Power Differences Between Shootout Modes

[SPIKO]

I hope I havn't oftended you Champ, this was not my intention, I am just stating my point of view!

[MercuryXr6Turbo]

Further to the last 2 posts... why is there such variances between dynos? Sometimes even different workshops, but same brand of dyno (Dyno Dynamics for example) are used but figures can read so differently as Bogan says. Does the tension on strapping the car effect it or something the workshop does to get a better "on paper" figure???

[mattyb]

I've juyst been showing this to some mates and we are in a heated discussion, I've asked this before but can't find the thread where I asked it...

My car runs 359rwkw and 1000+Nm when run on a mainline dyno in gear 3 of 6 with the ZF auto. What difference would I see being run on the same dyno, in 4th. Some people have their cars tuned in 4th and some in 3rd (six speed boxes). If I had my car dyno'd in 4th would my power readout be higher/lower and by approx how much, and I'm assuming my torque would be down, but by how much??? Please help as due to the excess alcohol consumption today the arguements are flairing up... ONE TIME!

[SPIKO]

It depends on the tune fellas! Most tuning is in fourth on a 6 speed, if the car feel good and goes like hell don't worry bout the dyno figure!!!

[(BOOSTN)]

all pretty close results, beside the hot spot reading..thanks for that

[gtrskyline899]

Mainline FTW!!!

[bigpsi]

interesting to see the results, so many people just want to see a big number come up on a screen I guess this proves that a dyno power figure isnt everything...

[kartman]

It depends on the dyno, the Dynamic Test Sytems Dyno I use cannot be fudged without leaving evidence, strapping can effect power on dynos that don't connect the rollers, as the cars lift off the rear rollers they no longer need to be driven and less power is consumed more is read. As a law of physics, it takes more energy to accelerate a mass faster than slowly. So a dyno should give it's highest reading static, no acceleration as no power is being used to accelerate the rollers only to maintain the speed. On a fast ramp rate, rapid acceleration, the measured power will be less as more power is consumed accelerating the roller and drivetrain mass. A slow ramp rate will produce a higher reading. The difference between 3rd and 4th if the rate of acceleration does not change is the windage, this is the drag on the wheels and moving parts, gearbox internals and alike. Dyno Dynamics dynos produce higher power figures at faster ramp rates, this defies physics, it is the opposite to one of Newtons laws. This is why I personally take little credit in the readings off them.

[Turbo6FG]

If you really want some good info on how dynos work there is a 4 part article on the Nizpro forum called 'Dyno numbers why so different?'. It's very interesting though it might take a week to read it. Explains all about different dynos, their advantages & limitations, how people fudge the numbers & how they can be misused.

Once you read it you realise why dynos are just a tuning tool. There is no governing standard between different dynos. Generally they are fairly close but sometimes they are way out.

I used to take the numbers seriously but now just quote them for fun & to impress mates with Holdens who are none the wiser.

[kartman]

There is more to it than that, Thd DTS Prodyne is the only dyno to have connected rollers, front to rear, here is something we did to demonstrate why.

http://s226.photobucket.com/albums/dd214/4wheelinls1/?action=view&current=Howtocheatthedynorollers.mp4