400EX Dyno results for 17 different exhaust systems looks ugly!

[HY400EX]

These HP numbers are not that impressive over stock in some cases they are worse. They say the stock air lid was left in place. Seems like to me the best bang for your buck is just to remove the air box lid, re-jet and leave the stock exhaust on. Just makes me want to go out and waist some money on an aftermarket exhaust for less weight and more noise. Sure you might get better low end or mid range torque but if you gain in one area I’m sure you lose in another.
Check out the link
http://www.260111.s5.com/testtrx400escapes.htm (http://)

If the link does not work just copy and paste into your web browser

[bkelley]

E-Series was one of the best! That is pretty interesting, though.

[tri5ron]

link no worky

[bkelley]

400EX Pipe Test (http://www.260111.s5.com/testtrx400escapes.htm)

[tri5ron]

interesting article, but I would like to see what they got on the dyno with the stock pipe too. That's the one pipe that they did not provide numbers for. they DID say that there was not a SIGNIFICANT difference,... but it would be nice to know what the OEM pipe gave them, for the comparison.

I would also liked to have seen this comparison done without the lid on the airbox too.
I mean, they've already got the bike on the dyno,....
and they've already got the pipes on each time,...
so why not make a run with each pipe, with the lid removed too ?

I've often felt that I would prefer to have my quad as quiet as stock. When I bought it (used), it already had the Big Gun system on it.
I bought a brand new stock system off of Craigslist some time ago, and have considered doing the header pipe weld grind mod, and trying it out to see if I can tell the difference.

That just may be a test I do this spring, and if I have reason to go back to the dyno shop, I just may do it there.

Interesting read,... Thanks for posting it.

[slightlybent47]

Adding a pipe is not just for added HP and in most cases the aftermarket pipe is lighter.
And on a race bike every little bit help and all the mods will add up for a significant gain in HP. But for the average rider looking for a small gain in HP a pipe is probably the most expensive mod you can do that has the smallest gain.

[Donjuan400ex]

anyone have a conversion chart from dyno jets to kenin jets??

[honda400ex2003]

Width------Keihin # -- DynoJets # -- Mikuni #
0.0350---- 92.5--------- 92----------- 86.3
0.0360---- 95----------- 94----------- 88.1
0.0370---- 97.5--------- 96----------- 90.0
0.0380---- 100---------- 98----------- 91.9
0.0390---- 102.5------- 100---------- 93.8
0.0400---- 105--------- 102---------- 95.6
0.0410---- 107.5------- 104---------- 97.5
0.0420---- 110--------- 106---------- 99.4
0.0430---- 112.5------- 108--------- 101.3
0.0440---- 115--------- 110--------- 103.1
0.0450---- 117.5------- 112--------- 105.0
0.0460---- 120--------- 114--------- 106.9
0.0470---- 122.5------- 116--------- 108.8
0.0480---- 125--------- 118--------- 110.6
0.0490---- 127.5------- 120--------- 112.5
0.0500---- 130--------- 122--------- 114.4
0.0510---- 132.5------- 124--------- 116.3
0.0520---- 135--------- 126--------- 118.1
0.0530---- 137.5------- 128--------- 120.0
0.0540---- 140--------- 130--------- 121.9
0.0550---- 142.5------- 132--------- 123.8
0.0560---- 145--------- 134--------- 125.6
0.0570---- 147.5------- 136--------- 127.5
0.0580---- 150--------- 138--------- 129.4
0.0590---- 152.5------- 140--------- 131.3
0.0600---- 155--------- 142--------- 133.1
0.0610---- 157.5------- 144--------- 135.0
0.0620---- 160--------- 146--------- 136.9
0.0630---- 162.5------- 148--------- 138.8
0.0640---- 165--------- 150--------- 140.6
0.0650---- 167.5------- 152--------- 142.5
0.0660---- 170--------- 154--------- 144.4
0.0670---- 172.5------- 156--------- 146.3
0.0680---- 175--------- 158--------- 148.1
0.0690---- 177.5------- 160--------- 150.0
0.0700---- 180--------- 162--------- 151.9
0.0710---- 182.5------- 164--------- 153.8
0.0720---- 185--------- 166--------- 155.6
0.0730---- 187.5------- 168--------- 157.5
0.0740---- 190--------- 170--------- 159.4
0.0750---- 192.5------- 172--------- 161.3
0.0760---- 195--------- 174--------- 163.1
0.0770---- 197.5------- 176--------- 165.0
0.0780---- 200--------- 178--------- 166.9
0.0790---- 202.5------- 180--------- 168.8
0.0800---- 205--------- 182--------- 170.6
0.0810---- 207.5------- 184--------- 172.5
0.0820---- 210--------- 186--------- 174.4
0.0830---- 212.5------- 188--------- 176.3
0.0840---- 215--------- 190--------- 178.1
0.0850---- 217.5------- 192--------- 180.0
0.0860---- 220--------- 194--------- 181.9
0.0870---- 222.5------- 196--------- 183.7
0.0880---- 225--------- 198--------- 185.6
0.0890---- 227.5------- 200--------- 187.5

[honda400ex2003]

this one looks remarkably similar to one that was around quite a while ago from atv sport. it was shootout, goes long, gets ugly. most of those exhausts are pretty old and are not offered anymore. these look to be full exhausts. actually i just found it, it is the shootout but has the pictures attached still. this is a good find. thanks again. the jetting and everything is good to have to find out what they were at for best performance on the exhausts.

http://www.atvsport.com/output.cfm?id=30961

heres the atv sport one. steve

[rinaldi]

Originally posted by bkelley
E-Series was one of the best! That is pretty interesting, though.

I do say I love that White Bros on your quad. I just installed a Motoworks for mine and haven't rode it since install. Been parked until spring. Sure love the look of the E2.

[chucked]

I believe that article is about 10 years old. A few of the pipes in there have been discontinued for a while.

[HY400EX]

Originally posted by tri5ron
interesting article, but I would like to see what they got on the dyno with the stock pipe too. That's the one pipe that they did not provide numbers for. they DID say that there was not a SIGNIFICANT difference,... but it would be nice to know what the OEM pipe gave them, for the comparison.


If they provided that info. The aftermarket manufactures probably would not sell to many systems.

From stock to aftermarket, there is a big difference. When I put my DMC on (Advantage Performance) the thing pulled SO much harder from the mid-range on up then stock. I raced a stock 06 and it pulled by him by a noticeable amount.

They were saying between different PIPES, there wasn't that much of a difference.

Stock 400ex's are like 24hp to the wheels, maybe 25. So to get in the high 27's is good for an exhaust.

Between the aftermarket pipe, timing key, and filter, it makes the 400ex a different animal. Stock exhaust makes it a slug.

Plus I don't know what you guys expect. Exhaust system's are not a miracle. They will not put your 400ex up to 35hp. It's an exhaust.

The 2-3hp gain is normal for an exhaust system on a lower output quad. If you had a built 440, and went from stock exhaust to aftermarket, there would probably be damn near an 6-7hp gain.

400ex's aren't very aggressive engine's stock. That's also why 450's get much more out of just an exhaust.