59 replies to this topic

[TFD]

Hi people, I've got a small question: What are the wheelpower figures you guys are running with these tuning stages. Not to start a discussion all over but bhp or flywheel numbers dont say much to me. So if you have them (and the sheet?) let me know :-) Thanx, Daniel

[TheRealVXed]

NA/Turbo/SC?

[TFD]

Sorry, FI that is. In the wrong thread btw. Can someone move this to Mods n Tuning please.

[Bumblebee]

A lot of the wheel hp figures are estimates unless you go on a hub dyno even then some say they arn't accurate

[Boombang]

Surely a wheel horse power figure isn't an estimate if measured on a set of rollers using real wheels?

 

It might not be accurate though, and can easily be manipulated using differing gears, tyre pressures and the tyres themselves...

[TFD]

Err... Wheelpower is meassured, bhp is guessed... Therefor Im looking for whp figures. Unless everyone takes there engine out to put it on an enginedynometer. Not looking for the discussion unless everyone wants to offcourse :-)

[The Batman]

Very few people will have whp figures it's not the norm in the uk.

[Mike (Cliffie)]

You need a hub dyno like they have at Torque Developments for a WHP figure. Most UK dynos only give a corrected flywheel figure.

[ghand]

Have a look on page six in Tuning and Mods section under what bhp is everyone running That's a full list of most modded VX s bhp but all from RR I would think. They are more or less in the right ball park how accurate do you need? Are you bothered to a few bhp either way and most use the same RR after mods so increases will be reasonably accurate. .

Edited by ghand, 16 September 2013 - 01:07 PM.

[slindborg]

WHP is simply the wheel version of BHP, I know BHP is 'brake' horsepower but its become the standard declaration of power..... I guess going metric is a better route but the numbers sound poo

 

WHP is less messwithable than FlyHP, but is better for comparissons.

 

Hub does delete the tyre from the equation which is a bonus.

Then you have single or double rollers roads.... or even rarer the belted roads.

[PaulCP]

WHP is simply the wheel version of BHP, I know BHP is 'brake' horsepower but its become the standard declaration of power..... I guess going metric is a better route but the numbers sound poo  .

That's not going to help the argument to go metric lol

[ghand]

Have a look on page six in Tuning and Mods section under what bhp is everyone running That's a full list of most modded VX s bhp but all from RR I would think. They are more or less in the right ball park how accurate do you need? Are you bothered to a few bhp either way and most use the same RR after mods so increases will be reasonably accurate. .

Now on the first page seeing as I have cocked up the list adding my bhp

[smiley]

What are the wheelpower figures you guys are running with these tuning stages

 

Depending on the dyno itself, a rough rule of thumb for the vx/speedster is to deduct 15 to 20% horsies to convert from crank to hub.

 

Generic rule of thumb is anything between 0 and 30% loss iirc.

[TFD]

So this is not really getting were I want to. I understand the whole hassle with bhp guestimations and losses and therefore only focussed on wheelpower since thats the only meassured power and therefore most sensible way of comparing in my opinion (except the maha RR).

 

 

[ghand]

So this is not really getting were I want to. I understand the whole hassle with bhp guestimations and losses and therefore only focussed on wheelpower since thats the only meassured power and therefore most sensible way of comparing in my opinion (except the maha RR).    

So that list of everyone's BHP is of no use to you even as a guide.

[slindborg]

 

What are the wheelpower figures you guys are running with these tuning stages

 

Depending on the dyno itself, a rough rule of thumb for the vx/speedster is to deduct 15 to 20% horsies to convert from crank to hub.

 

Generic rule of thumb is anything between 0 and 30% loss iirc.

 

 

 

erm, deduct from hub to get crank

I do have a graph of the losses on mine, from the only place I trust to get a RR plot as right as possible. Losses arent a straight line

 

in short, stage tuning is a load of cock

Edited by slindborg, 16 September 2013 - 03:44 PM.

[slindborg]

Doh, add

[TFD]

@Ghand: If i would know the losses than it would. Like said by others, the guestimated losses can differ a lot. A meassured 250 whp can be 280 bhp on one RR and 300 bhp on another.. Dont get me wrong, I appriciate the effort.

[smiley]

speedsterclub.nl has a few maha runs from 2010 and 2011 listed.

 

Here's my loss.

 

[P11 COV]

I think the simple answer is that most on here will not have WHP figures as we get given the calculated bhp figures given to us by the RR establishment. (I am not aware if WHP figures are put into info from dynos.)  I agree a comparison of WHP would be a more reliable way to do it.