Stag Power and Torque Curves

[Peter Hills]

Hi folks,

Does anyone have what might be called 'representative' power and torque curves for a standard Stag?

If so, please PM me.

Peter Hills

[jleyton]

Hi Peter,

I don't know how valid these are, or even where they came from, but I hope this may be of some help.

Cheers

Julian

perfcurv.jpg

[Peter Hills]

Hi Julian,

Many thanks. I'm sure they will be a very good start. They seem to be pretty close to the figures in James Taylor's little Stag book.

Do you - or anyone else for that matter - know how much allowance should be made for 'at the wheels measurements'?

Peter

[Motorsport Micky]

That's a very variable figure unless defined better. Size of wheels, tyres, pressures used, manual gearbox with overdrive, automatic you get the drift ? nominally I always use 10% reduction.
A rolling road session will give you an idea but bear in mind these vary with some roads measuring ponies (which makes the car owners happy) and other roads measuring horses.

Micky

[Peter Hills]

Thanks, Micky.

I think some horses in the past have been show ponies!

Peter

[DJT]

If it is of any interest, this is from the Fontwell Park ND RR a few years ago. Stromberg carbs, Lumenition, standard wheels, 185/80 tyres, 30psi rear pressure, 3.45:1 diff:

Rolling Road.jpg
Video: https://www.youtube.com/watch?v=ExyR-pQpIlc

[Peter Hills]

Thanks, DJT.

I notice your ZF Auto. Presumably the run was done with the gearbox locked - ie no kickdown?

Peter

[DJT]

Thanks, DJT.

I notice your ZF Auto. Presumably the run was done with the gearbox locked - ie no kickdown?

Peter

Hi Peter,

Should have said that at the time the car had the original BW35 and the kickdown cable was disconnected for the run.

Dave.

[jbuckl]

Hi Peter, any chance you can let us know why you wanted the curves?

B.T.W. Below is a nice explanation of Boulton & Watts work on horse power & illustrates that it all goes back to beer & pub talk (brewery horse power rounding of 600 pounds!)

Watt determined that a horse could turn a mill wheel 144 times in an hour (or 2.4 times a minute). The wheel was 12 feet in radius; therefore, the horse travelled 2.4 × 2π × 12 feet in one minute. Watt judged that the horse could pull with a force of 180 pounds. So: This was rounded to an even 33,000 ft·lbf/min.^[9]
Others^[who?] recount that Watt determined that a pony could lift an average 220 lbf (0.98 kN) 100 ft (30 m) per minute over a four-hour working shift. Watt then judged a horse was 50% more powerful than a pony and thus arrived at the 33,000 ft·lbf/min figure.^{[10][better source needed]} Engineering in History recounts that John Smeaton initially estimated that a horse could produce 22,916 foot-pounds per minute. John Desaguliers had previously suggested 44,000 foot-pounds per minute and Tredgold 27,500 foot-pounds per minute. "Watt found by experiment in 1782 that a 'brewery horse' could produce 32,400 foot-pounds per minute." James Watt and Matthew Boulton standardized that figure at 33,000 the next year.^[11]

[Peter Hills]

jbuckl

You said it!

There are 2 secrets to staying on top

:- 1. Don't give everything away.
:- 2.

If things work out as I hope, you'll just have to wait!

Peter

[jleyton]

jbuckl

You said it!

There are 2 secrets to staying on top

:- 1. Don't give everything away.
:- 2.

If things work out as I hope, you'll just have to wait!

Peter

Don't I get let in on the secret because I supplied you with the curves ?

Cheers

Julian

[Peter Hills]

Julian,

Please give me a phone number by PM or my own email - pre Jul 2013 Stag Mags have it - and I'll chat it over with you. Otherwise your closing note will have to apply for a little while.

Peter

[jleyton]

I was only kidding really - I'll wait in suspense

Cheers

Julian

Ps It's the other Julian (jbuckl) who had the (clever) closing note !

[Peter Hills]

Julian 1 or 2!

I'm quite happy for a discrete chat but don't want to go public yet. I needed the curves to be able to see - in due course - whether my car was reasonably representative before.....

Peter