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Metal cannot think, therefore it cannot be held re
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Discussion Starter · #1 ·
I'm jumping the gun slightly, but thought it timely to get this started. The Supertrapp system arrives here on Thursday, but I won't start testing until the end of the month because of my workload.
It would be nice to keep this thread on a technical level to make it easier for those who are interested in this aspect of performance upgrades and tuning.
So lets get a few things out of the way first. Yes it's expensive, and yes, to a lot of people, it's ugly. The reason I've chosen this system is purely because I've had such good results with Supertrapps since I first tried one in '89 on my FXR. (I'm not talking about the cosmetic pipes they do, just the ones with the external 4" discs). Personally I wish they'd made a 2 into 1 for the XR, or styled the 2 into 2 pipes like their original XR system, but heyho, this is what they make.
Firstly I'm going to check that the 02 bosses are positioned so that I can remove the sensors easily, and install the slightly larger wideband sensors I use on the dyno, without having to remove the exhaust. If not I will weld additional bosses in. The reason for this is that tuning the AFR is more accurate this way, rather than using a probe stuffed in the end of the pipe, particularly at low rpm where the exhaust tends to draw air back in and adversely influence the reading. It can be done with a tail probe, of course, but this way is quicker if I don't have to deal with spurious readings. This bikes a keeper, and it will see a lot of dyno time as I test different parts (particularly when I go inside the engine) so I need to make things easy for myself.
I'm also toying with the idea of having them ceramic coated black.
Tuning will be done using Directlink to remap the stock ECM as this is what I am most familiar with. Other high end tuners, such as SEST and TTS will give the same results, I'm sure. I will have to do ignition timing adjustments, so anything that only deals with fuel won't work for me.
I'll also post pictures of the installation, add comments to supplement the instructions, and post the dyno results. Obviously the dyno testing will be backed up by extensive road testing. I've done 3000m (and a rear tyre) already, so the all important driveability aspect will be obvious.
I'm excited, shame I have to work for a living, I want to know now!
 

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Intersting and I for one can't wait to see your results. I am curious about your using the wide band o2 sensors for A/F readings though. Will you be splitting the signal so that it goes to the ECM and reads your A/F meters or disconnecting the ECN from the o2 sensors? Thanks, Don
 

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Metal cannot think, therefore it cannot be held re
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Discussion Starter · #3 ·
With the Directlink and the OEM narrowband sensors removed (and disconnected) the ECM cannot go into closed loop. The signal from the wideband sensor in each header pipe is split between the Superflow software (where it is recorded), and the direct link "box" where the information is used to autotune the VE tables at different throttle positions and RPM levels. It does this by reading the amount of 02 from the sensors and comparing this reading with the original AFR and VE tables (which are from the same map that is in the ECM). If there is a difference, then the VE table is modified automatically. This new map then has to be reflashed into the ECM so that it knows. Once the VE tables are done, then I play around with the AFR. Only problem is that not all cells can be done this way, for instance 100% TP at 2000rpm, the dyno brake wont hold accurately, or the engine will stall if too high a gear. Similarly 5% TP at 5000rpm is too transient to get a reading. It is a real help, though, in most areas.
 

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Metal cannot think, therefore it cannot be held re
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Discussion Starter · #6 ·
It's here!!! And a very nicely made thing it is too. Also have a cunning plan developing to get a large K&N on there. Wish there were more hours in the day.
 

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It aint no good locking the doors, when the madnes
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Didn't understand a word of all of this thread, when do you adjust the carb?:devil:
Right after you throw your electronic witchcraft (fool injection) in the bin...:clap:

Ask Scotty.....
Have you fitted those pipes yet or are ya just gonna sit in front of that computer all day...:1eye:
 

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Metal cannot think, therefore it cannot be held re
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Discussion Starter · #10 ·
actually I'm modifying an XL map to get me started. No way am I fitting these until I can deal with the fueling requirements the way I want to. Been inside too many engines that haven't fueled properly.
By the way, what's a carb? Oh yeah, I remember. Think I have a Linkert on the shelf somewhere.....
 

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Metal cannot think, therefore it cannot be held re
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Discussion Starter · #11 ·
At last. I've started testing. As per Streetrackers method, I'm doing this on a Superflow, 4th gear runs, corrected to read the same as the more common Dynojet. I still have the stock aircleaner and flappy valve installed. The rev limiter cuts in at 6800 rpm on mine
Base run, totally stock 72.5 ft/lbs @ 3800 rpm and 83.5 bhp @6800 rpm.
Supertrapp with 16 discs and the stock map is 77.4 ft/lbs @4100 and 89.6 bhp @ 6800 rpm.
Between 4800 and 6300 there is a 10 ft/lb and 10 bhp gain. Below 3500rpm it is worse than stock, it doesn't pick up as quick when I start the runs.
On the road if I nail it at 4000 in first or second it lifts the wheel. in 3rd and 4th the wheel skips and the steering goes all wobbly. Feels like a Buell.
At low rpm it pops and bangs and "hunts". It's too lean. This definately needs a remap, which I shall do next, but I've run out of time today.
I've got to say though, above 4000, this is very quick the way the revs pick up. Time for some suspension upgrades now I think!
 

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Metal cannot think, therefore it cannot be held re
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Discussion Starter · #12 ·
Just loaded a map i've built and done some more runs. Torque is now up to 79.5 ft/lbs, no change in peak hp yet, but the biggest increase is at 5252, where both torque and hp are now up by 13 points over stock. That big "XR dip" has gone, in fact, it's the other way up.
Definitely finished now for the day. More fun next week. These pipes work guys!
 

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Metal cannot think, therefore it cannot be held re
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Discussion Starter · #14 ·
It's not a pipe to buy for cosmetic reasons, thats for sure. Looks a bit better on the bike than it does in the pictures though. At this rate though, the only view most others will get is from the back. Still got some serious tuning to do. I'll need a whole day on it, by the time I've played around with the discs as well as the mapping. Sorry, this stuff just excites me.
 

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Discussion Starter · #15 ·
Had the bike back up on the dyno last week, mainly to tune the VE tables and get the lower RPM drive ability better. Still had a couple of minor glitches that didn't make sense. Took the flappy valve and solenoid out and switched to NGKs and it works great now. Put nearly 600 miles on over the weekend. What a totally different animal. Between 4000 and 5000 the engine is so smooth, it feels like it isn't running!. Roll the throttle on from 80mph and it hits 100mph in the blink of an eye with no effort. Just smooooth creamy torque. Nail it from 100mph under any circumstance, including long gradients, and it's always up against the rev limiter (which I've now set at 7000) very quickly. The "seat of the pants" difference is quite astounding. Around town there is no loss of drive ability, although it's very slightly down on "grunt" below 3000, and no popping on the overun from any rpm level. I'm riding it harder and faster, but there is no change in fuel consumption compared to stock. Probably because I'm using smaller throttle openings.
Actually this pipe set up seems to suit the stock cams perfectly.
I'll put it back on the dyno soon and start playing with the discs.
 

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supertrapp

Hi Boz-My "seat of the pants" impression is very similar to yours since I replaced my Remus muffler(1 3/4" internal diameter baffle) with the Supertrapp muffler(2.5 inch internal diameter) over the weekend. I have noticed the same torque drop, poping, hunting, etc due to being lean under 3,500 rpm and the major gain in torque above 4,000 rpm. I will be working on a re-tune within the coming weeks as well with a Remus Powerizer or SEST. I will be very interested in the number of discs you end up with. Can you please tell me what the internal diameter of the baffles are in your pipes? Do you plan to experiment with or run open end caps with less discs, or are you staying with closed end caps and more discs? Thanks and best of luck with your tuning. It is of such great value to all of us!!
Best regards-Mort
 

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Metal cannot think, therefore it cannot be held re
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Discussion Starter · #17 ·
Hi Mort, nice mod by the way. If I'd had the time it would probably be the route I'd have gone. I didn't measure the baffle, but I will do that when I have the discs off.
I've found in the past that the open end cap is good for really big motors, but tends to make the lower end suffer on "small" engines. Same with adding too many discs. I had to start somewhere, so went with what Supertrapp recommended, which was 16 for the XR. Interestingly enough the guy at Supertrapp that I speak with, told me that peak numbers would increase by 10%, but the biggest gain would actually be 10bhp and 10ft/lb, without a remap. They use the same dyno as me and were spot on with my results. Refreshing not to get any bulls**t from a supplier. If anything, I am going to try and use less discs rather than more, to try and pick up an earlier torque curve, although the interaction between the cams and pipes are going to influence things and it's probably not a mile off now. If Supertrapp had made a 2 into 1, then I would have started with 18 discs and a closed end cap.
I find the Sportster engines quite responsive to ignition timing as well, so I may be able to juggle everything and not lose much anywhere. I'm not pinging anywhere anyway, so i may add a bit of timing in the low MAP areas and see if it perks up at lower RPM.
What I can say 100% though, is that any exhaust mods of this nature MUST have the fueling dealt with. If we were doing this in carburettor world, it wouldn't be done without re-jetting!
I don't know how the Powerizer works, but would guess that it shoots for a predetermined AFR at different points, and then adjusts, but may not be the answer if it's designed for a more restrictive muffler. If you can get your head round learning how to use it, then the SEST will do everything you want. There is a map for the XR. (I stole the timing tables from it and copied them into the Direct link XL map I used as a start point). You will also be able to datalog, on the road, which is invaluable for sorting out driveability issues. I'll keep you up to speed with what I find.
 

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supertrapp muffler mod

Hi Boz-thanks so much for all the info and positive comments! I purchased extra discs, longer "race screws" and have the closed end cap that came with the muffler so I will try the closed end cap with 18 discs to see how she runs. I have only taken two short test runs and as you suggest I will certainly deal with the fueling right away. Looking forward to your ongoing results and will share mine as well-Best regards-Mort
 

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physics question-open end cap disc equivalent

Starting with the standard of 8 discs being equivalent to an open end cap with stock internal diameter opening of 1.5 inches, how many discs should be removed if the opening in the end cap is increased to 1 3/4 inches, and again how many discs can be eliminted if the opening in the end cap is enlarged to 2.0 inches internal diameter?
do the larger openings flow exponentially more air at an increasing rate with the larger openings? Mort
 

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Metal cannot think, therefore it cannot be held re
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Discussion Starter · #20 ·
Don't know, never tried it. Be careful though, the whole point of the disc system is to provide some backpressure. If you make the open end cap too large, then you will lose the effect. I did try running just the baffle once. It was flatter than a witches tit.
 
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