Rolling Roads

adeel · May 10, 2003

:duh: Pardon my ignorance... I know very little about a 'rolling roads'...

As far as I know a 'rolling road' discovers the top speed and BHP of a vehicle...

But how; like what do you do... Do you drive at full throttle through all your gears on the rollers or what...

Thanks in advance

Monster-Mat · May 11, 2003

its late..........i will answer this in the morning

tdiplc · May 12, 2003

Hi Adeel,

Take a look at http://www.tdi-plc.com/rrpage.html

Hope this helps

Mark :)

adeel · May 12, 2003

That's a bit of an in-sight, thanks mark...

However, once strapped down to the rolling road... then what... does one race it through the gears redlining each one... or...

Zee007 · May 12, 2003

does one race it through the gears redlining each one... or...

yep...... pretty much.........

Monster-Mat · May 12, 2003

not at all........you dont redline the engine.

you build the rpm up as you go through the gears.....when you reach 3rd- 4th(cannot remember which)

you rev upto below redline, let the engine coast, then as the rpm drop........nail it(non technical term)

this should give torque reading........and with calculation, including transmission losses....BHP aswell

this isnt 100% correct, its a while since ive done rolling road testing

Risky3301 · May 12, 2003

You should never REDLINE an engine, either on the road or dyno, there's not point anyway as your coming down both the POWER and TORQUE curve's on a NA engine, Most supercharged engines will continue to make power right up to the REDLINE (max engine rpm) but peak torque will have already been reached well before you've hit the REDLINE.

When using a Rolling Road or Chassis dyno, firstly the correct road load model should be used, Usally both power and torque are meaured using 1:1 gearing, I don't have the IS200 gear ratio's to hand, I guess this is 4th gear or as near as makes very little differance. Most engine power dedicated rolling roads will automatically calculate the loses caused by engine friction and drive train during Coast Down in gear. and give you either both power/torque at the Flywheel or road wheels. An engine that makes say 150 bhp at the flywheel will not make anywhere near that at the wheels and nearly manufactures quote power and touque at the Flywheel not the road wheels.