Bhp question please??

[bimmymak]

Hey guys,

Great forum by the way!

I have been reading lots of post on here (and also magazine reviews/articles) and I have noticed that when people have been dyno tested they very rarely achieve the claimed bhp that the manufacture claims?

I know in the sport car world it is quite common for cars to produce slightly more than the claimed bhp.

So is it just common knowledge that it's the opposite for sport bikes?

Bmw claim 199 bhp for s1000rr 2015 onwards.

Has anyone dyno'd a stock 2015+ and achieved this?

Many thanks

Sai.

 

[pof]

There are 2 figures, 1 is at the crank ie what bmw advertise (all manufactuers do). The 2nd is at the rear wheel which is the one that your bike is putting to the ground. "About" 20% is lost from 1 figure to the other.

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[Mick753]

My understanding was that the car world is no different than the bike world in so much as that most BHP figures quoted by the manufacturer are rarely achieved on a dyno other than their own, and those that do make more than quoted are generally figures potentially manipulated by the dyno operator.

But the figure quoted by manufacturers is as mentioned generally a crank figure, not sure if 20% losses from crank to wheel are the norm for bikes but it is generally 20-25% for cars depending on whether it is 2WD or 4WD, I thought bikes were more like 10% to be fair but that may be wrong

 

[Marzy]

I know for a fact MCN power figures are at the wheel. 196.7 was registered. A lot depends on Height above sea level, temp, variations in dyno's etc. Production of engine internals vary a lot too.

 

[alex]

I think a chain driven motorcycle would have about a 10% loss too.

 

[bimmymak]

Interesting. I guess there are lots of variables in the mix here.

Thanks for to input.

 

[alex]

Btw, dyno guy I went to said the 2015+ gets 184 practically everytime. Didn't say if that was crank or rwhp.


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[soofsayer]

The BMW bike configurator website states 195bhp for the current model, the technical spec sheet states 199, go figure .

 

[alex]

196BHP would be 199PS...

 

[HPlogger]

This has me wondering whether the salesman I bought my bike through at the dealership told me the truth or not! Regarding bmw's quoted hp for their bikes. Apparently bmw quote the guaranteed minimum hp the new bikes produce! There's a chance "the S1000RR as standard can produce up to 207hp." I wonder.

 

[alex]

Oh wow. What a cock.
207 would be WSBK power levels those engines are not stock!


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[soofsayer]

196BHP would be 199PS...

The website shows 195 BHP and 199 BHP mate.

 

[alex]

Sigh...cannot get the staff.


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[bananaman]

This has me wondering whether the salesman I bought my bike through at the dealership told me the truth or not! Regarding bmw's quoted hp for their bikes. Apparently bmw quote the guaranteed minimum hp the new bikes produce! There's a chance "the S1000RR as standard can produce up to 207hp." I wonder.

I can actually believe that....Trouble is, what dyno do you believe? So many variables out there....

 

[Marzy]

Hutchy beat last year's Superbike time around the IOM with a standard engine. Why? because its not so peaky and has real world power delivery.

 

[fast_ryan]

Power

205 bhp is achievable from a stock engine using an RCK3 but the service intervals are considerably shorter. Likewise you can buy a specially built Superstock engine from BMW HP Race Support for around ?9,000 which will easily produce those figures and is what the BMWs at the IOM TT were using. A WSBK specification engine supplied by BMW will produce upwards of 220 bhp.

 

[MacRR]

Does specially built mean blue-printed Ry?

 

[fast_ryan]

BMW HP Race Engine Kit

http://www.bmw-motorrad.co.uk/uk/en...e/engines/hp-race-motor-kit-1_.html&notrack=1

 

[pof]

My 5vy according to yam was 180 bhp but after its "losses" wouls be down to about 155 hp ie 20 % yes after a little engine work and bolt ons its up to 167 hp.
Same with the s1kr 190 something is bhp from engine but on dyno its 180 ish. Again with a bit of tuning and bolt ons 180-200 hp is acheivable on dyno.

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[soofsayer]

So a dyno 'estimates' engine bhp with assumptions the tuner uses?