rev box question

[400expooner]

i am thinking about getting a rev box and was wondering if it would be worth the money. also if i do get one which one would be the best or are they all the same

[Colby@C&DRacing]

if you have a high compression piston and cam I would recommend a rev box but if your engine is stock you would not benefit.

[TURBO400]

what is the best rev box tho for reliability, not tryin to blow it up

[KY Woods Rider]

I've been running the WB rev box on my EX for about 4yrs or so. I bought it for the different ignition curve, not just to get more RPM.

As far as whether it's worth it or not, I guess that depends on who you are and how much your money means to you. I've spent more money on things that didn't help anything at all, but then I've spent less money on things that helped a lot more.

As for the rev box, it did perk up the throttle response in the midrange and allows the motor to rev with more of a "free" feeling, which is exactly why I wanted it. Was it enough to be worth the money? To me it was, but I wasn't expecting it to perform miracles either. Several other people don't seem to think they help enough to justify the cost, so I guess that's just up to you.

[jsmith2232]

I had mine put on last year and ran it hard through the summer and so far i havent had any problems with valves or engine troubles, I can say that i put my stock one back on just for the fun of it and it is definitely worth the 80 bucks to get one especially if you have your airflow opened up.

[400expooner]

Originally posted by Colby@C&DRacing
if you have a high compression piston and cam I would recommend a rev box but if your engine is stock you would not benefit.


i dont have a high compression piston but i do have a aftermarket exhaust k and n air filter dyno jet and my air box lid removed. would that make a difference.

[wilkin250r]

Originally posted by 400expooner
i dont have a high compression piston but i do have a aftermarket exhaust k and n air filter dyno jet and my air box lid removed. would that make a difference.

Not really.

If you were to look at a dyno graph of a stock 400ex (or even one with basic mods like a pipe and filter), you would see the horsepower peak somewhere around 7000rpm. After 8000rpm, the the power starts to drop off very quickly. By the time it hits the rev limit at 9000, it's really not making any power, so what's the point in revving past that with a high-rev CDI?

With engine modifications like a high-compression piston, aftermarket camshaft, and porting to open it up and let it breath, the engine will easily rev past 9000rpm and still be making good power, so a rev box would certainly be useful. However, unless you have those modifications, higher revs won't get you anything.

If you're looking for cheap modifications to get more power, a rev box is not the answer.

[nicktrx400ex]

i have a mostly stock 400ex and i have a biggun exhaust revbox and it made more mid range and top end power. but it didnt raise the speed any. hope this helps. starts are good too.
Nick
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Mods
K&N filter
Pre filter
mosse nerf bars
Dyno jet kit
14 tooth front sprocket
holeshot XCR front and back
big gun rev box

[n811]

I put on the WB box and felt it was the first thing that made a difference from the start. My problem was that when I'm trailing sometimes 2nd was not enough and the bottom of 3rd was kinda doggy. the box allowed me to hold it up in 2nd a bit more and it was a good thing. hav'nt had to do any more abnormal valve adjustments

[hondarider2006]

I am running the Magnum rev box, and haven't had any problems with this one. The first one I had lasted about 15 minutes...and exploded?? There was a huge crack down the middle like it shorted out and kinda blew apart inside. C&D sent me a new one free of charge, and I sent the damaged one back. Been running this one for about 2 seasons now with 0 problems, not even cold starting;)

[400expooner]

thanks for all the information. i think that i will wait until next winter when i put a 440 kit in and port and polish.