Dynos that make ya smile!!!!

tbro · Postby **tbro** » Thu Jun 16, 2011 11:33 am

Ok,
I'm no expert like so many others (mean that in a nice way) when it comes to dynos and why my car has more mods than your but your has more killerwasp etc.

I personally take the final figures with a grain of salt but I do compare what I started with and what I end up with to see if I'm going in the right direction.

Torque to me is the ability to pull through the rev range, HP is a fairy figure that make everyone happy!!! (remember I work on units with 500hp and 2000+++ ft/lbs torque)

So, go for your life comparing different figures but at the end of the day "all the bullshit stops when the flag drops"

And please don't rag on that certain dyno, its getting tiring!!!

Terry

Postby **NitroDann** » Thu Jun 16, 2011 11:37 am

No power is the rate that something can achieve work. Torque is a useless figure compared with power, for anyone who has a gearbox. Torque is twisting force, and thats nice it tells you what an engine can move, power tells you how fast it can move it, with a gearbox the engine with the most power wins, every. single. time.

Dann

Ninja edit, its sort of necessary for the new people to know what dyno figures are real and what are rubbish so that they know whos actually getting results for their dollar.

greenMachine · Postby **greenMachine** » Thu Jun 16, 2011 11:55 am

Sheesh, not another power/torque catfight, please :roll:

.

Tbro has it, before and after, needs to be on the same dyno, same day preferably. The corrections can make all the difference, so keep the variables to an absolute minimum.

Dan, there is no reality about coloured lines on a piece of paper, when the variables/fudge factors are so numerous.

Dynos have two important uses where the results have some validity - tuning for performance, or doing back-to-back comparisons between cars or mods. The numbers game is feel good stuff, but if that floats your boat ...

:mrgreen:

PS Dan, you might want to re-read your post ....

Postby **NitroDann** » Thu Jun 16, 2011 12:08 pm

Its been edited. Thanks.

There is no power vs torque. The only people that argue that dont know how the two work, whats they mean, or how they interact. Power is the rate at which you can do work, more power more work, its that simple.

Race teams can dyno the same car within a couple horsepower on different months, time and again. Otherwise how could they perfect the last few horsepower, over and over again. Its just that MOST shops dont give a damn.

Dann

Guran · Postby **Guran** » Thu Jun 16, 2011 2:30 pm

Dann, power is very important but it isn't everything. Just look at Hellmun's performance on the track. His car has only 90kW at the rear wheels according to Mania's dyno, and yet he still does 1:09s at Wakefield! In his case, it's more about having lots of torque across a broad rpm spread (maximise the area under the curve), matched with the right gear ratios, and PLENTY of mechanical grip for corners and braking. Plus he's a good steerer.

For me, the torque curve from a dyno is very important. It translates directly to the feeling of acceleration you get in each gear. If the torque curve drops off at high revs, then you notice it as reduced pull at the top end ... especially if torque decreases at a slower rate than revs increase ie power drops. At the other end, if a car is lacking torque at low revs, then the torque curve gives you valuable information about what rpms to you need to keep above in order to avoid bogging down.

Postby **NitroDann** » Thu Jun 16, 2011 2:38 pm

I agree with you fully.

I never said peak power wins I said power. With any 2 cars, power under the curve is whats most important. I doesnt matter is you do it with 10million nm at 2 rpm or 2 nm at 10 million rpm. Its total horsepower under the curve that pushes you up the road. Torque determines this along with revs, but you cant have a paper drag race with a torque figure, power under the curve only.

This was my point, sorry for being so short an uninformative with it.

Dann

rjastra2 · Postby **rjastra2** » Sat Jun 18, 2011 12:11 am

I thought there was a simple formula that showed the relationship between kW and NM.

The relationship between power (kW) and torque (Nm) is expressed in the formula -

kW = (Nm x r/min) / 9554

or Nm = (kW x 9554) / rpm

Postby **NitroDann** » Sat Jun 18, 2011 10:20 am

yeah, but...

Torque is a measurable force. Power is only able to be calculated from that, knowing rpm at the same time. If you only know a torque figure you cannot say anything about a cars performance at all. With a power figure you can. With an average power figure across the used rpm range in each gear you know most of what you need to.

Dann