
a good circuit car DOESNT make a good drag car.
that being said.
graph 1= circuit (you want a smooth transition of power)
graph 2= drag (you dont want that on/off power on a circuit)

96 GSR-T

Correct, not to mention Graph 2 makes 500whp about 1500rpm sooner, now look at Graph 1's old tune and tell me what you think of it.......

tony413

haha the old 600hp tune was diffinately for a drag car. what was the owner going for?

i would still pick the 500hp tune simply because when you hit the apex of the corner and you are exiting, the 500hp tuned car is going to be more controllable in any platform. the 600hp car is just not a good circuit transition, because its like hitting no2 as soon as you get out of the apex, because the 500hp is going to be further down the track when that large rush of power suddently kicks it. the 600hp car will only catch up in straight away but they better be long enough to overtake and get a lead.

96 GSR-T

Its a street car, not a dedicated drag car, and it only sips E85.....

Tune 1 the OP posted:

GSR Cams
Full Headgames Race Head
FR Topmount
4" open DP
GT42R 1.01 @ 18-19psi

Tune 2 I posted

ITR Cams
Custom Port Head
FR Ramhorn
3" DP/Exhaust
T3/T67 Stg5 @ 22psi



On the old tune the car had no boost control, it was just 600whp in every gear and the car was turning 10.7's at 143 or so, I would imagine it had a low low 10 in it with some decent boost control. This tune would RIP on the street.

On the new tune he only got one pass his tranny wouldnt go into any gear but it think it was like an 11.5 @ 133 using AEM's speed based boost.

tony413

500whp running 11.5 doesnt seem right how much does that chassis weight ?

the T67 is lazy but easy 10's at the track however it would get raped horriblely on a circuit, by probably just a guy with a 400hp t3/t4 60trim :p. the GT42 looks really really decent for drag or circuit the curve has a nice transition on it.

96 GSR-T

He couldnt get the car into any gear on that pass, the selector was screwed, otherwise it would of went alot faster. Pretty sure the car is under 2400lb with driver, it use to cut 1.65 60's all day with an open diff, swapped in a Quaife and it still cuts the same 60's....lol

tony413

lmao at the same 60's. i hope he just sold the diff :p

96 GSR-T

Nah I think it got old replacing stock diff's every other pass, not to mention several windows in tranny cases and multiple local track oil downs...... haha

tony1

A couple things to keep in mind. In drag racing, the power made in the rpm band the car sees on the track is all that matters.

Where there is more torque (rpm), there is more hp. HP is what matters....

If you guys read that article and still want to question it based on what somebody ran at the track then you need to read the article again..

96 GSR-T

I am pretty sure I understand Tony, this is where a flat/linear powerband take over peaky powerband correct? A car that makes 500whp at 6500 and carries that to 10k is going to destroy the car that makes 425whp at 6500 and it takes until 10k to reach 500whp, just to shift and be back at 425whp, or is it just too early for me to be commenting on technical stuff?

tony1

Correct. The car with the most average hp will win, assuming all other things are constant.

black_EM1

This explains why my car runs so slow at the track. That, and I can't drive. Thanks for the helpful info, it's good to see some discussions back in here again.

tony413

more power over the same amount of distance.

Tony the Tiger

What if traction is the main issue, say a big power street tire car? From that, I would think that a flat torque curve with linear HP would be better instead. Everytime I see a car with huge torque but steady dropping (but with a flat HP though), it just blows the tires loose; although for the same given HP, a flat HP curve will be the fastest in the straight line with 100% traction.

In the world of road racing for example, handling is always first but power comes second. Cars are tuned to make the most power than the car itself (traction, susp, chassis, etc) could handle. I always see cars like like Indy, F1, LM, etc... would have a flat or even rising torque curve instead (peaky powerband) because traction is even harder to attain when the car is accelerating during a corner. When I tried to tune my Integra this way with a totally linear HP curve, I have discovered way more traction and the car hooks pretty way better than my typical horsepower curve.

Here's my low boost (car hooks well even on winter tires):

tagperformance

I'm pretty sure with some more compression and a good turbo manifold it would spool alot sooner and there are other variables that can be factored in to improve the 1st graph. I was looking at how much sooner graph 2 was making alot more power and not the torque curves. even though i see graph 2 falls of quite a bit it does hold its power across the power band.