curious about HP

[steve7467]

Ok this maybe a little bit of a dumb question, but i was wondering about the horse power i'm going to get out of my quad. i have a 02 400ex. they come stock with about 27 i think. I got the dmc alien full exhaust. they claim it adds 7hp. so its probobly closer to 5 so thats 32 then i have it jetted and k&n with no lid. maybe what 1 more? now i am having a JE 10.8:1 416 piston and a hotcams stage one. i am hoping for 8-10 out of that combo but that also puts me at 40-42. and that sounds really high. well just wondering what you guys think. thanks

[Glamis400ex]

That is really high. No pipe will give you 7 hp, my DMC gives me 2 hp I think, but I also added a K&N and removed the airbox lid, removed the choke and added a Dynojet kit.

If you are going to do the 416, don't short change yourself with a stage 1 hotcam. That is for a stock motor 400ex, get at least a stage 2.

Glamis

[seven]

I would guess between 32-35

[RAPTORAZ]

The 7 horsepower gain DMC is talking about is in the midrange. You're only gonna gain about 2 horsepower peak. As for the 416 kit. I'd say 32-33 horsepower with a Stage 1 cam, and 34-36 with a stage 2 cam.

[steve7467]

raptoraz what do you mean by peak horse power?

[RAPTORAZ]

Peak horsepower is the highest horsepower reading that an engine can produce. If it makes it peak horsepower at 7600 RPM, then all horsepower readings below 7600 will be lower. Kinda hard to explain without showing you some graphs.

[Steve-o 400EX]

Yea, i agree with RaptorAZ, peak it the highest hp it produces but in some areas you may see a gain of 7 or 8 hyp over stock. If you were to look at a dyno chart you will see what we mean. I will try and find one on here to let ya see what we mean.

[Steve-o 400EX]

Here is a dyno chart. As you can see, there are bigger gains in some areas over stock than others. DMC just took the biggest gain and said thats how much you get. Nothing will give you a steady gain all the way through, you will be higher in some areas more than others.

Dyno Chart (http://www.exriders.com/vbb/showthread.php?s=&threadid=33942&highlight=dyno+chart)

[300exjuggalo]

try it on a dyno :eek2:

[Bretmd94]

with both the exhaust and intake with no lid you might gain 6. Exhaust really doesnt do much at all if you dont let the bike breath. Most of the gain will be in the mid range and not at the top end. (it will make it more torqey)

The high compression piston and stage 2 cam will add a couple hp. But if you get porting also it will really make that piston and cam come alive. You are suffocating the abilities of the stage 2 cam, and piston, with out porting. Opening up the valve more isnt going ot make that great a diferrence if the fuel cant get through the hole any faster.

I am planning on a small bore, if not stock, stage 2 cam, 10.75:1 piston, and a decent port job. This will keep some reliability. The really big bores, and the really high compression ratios kill reliability.

[Dune Surfer]

I think with my mods I have about 34-37 I would think you will be in the 34-36 range