dyno dynamics, lower reading dyno?

[Arronleeds 9]

curious to know if anyone here has had their tuned car on a dyno dynamics dyno and compared to another dyno they were tuned on, had mine on today and when the car was mapped in october on a dyno developments dyno it made 440bhp and 413ibft, today on a dyno dynamics it only made 396bhp and 396ibft, seems like a big loss just from a different dyno.

[gregozedobe 1,774]

8 hours ago, Arronleeds said:

 seems like a big loss just from a different dyno.

 

A lot can depend on temp (and especially heat soak), also the settings the operator chooses to use can also make a significant difference, as well as running in 2WD vs AWD.  That said, there seem to be some dynos that are known to be pessimistic compared with other more optimistic ones.  I can't remember the specifics of which dyno is which, sorry.

[Arronleeds 9]

15 hours ago, gregozedobe said:

 

A lot can depend on temp (and especially heat soak), also the settings the operator chooses to use can also make a significant difference, as well as running in 2WD vs AWD.  That said, there seem to be some dynos that are known to be pessimistic compared with other more optimistic ones.  I can't remember the specifics of which dyno is which, sorry.

just find it weird how my car isnt down on boost or showing any signs of a leak, the turbo on my car can produce 440bhp all day long and has done on many many dynos. so how can i have lost 44bhp from dyno to dyno? according to my dyno graph, the intake temps were 11c, i did notice one thing, he ran the car in 4th when my tuner does it in 5th, when i heard the car ramp up, it didnt sound like the run went on for that long either.

[Penguin 1,246]

So many variables I wouldn't worry.  It's unlikely you'd see a repeat output/graph with the same car, on the same dyno never mind on different dynos, at different times. 

 

 

[slider09 1,332]

Exactly why dyno figures are useless; just top trumps bragging rights whilst at the pub (if you can remember those days ).

A little like 0-60 times. Can fluctuate slightly even on a DSG.

If you are worried, go back to the original Dyno and see what that reads.

Temperature, fuel, Dyno, calculation used, how tight the straps are all affect the final figure.


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[veneeringman 542]

I’d be more inclined to do logging on the car rather than believing a Dyno.
That’s the only thing I liked about the JB4, it gives you an insight into boost / ignition etc.


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[gregozedobe 1,774]

The variability of results from dynos are why quite a few people believe trap speed at the end of a 1/4 mile run is usually a better indicator of a cars power/weight ratio.  If you have increased power your trap speed should be higher, if trap speed is the same then you do not have an effective increase in power.

[golf7.5r 352]

 

Welcome to the world of dynos!

 

Check some of these vids out - 

 

[Arronleeds 9]

my tuner does the dyno runs in 5th, this was done in 4th, the intake temps etc were spot on, i had momentum in the car and he also logged it and sent the logs to my tuner. if a turbo is producing the same boost as it was the day it was mapped, surely there is no way the car could be down on that much power unless it was something wrong with compression etc?

 

ive logged it myself and cant see any obvious issues, the only difference from when it was mapped is ive removed my r600 and added another silencer to the exhaust, i know dyno figures dont mean much especially when youre comparing 2 but ive just been sat thinking, surely 44bhp difference means either 2 things, issue with the car or its been fiddled.

[golf7.5r 352]

It doesn't work like that - the dyno is measuring wheel horsepower and the figures you got are flywheel horsepower. There is a correction factor that is added by the dyno operator to do the conversion and some operators are use a very generous figure, especially if they dyno'd your car in 2WD mode as this does not take into account the extra rear diff losses.

 

Different gears will produce different figures too.

 

[Arronleeds 9]

the thing is, if for example i took my car back to my tuner and it was also 44bhp down on that one, and all variables such as temp and fuel were the same, what could cause it to be that down on power? if the turbo is producing the same boost, then would it not have to be something after the turbo thats at fault?

[Arronleeds 9]

1 hour ago, golf7.5r said:

It doesn't work like that - the dyno is measuring wheel horsepower and the figures you got are flywheel horsepower. There is a correction factor that is added by the dyno operator to do the conversion and some operators are use a very generous figure, especially if they dyno'd your car in 2WD mode as this does not take into account the extra rear diff losses.

 

Different gears will produce different figures too.

 

according to the dyno dynamics dyno from the other day, the wheel horsepower was 337 and the flywheel power was 396 thats a difference of 18% which seems like a lot.

[golf7.5r 352]

1 hour ago, Arronleeds said:

according to the dyno dynamics dyno from the other day, the wheel horsepower was 337 and the flywheel power was 396 thats a difference of 18% which seems like a lot.

What hardware have you got on your car?

 

18% is pretty typical for 4WD cars.

[Arronleeds 9]

2 hours ago, golf7.5r said:

What hardware have you got on your car?

 

18% is pretty typical for 4WD cars.

Pikey r600 with turbo technics intake pipe, 3.5" decat to 3" catback, magic intercooler, littco l380x, apr coil packs and ngk r438-8 plugs.