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Having adopted 7 exhaust units (three '05 and newer model years) to store in my rental shed (just 5 more and I can start the 12-step program!!), I got to talking with Hank at Rhinewest about the change in construction parameters that I thought occurred in '05. He confirmed it, and wuz aware of it due to the many swap-outs he has made whereby the OEM units were exchanged for the Remus setups.

Using a dial caliper (micrometer is what I call it?), I measured the exhaust flange I.D. and O.D. of the units. All measured identical in mm. Then I measured the O.D. of each of the exhaust pipes. These pipes snake around each other before combining to go into the collector just before the O2 sensor, near the catalytic converter. There are two different measurements evident.

32.5mm O.D. for the '99 - '04 units.
34.9mm O.D. for the '05 - up units.

These measurements are as close as I can get, using well-worn eye-candy checkers!! ;) My question to Hank wuz; why? He sez he thinks it has sumpthin' to do with the change in HP, beginning with the '05 model year; that the change for '05 and newer models resulted in freer/better exhaust flow; AND that if one were to install a larger O.D. unit on a '99 to '04 engine, and not modify the Motronic programs, the engine idle may be affected, along with some other less than desirable performance factors (likewise a performance hit with an '05 up unit, installed on a '04 or prior model). He stressed that it wuz only his opinion, and that there may be more to it than that.

Sooooo - is there??? I certainly don't wanna give/sell an exhaust unit that is not model year specific for installation. Hoping to hear from some of you mechanic/engineer types with good info. Thanks in advance.
 

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Dick said:
Sooooo - is there??? I certainly don't wanna give/sell an exhaust unit that is not model year specific for installation. Hoping to hear from some of you mechanic/engineer types with good info. Thanks in advance.
As I understand it the '05 and later models got their horsepower from better breathing. The cam profiles were changed, the exhaust system was changed and the fuel/timing profile was changed. The peak horsepower on an '05 or later comes at a higher RPM than the earlier engines.

To answer your question, I do not believe there would any negative impact using an '05 and later exhaust on an '04 and prior bike. There might be a *slight* gain in power in the upper RPMs. The idle would not be affected since the motronic controls the idle to a specific RPM. I do not believe the back pressure would be enough different to impact the mixture.

Putting a pre '05 exhaust on an '05 or later might take a couple of horsepower away since the exhaust changes were a part of the whole package.
 

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Discussion Starter #3
Randy said:
As I understand it the '05 and later models got their horsepower from better breathing. The cam profiles were changed, the exhaust system was changed and the fuel/timing profile was changed. The peak horsepower on an '05 or later comes at a higher RPM than the earlier engines.

To answer your question, I do not believe there would any negative impact using an '05 and later exhaust on an '04 and prior bike. There might be a *slight* gain in power in the upper RPMs. The idle would not be affected since the motronic controls the idle to a specific RPM. I do not believe the back pressure would be enough different to impact the mixture.

Putting a pre '05 exhaust on an '05 or later might take a couple of horsepower away since the exhaust changes were a part of the whole package.
Thanks, Randy. I couldn't converse knowledgeably with Hank about this, cuz I ain't knowledgeable; butt my gut feeling wuz that if the up/down installations would cause a detrimental impact, there would have been a TSB or sumpthin' and word would've made it's way to the community.

Thanks again, Randy.
 

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When I put a Remus on my 05' I was very supprised at the difference in size of the inside of the pipes. Some of the headers had very thick and sloppy welds. If I was to ever put it back on I would take a small grinder and clean up the welds inside. On thing I found strange with the Remus was they were not equal length headers, just ran straight back to the collector, much better quality than stock though. I also installed his cam gears and with both the LT runs stronger!
 

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Discussion Starter #5
dmatson said:
When I put a Remus on my 05' I was very supprised at the difference in size of the inside of the pipes. Some of the headers had very thick and sloppy welds. If I was to ever put it back on I would take a small grinder and clean up the welds inside. On thing I found strange with the Remus was they were not equal length headers, just ran straight back to the collector, much better quality than stock though. I also installed his cam gears and with both the LT runs stronger!
Yep, Doug. You're right on the exhaust units having sloppy welds. Some sure seem like they pose an internal obstruction to a smooth exhaust flow - others seemed better, butt not perfect.

I wuz standing at the Rhinewest counter last week and had a leetle time while they cranked on the computer to pull my invoice - noticed the dyno chart of the '05 LT test they did. One stock; one with Remus and no cam sprocket; and one with sprocket and Remus. (It might have even had the two variants of the Remus cans, butt I'm not sure). At any rate, the chart/graph lines looked pretty impressive off the computer.

Those guyz are always tinkerin' with somethang related to engine mods; I think they have a chip guru that knows his stuff.

Best.
 

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Discussion Starter #7
mgbmw2002 said:
Would someone care to explain what/how a cam sprocket would change engine performance? Is it something like the Connie's variable valve timing? MG
I sure can't explain it, butt click here for some info from the dudes that do it. HTH.
 

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I put a Remus on my 02 LT at the rally last year and one thing it did was clear up a vibration I had been getting right at 4.5k rpm. It didn't do it before or after, just in that small band, but the new exhaust seemed to fix that. I also installed a new chip in the computer, but have not had the chance to give it a try yet, as I am waiting on parts for other stuff I've worked on.
 

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A question for those of you that have changed the chip, cam gears and/or exhaust system: What change, if any, have you noticed in your fuel economy?
 
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