Raptor Forum banner
1 - 20 of 32 Posts

·
Registered
Joined
·
227 Posts
Discussion Starter · #1 ·
So I'm contemplating on fixing up a 04 660 I got for 1800 (reason y I joined this site) IV always liked the looked of dual exhaust but does it really help ur performance compared to a Dingle exhaust? With a$700 price tag I wouldn't wanna waist my money.
 

·
Super Moderator
Joined
·
17,061 Posts
Yes, duals make more hp than singles. How much more depends on which single pipe you're talking about, and so would any value judgement over whether it's worth it to get a set of duals over a single.

If your budget is tight you can get a good single like a Yoshimura or find a used CT or sparks and make better use of the extra cash with other mods. If you're planning on building the engine at a later time the duals shine better with motor mods.
 

·
Registered
Joined
·
227 Posts
Discussion Starter · #3 ·
I'm not sure if I plan on building the motor or not.. for one I'm not sure what I should do an shouldn't. Its got an hmf muffler with stock header. Jetted with gytr filter with no air box. N that's it.

Any suggestions? I'm thinking perhaps a stage 2 hot cam
 

·
Super Moderator
Joined
·
17,061 Posts
Pick up an HMF header, 11:1 piston, stage 2 hotcam, and hd valve springs. Should be somewhere in the ballpark of that $700 set of pipes.
 

·
Super Moderator
Joined
·
17,061 Posts
Stage 2 cam requires the HD valve springs, if you want a drop in you'll have to go with the stage 1. If you're drag racing or running wide open a lot I wouldn't recommend it but if you're commonly in tighter trails or low rpms and you don't have a desire to build it up in the future then it may be a reasonable upgrade.
 

·
Registered
Joined
·
227 Posts
Discussion Starter · #7 ·
Well most of my riding is trail riding. But I still want to be able to get some speed while at the dunes. That's why I suggested a stage 2 cam.
 

·
Master of the Electron
Joined
·
15,629 Posts
Question (from a pure physics standpoint)...

Why, in the case of the Raptor (single cylinder, dual exhaust valve), would dual exhaust flow any better than a single exhaust with the same pipe cross sectional area as the sum of the duals? In other words, if I run duals with 1.5" diameter tubing, they have a cross section of 2.5 sq in each, or 5 sq in total... so if I ran a single with 5 sq in cross section (2.25" diameter) the flow would be the same.

Ignore the exact numbers I'm using, they're just for example... but the principle stands.
 

·
Super Moderator
Joined
·
17,061 Posts
Well most of my riding is trail riding. But I still want to be able to get some speed while at the dunes. That's why I suggested a stage 2 cam.
Then you'll need the HD springs, and if you don't want the bottom end to feel lethargic from the loss in dynamic compression you'll want an 11:1 piston to go with it and we're back to "pimping" it out.

Question (from a pure physics standpoint)...

Why, in the case of the Raptor (single cylinder, dual exhaust valve), would dual exhaust flow any better than a single exhaust with the same pipe cross sectional area as the sum of the duals? In other words, if I run duals with 1.5" diameter tubing, they have a cross section of 2.5 sq in each, or 5 sq in total... so if I ran a single with 5 sq in cross section (2.25" diameter) the flow would be the same.

Ignore the exact numbers I'm using, they're just for example... but the principle stands.

QM, you've equalized area but we need to address the other side of the equation. Flow is also dependent up on the velocity of the exhaust gases. An equal length headpipe on either side will allow for less reduction in velocity pressure than running two unequal length head pipes into each other (creating turbulence from the fact that the exhaust in one of those pipes is moving slower than the other because of the different distance traveled and bend encountered while doing so) and then increasing in size to a large single pipe (with a larger space to expand the gases will move more slowly). That's not to say any dual will best any single but the best duals have an inherent advantage in design which reduces the negative impact on velocity pressure. Of course we know it's easy to screw something up in implementation.

The larger Sparks singles (XX6, Krackinator) are on par with if not capable of exceeding the power output of the lesser designed duals, ie: LTE with their unequal length, extensive bends under the tail and lack of significant step up. The monsters, with their multiple bends but essentially equal length step up pipes should perform better and claim to do just that though I have yet to see numbers showing how the monsters compare to anything. The Barkers with the most direct headpipe route and reverse megaphones should in theory, have the most advantageous design of the lot.

I once believed that duals were a gimmick, then that their benefit only existed on a drag bike. This of course was back when I actually remembered my collegiate physics courses :D. Despite my vocal support for the established single exhausts of the day my speculation was met with fact and I was proven wrong. This was back in the fall/winter of 2004 and by the following spring I had a set of Barkers on my 660.
 

·
Premium Member
Joined
·
2,576 Posts
i'm surprised nobody is talking about the DMC duals. I really had my eye on them, or maybe the Barkers. But i like the DMC has a welded bracket to the frame and not a clamp. the clamp just makes more peices. I like that the Barkers have more options, but more cost as well. After reading the thread by THQ i think i am going with DMC Force 4 with silencers for the beach.
 

·
Super Moderator
Joined
·
17,061 Posts
i'm surprised nobody is talking about the DMC duals. I really had my eye on them, or maybe the Barkers. But i like the DMC has a welded bracket to the frame and not a clamp. the clamp just makes more peices. I like that the Barkers have more options, but more cost as well. After reading the thread by THQ i think i am going with DMC Force 4 with silencers for the beach.
Because they don't make them for the 660.
 

·
Super Moderator
Joined
·
17,061 Posts
Monsters are the best compromise, in frame but a better, less restrictive design than the LTE. If only I knew how well they did against the Barkers I'd be able to determine if there is a performance gap and if it's one worth worrying about.
 

·
Premium Member
Joined
·
2,576 Posts

·
Registered
Joined
·
227 Posts
Discussion Starter · #18 ·
IV Bern reading n read alot if reviews on barkers n they all say they look n sound good Capt the mounting brackets suck they say
 

·
Super Moderator
Joined
·
17,061 Posts
They use straps, as do LTE these days IIRC. I had one break once after a particularly rough ride through some whoops but otherwise have no problems with their performance or with the canisters coming loose or sliding out. Nice part about straps is that they will give where hard mounts bend or break, so if you accidentally step on the pipe getting on the bike you won't ruin your riding day.
 
1 - 20 of 32 Posts
Top