NoHope

Recently had my car dynoed, produced 326 RWHP and 347 RWTQ. I thought the drive train loss was about 18% for an automatic, but someone on another forum said it's not that much.

If it is 18% loss that means my car should be making 384 HP to the flywheel.

Also, don't know if it matters but it's an all stock tranny with 2.73's in it.

94 White T/A

15% is probably closer, but 15-20 is the guideline. with a ls6 intake, LM1, lid, and tb, 326 is nowhere near extraordinary. remember these engines actually made 350 at the crank, so minor bolt ons will get you close to that at the wheels

Bazman

It's not an exact science as there are more variables with an auto and converter than with a stick shift. 19% is an accurate drivetrain loss on one combination I know of between engine dyno and chassis dyno.

Also a T56 has picked up 38rwhp on same car/engine over the auto.

But those figures are specific to the comb and your results might vary.

I doubt it would ever be as little as 15% however, maybe with a custom lock up that can handle full throttle in 3rd?

I work on 19% myself for an auto and converter and 12% for a T56, but that is on something over 450rwtq.

ramairws6

iTrader: (33)

Mine was exactly 20% so ya, lots of variables...

NoHope

How can you figure out exactly what your drive train loss is? Dyno's record horsepower put to the wheels, but not to the crank of the engine right? I'm a little new to this stuff.

94 White T/A

You'd have to pull the engine and dyno it at the crank, then put it in your car and dyno at the wheels the difference between the two is the loss.

And yes, these guys are right in saying a 4l60e is closer to 20. It was late and i said it wrong. 15-20 are the guidelines for most vehicles, 4l60e being on the higher end because its an auto, the T56 will be at the lower end being a manual

ramairws6

iTrader: (33)

I broke my motor in on the engine dyno and then tuned it after on the chassis dyno. Can't get anymore accurate then that!

CurtDrums

Your calculations should be:
326/.82=397.56hp

DANOZ28

iTrader: (1)

if your ? is the diff between stick & auto on the same dyno its about 15rwhp.

NoHope

Thanks!

john kilgore

l don't think the energy lost is constant. The parts in the 700-4l60e are heavy. So if you spin it quickly it will take more power then if you do it slowly. lt's all about time. The differance between walking and running.

5.7stroker

iTrader: (36)

Thread bump.

If car A below has say 425 rwhp on a dyno, how much rwhp would it have if it had the parts in car B instead, all else the same? How much at the flywheel? Trying to get an idea what dyno and flywheel numbers would be if my car was manual even though ET at the track tells the whole story anyway. Just curious.

Car A: 4.10 gears, Dana S60, 4000 stall, 4l60E
Car B: 4.10 gears, Strange 12 bolt, T56

PBA

On the dyno the numbers between a manual transmission and automatic transmission can be large as the torque converter is not multiplying torque on a dyno as when accelerating. Locking up the torque converter clutch will bring the numbers closer between the two. A manual transmission will always give better numbers as there are no pumping losses as with an automatic transmission. The 12 bolt takes less torque to spin than the Dana 60. John Kilgore and I have discussed this many times over the years and it is all about time, as the energy lost is not constant.

5.7stroker

iTrader: (36)

I've read that a good rule of thumb is to divide by 0.85 when going from a T56 to a 4000 stall to estimate the number on a dyno with the converter locked. So 425/.85 = 500

A S60 robs 5% hp on average over a 12 bolt.
500 * 1.05 = 525

This 100 hp difference sounds ridiculous, I'd say 60hp difference max. So 485 seems more realistic assuming both setups are on a mustang dyno.

98CayenneT/A

Trap mph

5.7stroker

iTrader: (36)

123mph with a weight of around 3400 would be my guess.

Jays_SSZ28

iTrader: (2)

Anyone on here dyno their own Automatic and six speed cars on the same dyno one after the other?

No? Then how are you giving numbers?

I have a 2002 SS M6 and a 2001 Z28. The Z28 is an exact clone of the SS. I used all original parts from people parting out their cars back then. I did the tuning on both. Same modifications, same day, same dyno.

The A4 car put down 333 hp.
The M6 put down 326 hp.

Both in 1:1 trans ratio.

How does that play into the theories. I know, it doesn't. It's one car vs the other, but if thats the case how can a person say that an manual trans car will put down x amount hp more than an automatic....

Game ova

Put down 765/910 with the 6 speed. 742/1045 with an unlocked auto (th400). Same dyno... same weight (mustang dyno).

https://youtu.be/2GkXM1cT5Ts

https://youtu.be/r8Kw46Mu-ps

Jays_SSZ28

iTrader: (2)

So a manual doesn't make more power?

Is that the same car but different day? I can only get one video to play.

Game ova

Manual does, but it's not as drastic of a difference as most people think. And yes, different day.... but nearly identical conditions.