Top Fuel bike engine 3

[outlaw695]

Designing a V4 2500cc, OHC 4 valve engine based on the yamaha VMAX engine. Target is 1000HP @ 9500rpm!supercharged, nos, running ELF race fuel. Help me out with the right bore/stroke ratio, rod/stroke ratio, valve sizing, etc. Very interested to hear your results

 

[TrackRat]

You need to define the size of the ponies... when you're talking HP.

We have SAE dyno Horseys which are few but strong. We have race engine builders with lots of tiny Horseys to make big numbers. We have magazine Horseys which you obtain by taking a un-SWAG and then multiplying that number by 1.5 to obtain California HP. Then we have chassis dyno "corrected" Horseys where you use as high a driveline loss correction factor as a really ignorant fanboy will believe. Then we have race track B.S. Horseys where you tell everyone that your stock block 350 CI engine with one 4-barrel makes 600 HP @ 8000 rpm even though the valves float at 6500 RPM.

Ya definitely need a scorecard if you're gonna talk horsepower, so you can tell the players, the liars and the damn liars.

 

[patprimmer]

And the basically truthful customers ignorantly repeating the lies they were fed and believe.



Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

http://eng-tips.com/market.cfm

for site rules

 

[lawayosh]

Don't forget to enter the driver variable into any on-track performance numbers. As Rod is well aware, the applicator of pedal to metal does make a difference. Even if the '68 Camaro did make 500 HP, just switching drivers could produce faster times.

Having played with a '69 Z/28 back when, horsepower numbers were for egos. Chassis set-up on early pony cars was where you could quietly make a real difference.

Yosh

 

[turbomotor]

Speaking to TrackRat's comment about horsepower and liars, it is refreshing to see actual data and not just hype.

I think that the 1989 SAE paper on the Honda F1 engine gives good, reliable numbers.

http://www.sae.org/servlets/productDetail?PROD_TYP=PAPER&PROD_CD=890877&REQUEST_FROM=MOTORSPORTS

The summary (above link) doesn't give the power numbers that correspond to the 4 bar absolute manifold pressure setting, but I think I remember those numbers as 1100 bhp from a 1.5 liter engine.

I think Toluene (methyl benzene) was used for two purposes: 1. It has good knock resistance, and 2. It has a high volume specific energy, which fit well with the then current F1 fuel quantity rules.

Dick