Dyno depression - poor results

[Harley103]

Finally took the mustang to a highly rated dyno centre near me today for a power run. I was curious having added a Steeda CAI with the restrictor now removed, a cat-back H pipe system, and a JDM tune which has greatly increased throttle response and drives silky smooth.

Firstly, here's the figures for power at the rear wheel. Always much less than stated flywheel power but I don't have any other specs to compare it too. This is the 'real' figures I suppose that no one normally shares

Now, onto the predicted flywheel power figures and....

Ta da! 416hp, 281ftlb torque Less than factory power specs in the first place. Cant say I'm too pleased.

For info, the car was running on 95 octane fuel, its my daily driver and shell nitro is 26p per litre more near me. The tuner said I could probably expect about 10hp more with 99 fuel in it.

Also I was running the stock P-zeros. Without bringing the subject up myself the tuner mentioned my tyres seem to hard as there was no slippage at all on the dyno which indicated to him the tyres are a bit too hard for normal use. He again would expect another 10hp at the dyno with better tyres.

What's your thoughts folks? I've seen others on here with 440hp dyno figures from similar set ups.

P.S it could be worse. There was a R33 skyline in the workshop that morning with a completely toasted engine. The owner said he put 3 litres too much oil in the engine :headband: Cylinders 2-6 compression 140. Cylinder 1.... 46

Sponsored

 

[robertwsimpson]

is it just me or is that running super rich? I haven't looked at air to fuel ratios on these cars yet, but wouldn't a 13.5-14 make a lot more power and be relatively safe? Please don't roast me if I'm wrong!

 

[Harley103]

The dyno tuner did comment that the air fuel ratio looked spot on to be fair, can't imagine JDM screwing that up either

 

[robertwsimpson]

I'm guessing it feels stronger than stock?

 

[Centurion07]

Can't see the pics.

What was the whp?

 

[Harley103]

Ah damn pics do my swede in...

Whp was 320hp at 7000rpm and 291 ftlb torque at 4583 rpm

 

[Centurion07]

I'd get it tested somewhere else.

Mine made 360 at the wheels as standard, 370 with the PMAS intake but have no idea on the flywheel figure and it made my brain hurt trying to work it out!

Either his calcs are wrong, the dyno is iffy or your car is seriously sick to the point where you couldn't not notice.

Does it feel down on how it felt before the mods? You sure the map and restrictor removal are compatible? Might be worth asking JDM to double check their side of things?

 

[Manders Mustang]

Pictures aint working; but that's incredibly low o.0!

 

[Centurion07]

Pictures aint working; but that's incredibly low o.0!

Yes, 320 IS low. ;)

 

[Manders Mustang]

Yes, 320 IS low. ;)

for the gt you tool :lol:

 

[Centurion07]

 

[Gibbo205]

Finally took the mustang to a highly rated dyno centre near me today for a power run. I was curious having added a Steeda CAI with the restrictor now removed, a cat-back H pipe system, and a JDM tune which has greatly increased throttle response and drives silky smooth.

Firstly, here's the figures for power at the rear wheel. Always much less than stated flywheel power but I don't have any other specs to compare it too. This is the 'real' figures I suppose that no one normally shares

Now, onto the predicted flywheel power figures and....

Ta da! 416hp, 281ftlb torque Less than factory power specs in the first place. Cant say I'm too pleased.

For info, the car was running on 95 octane fuel, its my daily driver and shell nitro is 26p per litre more near me. The tuner said I could probably expect about 10hp more with 99 fuel in it.

Also I was running the stock P-zeros. Without bringing the subject up myself the tuner mentioned my tyres seem to hard as there was no slippage at all on the dyno which indicated to him the tyres are a bit too hard for normal use. He again would expect another 10hp at the dyno with better tyres.

What's your thoughts folks? I've seen others on here with 440hp dyno figures from similar set ups.

P.S it could be worse. There was a R33 skyline in the workshop that morning with a completely toasted engine. The owner said he put 3 litres too much oil in the engine :headband: Cylinders 2-6 compression 140. Cylinder 1.... 46

1. First of all did you tell JDM you had the Steeda CAI and had removed the insert?
2. What gear did they run the car in?
3. Wheel dyno's cannot calculate flywheel accurately, using a set percentage such as 15%-18% gives a rough estimate, but if you want more accurate flywheel figures you need a maha, hub or engine dyno.
4. Octane 95 does not exist in the UK, our fuel ratings are in RON, as such RON 99 (Vpower / Tesco 99) is equivalent to Octane 93. So did you tell JDM you were running Octane 91, 93 or 95?
5. This is why wheel dynos are absolute BS, because yes tyres, tyre pressure, wheel size, gearing can impact the result, a maha dyno cannot be fooled, due to how it calculates flywheel power. The Pzero should not spin up, its actually a soft tyre, only 220 wear on the treadwear ratings, hard it is not and if this is a highly regarded dyno shop he does not seem so knowledgeable and if hard tyres were an issue then he could simply spray WD40 on them.
6. Also was the car cooled down before running or did it go on hot?


If you want to do dyno shootouts Maha's are best due to their flywheel accuracy, otherwise dyno's are simply a tool to measure before and after modifications.

 

[Harley103]

Rear wheel figures


Estimated flywheel figures


1. I told JDM I had a Steeda CAI and confirmed 3 times the tune would allow me to remove the insert. Steeda's engine damage warning for removing the insert without a tune made me super nervous of this.
2. They ran the car in 4th gear. I know sod all about dyno's just went along with what he said
3. He did state the flywheel calculations aren't accurate, but still..
4.My mistake typing octane 95 above. I told JDM specifically I was using UK 95 which I believed to be equivalent to US 91. Again, was a bit nervous of getting a mix up so I was quite specific with them to get the point across.
5. point taken
6. Car went on reasonably hot, had travelled 20 miles to get there. Obviously there was a front fan and a rear extractor and he said that the intake temp was 25C

And Centurion, the car always felt healthy to me. Yes I fitted the exhaust and CAI on day 1 but it felt great. The JDM tune I had later on made the throttle response feel so much better. The car feels lovely, runs silky smooth. Wish I'd never bothered now but I can't undo thinking there may be a problem!

I've never heard of a Maha dyno before, don't even know where to start looking but I'm going to have to give it a go to sleep at night

 

[Gibbo205]

1. I told JDM I had a Steeda CAI and confirmed 3 times the tune would allow me to remove the insert. Steeda's engine damage warning for removing the insert without a tune made me super nervous of this.
2. They ran the car in 4th gear. I know sod all about dyno's just went along with what he said
3. He did state the flywheel calculations aren't accurate, but still..
4.My mistake typing octane 95 above. I told JDM specifically I was using UK 95 which I believed to be equivalent to US 91. Again, was a bit nervous of getting a mix up so I was quite specific with them to get the point across.
5. point taken
6. Car went on reasonably hot, had travelled 20 miles to get there. Obviously there was a front fan and a rear extractor and he said that the intake temp was 25C

And Centurion, the car always felt healthy to me. Yes I fitted the exhaust and CAI on day 1 but it felt great. The JDM tune I had later on made the throttle response feel so much better. The car feels lovely, runs silky smooth. Wish I'd never bothered now but I can't undo thinking there may be a problem!

I've never heard of a Maha dyno before, don't even know where to start looking but I'm going to have to give it a go to sleep at night

1. Double check with JDM on this that the tune they supplied you should remove the insert.
2. 4th is the wrong gear, that is why your torque figure is so low. On a dyno you should always run in the gear closest to 1:1, so they either are not as clued up as they making out or their dyno has a low top speed limit. On the Mustang 5th is closest 1:1, this will yield the correct torque figure.
3. Good, find a place with a maha, where in UK are you?
4. Octane 91 gives around 10-20BHP less than Octane 93.
5.
6. IAT sensor is not always issue, could be something else hot, the car has a lot of sensors if something was a little too hot the car can pull timing quickly, though you can normally see it in the curve.


The best way is a dyno day for Mustangs, because then you can compare with other cars and if stock cars are making more power than you, well you have an issue. ;)

 

[robertwsimpson]

from my experience, doing a pull in a higher gear will nearly always result in higher numbers. Have them do a 5th gear pull for sure.

Sponsored