Dyno in third gear? ( W58)

[Jorrs]

perhaps ? though maybe he had his reasons.

[rxbenny]

the power output is wank factor, a dyno is a tuning tool and you will get different power readings based on many variables.
Find a shop and get your car dynoed there consistantly to find out how much difference each mod does.

i am sure he had his reasons cos if he wanted to hide the 3rd gear fact would he have noted it on the dyno printout.

[Lench]

what about automatics?
there were a few soarers at the last dyno day i went to and they were all autos (im guessing 3 speed auto?)
so do they wind it up til it changed to 3rd? or do they take a reading from a standing start?

[Jorrs]

autos they run in 2nd gear. i believe

[LeeRoy]

A friend when he got his car dynoed at a dyno day asked the guy to do a power run in 4th then 3rd. He made 162kw in 4th and only a few % more in 3rd. The difference was so small as in around 5kw from memory.

- LeeRoy

[oldcorollas]

that's kind of what you would expect... if the dyno is set up right..

dyno only knows two things.... torque on the rollers, and speed of the rollers... from that, it works out power.

using third increases torque, but decreases speed... slower speed means less diff losses.. but more gearbox losses.... but the difference in tractive effort means the ramp rate of the dyno needs to be changed etc etc....


meh... dynos...

[JustCallMeOrlando]

If it was a Dyno Dynamics dyno in Shootout mode, you'll find it's due to the speed range that the car is supposed to run through for the most consistent result. This was covered before when Johal had his dynoed.

[RONA]

Just for arguments sake when my car was tuned it ran 110.7rwkw in third and then in 4th made 112.9rwkw and that was on a dyno dynamics dyno.

[TheToyman75]

After the first post these two are the only 2 that should be left here, I almost thought I was at the Fast 4"s forums until I read these:

that's kind of what you would expect... if the dyno is set up right..

dyno only knows two things.... torque on the rollers, and speed of the rollers... from that, it works out power.

using third increases torque, but decreases speed... slower speed means less diff losses.. but more gearbox losses.... but the difference in tractive effort means the ramp rate of the dyno needs to be changed etc etc....


meh... dynos...

If it was a Dyno Dynamics dyno in Shootout mode, you'll find it's due to the speed range that the car is supposed to run through for the most consistent result. This was covered before when Johal had his dynoed.

This is the Tech and conversions section so please don't just parrot what you have seen written somewhere. There is allot of misinformation out there and this thread is a great example of that.

Thanks to Stu and JCMF for a voice clarity at the end of allot of misinformation. A dyno Dynamics Dyno has a range of accuracy and efficiency just like all machines. If not used correctly then the results will be incorrect. As a guide the ideal spped of opperation is 140 kph, hence the power run being done in 3rd gear as opposed to 4th (Not that the result would vary much anyway)

[stradlater]

I didn't mean to cause a whole bunch of indiscretions, it was a legitimate question that I didn't know the answer to.

[CrUZida]

I didn't mean to cause a whole bunch of indiscretions, it was a legitimate question that I didn't know the answer to.

The problem is that its a legitimate question that a lot of people don't know the answer to, yet they feel they need to regurgitate crap they've heard on the forums over the years.

[Joshstix]

Yep it's a legit question and there is a hell of a lot of misinformation out there. Whether it be outdated info that has since been proven incorrect, or simply rubbish that people who like to sound knowledgable have made up.

The dyno manufacturers each have preffered measurement methods. Last time I read the info on this topic from Dyno Dynamics they were specifying that the gear which has the car making peak power as close to 140km/h should be used. There are real world limits to this though especially for cars with very violent transitions onto boost where it is often needed to use a higher gear in order to avoid too much wheelspin.


Edit: You beat me to it Cruz

[Jorrs]

hey the stuff i said wasnt from any forum, was from the guys i use to dyno my car.

[Joshstix]

hey the stuff i said wasnt from any forum, was from the guys i use to dyno my car.

If that's what your dyno guys truly believe then I'd be a bit hesitant in taking too much notice of what they have to say.

Saying that you will get much higher readings in a lower gear isn't really correct. Sure you'll get higher tractive effort readings, but this is an indication of torque which is only half of the story when it comes to power. In order to measure power you need speed as well and in the lower gear the speed of the roller will be lower. This will more or less even out over the different gears.

Having said that, it is very possible that the dyno guys told you what they did because it's easier than giving a valid explanation.

[CrUZida]

A LOT of places that own a Dyno Dynamics dyno have not done the accredited training, and thus will not know how to use it properly.