Super Monza for charity - child cancer research

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Tom Russell
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Powolotti wrote:I was surprised (and suspicious) as you are. Transmission was 1) calcualted by the Dyno (Amerschläger P4) and after the low peak and high torque 2) checked by a Lammy gearbox table and the calculation was correct. All runs are in 3rd gear. Varitronic Ignition has to be set at the Dyno software (Value 0,5 - which means 2 pulses per revolution). The people owning the dyno also checked everything again.
I think it is important not to look at bhp on different dynos, but on the curve itself - how does the engine perform and when (at which revs). The Dyno i use has a 5% +/- tolerance, so in the worst case you might do a run with + 5% (eg 31,5 bhp) and on another run you will read -5%, 28,5. Tyre pressure and engine temperature also make differences. At the Dynoplace there was an exhaust from Pipe Design, "Duster" which is also a very long and fat pipe and produces about the same curves like the italian SM pipe on heavy tuned malossi cylinders.

I am getting a CE pipe within the next week and will test it against the italian pipe, maybe these two are totally different (?)
Thanks for confirming all of this :)

It will be very interesting to see how the CE pipe (that I have) compares with the others you have tested on this kit, and obviously it would be great if you would continue to post your findings up on this forum :D
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Powolotti
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thx Tom, I do :-)

I think I am with your riding style Adam :-)

Darell I think it did exactly what CE and/or TS said, 30 bhp with a 30mm carb. All higher bhp runs were with either bigger carbs, other pipes and other heads. But as you said, important is to see what differences modifications do. I am still thinking about the venturi in the exhaust you mentioned - can you explain this again please? As all runs on the untuned kit are done, I will port the kit now. I have very good results with ports like they are done to 125cc bridged moto-x cylinders or also the Stage 6 R/T for example - is this what you refer to as well?
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Darrell Taylor
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a triple ex port likes a smaller ex duct especially on upper and lower floors but outflow can be reduced if it becomes too small so the addition of a venturi speeds up and aids the blowdown phase before the blowout phase begins ,typical outlet sizes are 41 x 35 if you turn up a sleeve in alloy and press into the ex stub as the lamby duct is too short to put in there ,so the ex stub will become an extension of the ex duct wide 41x41 to narrow 41x35 back to wide at 41x41 in some instances a simple collar with a step in it works just as well but a flowed reducer along the lines of a de laval nozzle is favour

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Last edited by Darrell Taylor on Sun Jan 27, 2013 11:28 am, edited 1 time in total.
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Adam_Winstone
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Darrell Taylor wrote:a triple ex port likes a smaller ex duct especially on upper and lower floors but outflow can be reduced if it becomes too small so the addition of a venturi speeds up and aids the blowdown phase before the blowout phase begins ,typical outlet sizes are 41 x 35 if you turn up a sleeve in alloy and press into the ex stub as the lamby duct is too short to put in there ,so the ex stub will become an extension of the ex duct wide 41x41 to narrow 41x35 back to wide at 41x41 in some instances a simple collar with a step in it works just as well but a flowed reducer along the lines of a de laval nozzle is favourite
^... I've tried running that through Google translate but I can't determine the language that it is in. Some of it seems like English but the rest of it goes completely over my head :shock:

Adam

PS - I am trying to keep up :oops:
Darrell Taylor
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little off topic but describes the concept well,instead of making ports bigger i was making them smaller

its from 2006,was an ar50 40mm bore added 2 aux ex ports as part of 5 extra that was added so left the ex duct too big as well as been a bad design in the first place,outlet size ended up 28 wide 22 tall
great result made nearly 16bhp and 6.8 ft lb tq and won many championships

was a long duct so reduced it section original port roughed out and engineers blue
Image

insert during making up
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pressed into place prior to final shaping
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final port layout
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Adam_Winstone
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Thanks for th eextra info.

From what I am understanding, this is a case of forming the port so that it becomes the initial stage of the expansion process, which is then carried on by the expansion pipe. The size of the venturi and resultant angles then control the sonic wave/pulse element of the expansion.... which then takes you into the realms of exhaust/expansion design, with lengths and angles, etc.

From the little I know of expansion theory, I think that I'll leave the design up to you and others :), however it is nice to try to grasp what/how/why aspects of tuning have an influence on performance return. I think that I am best off letting others do the design, with me just having a reasonable undertnding of which components might come together to result in an engine that functions reasonably well as a whole.

Thanks for the lesson.

Adam
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Powolotti
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thx a lot Darrell for sharing!! Very interesting, I dunno if I have the time to try it on the charity engine...finalisation date is coming closer. I bring the engine to germany to the SIP-Customshow, where I have a small stall promoting the raffle and then the engine will stay in germany at a mate who brings it to the rally where it is raffled.
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Darrell Taylor
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If time is limited then a short piece of tube 10mm long with say 38/ 39mm id pressed into the stub might make a faster test to try ,no guarantees as to if it will improve but worth a try,has worked for me on most but not all
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Powolotti
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i am too interested anyway that I wouldn´t try it...was thinking all the time what i could put in that doesn´t need much machining
meet me on Facebook: Michael Powolotti

some of my tuning work:
http://www.facebook.com/pages/Powolotti ... 6938811863

my club:
http://www.wiener-spitzbuam.at
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Powolotti
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i have a 2k compound that resists 350°, but first I don´t know how long it will withstand the much higher temperature and second I am afraid it will be pushed back into the cylinder :o
meet me on Facebook: Michael Powolotti

some of my tuning work:
http://www.facebook.com/pages/Powolotti ... 6938811863

my club:
http://www.wiener-spitzbuam.at
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