To The People Losing Their Minds About My E36 M3's Dyno Results, Here's An Explanation

My E36 M3 was put on the dyno recently. The resulting power figure was 279bhp, but it seems there's a lot of confusion between bhp at the wheels and bhp at the crank. So here's an explanation!

Alex Kersten

09 Jul 2016

This video has caused a lot of confusion in the YouTube comments, with people saying stuff like “I thought he was a car guy… This dyno doesn’t measure bhp. It measures whp. 279 x15% loss is around 317” and “You guys are aware that dynos read WHP and not BHP?“

So to set the record straight, I Facebook messaged Charlie from Surrey Rolling Road this morning and asked for an ‘official’ response on the matter. Here’s what he sent back, which I’m hoping will clear things up for people…

What does the dyno measure?

WHP

Are the figures for Alex’s car at the crank or wheel?

Crank

Whoa… you just said that the dyno measures at the wheels!

It’s common in Europe for dynos to add the drivetrain loss to make a crank estimation graph. It is always an estimate but it allows the customer to relate to the manufacturer’s crank figures.

Does the dyno also plot in WHP?

Yes, it stores a WHP graph for every car, then depending on what the customer wants we can print out WHP or crank HP.

Why do I see lots of WHP figures around the internet?

America uses mainly WHP figures only, as does Russia and the middle East. Australia uses Wheel KW mainly.

So who’s right?

No one, and everyone. There is no wrong or right way of doing it. As long as you get a consistent number you can compare to when you’ve done some mods.

What do you think is wrong with Alex’s car?

Alex bought it. It was probably putting out over 300bhp before he got his hands on it…

To The People Losing Their Minds About My E36 M3's Dyno Results, Here's An Explanation

So there you have it, ladies and gents. From the horse’s mouth, this is why my car was making 279bhp at the crank and not 279bhp at the wheels (that would have been incredible had that been the case!).

Next up, I’ll give the car a proper service, get those valve clearances and suspension issues straightened out, and will fit a new exhaust system and a Pipercross air filter that was donated to Colin just last week.

Then, it’ll be back to Charlie’s dyno to see if my E36 M3 can get over 300bhp (at the crank).

Comments

you should get it back up to 316 bhp after exhaust and tune up

WHP is just a more true representative of power as that is the usable power available to the driver. When the dyno is calculating drivetrain losses there is no way in hell it is 100% accurate. So using WHP removes any drivetrain loss variable. I

Turbo. You need it

So what’s now the difference between BHP and WHP?

Im too late to comment but 15% is usually the loss by a FWD vehicle. RWD usually see 20-25%

Good article delving into the logic of whp vs bhp http://www.superstreetonline.com/how-to/engine/modp-1005-drivetrain-power-loss/

My formula is in newton meters. I hav no clue about that pund feet :D

Hey Alex you might wanna look into replacing the bolts the connect the driveshaft to the Tranny, through the flex disk! So happy we both have E36 M3s bro, can’t wait for videos on Colin!