Thread: variable length intake manifold & exup

YouTube - YCC-I YCC-T YZF-R1

note the YCC-I demonstration, i had this on my R1, at low rpms the runners stay down and at higher rpms they extend , probably has some kinda actual influence on the power band, would probably benefit the VVL engines more

also the EXUP system involves a valve placed in the exhaust (looks like a throttle body) its controlled by a servo , at idle and lower rpms it stays closed to raise low end and midrange and at a given rpm it snaps open

theyve been using the exup for years so im assuming it works well...

so my theory, would any one try doing these modifications? the intake manifold would be a bit of a strategic one and would take some really good reverse engineering of the yamaha manifold ,hell for all i know this is impossible, however seems like a good idea right? not sure

just thought id share some foreign technology to the sr20 crowd

I'm not sure I see the point in the two TB's, at least for a non-ITB setup.

It seems like your chocking the engine until a certain RPM, then you open the other TB's up to let more air in.

Whats wrong with just leaving them open? Maybe for ITB's the length affects it more?

nah, i think thats just some weird crap as part of their computer controlled throttle, i forgot to mention to ignore that part, itd work if we had spec v like manifolds with secondary runners...my emphasis was on the retractable intake runners

those are awsome intake manifold setups, it really goes to show you hows the sr20de/det/vvl are all really a primitive intake manifold setup compared to those. even though im sure on one level or another they may or may not benifit our engines, the design is definitly far ahead of the intake manifold styles our car uses, and alot of other cars too

the acura integra gsr has secondary butterflies, i cant find a pic of them, but they have a design like that, but from what i have seen in the past the honda guys remove those, not sure if this increases the flow of the manifold or decreases the efficency of the design of the manifold which in returns decreases the flow

BMW used variable intake length (maybe a decade ago) that worked differently. The length started out long, and was shortened as rpm increased. It used a sea shell shaped apparatus. This was on some 3/5 series engines.

we did have a thread circulating around here though mentioning the shorter manifold would be worse for all motor right? i think

which would make sense shorter runners get better low end longer runners get better high end?

Variable length intake manifold - Wikipedia, the free encyclopedia

It looks like there are quite a few companies out there using this. (I like BMWs approach more though.) I someone made a setup like this they could get there de up to ve power levels, pretty cool stuff

Isn't that what they are doing in that video where the longest ITB's get moved up? 1:10 in

yeah but its a wholy different system, one part is the computer controlled throttle the other is the intake, you can have one without the other, i think the suzukis did it...on a side note on most if not all the 07 r1s the throttle system was very problematic, at 5500rpms in second if i cracked WOT the bike did absolutely NOTHING, it sat there and had a nice 5-10 second delay unless i cracked the throttle again, it didnt sit well with me at all

This seems to have two things going on. The length of the over-all intake system can change, and it gets longer at higher rpm (opposite of other systems). This is seen in the accordion action of the pipe (similar system on the new V-Max bike).
But it's also a variable length individual throttle body horn, using the secondary throttle bodies to allow the throttle body position to change with respect to the intake ports and the horn opening.
I'd bet the reason for both of these controls is to take advantage of intake resonance and maximizing the power potential hidden within during much more of the rpm range than other systems. Intake resonance is a concept with which I'm not entirely confident in explaining though.