Someone recently started a thread saying they'd had their 197 dynoed on a chassis dyno that bolted to the hubs rather than having the wheels drive a roller.
I got a little annoyed that the dyno operator had told the person that the 158.5 bhp the car had gotten on that type of dyno equated to 192 bhp (195ps) at the wheels. Which would have been a good figure (only 2 ps short of factory claims) for what was a pretty new car.
Here's a dyno manufacturer who makes those sorts of dynos that bolt to the hubs that's done tests on 552 models of cars. You can see how much power they put out on that sort of dyno.
http://www.rri.se/
Sorry I keep repeating "that sort of dyno" but its necessary to point out that because the wheels are removed and the dyno bolts directly to the hubs the power loss in the tyres isn't allowed for. So that sort of dyno gives a higher reading that a chassis dyno that uses rollers.
Unfortunately they haven't dynoed a 172 or 182, but they dynoed a 197. It produced 172 bhp @ 7107 rpm and 141 lb-ft @ 5416 rpm on that sort of dyno. That's 12% less power at the hubs than Renault says the engine produces at the flywheel. On an ordinary chassis dyno with rollers it would produce about 165 bhp.
The cars where the percentage of claimed power was lost between the flywheel and the hubs was highest were a Nissan Primera with CVT transmission and Audi 4WDs.
I got a little annoyed that the dyno operator had told the person that the 158.5 bhp the car had gotten on that type of dyno equated to 192 bhp (195ps) at the wheels. Which would have been a good figure (only 2 ps short of factory claims) for what was a pretty new car.
Here's a dyno manufacturer who makes those sorts of dynos that bolt to the hubs that's done tests on 552 models of cars. You can see how much power they put out on that sort of dyno.
http://www.rri.se/
Sorry I keep repeating "that sort of dyno" but its necessary to point out that because the wheels are removed and the dyno bolts directly to the hubs the power loss in the tyres isn't allowed for. So that sort of dyno gives a higher reading that a chassis dyno that uses rollers.
Unfortunately they haven't dynoed a 172 or 182, but they dynoed a 197. It produced 172 bhp @ 7107 rpm and 141 lb-ft @ 5416 rpm on that sort of dyno. That's 12% less power at the hubs than Renault says the engine produces at the flywheel. On an ordinary chassis dyno with rollers it would produce about 165 bhp.
The cars where the percentage of claimed power was lost between the flywheel and the hubs was highest were a Nissan Primera with CVT transmission and Audi 4WDs.
