He knows that he is talking about, but he is just wrong. One of those people that have spouted crap for so long that they now believe it is actually true. I believe its a psychological disorder, he is probably quite medicated just so he is not a danger to the public :)...it similar to believing in religion, pure mentalist deranged behaviour!

Didn't notice you'd left! haha.


Just kidding. Was like a black curtain fell when you got banned. :D


At least we all get a temporary reprieve from the WRX vs STI aRSe_**** bollox. Thank god!

American conversion to go from whp to fwhp is whp * 20%

Superior drivetrain.....You couldn't make it up..:lol1:

I'm really surprised the other two Wrx stooges never had his back on this occasion as they usually do...

Hasn't Dykmuncher got a job as a secret agent for the Russian military and is currently cruising the South China seas in one of his yachts?

Oh, maybe that was just one of his other dreams.

Apparently he doesn't come on here much anymore(so he says) Rumour has it he is busy trying to master his 48th fighting style...

Mine 05 sti puts down around 270whp through it's boots, loses around 50hp through the drivetrain, when put together gives me a printout for 322bhp give or take as a median and that's at surrey rollers. Either way i prefer to know the whp as that's the end power your putting down and playing with, to me engine horse (bhp) is just an estimate used for bragging rights.

Only thing with using a percentage to calculate transmission loss is that as the power increases so does the loss, but why would there be an increase of a loss as the power rises, using 20% loss at 1000bhp you would lose 200bhp, compared to 60bhp at 300bhp, why would you lose an extra 140bhp all of a sudden? not saying it's wrong or right just curious!

isnt it just % loss through heat/friction?
i dont know but thats my assumption

Good article

http://www.superstreetonline.com/how...in-power-loss/

Obviously every car is different and there are many factors contributing to transmission loss. The total power lost between combustion and forward motion is specific to each vehicle and therefore no single rule, percentage or fixed number, could possibly apply to all vehicles.


You're talking about losses from various areas including; Air friction, oil friction, bearing friction, oil seal pull/friction, rotating masses, forces of inertia, drag, windage, pumping, heat and more, all of which are different for every engine, transmission and driveline design.

Interesting, so basically every car is different and you can't apply a general rule! :)

Pretty much, something with permanent 4wd is never going to have the same transmission losses as fwd/rwd.

Would be interesting to see several cars at differing power levels do b2b runs on hub dyno a and dyno dynamics and see if there is a pattern

In theory, shouldn't a wheel dyno be able to accurately calculate the transmission losses?

If the car is at a certain speed and you put it into neutral, then with a theoretical zero-loss transmission it is only the friction of the dyno itself that will slow the machine down. But the rate of deceleration will be greater dependent on the transmission losses, so could be calculated.

I would have thought?

Won't be zero loss from the car though, the front diff, rear diff, prop, gearbox, driveshafts, bearings, seals, brake friction, tyres, oil friction & air friction on rotating car parts will all slow it down.

Never said it was, but maybe not as clearly written as I thought :)

You can measure the deceleration of the dyno itself with no vehicle on it (test conditions, if you like) and get a base point of the machine's losses.

Then when a car is on it, knocked into neutral, you could (in principle) measure the deceleration...do some maths...and get a (more) accurate measurement of the specific vehicles losses?

This is true. That doesn't sound like a bad idea to be honest.

Do we know how the dyno software calculates the flywheel power from its true wheel/tyre inputs?

Hmmm....just Googled this and it seems some dynos do this. Doh!

Whether it is accurate is another matter.

I thought it measured mechanical drag on run down somehow. Sure I'd read that somewhere before. Lol.

Problem with putting the car into neutral is you're then removing the various friction/pumping losses associated with the engine. Best way to do it would be just to get off the throttle and let everything coast down to idle.

Agreed - think they call it "coastdown losses". But perhaps it's no better than a fixed % in practice.

I remember asking Charlie at Surrey Rolling Road about this a few years ago and, whatever the technical answer is, his advice was to use the same dyno all the time, one that's consistent, and look for changes/improvements each time rather than absolute figures.

But we *all* want the bragging-rights flywheel figures, don't we :norty:

I completely agree. All dynos will give different results, so stick to the same one, look for improvements and always road test to see if it drives better afterwards. Don't chase numbers, it starts to get expensive! :)

Has Trinity been banned too????

Probably. He brought the whole "WRXs are poverty spec" to a DV thread.

Trolling gets you banned (eventually)

Yes, the loser has been banned once again! :luxhello::thumb::lol1:

Well that brief visit didn't last long! LOL


Looks like the whole DV thread was deleted too. Shame. I made some good points in there, shame to delete the whole thing. Was no where near as bad as other threads that seem to remain. Very odd.