new old member

[BoxerOtto]

i've been part of this site since 2008 and haven't filled this portion out yet, so its probably time. i stopped posting progress with my build because alot of the stuff i was atempting was unproven and seemed to be taken as a clear solution.ex turbocharging a single. i pretty much exhausted all options regarding the rhb 31 turbocharger on a 418 cc single and for my use concluded that it wont work for my application. i turned then to supercharging thinking i could boost it with a centrifugal charger from a bombardier seadoo. again, too large of a unit even turning slower did not work, and gearing it to a higher speed could not overcome the powerloss to drive it verses the "slippage" of the turbine wheel. next i purchased an amr 300 and have actually made real progress with it. make no mistake the engine still requires some modification,but at least it works. i do not have a dyno to test it for actual power increase, but i would guess 25% to 30 % at 10 to 12 lbs boost. there is very little gain at 0 to 6 psi that people think all they need is a little boost to help, that is used up in the turning of the charger. i ran out of time last year ,so this year the new trial is alcohol injection to keep the intake charge cooler. i did a 7 day 3200 km trip with it july 2014 and was completely sucessfull even with 25 to 40 celcius weather and many hills. i will post pictures if i can figure it out again.

[UAofE]

Matching plenum volume is very important for a single because you're basically relying on the momentum of the turbo wheels and air mass to make boost after the exhaust stroke.
Too much volume (long pipes or excessively sized intercooler) and there isn't enough energy in the exhaust stoke to pressurize it.
Too little volume (compressor discharge directly to the intake) and there isn't enough momentum energy in the turbo wheels to compress the air.

Total volume should be close to the same as the cylinder displacement.

[BoxerOtto]

yep been there done with that. the amr 300 at 1 to 1 works, simpler plumbing ,lighter, doesn't heat the oil, torque throught the powerband. i gave the turbo the benfit of the doubt, it was cheaper,but could not perform close to the power of the supercharger. i will post more on the subject when ican post pictures.

[pietenpol2002]

Welcome back BoxerOtto. Great to hear of your success with supercharging. And please do post up a thread to educate us further.

Regarding plenum sizing.

Total volume should be close to the same as the cylinder displacement.

Full disclosure - I'm not speaking from experience here. But, it has to be true because I read it on the internet. Right?
The above statement is indeed correct for 4, 6 and 8 cylinder engines. However, in the link below, turbo/supercharger guru Hugh MacInnes details in a page from one of his books the surge effect present with singles and even twins that requires a plenum 2-3 times the engine displacement. Of course plenum displacement can include tubing runners and the aftercooler.
And other credible references seem to support Mr Macinne's ratio.

http://www.duccutters.com/pdf/PlenumSizing.pdf

There are also a number of other discussions here on the board related to plenum sizing.

https://www.dieselbikeforum.com/view ... ?f=2&t=742
https://www.dieselbikeforum.com/view ... ger+plenum

And then we may be approaching the point where the administrators would be suggesting this be moved to the techinical section.

[BoxerOtto]

i'm sure if i had vw's and bosch's budgets i supose anything is posible, but i don't, so for me and my project the supercharger just plain works.

[Tetronator]

Please continue the conversation, I'm reading with great interest.