perhaps that's the problem, a dyno needs to be run in the closest gear to 1:1... for the 6 spd manual its a 4th gear pull...

 

Really? 1:1 ratio or closest... hmm... I looked up the C32 and it's gear ratios are as follows...

Gear Type 5 Speed Automatic w/ Touch Shift
Final Drive 3.06:1
1st Gear Ratio 3.59:1
2nd Gear Ratio 2.19:1
3rd Gear Ratio 1.41:1
4th Gear Ratio 1.00:1
5th Gear Ratio 0.83:1

So, presuming it's the same transmission... maybe that WAS the problem!

Thanks Derek! I think I'll call Paul tomorrow and ask him if it's supposed to be that way on the automatic too... if so... maybe he'll give me a discount or free retest.

EDIT: Funny thing, if you multiply the HP numbers I got on my last dyno run with the second gear ratio, you get the stock HP numbers for the C32 AMG (354 HP).

 

At least, through your use of the AWD powered Mustang Dyno, you were able to achieve full RPM. I'm going to try to find one in Los Angeles when I get back home...

I forgot you are running a auto trans... My previous post may not apply to your car... I have no experience with them on a dyno...

 

Go to the Mustang Dynamometer site and use their locator... it should help make your search easier.

Hint: look for any of the MD-AWD series...

 

Well, it seems we're all still pissing in the dark. At least we now know that full RPM can be achieved on a front roller powered AWD dyno. Thank you MMZ ! Although something is still amiss with a the #'s as we all know.

I know I can get to 5,000 RPM on a rear wheel dyno with the removal of certain fuses, then the engine mysteriously cuts-out (same with Woody). I think we'll eventually get down to the bottom of this, with a few more experiments.

When I return to LA, I'll see if I can track down a Mustang AWD powered dyno and see if it will allow me to get to redline also...

I'm wondering if the AWD dyno reads the the power being delivered to the front wheels and factors that in to the overall HP/TQ readings. And since our cars are only rear drive, it mathematically adjusts the readings.

For example; if you put a AWD 100 hp car on the AWD dyno and all four wheels are putting power to the front and rear rollers, it would read 100hp. But, if you put a 100 hp rear wheel drive car on the AWD dyno and it senses that there is no power being delivered to the front wheels, would it think there is a 50% power loss and read 50 hp ?

It sounds theoretically possible. This could explain MMZ's #'s... Because in my opinion, they are about 50% less than what they should be for a SRT6.

 

According to Paul, he had it in the 2-wheel drive mode, but with the rollers still linked. And he has done another 2-wheel drive vehicle over the weekend without issue (again with the front and rear rollers belted together).

I've set up a second appointment with Paul at EIP Racing for wednesday and we will get the Mustang Dynamometer guys on the phone prior to doing the first run and let them run Paul through the settings to see if anything is amiss.

Also, I will probably pull fuses 17 + 18 ahead of time... should I pull the Anti-Lock Brake system fuses too?

 

It wouldn't hurt... Or you can just pull the single fuse in the ECU housing that feeds the entire system. I have photos of this fuse in a post somewhere... I think it's #3 from the front on the right hand side of the ECU as you are looking into the housing...

 

The car makes less boost in the lower gears as well. The engine revs so fast that it cannot build boost. This has been tested by us C32 guys and the car makes like 10 psi in 1st gear, 11 psi in 2nd, 12 psi in 3rd, and 14 psi in 4th and 5th gears. So you are down 3 psi from max boost by testing in 2nd gear. We always run in 4th gear on the dyno and get about 293 rwhp and 300 rwtq.

I just looked at a full pull through the gears and my 2nd gear maxed out at 265 rwhp.

 

Yeah, 4th will be preferred, but there is definitely something else out of whack...

I'll keep you posted.

 

OK, I may be WAY off base here since I've never actually used ANY dyno before, must less a MD-AWD, but in 2-wheel drive mode does the dyno adjust for the inertia required to turn the front roller if they're still linked? Or does the dyno assume that if it's in 2-wheel mode that the front roller isn't connected?

If your car is spinning the front roller too, but the dyno doesn't know that it's still connected, it seems like that would have a noticeable effect on the results...

Again, just a wild guess from someone with no first hand experience.

 

Grant, I was thinking the same thing as you.
In 2wd mode, I bet the belt is supposed to removed, or the front rollers unhooked somehow.
So...like you said, the dyno computer thinks the car is just spinning the rear rollers and measuring horsepower based on that, when actually the car is using up extra horsepower to spin the front rollers also.

 

Grant & Eracer76,

Nope... these dynos have the rollers linked to get around at least major issues with modern vehicles.

1. AWD vehicles with special computer controlled limited slip transfer cases.

2. RWD vehicles that have a ESP (Electronic Stability Program) in which the computer gets REALLY annoyed with the front wheels standing still and the rear wheels spinning like mad. Generally the ESP thinks you are spinning tires in the rain or mud and it cuts the engine power down to protect the drive train.

Hope that helps.

 

OK. I wasn't sure if the dyno was made for situations like yours, or if it was made for AWD and the belt should have been removed.

As long as the results factor in that your rear wheels are having to spin BOTH rollers...

 

Whoo-hoo... Got the answer from Paul (the Technician).

He called Mustang Dynos before I came and said that the problem was the dyno was 'set' in 2-wheel mode, with the rollers connected by the belt.

With that extra mass and being in 2-wheel mode, the calculations are incorrect.

So, we threw the SRT6 back up on the dyno and lo-and-behold 249 HP @ 5,750 RPM and 252 FP Torque @ 4,500 RPM. The curves look almost identical to the ones I posted previously. I'll scan it in later tonight.

The only thing preventing more HP out of it is it forces the transmission to shift... I suspect a manual will have a better time of it.

Also, we ran this test in 3rd gear... he was reluctant to do 4th because of the RPM of the rollers becomes VERY high.

I'll take this as a good baseline and probably the car was de-tuned some for California... at least compared to the 275 HP on the SRT6 dyno from the UK.

Next stop... Pulley set and Upsolute Upgrade... I'll be doing dyno runs after each mod.

May do the Upsolute first as it's the least expensive of the two.

EDIT: Oh yeah, Paul didn't let me pay him this time because the dyno wasn't set right the first time.

 

MMZ: You get a gold star for the day. I would love to see the printout even though I run the N/A... I would like to compare the torque curve and Air/Fuel ratio.

Good work. This has been a perplexing problem for a few years now, especially for my use of the car, now I know a viable way to start really tweaking the HP out of my car... I would also like to compare the % of powertrain loss between the auto and manual...

I'll definitely track down a MD when I return to LA after this job...

Again, KUDOS !!!

 

Here you go sir...

I don't have the A:F numbers, but I can tell you that it was almost 11:1 across the entire RPM range... REALLY clean.

 

So...basically Grant and I were right after all.

 

Yep, you were... even the tech misunderstood... so we all learn something...

He retested for free... so I'm not complaining...

 

No, you can't beat that.
Your numbers still seem kind of low though. There shouldn't be a 80 hp loss due to the driveline. Maybe its because it was done in 3rd gear which isn't 1:1?
It seems like it would be hard to do a real pull on the dyno with an automatic that likes to down and up shift on its own, even when in manual mode.

 

Hey alright!!! That's a really sweet looking Torque curve, I'm now curious as to how the torque curve looks on the Limited. Can't wait to see what HDDP gets out of his car.
Since your losing 24% through the drivetrain, I'm guessing the standard tranny would see a waste of about 19-20% loss, so my stock limited might put down about 174 hp to the ground. I would be happy if I could hit 200 hp with future mods. We'll see what HDDP gets.

Good Job Timelord.