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The Hawk
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Discussion Starter · #1 ·
Picked up a Supertrapp muffler to replace the D&D fat cat muffler. Looking for something a little quieter with equal or better performance. Put it on today and made a run without any discs or end cap. It was as loud as the D&D at idle but quieter at cruising speeds. Came back and installed 18 discs and the end cap. Much quieter but not to quiet, seems just about right. Made a run, including some WOT up to 9000 rpm. Got back and downloaded the log file from the VRFID and it looks like it wants a little more fuel at the 2% throttle areas below 5000 and a little less in the 5% and 7% areas. At WOT it was nearly the same with a little more fuel below 7500, and about the same above except at 8000. Interesting thing is at 8000 it wanted 110% more fuel on the rear cylinder where I had been having issues with it going dead rich and trying to lean out to 65% of the front cylinder. The ecm now wants to run it at 84% of the front, a big improvement. I have a race tomorrow night and will make a couple of runs with the discs in place then try it without them. This is all very preliminary but looks promising.

Only issues so far are the muffler weld seam is on the outside and is visible and since it is made of stainless steel it looks like it will yellow on about the first 1/3 of the muffler. I will leave it on for a while and see how I like it. It does tuck in real close and I don't think it will drag on hard right turns.

Mike
 

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Not from 'round here
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Elgavilan said:
Only issues so far are the muffler weld seam is on the outside and is visible and since it is made of stainless steel it looks like it will yellow on about the first 1/3 of the muffler. I will leave it on for a while and see how I like it. It does tuck in real close and I don't think it will drag on hard right turns.

Mike
Can't you loosen it from the headers and rotate the seam to the inside or bottom?
 

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Elgavilan said:
Picked up a Supertrapp muffler to replace the D&D fat cat muffler. Looking for something a little quieter with equal or better performance. Put it on today and made a run without any discs or end cap. It was as loud as the D&D at idle but quieter at cruising speeds. Came back and installed 18 discs and the end cap. Much quieter but not to quiet, seems just about right. Made a run, including some WOT up to 9000 rpm. Got back and downloaded the log file from the VRFID and it looks like it wants a little more fuel at the 2% throttle areas below 5000 and a little less in the 5% and 7% areas. At WOT it was nearly the same with a little more fuel below 7500, and about the same above except at 8000. Interesting thing is at 8000 it wanted 110% more fuel on the rear cylinder where I had been having issues with it going dead rich and trying to lean out to 65% of the front cylinder. The ecm now wants to run it at 84% of the front, a big improvement. I have a race tomorrow night and will make a couple of runs with the discs in place then try it without them. This is all very preliminary but looks promising.

Only issues so far are the muffler weld seam is on the outside and is visible and since it is made of stainless steel it looks like it will yellow on about the first 1/3 of the muffler. I will leave it on for a while and see how I like it. It does tuck in real close and I don't think it will drag on hard right turns.

Mike
one thing that can throw you, i know it screwed with me. a lean condition bad enough to cause a miss that is hard to hear on a dyno run will show rich on an o2 sensor because of the un burned fuel in the pipe. i tried to tune out a rich spot on the back cyl with one of the first pipes i built for our v-rod and actually got lean enough for the cylinder to quit running at that rpm and it showed an a/f ratio in the 9`s. i ended up putting the same numbers in the back as the front. the power came up and i left it that way despite a too rich a/f reading.you can also get a rich a/f reading from a pipe that really scavenges well because it is pulling a lot of raw fuel out during overlap. my point being that the o2 sensor is handy but you definately need to watch the hp too.
 

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The Hawk
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Discussion Starter · #5 ·
Electro said:
Can't you loosen it from the headers and rotate the seam to the inside or bottom?
You can rotate it but the mounting boss welded on the side will then be on top and I would need to fabricate an L-bracket for the mount. No big deal and I might end up doing that, just need to figure out which is worse, having the seam visible on the side or the mounting boss and bracket on top.

Mike
 

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The Hawk
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Discussion Starter · #6 ·
lbrown said:
one thing that can throw you, i know it screwed with me. a lean condition bad enough to cause a miss that is hard to hear on a dyno run will show rich on an o2 sensor because of the un burned fuel in the pipe. i tried to tune out a rich spot on the back cyl with one of the first pipes i built for our v-rod and actually got lean enough for the cylinder to quit running at that rpm and it showed an a/f ratio in the 9`s. i ended up putting the same numbers in the back as the front. the power came up and i left it that way despite a too rich a/f reading.you can also get a rich a/f reading from a pipe that really scavenges well because it is pulling a lot of raw fuel out during overlap. my point being that the o2 sensor is handy but you definately need to watch the hp too.
Good to know Mr. Brown, thanks, I will keep an eye on the performance and see what it does.

Mike
 

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Will the Supertrapp baffle fit inside the D&D muffler? If so it would be easier to drill a couple of baffle mounting holes on the inside bottom of the Fat Cat to secure the Supertrapp baffle. For the sportbikes you can normally buy baffles in quiet or race exhaust outlet sizes.
 

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Hi Mike
That's a cool experiment. I did a similar thing on a twin cam with Hooker 2:1 headers and a s/trapp can from Summit. The hooker is a short 2:1 and got real loud right under my ear. To hide the seam I moved the piece on the pipe and polished up the marks where it came off. For some reason that set up worked best with 18 discs and an open cap, which was nothing like supertrapp's guidelines. It made good power & was quieter that the hooker can though, and of course went a golden colour.
 

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spit happens
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I have a race tomorrow night and will make a couple of runs with the discs in place then try it without them. This is all very preliminary but looks promising.
Remember Mike,Horsepower will show in mph not ET.
 

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The Hawk
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Discussion Starter · #10 ·
skipmccall said:
Will the Supertrapp baffle fit inside the D&D muffler? If so it would be easier to drill a couple of baffle mounting holes on the inside bottom of the Fat Cat to secure the Supertrapp baffle. For the sportbikes you can normally buy baffles in quiet or race exhaust outlet sizes.

Nope, the D&D is 3.5" and the Supertrapp baffle is 4". It is possible to get the core part to fit with some trimming, bending, etc, but then the discs would not work.

Mike
 

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I'm a lot more interested in the bike's front end actually. Is that a Buell front wheel and ZTL brake set up I see? On the stock V-Rod fork? Could we have a little close up of that? Ok I'm nosey, I admit it, but that is a fascinating modification. Are you using the stock master cylinder with that caliper? How is the power and feel? Oh, does that Supertrapp set up improve the cornering clearance at all?
 

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The seam shows because you have the botom of the muffler facing out, but I assume you know that. The bolts and seam should be on the bottom.
 

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The Hawk
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Discussion Starter · #13 ·
Well, back from the races earlier than I expected. The exhaust mod was great. I started out with 18 discs, set the VRFID at the trouble spots on the rear cylinder to 100% of the front and 100% on the BLM table so it was equal to the front cylinder. First run off the trailer ran a 10.80 at 123 mph. Bike ran real strong and felt stronger in the upper rpm areas. Looked at the VFRID map for the rear cylinder and at 8000 it was 98% of the front but only 75% for 8500 and 9000. I applied the changes and made another run. Lost traction off the line, spun badly, let off and got back in it and still ran an 11.02 at 125 mph. Pulled real hard on the top end. Made some more adjustments and took out 3 muffler discs to see if a little more back pressure would increase power. Made run 3 up against a Hayabusa with a wheelie bar and slick. I spun way to much off the line and he got out about 20 feet on me and then I ran right with him for the rest of the track. The bike pulled really hard up top, I had a hard time keeping my butt planted in the seat, kept wanting to ride up the back of the seat. Reminded me of how hard it pulled with the turbo up top. Ran another 11.0 at 125. The log showed I was feathering the throttle to stop the wheel spin for the first 2 seconds of the run. Overall I really like the exhaust that way and it runs real well. I had a guy that works for a custom bike shop come up and say that it sounded really good and what exhaust was I running.

Now for the bad part, on the last run, coming back down the return road the clutch felt real wierd, getting a mechanical bump feed back in the lever, not good. Got to my pit and pulled the clutch actuator cover and the slave cylinder and it was evident something real bad was up. The inner snap ring that holds part of the clutch together had come out and caught between the slave cylinder and the AIM and there was a lot of aluminum shavings, the rubber cover on the slave was all torn off so I put it on the trailer and will be tearing off the clutch side cover this AM to see what damage was done. The motor still runs well, oil pressure was still up so I think the only damage is to the side cover, maybe the AIM and the slave cylinder. I will post up when I get it figured out.

Mike
 

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The Hawk
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Discussion Starter · #14 ·
Philthy said:
I'm a lot more interested in the bike's front end actually. Is that a Buell front wheel and ZTL brake set up I see? On the stock V-Rod fork? Could we have a little close up of that? Ok I'm nosey, I admit it, but that is a fascinating modification. Are you using the stock master cylinder with that caliper? How is the power and feel? Oh, does that Supertrapp set up improve the cornering clearance at all?

That front wheel setup is a Buell XB wheel and brake. You can get the adaptors from Eagle HD. I am using the stock master cylinder and the brakes work great, much more feel than the stock brakes and it will stop quick. Do a search on the forum and you will find lots of info about the Buell wheel setup. The exhaust does not drag, it drags the pegs first.

Mike
 
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