joni
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| posted on 8/9/10 at 08:22 PM |
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manifolds length
hi should a manifold have equal lengths of pipe for a bec or is this not needed and if needed why??? what id should you use for a 929 blade race
manifold thanks jon
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Jon Ison
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| posted on 8/9/10 at 08:26 PM |
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To get the best from it yes, you wont go far wrong if you replicate the lengths Mr Honda used on the original bike manifold.
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Andy B
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| posted on 8/9/10 at 08:43 PM |
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Mr Ison is right - equal lengths are really important - for car use where the midrange is important try this
Primaries 550mm long
Secondaries 150mm long
Primary OD 11/2" at head for 100mm
then step up to 15/8" for remaining 450mm
Secondaries 17/8"
Final exit pipe 21/4"
A tuned CBR954 we did for a sidecar made 183bhp on these specs and they are not dramatically different to the 929
hope that helps
regards
Andy
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MydT9
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| posted on 8/9/10 at 08:44 PM |
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quote:
Originally posted by joni
hi should a manifold have equal lengths of pipe for a bec or is this not needed and if needed why??? what id should you use for a 929 blade race
manifold thanks jon
Header lengths and diameters are absolutely crucial, its a science all of its own - as mentione dabove, you won't go far wrong using the
standard header measurements for your design.
Myd
Myd
http://uk.youtube.com/watch?v=RPWhhbaPG4o
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SPYDER
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| posted on 8/9/10 at 08:55 PM |
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quote:
Originally posted by Jon Ison
To get the best from it yes, you wont go far wrong if you replicate the lengths Mr Honda used on the original bike manifold.
This could depend on whether or not you wish to include the HIVEX exhaust gizmo from the standard 929 exhaust.
Would I be right in thinking that the primaries on a 4-1 "race" system should be the length of the standard ones measured up to the
HIVEX?
I've seen a few BECs with stepped diameter primaries and some with tapered ones. Just goes to show that there are many solutions to the same
perceived problem.
We ditched the HIVEX on our 929 BEC install and cut up two standard titanium systems and produced a "cut&shut" system including our
own collector.
System is Ti all the way.
We paid scant attention to acheiving equal lengths and might have sacrificed a little power in the process.
Not much though, methinks.
The car feels quicker than our previous 918 engined Fury despite having a taller diff ratio and bigger tyres.
Our car is only for trackdays though, so a small power loss is tolerable.
Jon Ison is right though. Mr. Honda has already done the sums for you.
And so has AndyB.
Take your pick!
Geoff.
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