Water Brake Dyno help

[Arthur Pain]

All,

We currently are trying to work the bugs out of our water brake dyno set-up.

Basically, our dyno absorbs power at low RPMs, but

a) the fully loaded wide open throttle operation point varies from test to test

and

b) when we unload the engine to run at higher rpm, the engine runs away on us (unloads at a very high rate after about 9000 rpm).

we use a land-and-sea dyno with the manual load control valve.

anybody out there experienced with water brake set-up and operation willing to lend me some advice?

jim

Congrats to all who ran well in Pontiac. This was my first year with FSAE and i'd have to say i was impressed as hell with what i saw.

[Arthur Pain]

All,

We currently are trying to work the bugs out of our water brake dyno set-up.

Basically, our dyno absorbs power at low RPMs, but

a) the fully loaded wide open throttle operation point varies from test to test

and

b) when we unload the engine to run at higher rpm, the engine runs away on us (unloads at a very high rate after about 9000 rpm).

we use a land-and-sea dyno with the manual load control valve.

anybody out there experienced with water brake set-up and operation willing to lend me some advice?

jim

Congrats to all who ran well in Pontiac. This was my first year with FSAE and i'd have to say i was impressed as hell with what i saw.

[B Lewis @ PE Engine Management]

Jim,

Try restricting the output of the brake with a valve to find the sweet spot. We have found this to be effective at increasing the usable range of the dyno by providing some back-pressure.

[ArthurPain]

Hey all,

Just wanted to say that I tried the above fix, by removing the specially sized orifice from the exit port of the water break and installed a valve in its place. The valve gives me much greater control over the back pressure.

Well... it worked. The dyno runs much better!

Tnx!

[B Lewis @ PE Engine Management]

Jim,

Glad to hear it worked. Good luck with the tuning.

[Trans Am]

I suggest you check out Land-and-sea.com as they have load charts for each dyno they sell. Try and keep your dyno operating in the range where the most torque is rejected; remember that most motorcycle engines have an ~ 2:1 gear reduction before the output shaft. I also recommend checking out their autoload setup as their newest version controls the RPM very smoothly and makes controlling a peaky engine much easier.

-Trans Am