Horsepower explained

[KingLamoni]

So when I dyno my GTS should I have the test done in Drift mode?

 

[turboAWD]

So when I dyno my GTS should I have the test done in Drift mode?

If it's a 2-wheel dyno, I believe that's a yes.

 

[General_Vodka]

All I know is that CHP means California highway pirates and I don't want those anywhere near my cars lol.

 

[turboAWD]

All I know is that CHP means California highway pirates and I don't want those anywhere near my cars lol.

You and me both, friend..

 

[KingLamoni]

Seeing that the turbos on the car are smaller would also explain the PEAK TQ numbers down low. The compromise with that is that smaller turbos efficiency are in the lower end, and become less efficient at higher RPMs or speed. There is really where the PURE turbo upgrade or others could improve here. You would shift the power band to the right, lose lower PEAK power, but gain it on the top.

Looking forward to seeing where those aftermarket kits are heading.

I recently found the PURE turbo upgrade and am very interested in it because it is a "bolt on".

 

[turboAWD]

I recently found the PURE turbo upgrade and am very interested in it because it is a "bolt on".

Bolt-on how? You're going to need a flash tune for those, minimum.

 

[KingLamoni]

Bolt-on how? You're going to need a flash tune for those, minimum.

What I meant is they are a direct replacement for the factory turbos. The ECU I know will need remapped.

 

[turboAWD]

What I meant is they are a direct replacement for the factory turbos. The ECU I know will need remapped.

Ok. And, based on FP's experience, a built transmission as well..

 

[Brandondrums]

I think standards for advertised HP rating needs to be updated. They are all inaccurate and each manufacturer (can) report them differently and sometimes the country of origin dictates a different method even for exported cars.

An example is that for quite a while in Japan, cars couldn't be made to have more than 280 advertised HP. The result is plenty of cars making far more than that in reality like the R32 Skyline or Subaru 22B which were absolute monsters with just "280hp". Reality is that they were 350+

Anyway, the Stinger is almost certainly being rated by it's "usable" power which some German manufacturers do like BMW and Porsche. AKA power at the wheels after drivetrain and accessory losses. I'm sure American manufacturers will claim bench dyno numbers of the engine without any accessories being driven. So it's not just transmission losses but also from steering pumps, alternators and AC being taken out of the advertised power. That explains why a Mustang GT with 465 HP is slower to 60 and the quarter than a stinger. The stinger might literally be making more power than the 5.0 if tested the same way on the bench.

All that aside, as the OP pointed out, having all that torque down low is a major advantage for acceleration. The average HP being made throughout the rev band is actually much higher than say a naturally aspirated engine making more ponies at peak.

Example: A 2015 Porsche Carrera 4S is rated at 400 HP. It makes peak HP between 5,500RPM and 7,000 RPM. The Stinger is every bit as fast through at least 100 MPH and weighs nearly 800lbs more (my dad has a '15 4S). Why? It's making more actual power at every part of the rev range except at the top than the 911 by a good factor and has 8 gears instead of 7 so it can stay in the power band better. Every shift on the 911 drops the power significantly - almost 100 in some cases. A shift on the stinger might not drop power by more than 30 ponies.

Breakdown:
WOT HP of the Stinger at 3,500 RPM is 350hp at the wheels.
WOT HP of the 991.1 C4S Porsche at 3,500 RPM is 160hp at the wheels.

Punching it casually from a cruise gives the stinger a nearly 200hp advantage in this case. This strategy will play out against endless cars on the street. This is why Tesla's are absolute legends of acceleration. Torque distribution matters more than power for stoplight to stoplight and butt dyno feel.

Stinger:


Porsche:

 

[Eastcoaststinger]

Correct. A dyno measures whp (wheel horse power). "Typical" (hotly debated) drivetrain losses are something like 10-15% for FWD, 10-18% for RWD, 17-25% for AWD. Just roughly: a 3.3TT Stinger engine might have 400 hp when tested all by itself (removed from the car on a stand) - that's "chp" - crank horsepower. Chp is the number you see in all the magazines, manufacturer's claims, etc. It's obviously the higher number, so they'll quote that.

Using a 20% drivetrain loss (friction, etc) for an AWD Stinger, 80 of those hp get turned into heat, and there's only 320 hp measured at the wheels. An RWD Stinger might measure (400 - 10% = 400 - 40 = 360) 360 hp measured at the wheels. Of course, those are the "worst" and "best" cases. For the Stinger, it might be 15% RWD, 20% AWD so that the numbers are much closer. Or not. You'll get all kinds of debate over the "actual" number, and it's hard to know, because you'd have to remove the engine from the car to get the REAL chp value, THEN dyno it in a given car to get the whp value.

And each car might be slightly different due to manufacturing tolerances. If the typical Stinger has 390 chp +- 5% (min 370, max 410, roughly) and RWD losses between 10-13% and AWD losses 17-20%, then the worst combination - 20% AWD with 370chp = 296 whp. Best case, RWD 10%, 410 to start = 370 whp. The guy with 296 whp would complain he can't get the same 1/4 mile as everyone else, and the 370 whp guy would be declared a "factory freak". Yet they're both "within spec". They all got at least 365 chp, as advertised.

Most videos I’ve seen with stingers on the dyno show the same or nearly the same hp and tq numbers between awd and rwd

 

[Justin B]

Horsepower is how fast you hit the wall.

Torque is how far you move the wall.

 

[MerlintheMad]

Horsepower is how fast you hit the wall.

Torque is how far you move the wall.

I get to share this again (someone on here a couple of years ago posted it to clear up my mislabeling of oversteer and understeer. )

 

[Regs120]

Torque is basically the force the engine exerts to put its power down to the ground through gears and the axles while horsepower is the cars actual ability and capacity to accelerate to speed in a given time. So in race cars the quicker you can push that power through the gears the better, but obviously you still need horsepower to keep up that force through the bigger gears.

 

[rpoffen]

Torque is a measure of static rotational force. That is why it is measured in lb-ft (or equivalent metric rating of force at a certain distance). 1 lb-ft is the torque of pushing at the end of a 1 foot long rod with a force of 1 pound.
Horsepower is the measure of actual work performed. Since torque is a static force, it alone does not do any useful work. Torque while rotating does actual work, so it is measured in HP.