it seems that no one wants to reveal there whp figures

Yes, only pub figures in this thread

P.S I think it's just Nigel that has presented a WHP figure

I made 347 @ wheels but as you know Freddan, you can't compare wheel power between dynos, it's apples and oranges

It states it on my graph i posted earlier in the thread

271wbhp

Ben

I just want to see the difference between Wheel HP and Crank HP.
By the way how do they calculate the Crank HP?

OK, Im not trying to rubbish anyone's power figures here just trying to educate the few on here that do not understand the whole picture

Read this page, all of it!!

http://www.pumaracing.co.uk/POWER3.htm

I think that it would make things a lot more accurate if people quoted WBHP figures then used a single formula for all despite what dyno is used

As Dave from Puma race engine has come up with one we may as well use that

That is

Add 10 bhp to the wheel figure and divide the result by 0.9

This unfortunatly will not take out the accuracy differences from one dyno to another but its a hell of a lot more accurate that quoting Flywheel bhp when all dyno operators seem to be using different transmission losses

In Fleas case they seem to have used nearly 30% as a transmission loss, this seems excessive to me especially as VW and Bosch both work to 15%

AS i said above im not trying to rubbish anyones figures but if we all work to the same formula then at least we will all be singing from the same him sheet

using this formula i got these results

Flea- 396.6 BHP
benny- 312.2 BHP


If anyone else wnats to put up there WBHP figures i can work it out, or you can use the formula above yourself

It would be nice to get some figures from other dyno's as well especially if you have run the same car on differing dyno's, this way at least we can check just how close each dyno is.

thats alot of transmission loss there,my car made 295whp and 338bhp so i have more whp then benny and less bhp then him so thats will confusing whos car as more power then

Well I have 389 WHP and 430 BHP.

On a proper Dyno.

295 + 10 / 0.9 = 338.9BHP your figures are spot on
271 + 10 / 0.9 = 312.2BHP so yours is quicker

Sigh... black and white

I love Dyno debates.

So yours is very close, i think we need to bear in mind they will never be exactly what the formula predicts

Your results suggest that your dyno is conservitive with its results, by 13bhp, percentage wise its very minimal

Funily enough, reading TurboJ's results from his sig, 322 WBHP +10BHP=332 / 0.9 = 368.8 flywheel BHP

Thats on a Dastek dyno as well and its being concervetive by a similer amount percentage wise, so it shows that the dastek dyno's are giving similer results.

Flea, Do you have your PT graph to hand, as your one of the very few people to run on both dyno's we should be able to compare the two accuracy wise

Not really as I’m only ever interested in WBHP & Ft/lb. Flywheel figures never impress me....even if they are 100% correct.



That run was with the injectors running out of duty still had another 1000rpm to go so I probably would have made 370ish with that run

Both dynos are mechanically different and utilise different software. What they have in common is they are both designed to measure flywheel power because that is what we use in Europe unlike the yanks who work with wheel power. If you want to compare wheel power results then frankly you need to understand the dyno mechanisms not some generic internet formula. You can't have it both ways, you accept one or the other, I would be inclined to accept the one the manufacturers have engineered it for.

Anyway, these are the revised figures:

Flea - 457bhp becomes 397bhp (GT3076R @ 1.9bar)
Nigel - 395bhp becomes 339bhp (GT2871R @ 1.7bar)
Benny - 366bhp becomes 312bhp (GT28RS @ ???)
Luke - 338bhp becomes 288bhp (GT28RS @ 1.5bar)
AshP - 335bhp becomes 286bhp (GT28RSR @ 1.37bar)
Owl10 - 320bhp becomes 273bhp (GT28R @ ???)
Carphone - 259bhp becomes 222bhp (Standard @ 1.2bar)

Effectively your saying the above cars are all knackered! Carphone buddy, your remapped standard car is only making standard power!!

Or are they?? Perhaps they are making the power you would expect to see from a well setup coupe with all the mods +/- 10bhp?

So the infamous Dastek dyno. They are getting quite popular in this country - the reason, they happen to be the cheapest by quite some margin. Anyway, I have indeed been to a Dastek dyno quite recently, in fact it was December.

383whp @ 5803rpm (1.8bar)

Now hang on a minute, that can't be right can it?? How have I lost 61whp (yes that is right, at Powerstation I only made 322whp at 5800rpm) in just a month?? Indeed, the run in December was with my old 440cc injectors, the reason the torque drops sharply at 5800rpm is because my injectors were at 100% duty therefore I had to drop the boost with the Apexi to 1.5bar to the redline. So anyway, with the Puma formula I made 437bhp at only 5800rpm, that's pretty good going Indeed, that leaves another 2000rpm left to run at full boost which I can now do because I have 580cc injectors!! So which figures are best correlated, wheel power of flywheel power? Given that I only made 390bhp @ 5800rpm at Powerstation, it looks like they are undereading compared to the Dastek dyno??!! Oh dear, what are we to do? The fact is everyone makes less whp on a MAHA dyno, Jason you wouldn't even break 290!

This is what I mean Jason... black and white, not really is it?

What have you done here???

Used the WBHP to calculate what the fly should be??

I was of the understanding that they don't measure flywheel power , they only estimate it. The only thing rolling roads measure is power at the wheels, anything else is estimate?!

Powerstations figures always seem to cause arguments on the many forums I'm a member of. Dave Baker of pumaracing seems to think their figures are way off :

http://www.pistonheads.com/GASSING/topic...nichip...&mid=0

As with all rolling roads though, theres no point comparing between different rollers as it's pointless due to different losses / calibrations etc. Flywheel figures are also nearly always a bit of a fudge, so in my opinions the only real comparisons are to be had at the same rolling road, comparing wheel figures.

Ben

All in my opinion of course

You will find that car manufacturers test the output of there engines on an engine dyno, thats why they get flywheel BHP, its more accuarate.

Any chassis dyno measures WBHP then using a transmission loss calculation works out the flywheel BHP, so the WBHP has to be more accurate

Can your car be loosing nearly 30% in the transmission??

The dyno is not measuring at the flywheel so the only accurate reading here is the WBHP

And a standard car thats done who knows how many miles running slighly more boost that standard with a conservitive map is doing pretty well to be making standard power, especialy as the dyno could be reading under.

Flea, im not going to argue with you about dyno's, as with anything in this industry everyone has there own opinion on products, i dont have one about the dyno that powerstation are using, i have never been near one so i dont know but the fact is that it has to be measuring WBHP, yours is 347bhp, if its as accurate as your saying then thats the figure that is more important.

I think this statement speaks volumes

"Powerstation's bhp figures are a load of absolute cock to be frank about it. The wheel bhp numbers are far too low and the transmission losses far too high. Why they don't get it sorted out properly I have no idea. It must be obvious to them comparing data with any other rollers or am I crediting them with too much intelligence?

It's very rare to come across a set of rollers which reads low on the wheel bhp numbers, which after all is the only thing that rollers really measure or can be calibrated to. The only other one I'm aware of is John Clarkson Autos in Chorley who have a Dastek system which I find are usually dead accurate. For some reason his also reads very low at the wheels and high on the losses although the combined flywheel numbers compare well with other data. I'm not sure I can say the same for Powerstation's flywheel numbers but don't have enough back to back data to be certain.

Although it's a subject I've studied for years and have written more about than just about anything else on my website I still don't see how you can set up rollers to read low at the wheels and high on the trans losses. The trans losses are simply tyre and gearbox drag measured on the same rollers but as negative numbers and if the rollers have been calibrated low then surely the wheel numbers and trans loss numbers should both be low.

One day I'll have to ask Gerry at Dastek what jiggery pokery it takes to achieve this but it makes it bloody difficult to compare such rollers to anyone else's. It also makes it impossible to use my normal trans loss equations which of course rely on accurate wheel numbers to produce reasonable flywheel 'guesstimates'."

Dave Baker
Puma Race Engines

The only saving grace its seems is Dave says to that Powerstations dyno reads low for WBHP, so using the same calc will always seem a bit low

Tricky, I made 383 wheel horsepower at 5800rpm on a Dastek dyno just over a month ago, you can see the graph. So it that my true wheel horsepower?

Also your calculations are incorrect, it is not 30% but 24%

455-347 = 108/455 = 23.7%

The Dastek dyno gives me 8% transmission losses which is equally impossible.

415-383 = 32/415 = 7.7%

So how do you account for the difference in wheel horsepower between the two dynos on the same engine, yet the flywheel figures are really quite close?

Do you also agree with the revised figures, are all these cars really making such low power, because if they are then they are ALL fubarred?

Without being too harsh to Dave, he does admit that he doesn't own a dyno and he also has no idea on the "jiggery pokery" they use so I wouldn't read too much into his opinion either, he is just writing about it with more questions than answers.

Quoted from Paul on the same PH thread, he is the guy I know well at the Dastek dyno I use, the above linked graph was run by him.

"Dave, if you go on the MLR forum and do a search under Gerry Gaffney you will find he has put alot of time and effort into posting up why he believes its best to measure power at the flywheel and not rely "too" much on power at the wheels. I am a believer of this too, especially since owning the Dastek dyno and having used other dyno's. Alot of the percieved "guestimates" are infact measurements read by the dyno on coastdown. Obviously there are such things as transmission inertia and tyre pinch on very high powered cars which no-one can ever measure accurately on the dyno as each car is different, so an average of that is taken. But what it does do is cancel out alot of the unknowns and produce much more consistent power at the flywheel figures."

So Gerry at Dastek UK (MD), believes in flywheel power too, just like I said.

Yeah Flea, your fugures seem correct, i just guessed at 30% after glancing at it, i did not bother to work it out anymore accuratly

But i dont care about flywheel figures, i care about WBHP, i would say as Powerstations results seem to be well known for there inacuracy i would work from the dastek results you have

So you have 383Wbhp, and as Dave has said the powerstation dyno seems to read low on WBHP figure so the Wheel figures may be a whole lot closer than you think


Just forget the the flywheel figures, look at the WBHP

Dastek = 383 maybe slighly reading high
Powerstation = 347 Dave, who knows what he is talking about says its reading low

there is only 36BHP between the two, seems like an easy one to call i think

As for everyone elses figure from the Powerstation run, well there dyno seems to be reading low so using the calc that i have put up you will be getting low figures, how much lower? i dont know, take it to a different dyno and see what WBHP figures you get you may be hapily surprised

320 ish bhp fly, 260 ish wheels @ powerstation (290 lbft)
299 ish bhp fly, 270 ish wheels @ PT. (280 lbft) approx 1year ago. pointless comparing between rollers IMO.

EDIT: TBH i couldnt really give two figs as to the power, the reason for running it was to check fuelling is safe and.... well it isnt, but at least now i know, and can drive accordingly untill its sorted.

Its nice to have a pub figure, but if someone comes up to you and says i have an xxx bhp car what does it mean? nothing really.

Flea there is no end to an argument like this, one fact remains though is that all dyno's will read slightly different from another, but its been ducumented that Powerstations dyno is inaccurate

And the only really accurate way to figure out flywheel bhp is with an engine dyno, as no-one is using one then we should only take WBHP into concideration as that way we dont need to take into account the varying transmission losses that different dyno operators seem to imply, one figure that cannot be massaged by the operator is the WBHP

I think 10BHP is a small enough amount to be put down to the difference in rollers

Tricky you haven't read my post...



You can't compare wheel power at two different rpm points, it is totally dynamic. There is a 61 wheel horsepower difference between the dynos at 5800rpm. At the same point the Dastek says I have 415bhp and Powerstation only 390bhp.

If you only care about wheel horse power then you are ignoring the advice of two professionals, 1. The MD at Dastek 2. A tuner who uses a Dastek every day.

Puma Dave, well he admits he doesn't know how dynos work, he doesn't use one.

Exactly, although you could have just popped up the road for a fueling check

I like that song too...Michael Jackson is it not.