Scrambler 800 Track Bike Tuning

[koko64]

Initial dyno mapping gained 8hp. We held off on the fine tuning and individual cylinder mapping until we test the exhaust. The dyno operator feels there's 3-5 hp more to be gained from individual cylinder mapping and another 3-5 hp with a 2-1-2 system. First run will be with the new pipe and if it makes more hp we'll keep it on and finish the tuning. If it's a dud we can revert to the 2-1 pipe and finish the tuning.
Well see.

[greenmonster]

 

[Howie]

Impressive!

[koko64]

I've been checking dyno charts for various exhausts and I think a 2-1-2 pipe should make significant gains in the midrange rpm which will be useful at the tight and technical local track.

[MonsterHPD]

Interesting, I'll follow this, looking forward to some dyno graphs. If you can get that much improvement without opening the motor, that's really great!   

I rode a friends scrambler quite a lot in 2022, I actually found the motor quite OK, but the suspension was really, really bad. I hear that bike is now beeng upgraded with an Öhlins shock, and Andreanio cartridges. I'm looking forward to a test ride this summer :-)

[koko64]

I think the improvement is because the motor is so restricted, rather than any special tuning tricks

[koko64]

Kamna built an 850 big bore Scrambler with 45mm inlet valves, porting and a K&N pod filter with a PCV. It made 87ps.

https://www.ducati-kaemna.com/tuning/best-practice/2-valve-tuning/ducati-scramber-800-tuning

https://www.ducati-kaemna.com/media/igallery/s/i/silvio_schulze_-_scrambler.jpg

[stopintime]

Kämna has always used "calculated" power, like Ducati did. Roughly 10% high.

[koko64]

I know of dynos that have varied by 10%+ and they were dynojet 250 models. Even the updated software reads 10% less hp. I have to take that into account comparing dyno charts on the same dyno 10 years apart.

[stopintime]

, but of course, the changes are what you evaluate by - so it's not very important.

[koko64]

Should have the final dyno tuning completed as soon as the alternate exhausts are completed. A Delkevic 2-1, Zard 2-1 dual outlet and Zard 2-1 dual outlet race pipe. The Zard pipes are crash damaged pipes I'm repairing with the help of a mate who was a boiler maker. He works like an artist. They are expensive exhausts, so finding beat up examples was a necessity. The ultimate pipe would be an Akrapovic 2-1-2 if i had the money.

Cognisant of issues with 2-1 exhausts on larger desmodue motors (750+), I was caught between packaging and tuning issues. The Scrambler is a low bike and twin shotgun mufflers can ground easily in the canyons. It explains why the Zard and Termignoni race pipes are high rise "Scrambler" types. Since I regularly take the GLW pillion, the pipes will be tucked into a ow mount location. The Zard pipes mimic the 2-1-2 design, but housed within a mono muffler design and I'm trying to get that result within the tight confines of the little Scrambler. Another detail was having the crossover as short as possible before the muffler entry. What I'm trying to do is adhere to a blend of the 2-1-2 configuration as the Monster/888 crossover style influenced by the M1100 Evo 2-1-2. Historically these appear to be two of the best exhaust designs for larger desmodues. That's all theory however, and only dyno time will tell.

[koko64]

 
Links to vendors regarding each pipe to be tested. The high pipe will be fitted low to the stock headers.



 https://www.ebay.com.au/itm/144527622152?chn=ps&_ul=AU&norover=1&mkevt=1&mkrid=705-139619-5960-0&mkcid=2&mkscid=101&itemid=144527622152&targetid=1741701787098&device=m&mktype=pla&googleloc=9071295&poi=&campaignid=18278742238&mkgroupid=141565058112&rlsatarget=pla-1741701787098&abcId=9301725&merchantid=118974818&gad_source=1&gclid=Cj0KCQiAz8GuBhCxARIsAOpzk8zI8HBcAQ1ZVkU7WPf4-L9Zf14s-LpTIu5Q4vaOuUPn2iqTj1GmYTYaArJIEALw_wcB


https://www.ebay.com.au/itm/395052555946?chn=ps&_ul=AU&norover=1&mkevt=1&mkrid=705-139619-5960-0&mkcid=2&mkscid=101&itemid=395052555946&targetid=1741701788338&device=m&mktype=pla&googleloc=9071295&poi=&campaignid=18278742238&mkgroupid=141565058112&rlsatarget=pla-1741701788338&abcId=9301725&merchantid=494523409&gad_source=1&gclid=Cj0KCQiAz8GuBhCxARIsAOpzk8y-S0UvUkEuEM6CVPgUazJqJLzpFf5ENo2H0_KaHshscv1ZhkKgfJQaAteBEALw_wcB



   https://delkevic.com/18-stainless-steel-oval-muffler-to-fit-scrambler-800-2015-2020/  

   

[greenmonster]

The old spaghetti crossover worked well also IIRC.

[koko64]

The old spaghetti crossover worked well also IIRC.

Yes it gave an increase in peak hp. I thought of having two of these with a crossover added like the stock system but the feed pipes to the mufflers would not be the same length. Unsure of it will be an issue. It would be an expensive test.


https://redirect.viglink.com/?format=go&jsonp=vglnk_170863573772911&key=7380040348cb056f0e988195afaf9852&libId=lsxpke1a01000c6m000UL46cpq1vu&loc=https%3A%2F%2Fducatimonsterforum.org%2Findex.php%3Faction%3Dpost%3Bquote%3D1470120%3Btopic%3D79771.15%3Bnum_replies%3D27%3Bsesc%3Dd1592da8d13c5793d5ac3e285f599b21&v=1&type=U&opt=true&out=https%3A%2F%2Fdelkevic.com%2F18-stainless-steel-oval-muffler-to-fit-scrambler-800-2015-2020%2F&ref=https%3A%2F%2Fducatimonsterforum.org%2Findex.php%3Ftopic%3D79771.15%3Btopicseen&title=Post%20reply&txt=https%3A%2F%2Fdelkevic.com%2F18-stainless-steel-oval-muffler-to-fit-scrambler-800-2015-2020%2F

[koko64]

I've noticed that the dyno charts of the various Scrambler (performance orientated vs style orientated) exhausts available appear to give about 2- 3 hp at the top and bottom end with the midrange the same. Most appear to be types of 2-1 systems. I haven't yet found a dyno chart for the Akrapovic 2-1-2 twin shotgun style mufflers. I'm interested to discover the influence on the power characteristics of the 2-1 style system and how it interacts with the 2-1 single TB manifold and long duration cams.

The high rise scrambler race system arrived , but the muffler was completely gutted. It's a pretty involved and expensive welding task to rebuild it with dual cores so I'll leave it to another time. The dyno test will be with the short twin outlet Zard vs long Delkevic 2-1. I think the main test here will be length of the link pipe although the Zard internals are a bit funky. The Zards internals have a short link pipe entrance to an open cavity tube lined with baffles surface then perforated core mesh surrounded by fibre packing, then it enters a Y tube exiting to twin large diameter outlets. The homolgated version has a cat in the cavity and 10-15 mm db killers in the outlets. The non homologated version has no cat and larger diameter, removable db killers. This Zard Linited Edition pipe has had its db killers removed and no cat, so it's clearly for race use only.

Dyno time will tell.