Whoopsy water + some air box and intake mods

[stopintime]

Cutting a cyinnder every speed bump... hmmm. It had rained a whole week, so I checked a few connectors. No effect. Had some time, so cleaned my air filter...

 

[koko64]

Water injection 

[koko64]

Seriously though, I've never liked how close the air filter is to the top of the velocity stacks on some models.
It led me to relocate the filter to the top of the airbox lid to maximise the space or volume available for the stacks to draw on during each intake event.
The carb models were particularly bad. Made some gains there on the dyno. The tank shape had to allow enough space between the filter and the underside of the tank for it to work though.

What is the distance between the top of the stacks and the filter?

[stopintime]

I don't know the height measurements, but I have doubts about this being a significant improvement area. Because the lid is open and the filter very unrestrictive. What does make a huge difference is work done to the intake. My 839cc well built engine made 99 bhp (Kämna numbers which were "calculated" the same way Ducati always did)(about 10% bullshit), then detuned to let the engines survive more than a year. Now about 86 honest rear wheel bhp. That's great numbers. Biggelaar offers to do more - besides my already nicely done port & polish in the heads he wants to modify the rest of the intake and with a serious face claim further 10bhp. That, of course, will make me kill my engines in a much shorter time, so I have declined since 2020. Not sure how much longer I can resist... However, I'll ask if the air filter box/stacks can be modified to work better. If so, I'm going to be close to 100 rear wheel bhp.

[koko64]

I wish my SC800 made 86hp.
My high comp, ported, M900 made 86hp/68 ft/lbs torque. The airbox mods gave me 4-5 of that.

I've thought about an 1100 crank and 90mm bore in Scrambler cases to give 910cc. Then better cams and twin throttle bodies.

Or I could buy back my M1100 Evo.

[MonsterHPD]

I wish my SC800 made 86hp.
My high comp, ported, M900 made 86hp/68 ft/lbs torque. The airbox mods gave me 4-5 of that.

Hi,
would be interesting to know exactly what your airbox mods were.

A member on the german ducati.1 forum is an experienced engine developer at one of the big german car / engineering companies. He has made pressure measurements inside the inlet system, and has concluded that the combination of uneven inlet suction events and an unsufficient airbox volume results in the HOR cylinder having less air than the VER cylinder, resulting in a power deficiency of about the magnitude you mention. Acc to him, it´s also the reason the VER cylinder´s running hotter than the HOR; it´s simply working harder.

I don´t have any actual measurement records or similiar to verify this, but I do trust this person to know what he´s talking about. I will certainly at least open up the airbox lid on my ST2-motored SSie track bike for next year.   

[koko64]

I'll email you some pics including the dyno chart. The photo host sites don't like me any more.

[MonsterHPD]

Hi,
I now have the pics, and relevant explanations. I´ll post them here, if it´s OK with you both.

[stopintime]

Please do 

[koko64]

No worries.