what's the HP Gain from Aftermarket exhausts?

[srx2002]

I was wondering ...what's the average amount of HP gain from an Aftermarket exaust? I'm thinking all of them will come within 1-2 HP from another....but has anyone ever dyno'd a bike with just the exhaust...no other mods?????

 

[maleko89]

When I upgraded to Mark's exhaust, I went from 110 to 116 horsepower. I think that's pretty good.

 

[shawn kloker]

I dynoed 121 recently with exhaust and stage 7 .

To me the sound alone of the exhaust is worth every penny.I first drilled mine,then put on supertrapps.Messed around with discs and open end caps for a while.Then I met Paul C. and heard his full system and knew I had to have one.It sounds like a built small block chevy through headers now.

Everybody looks when they hear it coming or going.Even the harley guys get excited till they figure out its a yamaha.

 

[turbostang]

I dynoed 121 recently with exhaust and stage 7 .

To me the sound alone of the exhaust is worth every penny.I first drilled mine,then put on supertrapps.Messed around with discs and open end caps for a while.Then I met Paul C. and heard his full system and knew I had to have one.It sounds like a built small block chevy through headers now.

Everybody looks when they hear it coming or going.Even the harley guys get excited till they figure out its a yamaha.

Which system do you use? I just removed the stock system from mine, and am wondering which one to install.

 

[shawn kloker]

I actually have ufo pipes with hmf 12" polished cans.

 

[maleko89]

I have Mark's exhaust. SS headers, 14 inch cans with 2.25 inch downturn tips. If you like the goldish color that the SS headers turn...or not Mark can do whatever...same with HMF's. If I had to choose I would close my eyes and pick that way. If you want to be really abnoxious, get Kerker 4 into 1 like Morley has. I believe he's running small 1.5 inch baffles. I lost about 10% of my hearing from following his bike.
I would definitely do at least a 2.25 inch outlet. The bike definitely has more of a deep growl at idle....and really has a nice bark when opening it up.

 

[Rusty McNeil]

Here's a question for all.

Would you buy an HMF system new in the box for 1/2 price if someone swears that they could not get it to fit properly without leaking and being highly stressed into place? This person is an old hand at this stuff and knows what he is doing but still says the thing won't fit.
Would you take a chance on it at 1/2 price?

 

[maleko89]

If it was me, I'd call Mark McDade and ask him to mod it for you. Tell him it wont' fit. Then, just send it to him and he'll get it to work.

 

[Rusty McNeil]

Is that the Mark's exhaust guy? If so I'm sure he could fix it.

I've seen his systems and the guy does beautiful work, I would lean his direction for a new system but if I buy new I'm gonna want carbon cans. Problem is I also want stainless pipes and I'm not seeing anyone offering that combo; at least not advertised on line. Might be time to make a few phone calls.....

 

[maleko89]

Yep, that's the guy. Mark can get carbon fiber....different colors too. HMF is the same way.

 

[srx2002]

umm...OK.....so back to my Original question about Aftermarket exhausts with relation to making horsepower......anyone??? or is it a nearly a 1000 bucks for some sound?


P.S would like hear fro someone who ACTUALLY has a dyno sheet with just an Exhaust compared to the stock set-up

 

[maleko89]

My example is with just an exhaust change. Before dyno...110...after dyno 116. You're not going to see much more than that with just an exhaust change. If you do, the tune of the bike before was off or bad.

 

[mikemax04]

My personal opinion is that if the stock exhaust is in good shape and you like the looks, keep it 'till you drop the bike or mess them up somehow. One bike mag has the Max putting out 116 hp at the rear already (2003). You will likely not feel the extra hp gain by the seat of the pants because as you already know, one day it will feel stronger than another because of atmospheric conditions and your personal expectations.

Don (old man) Smith from VMOA said it's hard to beat a good tuned stock bike and I have to agree. Raced another fellow Maxer from these parts who claimed to have 117 ponies with his mods and I pulled away from him, to his amazement. You can buy mods that look different, cost a lot and make a lot of noise, but will not give you your money's worth except perhaps NOS. Just my :twocents: worth.

 

[Maximum]

I like the way the stock exhaust looks, but wanted to tweek the look and the sound. Bought the following exhaust tips from a guy out of Quebec that looks like they will fill the bill. Bid on them before, but they got up over 300.00 so I backed off. Still wound up paying 285.00, but that's a lot less expensive than the systems I've checked out, and I don't like the look of the "cans" most of them have. For me, the squared off cans don't match the sweeping lines of the Max, but again, that's personal. If you like them, watch ebay because the guy will probably have another set up for bid. I'll let you know how they pan out when I get them installed. If I don't like them, I'm certain I can re-sell them--they seem to be a hot ebay item. Somebody always bid them way up on me!

 

[Lew L]

Might be time to invest in some lg dia. alum bar and spin up one of my poor old hand crank lathes. I'm sure I could make those for half the cost at E-bay.

BTW:
I have 2 rear brake struts very simular to the guy from Canada sitting in my kitchen. Have taken pix but haven't figured out how to post as they are too large to do easily.

PS:
Don't forget the weight savings. Every 5 pounds is equal to about one horsepower. Really.

 

[Maximum]

I'm certain you could, Lew. My problem is the cost of the lathe on top of the aluminum bar.