2 foot long intake yields 10% boost!

Oh...maybe the 20 mm diameter was too large?...was that ID or OD?....I think the pipe I am using is ...err will be 15 MM ID.....the pipe I made my 27" pipe was I thnink about 11 MM I believe....have to remeasure to be sure....
Andrew
 
Hmmmm....after further extensive reading online about this topic it appears that the tunes length should be a good bit shorter!....Hmmm...I wonder if it all boils down to trial and error but in all fairness I think the site I listed above may have been for 4 stroke engines which would explain the long long pipe....according to 3 other sites (after I used their mathematical formulas), I am more in the area of 14 inches but then again that may be for a four stroke and would have to be halved again for the 2 stroke since we have twice as many port openings for the intake...I will tinker more....probably build another pipe (straighter ) and the lop off lengths a little at a time until I reach max speed up my test road....hopefully tomorrow if the weather cooperates.
Andrew



you need a flow bench,some raceing shop,s have 1 but it,s alot of work and money{it,s all labor} to tune it for a certin rpm range it,s very time consuming.
 
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you need a flow bench,some raceing shop,s have 1 but it,s alot of work and money{it,s all labor} to tune it for a certin rpm range it,s very time consuming.


a flow bench will measure the cubic feet per minute of mixture flowing threw an object at a certin atmosphric pressure drop. that,s how they measure carb,s.a 600cfm {cubic feet per minute}holley will flow that.it,s a very specialized tool and is usally the differance between winning and losing.
 
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a flow bench will measure the cubic feet per minute of mixture flowing threw an object at a certin atmosphric pressure drop. that,s how they measure carb,s.a 600cfm {cubic feet per minute}holley will flow that.it,s a very specialized tool and is usally the differance between winning and losing.



the atmosphric pressure at sea level is 14.7ib,s per square in.the higher you go the less pressure their is,that,s why most engines allway,s make more power at sea level.
 
Yes a flow bench sounds good...BUT it is used to messure flow that is constat, not pulsating. It is a great tool to check for flow restrictive shapes and surface finishes on the ports, etc.
The length of the pipe be it exhaust or intake, works like a chamber to create an airspring pulsating at the rhytm needed to feed the combustion chamber and to pull the burned gases out at a certain rpm.
So no. I don't think a flow bench will give you the answer to the lenght of pipe needed.
It would be like trying to fine tune a classic church organ with it. The lenght and diam and shape of the pipe will give you a note. You just need to find out what note is the one that makes your engine sing(at a certain rpm). And yes trial and error might be the way to go.
 
Yes a flow bench sounds good...BUT it is used to messure flow that is constat, not pulsating. It is a great tool to check for flow restrictive shapes and surface finishes on the ports, etc.
The length of the pipe be it exhaust or intake, works like a chamber to create an airspring pulsating at the rhytm needed to feed the combustion chamber and to pull the burned gases out at a certain rpm.
So no. I don't think a flow bench will give you the answer to the lenght of pipe needed.
It would be like trying to fine tune a classic church organ with it. The lenght and diam and shape of the pipe will give you a note. You just need to find out what note is the one that makes your engine sing(at a certain rpm). And yes trial and error might be the way to go.


at higher rpm it does become constant,only at off idel does it pulsate,thats why boost bottel,s only work at lower rpm.seen a few flow bench,s on ebay starting at $750-14,000.
 
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Hmmm....so if I understand correctly, we should tune the intake runner length for max power at max rpm then rely on the boost bottle to smooth everything out at the low and mid range....That almost seems ideal....covers the entire power band....low mid and high end....I like that!

Andrew
 
I'm impressed! Most people don't exacute there plan! You certainly didn't fail, You just found out one way it doesn't work. Sounds like when you find the happy medium for top end & low end you will be onto something! Can't wait to hear how next one works. I do like the ram air idea. Their is a ton of possabillities for that. GOOD LOCK!
 
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Hmmm....so if I understand correctly, we should tune the intake runner length for max power at max rpm then rely on the boost bottle to smooth everything out at the low and mid range....That almost seems ideal....covers the entire power band....low mid and high end....I like that!

Andrew


now you got it,tuning is allway,s a trade off.you give up 1 rpm range for another that allway,s make the other hard to drive{that rump rump sound of a hi-po cam}is reversion made by the long deration of the open valve, at low rpm it make less power then stock{hi-po parts allway,s come with a rev range. example say a torker singal plane intake manifold is rated from 2500rpm-6500rpm anything below 2500 it accually makes less power then stock}but at high rpm it really pick,s up because of the {raming effect}.most people get around this by lowering the rear end gears{higher numbers numericly}.then your back in the power range.getting greater torque multiplicatoin {say from 3.08 to 4.11 will give you aprox 25% more torque}the draw back is max speed will suffer.in 4th witch is usally 1 to 1, at 60 mph the rpm,s would be around 4000rpm.hearing a engine screaming for say a 1/2hr drive is not a nice thing.not to mention the gas used.
 
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Good real world example Dave...I do remember the Torker manifold....I wanted one so bad as a kid...well teen at least....I think with the HT engine I will be satisfied to build a torque monster....I mean the thing maxes or feels real explosive (makes me nervous that she wants to blow up) around 6K anyways.....I feel confident if I can get some torque going I can always gear up with a steeper gear to keep the revs reasonable and hopefully increase cruise speed without sacrificing too much acceleration...all the while keeping rpm's reasonable.....without hi tech dyno's etc...I think what I will do to measure performance is to change the gearing of my stock bike to 36 T to match my experimental bike's gearing and race them head to head with a friend (adding weights as needed to match bikes/riders up) or maybe against the stopwatch.....I'm thinking the head to head may be better because it would show visually and without too much doubt which configuration has better low/mid/high speeds without the need for having a lot of people along the road with stop watches....Of course I would probably do rolling starts to eliminate wearing out the clutch or stalling the engine under pressure of getting a good launch off the line.
Andrew
 
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