Rolling Road Question.

[jon_r]

In an ideal world if I was making 172 at the flywheel, what will the @ the wheels figure be?

Is there a 12% transmition loss?

cheers

 

[McBunny]

transmission loss varies from car to car and power depends on tyre pressure and rrs arnt acurate at all so disregard the figures lol

 

[jon_r]

so shall i pump the tyres up to 100 psi

 

[McBunny]

yeah you will get more power

 

[jon_r]

*finds foot pump*

 

[Rich-D]

The majority of fwd cars have a transmission loss of ~15% but this is only an approximation and does vary from car to car, however for the 172 its actually about right...

At a RR session last year where several 172s ran, two totally standard cars both made 144bhp @ wheels.

Now with 15% losses, this gives you ~169bhp @ fly, which equates to the 172bhp (DIN) or 172ps that Renault quote!



If you get mid 140s @ wheels you should be happy!

 

[jon_r]

http://erc.qmuc.ac.uk/cliosport/gallery/full/1079704072__42ID0028.jpg

http://erc.qmuc.ac.uk/cliosport/gallery/full/1079360821__cda3.jpg

 

[BenS_172]

Except you cant trust any figure from a Rolling Road.

Only good for doing remamps etc..

Dyno is the only way to go to really measure an engines power.

 

[Rich-D]

Quote: Originally posted by ben_ren19.16v on 19 March 2004


Except you cant trust any figure from a Rolling Road.

Ok for a rough idea, and for back-to-back comparisons on the day.

Speaking of which...

Jon, are you going to do a run with the standard setup and then fit the CDA and do a re-run???

Would be nice to see the results, as weve done this with a Viper in the past and wanna see how the CDA compares!

 

[jon_r]

er i can try, not sure whats happening as far as number of runs go tomorrow.

Ive got an itg panel filter on its way as well, but i dont think itll arrive in time.

 

[Rich-D]

Be good if you could compare standard to CDA mate...

We did this with a Viper. Just run as standard, then disconnect the inlet hose, leave the airbox in place, twist the inlet hose up so you can attatch the CDA, tighten the clips and re-run!

Takes a couple of mins to do the swap, rather than removing the airbox and all the pipework.



Oh, and get graphs if poss please!