| Author | Message | ||
     Kinder |
I tried a search but nothing came up.  Looking for the exhaust valve opening point, closing point and center line, valve sizes and any other useful specs for exhaust design. I was looking to buy a set of FS headers (and I may yet) but started looking into getting custom ones done that would mate up to the majority of slip ons available. Thanks  (Message edited by kinder on March 14, 2011) | ||
| Nillaice |
did you mean to post in teh XBoard? i don't know of any valves in an 1125 muffler what do you mean by 'FS HEADERS' what is your objective? | ||
| Kinder |
Sorry if I'm not being clear.  I'm looking for cam durations and stock sizing for the exhaust valves. I was going to purchase the Free Spirits 54mm headers but have decided to look into getting some custom made ones that will work with most of the aftermarket slip-ons. Basically I'm looking to build/ design a set of equal length headers. I could use the specs to determine some base measurements to start with. This is new to me and I'm not out to create a new slip-on. I just want to try some stuff out and this is one of the things I have decided to try. | ||
| Jdugger |
Buy the Buell race full exhaust system and call it a day. You have a mandrel bender and a few feet of thin wall SS DOM tube? | ||
| Fastcarr |
Here's a hint: You don't want equal length headers, this engine fires asymmetrically(2 cylinders, 1 crank pin). I'll leave the math as an exercise.  | ||
| 1_mike |
Kinder - You are plenty clear in your question. It's just that most people are confused by a person that's looking to design & build a new part....the "correct way"...! You are correct in that the cams opening and closing rates, along with other information is critical in designing your own...in this case, a full exhaust system. I applaud you in your efforts to do something "your" way. Not just following everyone else...! Beside...as Dean (Keda) knows...it's MUCH more fun. Have fun. Mike (Message edited by 1_mike on March 15, 2011) | ||
| Kinder |
Jdugger: have a friend who works at a custom Harley shop. They have a mandrel apparently. And even without one you can just use a larger dia piece for the bends.  And I can get tubing from them, muffler shops or one of many online companies. Fastcarr; I figured that it was an asymmetric engine like the VR6. Now the only headers that have posted any gains on that car were a set from a company called S2 metalwerks. http://www.flickr.com/photos/wayne92slc/4158208056 /in/photostream/ Notice how much closer they are to equal length? Now before someone pipes up how "that's a car engine" crap... It's a 4stroke cycle engine. It's does not somehow change the laws of fluid dynamics. It's just an example on how things can be different yet the same. :P Our stock set up has the rear pipe being about 40% longer than the front. I think there may be a bit of gains here (1-3) plus some rpm acceleration being freed up. So many people tell me to get the Erik Buell Racing one and call it a day. Well IMO The EB Racing one is 1) fairly ugly, 2) Seems to be a lot closer to equal length vs stk, 3) has relocated the O2 sensors away from the primaries ( less obstruction?) 4) Too loud and 5) I have seen some dyno charts and while peak hp #'s are there the curve is not. I ride in the curve not at the top. Where do you ride in the curve? What I do find interesting about it though is the elongated primaries off the front cylinder. Almost like the front cylinder is Suppose to help scaveng the rear. But without some cam duration details and exact measurements like flow speeds and length one can't tell. http://froggypwns.com/images/AMA%20Races%20at%20NJ MP%202009/slides/IMG_6281.JPG Just like Dean saw a way to use his fab skills to fit a car muffler onto our rides I want to explore what else we can do before going inside. I have always looked outside the box when doing stuff. Quick example, my car is a Subaru Legacy SpecB. When I upsized the turbo I was told time and time again to switch to a FMIC. I didn't like the amount of cutting it required so decided to try an Air to Water Intercooler. More complex in some ways easier in others. Results are it works just fine for my car and offers me some bragging rights. (Message edited by kinder on March 15, 2011) (Message edited by kinder on March 15, 2011) | ||
| Jdugger |
> And even without one you can just use a larger dia piece for the bends Not really. The tube will tend to buckle on the inside of the bend and create flow problems. You can weld together segmented curves by cutting paired sections of tubing "pie", but it's a bit of PITA. > Where do you ride in the curve? Between 6 and 11k, mostly. But, I'm on the track. I *do* remember a couple of exhaust systems with very long primaries on the 1125r. They were used in the Moto-ST race series, I believe, and designed to boost torque at the expense of top end HP, which was limited in that class, anyway. It was *outrageously* loud. Even louder than the Buell Race Exhaust, which is almost embarrassingly loud, even at the track. I get crazy looks when I start my bike in the paddock. I think if noise level is a concern, and I want to say thank you for being considerate of noise level if you intend for your solution to be a street legal one, the Erik Buell Racing and really any of the existing pipes I'm familiar with are not good choices. They range from loud to very loud. | ||
| Kinder |
So does anyone know where I can get the specs I'm after? | ||
| Nillaice |
sorry for assuming. your project is well beyond my skill set, and i can not provide teh answers you need | ||
| Kinder |
^ no probs... Ty for wanting to help. | ||
| D_adams |
I don't know exactly how accurate these numbers are. 72 degree v-twin, I forget the valve sizes, but they're pretty big for what the engine size is. The overlap is pretty long for the cams. There's a reason for using staggered length primaries on the 1125, it's for scavenging. Going to an equal length is a little counter-productive unless you're going to keep them totally separate. Even so, you will probably see a large loss in power going this route. You'll have to do ignition timing changes, in addition to fuel changes, probably some cam timing modification also. You will definitely need a dyno for tuning it correctly. I do not envy you this task, it's WAY more than I want to get involved in. I think the stock outlet at the exhaust valve is around 1" for the small tubes. I wouldn't go over 2" (stock is 1.75" roughly) for the merged primaries, you'll want about 15-18" max of that, then merge into 2.5" tubing, assuming you're using 16 or 18 gauge stainless. You can use a megaphone or taper out to 2.75" (from a 2" collector) to get some pretty decent power, but again, that's using a merged system. Please keep in mind, I am NOT a professional anything and I'm not tearing into my engine at this time to verify the numbers posted above. In all honesty, you need to get a good dial indicator on a mag base and a good degree wheel to do the work yourself. It's really the only way you will ever know for sure what the numbers are. (Message edited by d_adams on March 15, 2011) | ||
| Ridenusa4l |
ask Erik Buell Racing?? Jake | ||
| Ohsoslow |
lol at the haters. Kinder, maybe try contacting Rotax? not sure if they would be willing to give out that sort of info. or maybe to contact E-B-R, they might be able to help you as well. keeps us updated if you get something going on this. | ||
| Fast1075 |
Dean nailed it...you are going to need a good dial gauge and degree wheel anyway if you are going to play with the cams. | ||
| Albert666 |
slightly off topic again but regarding the vr6 engine, the actual primary lengths are equal, even if the pipework isn't as there's exhaust length in the head due to layout, this is what we built in 2002 for the 24hr speed record, originally the diablo with a 'w12' engine, effectively two vr6's stuck together, not the best pics but all i could find, theres about 150mm inside the head on alternating ports so you have one long pipe, one short, one long etc, but all total primary lengths are the same, it was a ballache to make and fit, the diablo wasn't fast enough so they changed the bodywork to vw w12    | ||
| Kinder |
Thanks for the info. I have already talked to a fab guy here that seems confident that we can get my design to work. They have experience custom making equal length exhaust systems for Harleys and feel the Buell will prove no different. They also recently unpacked a dyno they had bought two years ago! My buddy who just started there is responsible for setting it up and will be runing it. Maybe I can get some base runs with stock setup vs new headers with stock bits! He also mentioned maybe using 2 different sized pipes for front and rear to help balance timing of gas flow. Looking back I think that may have played into the Erik Buell Racing design. Bike goes to the shop on Sat so he can see what he has to work with. I'll keep you all posted. | ||
| Qwik59 |
I am very interested in this, quite a bit outside the box myself, built a 12sec Jeep, soon to be 10's haha. Also built an air/water IC setup for a friends Scooby few years back, crazy. Keep on with the search for more usable power my man!  |
