Turbo WR400

Maybe the beer is getting to me or maybe the engineer part of me can't rest, but I have been thinking about something for awhile.

Why not take a small (2-5") 12-14V electric fan and mount it on the clean side of the airfilter, wired to maybe the taillight or another self-made switch? Maybe even to a rheostat that works off the TPS signal to increase fan speed with throttle position? I would imagine the fan would have to be able to hold up (not catch fire!) when exposed to low voltage such as idling. Actually fire (spark from the fan) may be a good reason to consider mounting it to the outside of the air cleaner somehow.

Any thoughts? I think it could be done safely and purposeful, the question is what do you think would happen to the performance? Would the air velocity possible decrease due the lack of need to "suck"? Anyone crazy enough to have tried this one yet? ANyone think I'm crazy for posting this?

I have one of those mini battery fans I was going to temporarily install in the airbox pointing into the filter before the next ride to give my theory a try. Nothing scientific like dyno or intake flow meter, just seat of the pants. I was going to try using both the airbox lid w/ snorkel in and with the lid removed. I can't tell much if any difference in power with the lid removed (00 WR timed)now, just more noise.

What does everyone think? All comments welcome, slam away

I wouldn't bother with it - the fan doesn't have enough pressure rise to do you any good. A fan operates at inches of water pressure rise and a turbocharger compressor operatates at pounds per square inch pressure rise. The fuel system gets complicated when you use a blow thru carb. A friend of mine turbocharged his GSXR 750 for his senior project (Cal Poly San Luis Obispo) and it was a lot of work. Granted the thing hauled ass w/7psi boost but it was a lot of work.


That makes sense. Probably a lot work for a small benefit.

Hey Jay/Kevin, what about an R12 intake air or fuel cooler? :) Just kidding!

I think you ought to hook up a snorkel that attaches to the airbox inlet on one end and put the other end in your mouth...and when somebody tries to pass you...you should just blow like mad into the tube, and if it doesn't make enough more horsepower to stay ahead of the guy don't worry,...you'll black out from hyperventilation long enough that you'll never remember him passing you...Just think, you can ride all day thinking you're the best!!.....Seriously though, do you really think that a lack of horsepower is what's stopping you from going any faster?


As we have seen before, there is always ONE in the crowd that has to throw his two cents in.

There is always Nitrous oxide!! You could use it on the start and smoke everybody, (maybe your engine too?)

The real important question is what kind of beer?? :)

[This message has been edited by Kevin in New Hampshire (edited 07-11-2000).]

They make a very similar setup for Quads. The one I know of is for the Honda 250R Quad. They had to rewind the stator to produce about 400 watts of power. It gave it a decent HP increase but it was very bulky because they used a “squirrel cage” type fan and had problems with the packaging of the air filter.

They used a “modified” motor from Radio Controlled Cars to power the fan. My experience with those motors in the past shows that they would not stand up to that type of abuse.

I would think that the packaging constraints alone would be a nightmare.

If you are still interested you might post something on the board at www.atvconnection.com


What you're talking about is Supercharging.. Turbo charging uses exhaust gases to drive the compresser turbine and unless you have an intercooler to disapte the heat transfered from the exhaust gases then its really not bothering.. the intercooler on a bike like this would be the problem.

I spend alot of time at work working on turbos with 1.5m diameter compressor turbines.. these engines run a boost pressure of 3bar.. thats over 42psi!! pokin out over 5500hp.. imagine having 1/100th of that at the rear wheel!

Mitch is getting closer though! :)



**Ride it like you Stole it!**

Matt Porritt

99 YZ400F

Vist the Rubber Chicken Racing Online Shop

Discounts for ThumperTalk members.

What about an air scoop & a pressurised airbox? Maybe you could build a tube from the headlight area to the airbox? Didn't some bikes from the 70's or 80's run air thru the frame, from the airbox area to the steering head area. I have a homemade setup on my CBR900RR and it works well, but the speeds there are much higher.

I have seen a small lawnmower engine with an airpump from a car or something setup as a supercharger. It was belt driven I think and it turned a 3hp engine into a 5hp engine. Now if you could find the right size pump & drive it from the crank.

But seriously, with any of these ideas the HP gains would be offset by weight gains. That is if you are using your bike as a dirt bike, now if you are using it as a drag bike....


Any time you compress a fluid you increase the temperature of the fluid - you are doing work on the fluid. The real difference between a turbocharger & a supercharger is the source of 'power' to drive the compressor. The turbo uses a turbine to extract work from the exhaust gas, a supercharger is belt driven off the cranshaft (or electric motor in some cases).

Granted, there is some heat transfer through the center housing of a turbocharger but the aftercooler ( not an intercooler unless it is multistaged compression ) is there to offset the temperature increase due to the compression of the working fluid.


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