Rolling road Register

Fuzz · 29 Mar 2011 at 14:35

My boss pointed this site out to me today (my day off

) that none of us even knew existed.

It seems to be lacking in comments though.
So anyone that feels like putting their PERSONAL views forward that has been involved with their car on the dyno, your thoughts would be much appreciated.
None of this I knew a bloke who knew a bloke said it was OK rubbish.
If you've been there then we'd like to hear from you.

http://www.rollingroadregister.com/dynos/powerstation

kthksbye

MikeHiow · 29 Mar 2011 at 14:58

Quite a good idea, but as with anywhere, but rolling roads more-so, you are always going to find people with good and bad experiences, and people are more compelled to share their bad experiences.

Slightly off-topic, but do you not find your signature slightly ironic considering you only provide flywheel figures?

loltim · 29 Mar 2011 at 15:00

"Submitted by Bigone (not verified) on 29 March 2011 - 2:40pm.
What a rubbish place and an inconsistent dyno with some rubbish results, the staff are a bit thick too."

lulz?

merlin · 29 Mar 2011 at 15:00

MikeHiow said:
Slightly off-topic, but do you not find your signature slightly ironic considering you only provide flywheel figures?

They can ONLY take an engine out of a car and dyno it on a bench?

loltim · 29 Mar 2011 at 15:03

PS provide wheel figures dont they? or is it a guess using a lolformula?

merlin · 29 Mar 2011 at 15:04

Tim said:
PS provide wheel figures dont they? or is it a guess using a lolformula?

Measure tranny drag, measure atw, calculate the fly.

Fuzz · 29 Mar 2011 at 15:07

Tim said:
"Submitted by Bigone (not verified) on 29 March 2011 - 2:40pm.
What a rubbish place and an inconsistent dyno with some rubbish results, the staff are a bit thick too."

lulz?

Is that your personal opinion of the place of was it just for the lulz as you put it.

Berger · 29 Mar 2011 at 15:09

Scubascorpion said:
Is that your personal opinion of the place of was it just for the lulz as you put it.

Tim didn't submit that?

ScoobyDoo69 · 29 Mar 2011 at 15:09

Can I say that Rich is a moody arse who wants you in and out of his workshop as quick as possible... but I like the rolling road setup? O and Andy and Curtis are awesome?

MikeHiow · 29 Mar 2011 at 15:10

merlin said:
They can ONLY take an engine out of a car and dyno it on a bench?

Tim said:
PS provide wheel figures dont they? or is it a guess using a lolformula?

There was a massive discussion about it a while ago when I questioned a VXR with over 100bhp in transmission losses according to their WHP figure, apparently the WHP figure should be disregarded as they use a single roller system?

merlin said:
Measure tranny drag, measure atw, calculate the fly.

Many people a lot more clever than I will tell you that coastdown is not an accurate way to measure transmission losses.

ScoobyDoo69 · 29 Mar 2011 at 15:11

Back on the debate of how a PS rolling road works eh? Do a search! - but.... both rollers do the measuring as opposed to the just one at other rollers, hence the odd WHP figures. They're not to be taken as literal WHP figures, but as at the 2xrollers figures.

Skeeter · 29 Mar 2011 at 15:13

This will only end badly...

And as its the movement of the rollers by the wheels that is measured, then only the WHP can be accurate. The fly is either a formula or a subtraction of transmission drag, both of which are estimates. The only way to get accurate fly figures is to bench the engine on its own out of the car.

MikeHiow · 29 Mar 2011 at 15:14

ScoobyDoo69 said:
Back on the debate of how a PS rolling road works - both rollers do the measuring as opposed to the just one at other rollers, hence the odd WHP figures. They're not to be taken as literal WHP figures, but as at the 2xrollers figures.

That sounds more like what I was told, thanks

I do not want to get back in to that debate, just found Scuba's signature slightly ironic based on this

Skeeter said:
This will only end badly...

And as its the movement of the rollers by the wheels that is measured, then only the WHP can be accurate. The fly is either a formula or a subtraction of transmission drag, both of which are estimates. The only way to get accurate fly figures is to bench the engine on its own out of the car.

My point exactly

Fuzz · 29 Mar 2011 at 15:14

MikeHiow said:
Many people a lot more clever than I will tell you that coastdown is not an accurate way to measure transmission losses.

It's not brilliant no, but it's more cost effective than spending 2 hrs trying to bolt your hubs to a hub dyno or spending a day taking your engine out!!
It's about as accurate as you are going to get with the design of a car being a given.
The only thing making it inaccurate is the amount of squirm and deformation of the tyre under load compared to the coast down.

Skeeter · 29 Mar 2011 at 15:16

MikeHiow said:
apparently the WHP figure should be disregarded as they use a single roller system?.

PS is a twin roller setup. The US are more obsessed with WHP figures so tend to use single roller setups. The argument is that 2 rollers 'pinching' the wheel can cause additional drag which reduces the WHP figure, but using a coast down this drag can be then included in the transmission loss estimate to produce a more representative Fly figure.

loltim · 29 Mar 2011 at 15:17

Skeeter said:
PS is a twin roller setup. The US are more obsessed with WHP figures so tend to use single roller setups. The argument is that 2 rollers 'pinching' the wheel can cause additional drag which reduces the WHP figure, but using a coast down this drag can be then included in the transmission loss estimate to produce a more representative Fly figure.

Sounds about right. My Civic got 136whp on a maha dyno and 159whp on a dynojet.

ScoobyDoo69 · 29 Mar 2011 at 15:21

However, there are other dynos (dynodynamics rollers for example) which have 2 rollers, but only one of them does the measuring.

Fuzz · 29 Mar 2011 at 15:23

Give me half an hour and I'll try and reiterate something from Dave walker (AKA Emerald Tuning)
He writes in a few different publications and can probably be found on the net extolling the virtues of dynos..

Skeeter · 29 Mar 2011 at 15:24

The WHP figures will be spot on acurate, so long as the dyno is configured properly.

What you must remember is that they are acurate for that EXACT situation. I.e in Tims case, the power being transfered through the dyno by his car was exactly 136bhp in one situation, and 159bhp in another. These are correct for the individual situations, and cannot be compared as they are different machines.

They Fly figure is the one that can be compared as the power produced at the fly is the same irrespective of how it is measured. However, as we have said, measuring a fly directly is hard work, so instead a calculation is done to remove the drag applied by the transmission AND the measuring equipment and calculate a fly power level based on the WHP figure.

But again, this is done in different ways (formula, coast down, random guess work) so its highly unlikely that 2 different methods will produce the same result, so again, cannot be compared.

Only 2 dyno results on the same machine can be compared, and even then you are subject to a world of external factors like air temperature and operator and all sorts that can alter figures.

ScoobyDoo69 · 29 Mar 2011 at 15:26

Skeeter said:
Only 2 dyno results on the same machine can be compared, and even then you are subject to a world of external factors like air temperature and operator and all sorts that can alter figures.

And this is why I will only go to Powerstation to compare mods like for like. They actually have the engine power, and then corrected engine power for the difference in temperatures etc