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Buell Forum » 1125R Superbike Board » Archives 001 » Archive through March 15, 2009 » Doin somthing new

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Thread	Last Poster	Posts	Pages	Last Post
Archive through March 03, 2009	Tonedeath	30	1	03-03-09 10:18 pm

Author

Message

Steveoc

Posted on Tuesday, March 03, 2009 - 10:24 pm:

Sweet cant wait to hear it.....

Zac4mac

Posted on Tuesday, March 03, 2009 - 10:24 pm:

Wish I still lived in Beaumont.
I'd do that trip. it's a bit far now.

Z

Tonedeath

Posted on Tuesday, March 03, 2009 - 10:27 pm:

yea i go offshore sunday so i hope brent can get it done i didnt give him a date that i need it i told him be creative and take his time so i hope saturday it will be done

Steveoc

Posted on Tuesday, March 03, 2009 - 10:29 pm:

hit me up when its done...How long you go offshore for?

Tonedeath

Posted on Tuesday, March 03, 2009 - 10:34 pm:

well thursday is the day i actually go on the boat but the boat is not working untill sunday we go on a rig job so i should be off but i work 14 and 7 i come back on the 19th so brent might have my bike till then...

1_mike

Posted on Wednesday, March 04, 2009 - 12:08 am:

Maybe I'm off...but why...do I see so many posts about "loosing" too much back pressure?

Isn't that the idea...then tune the intake (ECM) to the exhaust?

Back pressure is the enemy of power.
Though..there is a power vs. noise relationship we must deal with.

Mike

D_adams

Posted on Wednesday, March 04, 2009 - 01:27 am:

Well, just looking around for 304 SS tubing and a Y-collector, I found this.

http://www.who-sells-it.com/cy/burns-stainless-llc -2037/exhaust-technology-2007-9240/page-22-fullsiz e.html

1.75" 2-1 collector for $110.

Then get 45 degree bends in different sizes.

http://www.who-sells-it.com/cy/burns-stainless-llc -2037/exhaust-technology-2007-9240/page-7-fullsize .html

Get 2 1.75" 45's at $34 each, followed up by a 2" 45 at $33.
Find the short 2" (5-10") long section of pipe, maybe a foot for $20?

Then whatever turbo style muffler you like, ie; Gibson, Borla, etc.

Total parts in tubing, roughly $230, whatever the muffler is, (Borla was $275) and a little bit of welding time in a good muffler shop with a tig welder. $600? $700? For an all Stainless system, not bad. Keep in mind, absolutely NO calculations or estimates were done to determine if this would even work. Just throwing out some numbers using fuzzy math. Now I need more beer.

Carbonbigfoot

Posted on Wednesday, March 04, 2009 - 10:10 am:

$979.00 doesn't sound so nuts now, huh?

R

Bob_thompson

Posted on Wednesday, March 04, 2009 - 10:50 am:

1_mike, quite possibly one thing to think about less back pressure/more H.P. is that with very little back pressure which will undoubtedly raise H.P. but will do so in a very narrow rpm band and for some racing as in drag racing would be fine. For much racing and street riding in particular it would be detrimental to good lap times on the track and horrible riding on the street where you need to almost constantly accelerate and brake much of the time using a wide rpm range. Some back pressure helps the mid ranges quite a bit. Xb9 proved this with ECM tuning getting more H.P. all through the rpm range and a stock muffler. Just my take. How about some other opinions? Bob

1_mike

Posted on Wednesday, March 04, 2009 - 12:16 pm:

Bob -
To some extent...you are correct. With todays cam shafts, a little back pressure will help the power at lower rpm's.

In my experience (cars & bikes), that once over 3500 or 4000rpm, the desire for back pressure quickly goes away.

My hunt for and what I ended up doing to my 03, R1 seems to have worked out well.

At the time, all of the full exhaust systems had a noteable dip in the torque curve around 3500rpm.
Seeing that the stock system did not have this dip, I bought a muffler (slip on) only and adjusted the butterfly valve in the stock header to be full open at 4500rpm.

The Dynojet piggy-back box is doing the fuel adjustments.
At the 3000 to 5000 range my bike runs better than and a friend of a friends...above 5000 they run about the same. His bike has a full D&D system.

When I say better...this is seat of the pants...no dyno.
My R1 also runs as well (a little better maybe) at low rpm and much better at higher (4500 and up) rpms than it did when stock (bought new).

Mike

D_adams

Posted on Wednesday, March 04, 2009 - 12:22 pm:

Google is your friend, "exhaust design backpressure" and you'll find a wealth of information. This was just an automotive site, but it still applies here.

"Exhaust Theory
There are two major areas of the complete exhaust system that are typically tuned for enhanced performance; the exhaust manifold or header and the rear muffler(s). The exhaust manifold�s length, tubing diameter and the manner in which each cylinder is linked to the other is critical when attempting to maximize an engine�s power output. The manifold configuration can be manipulated in order to generate maximum power at low, middle or high rpm, changing the shape of the power curve accordingly. Naturally some compromise must be accepted when tuning an exhaust manifold for a street-car as the goal is typically to ensure balanced power output at low, middle and high rpm. This is in contrast to a race-engine where the exhaust manifold can be tuned specifically for maximum performance at high rpm.

After the exhaust manifold or header, optimum performance comes from making the balance of the exhaust system as short and large as possible. This approach will result in greater engine efficiency for maximum power, as well as minimizing the weight of the system. Probably the best example of an optimized, no-compromise exhaust system would be that of an F1 racecar. If you have ever had the opportunity to hear an F1 exhaust note, I think you will agree that it is best described as deafening. Clearly an exhaust system that even approached such a volume level in a performance street-car would draw far too much of the wrong sort of attention. Therefore, a modern street-car exhaust represents a number of performance compromises in order to achieve an acceptable exhaust volume, as well as meeting emissions standards.

In order to accommodate the various components and baffling necessary for a street-car, the exhaust system becomes longer and the flow of gasses more circuitous as noise and emissions standards are addressed. Each bend in the exhaust tubing, catalytic converter, resonator and so forth introduces restrictions to the exhaust flow, particularly at higher rpm where flow is most critical. Exhaust flow can actually reach hundreds of miles per hour when the engine is producing maximum power, which results in power robbing friction along the exhaust tubing walls, particularly when the gasses must change direction. This friction results in increased backpressure that can be quantified with a pressure gauge. In addition to the friction issue, a tube or opening that is too small will result in extra backpressure as well. This backpressure restricts the amount of gasses that can be passed through the engine, resulting in a reduction of peak power."

D_adams

Posted on Wednesday, March 04, 2009 - 12:59 pm:

Ok, this site is just too fascinating to not pass on.

http://www.dinancars.com/bmw/technial-info/dynamom eter-testing-and-the-modern-bmw-engine

Exceptionally detailed breakdown of dyno testing. For anyone who wants to know what to look for in a dyno and it's operation, this is a good starting place. Yeah, it's for a BMW (nope, don't own one) but it's a pretty good read none the less.

Tonedeath

Posted on Wednesday, March 04, 2009 - 07:58 pm:

ok all you backpreasure freaks if yall have lost track of what this post is about. I am running a 2 into 1 system with a 12inch glass pack but for back pressure reasons we are welding in a baffle into the system right before the glass pack to help out. So far the system my muffler guy has come up with looks awesome comming out of the glass pack is a 2 inch chrome slash cut 90 deg tip that is just about in the stock location but instead of discharging onto the rear tire it spits out right into the people next to me..!!!!

Steveoc

Posted on Wednesday, March 04, 2009 - 08:40 pm:

Brent made some progress on it yet?

Tonedeath

Posted on Wednesday, March 04, 2009 - 08:49 pm:

yea he made progress in between jobs. He should be done tommorow i hope but im not rushing him we went over it all this afternoon its gonna look sweet. The chrome slash cut 90 sets it off plus its using the stock gaskets and clamps so the stocker can go back on easy.

Steveoc

Posted on Wednesday, March 04, 2009 - 08:55 pm:

Sweet looking forward to seeing it!

Tonedeath

Posted on Wednesday, March 04, 2009 - 08:59 pm:

well im hoping to have it back friday at lunch and wrap it with exhasust wrap and take a good long ride saturday because sunday im going on a rig job and probly working straight time until the end of april so saturday is my last chance.

01xjbuell

Posted on Wednesday, March 04, 2009 - 10:15 pm:

I'm sorry I even started the back pressure thing.... I'm just looking at the stocker and how much thought was put into the intertwined pipes inside the stocker. Figured this bike is tuned for a certain "flow" characteristic and wanted to keep my attempt as close to that as possible w/ maybe a little more sound.

Bob_thompson

Posted on Thursday, March 05, 2009 - 11:49 am:

Nick, I really believe you are on the right path. Just what I was hoping to accomplish also. My one failure was looks but its well hidden behind my fairing. I also have my stocker opened up in the outlet pipes and it sounds great. Performance with it remains high. Truck on. Bob

01xjbuell

Posted on Thursday, March 05, 2009 - 01:03 pm:

Thanks Bob, I even considered not giving my input here. I know exhausts have been hotly contested on the Badweb. Truth is, the stock pipe w/ tuning is making a ton of horsepower for a restrictive boat anchor hanging under that beautiful motor. Any exhaust with tuning most likely wont lose power over stock, since the EPA causes stock exhaust to usually be restrictive. I'm simply trying to mimic the stock ideas of fitting a long exhaust into a smaller area. Remember most superbikes have headers, to mid pipes, to high-mount/passenger peg mounted cans. How many other performance twins use a super short exhaust like ours? Aprilia? Ducati? Suzuki? the KTM superbike is the only other I know of off the top of my head.

01xjbuell

Posted on Thursday, April 09, 2009 - 08:48 am:

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