Sorry, I keep forgetting that some people know less than nothing about their bike and only want to stick with BRAND name parts. After all of the research and review reading I have done, the combination I mentioned is and will out perform any other similar combo. If you take the time to call either of these two and honestly seek advice on your riding style, they will refer you to the product that is going to get the job done.

 

Man, you just jumped from the frying pan into the fire. That's a pretty bold statement and will require some backup. It's going to take more than your "research and reading" to convince; post the dyno sheets.

Dave Mackie and RBRacing would have their feeling hurt if they knew that they weren't considered BRAND names.

 

Thanks for the info. It looks like the peak # are at about 3500 to 4000 rpm with the 204 that is a little higher in the rpm range than where the 255 come up to peak. So am I correct in assuming that the 204 are more mid range cams than low range cams.

Would the peak numbers with the 204 be a little higher than the 255 ?

 

In speaking of RBRacing and/or Dave Mackie not being name brands, there are many people that have no idea as to who they are or what they make, but with others like Vance and Hines everyone knows their name. As far as the research on them, it is all over the WWW (I am at work now and can not get the links I have bookmarked on my PC to transfer to my phone). If you ask around someone can surely point you to some good articles and some public domain websites with some dyno sheets and reviews.

 

I’m sorry too; I keep forgetting that some people don’t know what they don’t know. The LSR 2:1 pro stock is not a good match for a street bagger because they have relatively short primary tubes which make them better suited for a high RPM cam and therefore a lighter bike. Either the DME 510 or 575 would respond much better to a longer primary than the Pro Stock.
To quote their website
“LSR 2-1 Pro Stock
Pure Race Systems! No Baffles!”

The Pro Stocks come in two primary pipe configurations and neither achieves ideal exhaust gas velocity in the right RPM range for the OPs 103 Road Glide, I’m actually surprised that someone with your research expertise wouldn’t already know that; 1 3/4" which is too small for the 103", and 2" which is too large for the 103" unless you constantly run at 6500 RPMs. RBR are racers first, their performance parts hobby finances their racing business. I have spoken with them and they are pompous airbags, they rubbed me the wrong way and I wouldn’t give them a plug nickel for one of their dirty shop rags. They don’t care if they ***** you off because they don’t need your business, and they will tell that flat out. Their competitive smart-*** racer attitude bleeds over into the consumer side of their operation, and they assume everyone who calls is a complete idiot, kinda like you did with me in this thread. If you like the flavor of the RB Racing kool-aid, thats great, and you can keep it.

 

fabrik8r, you've made your point very clearly. Can you expand on the tubing diameters and exhaust gas velocities? Thanks...

 

I didn't come up with the formulas, but Ideal exhaust gas velocity is about 290 FPS at the midpoint of your cams' powerband.
(Piston speed / 60) X ( bore X bore / pipe ID X pipe ID)= gas velocity
(stroke X 2 / 12) X (RPM) = piston speed
I made an excel table with the formula in 500 RPM increments, so I can just plug in different values for a quick reference. There's probably a calculator on somebodys website but I never looked for one.
Basically too little velocity will be sluggish/non respononsive just like an oversized intake, and too much velocity will cause friction and start increasing backpressure. The other formula for primary tube length suggests that a stock cam would benefit from an exhaust system with 58-60" primaries. This winter I plan on building a 2:1 system actually matched to a 95" with Andrews 26 cams. Makes you wonder why primary length isn't a published specification for all exhaust systems, sure would make it eaiser to eventually figure out what "really" works, wouldn't it.

 

Sorry Im just getting back with you, iclick. I guess I missed your post earlier. Ive talked to you before about this very problem. I didnt have an oil temp gauge on my RKC but it would sshut doen to one cylinder before everyone else I rode with and one of the dyno tuners said that it probably was the early intake valve close from the SE255's creating the heat. I ran amsoil the whole time and tried an oil cooler but it wouldnt fit because of the O2 bung on the Thunderheader. I dont know what the temps were but the head temps had to be pretty warm because the EITMS was constantly engaging. I had the tuner richen it up but it didnt go away. I think the dip was because the Thunderheader was over exhausting in the rpm area where the dip was. I know youre a huge fan of these cams and I like the idea of the way these cams work but they just weren't for me.

When the temps got up, the bike also got sluggish as you would expect from any hot engine... When it was cool, very nice throttle response and great acceleration.

 

It certainly would. Thanks for the great response! Everyone says "this cam or this exhaust might be worth a look" and i get that but you can look at something and approve of it until the cows come home but theres no way to know its going to perform until you try it or someone else does and you copy them. I cant afford to just buy different exhausts and cams until I find what works best but at the same time, I dont want to do what everyone else is doing. Know what I mean?

 

I feel ya about doing something different from the herd, it’s part of the reason I retrofitted a 2010 SG OEM 2:1 on my 06, and once tuned, it turned out to be a solid performer, even with the CAT still in place (not even going there again). It’s really not a bad option. I also ran the FM 2:1 pipe w/ stock muffler on the same bike and it was a little stronger, I’m inclined to believe that a slightly different design would work even better. Truth is it’s all a mix and match trial and error game, and it’s designed that way to ensure future sales, otherwise aftermarket exhaust system specs would also recommend a specific cam or at least some compatible cam characteristics, but most product info focus is on looks and sound. Can you imagine no industry standards for publishing cam specifications, only highly experienced builders would be able to set up and tune an engine. When I first joined the forum I mentioned the idea of an exhaust specifications industry standard, and I got smacked down for being a tree hugging EPA ****. All I was suggesting was to publish the actual critical dimensions and design attributes so over time reasonable performance relationships could be identified to help everyone match exhaust to their build. Among most of the available manufactured systems, without looking at back to back properly tuned dyno runs, installed on the same bike, it would be hard to tell the difference in performance among the different systems in the same category, 2:1, 2:2, and now also 2:1:2. More often than not, the performance factor takes a back seat to appearance and sound, which explains why there are so many choices, yet the basic functional designs are limited. Unless you have the resources to build and test for yourself, it would be wildly expensive and very time intensive to develop or find the “perfect” exhaust system, for one specific build. That 2:1 Thunderheader in your sig pic is a proven top performer, if you can tolerate the sound level, there's no reason to get rid of that pipe. Unfortunately EPA noise and emissions, manufacturing and development cost, and aesthetics, prevent these bikes from being OEM configured for maximum performance potential, and the very same factors drive the aftermarket. I think it would be very surprising to see and feel the results of an otherwise stock bike with a purpose built intake and exhaust designed for the stock cams, with a high quality tune. Wouldn’t that be sweet to be able to buy a complete intake and exhaust system to bolt onto a bone stock bike that would guarantee max performance? Well it wouldn’t be profit effective for many reasons, so it won’t likely happen. Sorry to all for digressing so far from the original post.