59 replies to this topic

[Bumblebee]

I need to dig my dyno graphs out as im sure the wheel horsepower losses differ

Edited by Bumblebee, 16 September 2013 - 08:24 PM.

[Bumblebee]

Would be nice to get a few of us together and go on a hub dyno

[TFD]

@Smiley: Thats the reason I mentioned Maha banks... You are not suffering a +100hp loss on your engine. Never got around these type of banks anyway eventhough I had major discussions with Divalo and fans on the dutch Nissan forums.

[slindborg]

Would be nice to get a few of us together and go on a hub dyno

You don't need to go on a hub dyno... Just a normal set of rollers will be fine and more realistic as it has the tyre drag included.

[smiley]

@Smiley: Thats the reason I mentioned Maha banks...

 

The maha is apreciated as being accurate with calculating back correctly.

One of the opel club guys put on a stock astra just for the fun of it, and it was off by 1bhp on the crank result 

 

Also lot's of discussions on the device, and not even the maha operator being able to answer the conversion questions correctly gives it plenty of opinions on the black art going on to convert the values.

The stock astra result, and the predicted area the custom speedsters get on before, and seeing results afterwards, gives reasuring results for me.

 

In the end if you want whp values, get yours on a hub device.

Ludwig can help you:

http://www.speedster....php?f=1&t=5000

 

Here's my last years crankdyno run at a different company:

As not much changed enginewise, calculating back to the maha run i lost about 16% from crank to hub.

 

Edited by smiley, 16 September 2013 - 09:25 PM.

[slindborg]

Again, you don't need a hub dyno to get whp, infact you don't get whp from a hub dyno

[smiley]

Ok, so back to the openingpost.

I seem to be running 215 whp on my stage II SC, 3.35 pully with a full 2.5" tullett.

 

Edited by smiley, 16 September 2013 - 09:35 PM.

[garyk220]

AMD (way back when they were in Bicester) quoted horsepower measured at the wheels and then the conversion to power at the flywheel. IIRC my Stage 2 turbo was reported as 210bhp at the wheels after the conversion for barometric pressure, temperature, etc. Actual measured hp was 197, so about 10 higher than the standard engine at the flywheel.

[Exmantaa]

Same MAHA bank with different Stage 2 SC Speedster:

Still almost ~60HP loss, but a lot less than Smiley's. I think that's related to the double MAHA rollers in combination with the VX/Speedster rear wheel geo settings and tire type. Smiley's loss was measured on relative soft and wide R1R's if I'm correct, while mine was still on the stock road tires...

 

 

[Boombang]

AMD (way back when they were in Bicester) quoted horsepower measured at the wheels and then the conversion to power at the flywheel.

How else could you do it on a rolling road?

[TFD]

You dont need a hubdyno unless you want hubfigures. The RR everyone is using will do for wheelpower since this is whats meaassured on these things. 215 whp sounds ok Smiley. Doubt though that Exmantas less loss is due tires alone. The Duke had tthe same numbers as Exmanta with 235 widht 18" wheels and turbo.. Wich should have lesser losses since more efficient than SC right? Anyway, thats the maha bank. Some like it, I dont no worries :-) So stage 2 SC ~ 215 whp Stage 2 turbo ~ 210 whp

Edited by TFD, 17 September 2013 - 06:26 AM.

[Nev]

If you want to convert from wheel horse power to crank horse power most rolling roads use a correction factor of between 9% and 12% for the F23 gearbox in 4th gear. I've never asked what figure Courtenay use, it would be interesting to know if anyone has.

 

At the end of the day you simply can't compare one RR to the next, I'd just take your own car back to the same RR each time and compare it relative to the last time it was on that same RR.

 

HTH.

 

Edited by Nev, 17 September 2013 - 11:40 AM.

[slindborg]

The 'loss' varies on many things though:

TX oil type/viscosity

TX oil condition

TX condition (bearings etc)

CV joint condition

Ride height

tyre type

tyre pressure

the number of rollers

wheel bearing type

wheel bearing condition

wheel bearing torque

 

aaannnnd so on. so a simple figure which isnt linear for the rev rage anyway isnt going to help either.

Hence why the uncivilised world (the USA and Oz) has it right with WHP figures and only used crank figures when the engine has sat on an engine dyno.

[Captain Vimes]

It's odd that the car world in the UK always quote power at the crank/flywheel but in the bike world everyone uses WHP.

 

For comparison, my old GSXR 750 made 118 WHP in 1996 and my brothes 899cc ZX9r was making 131WHP (with exhaust and rejet).

It's shocking that a modern 2.2 litre car engine can only manage c.120 WHP from the factory.

[siztenboots]

lest not forget the tuners hot cup of coffee to give the sensor a stir in give a nice sae corrected power output

[slindborg]

lest not forget the tuners hot cup of coffee to give the sensor a stir in give a nice sae corrected power output

 

 

In an ice lolly for the 'before' run and in the coffee for after changing the air filter to give a 100bhp gain

[siztenboots]

hand brake on during the coast down

[TFD]

@Captain Vimes: I've been on several global car forums for years and generally the whole world talks wheelpower instead of bhp.

The power in UK, Netherlands, Germany etc. lies with the Tuners for most of the people and BHP sounds/sells better then whp I reckon.   

 

Edited by TFD, 17 September 2013 - 01:26 PM.

[slindborg]

It's odd that the car world in the UK always quote power at the crank/flywheel but in the bike world everyone uses WHP.

 

For comparison, my old GSXR 750 made 118 WHP in 1996 and my brothes 899cc ZX9r was making 131WHP (with exhaust and rejet).

It's shocking that a modern 2.2 litre car engine can only manage c.120 WHP from the factory.

 

 

Its not shocking really, I mean how much torque did those bikes have and also they were only propelling a couple of hundered kilos around, not 1000kgs+ so you need torque.

[smiley]

The power in UK, Netherlands, Germany etc. lies with the Tuners for most of the people and BHP sounds/sells better then whp I reckon.   

 

 

Over the years the vx/speedster community has gotten a very good eye on what mods work, which don't work and which combination should give you x amount of bhp (which you can then roughly convert back to whp if you liek those better)

 

The whole stage discussion is not so popular, but just tag we give cars here to get a rough idea of where your at, and because it's easier to understand, due to the main tuners listing the mods together as a stage tune. 

 

What i'm trying to say is, that if you give us the bhp you're looking for, you can get some spot on advice on what mods to do, to get there, without the whole stage discussion. Many, many went down this road before you with these plastic cars, so there are very little surprises (staying under 350 isch, as over that the list of proven technology becomes more slim)