How to make 40HP on a 400EX

[ajw2685]

http://www.ebay.com/itm/400EX-Spiral-Core-Exhaust-Intake-Kit-TRX400ex-Pipe-/300714438412?pt=Motors_ATV_Parts_Accessories&hash=item4603fa2f0c&vxp=mtr

You might be able to get 75HP if you get an electric supercharger as well.

I call BS on the 40HP claim. Not because it is clearly bogus, but because the kit does not come with any stickers. We all know that stickers add horsepower.

[junior636]

LOL, must be a turbo hidden in that exhaust somewhere!

[CJM]

Theres a seat for every arse as the old used car salesmen adage goes.

[dunatic]

Ive got 40.25 hp and I dont own either of those products.

Then if you turn on the juice it's 65

[Pittsburgh400ex]

Whats the real hp on a stock 400? CARB tests claim 34 on the 400ex, 42.6 on a 450r.

[ish416]

Whats the real hp on a stock 400? CARB tests claim 34 on the 400ex, 42.6 on a 450r.

A stock 400EX will usually put down 24 - 28 HP at the tires depending on the dyno, conditions and operator. Most 450s put down between 34 - 38.

[dunatic]

mine was old when I first bought it. It put up 29 hp on the first dyno run.

after it was built to 416cc, 41mm FCR, X6 megaphone, fully built head, 10.8:1 compresson, lightened flywheel and starter gear and tuned most of the day, it made 40+.

With the NOS turned up to 30 hp, it spins the clutch. so I backed it off to 25 and it's been perfect ever since.

[dunatic]

fully built head, cam, springs, rockers....sure why not.

My other motor (that has now passed away), was a 440 stroker. 416cc with 4mm stroke made 41.5, at the time only had a 39 FCR and a LRD system. Same head setup, fly wheel and starter gear.

[CJM]

I didnt see you had the head done, thats entirely possible then.

Stock head no way.

[Pittsburgh400ex]

Heh, why such a discrepencey? Does carb and/or manufacturers measure at the flywheel?

[ish416]

Heh, why such a discrepencey? Does carb and/or manufacturers measure at the flywheel?

Just like car manufacturers, everything is rated at the flywheel. I am not sure what CARB uses, I assume crank because their numbers are always the same number the manufacturer uses.

If it is rated at say 50 hp from the manufacturer / CARB you can throw it on a dyno and get a reading of 40 hp. Then you could assume you have a 20% loss of power through the drivetrain (transmission, chain, tires and axle).

Also, a dyno number without a baseline is useless.

[dxcody]

I would like to know what kinda HP Adam McGill's honda is throwing down.

For an XC quad I know it has to be a crap load...

He has Toby @ MXP trying to squeeze every drop out of that thing.