Thoughts on Hi-Velocity Intake Porting
This is a discussion on Thoughts on Hi-Velocity Intake Porting within the ZX-9R forums, part of the Kawasaki Motorcycles category; I've kicked the idea of having my cylinder head ported. Pat McGivern aka "Motoman" did a past ZX7 bigbore for me . The motor revved ...
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|09-29-2003, 04:55 PM||#1|
Thoughts on Hi-Velocity Intake Porting
I've kicked the idea of having my cylinder head ported. Pat McGivern aka "Motoman" did a past ZX7 bigbore for me . The motor revved so quickly and made great power. It was also cool because a friend and I had matching 93 ZX7's. I could always hop on his and compare, but I had 120HP and he had 107HP on a good day. We both started out around 107HP, full Muzzy/Dynojet kit, but I needed more. I currently have a 2002 orange/black ZX9R with the 998 kit, full Akro, Ivans,APE sprockets degreed@107/104, Factory+4, K&N, and Kleen air removed. The first time I dyno'd it was on a hot/humid day(90+) with about 250 miles on the break-in minus the Factory +4. It pulled 139.8 RWHP and I was told it was running rich. I will try to get back on this Sat. with 155 mains instead of Ivan's 160's, 1000 miles on the clock, and the Factory +4. Do you have any thoughts on Hi-Velocity Intake Porting?? I've PM'd people, but haven't received any responses. Winters approaching and I need a project, but the simpler the better. I had a nightmare with last years (998) project. Any thoughts or tips on getting more out of this motor "safely."
|09-29-2003, 06:54 PM||#2|
Joined: Mar 2003
I don't go by his site: MotoMan is obviously a zealot. Not that zealots must be wrong -- not so -- but if wrong they're generally blind to it and quite good at sounding as if their belief is the one true truth and just has GOT to follow out of logical necessity, and only conspiracies and stupid thinking can explain why just about everyone else says different. Hmmm, does that sound like MotoMan's site?
I've seen a small number of reports like yours saying the method worked for them, so that's a positive. I haven't seen anyone saying it failed for them, but that doesn't prove there aren't any.
An aspect to it is certainly true, which if he explains in exactly this way, I hadn't noticed on his site. Namely, that the kinetic energy of the moving air column in the intake tract is precisely proportional to the square of its velocity, or more precisely to the integration of the kinetic energies of each "slice" you could take of the intake tract accounting for the velocity at each point.
And, the work required to achieve greater than 100% volumetric efficiency -- to pressurize the cylinder above ambient -- is done by this energy.
Reducing the cross section of parts of the tract does increase this energy, so it stands to reason that there is a point where below this (narrower yet), added restriction from the narrowness exceeds the benefits from increased velocity, but above this, loss of velocity benefits exceeds reduction of restriction from increased cross sectional area. That point would represent the optimum -- either above this or below this would give less power.
Whether this optimum is at the size he says or not, I cannot say.
It would be interesting for someone else to do the work and try it on a ZX-12R head! :D
|09-29-2003, 07:59 PM||#3|
From: Oregon City, OR.
Joined: Apr 2002
KAWZXR998, I did respond to your pm, did you not get it? Yes I've did the work on mine and I've beaten a ZX-12 and a Busa on the dyno, head to head. My midrange to top end is stronger. I'll be doing the intakes on a ZRX over the winter also. Kawasaki is reducing the intakes and increasing valve size on the '04 ZX-6RR, sounds like they're reading mototune also.
|09-30-2003, 05:09 AM||#4|
Trenace- Wow, waay over my head. I'm just a simple guy who likes to have sleepers built. Thanks for the reply.
Moto24- I have NOT received any PM's, but am glad you responded. It sounds like they work out very well in a ZX9. Let me know, if you do the work, how much it would cost. As mentioned earlier, I have a brother that lives pretty close by.
|10-11-2003, 06:50 AM||#5|
From: Dominican Republic
Joined: Sep 2002
I will answer this one, but first let make some things clear.
1- Im a personal friend of Pat, but my answer is not clowded by that. If you go to Dom Rep. on his site site you can see that. BUT im one of the persons that chalenge him personaly 2.
2- I dont have a dyno, besides my pants.
3- I can go with the details of number if a person is very interested
4- I have worked with ports with the ZX9, I had a mototune F2 (157mph) only with ports, faster than a TL1000S and F3s.
First I made them 2 small and the result was not optimal. The choke point was rigth but the hole area of the port was 2 small so I started tinking and making my math(not complicated) Then I opened up a little bit (not the choke point) and the fuking ZX9 was a monster, lot more mid range, then i opened more :cry: .
One of the things interesting is that when the port area is rigth or 2 small when you take the air box and the filter and accelerate the fuel does NOT come up (I told Pat this "discovery"). This is not about speaking, is about testing.
Standard bore I SUGEST about 19.5mm of choke point.
PS. Take your time laping the valves.
|10-11-2003, 08:28 PM||#6|
Marcos- Thanks for the insight. Do you know off-hand
what percent 19.5 mm equals?? I think Pat suggests 35%.
|10-12-2003, 07:43 PM||#7|
From: Fort Worth, Texas
Joined: Sep 2003
I would put more miles than you have ridden your new piston kit before I put back on the Dyno. My Zx9 (1998) was new and when I worked at D&D Jon had it on the Dyno many times before the BESt stock H.P. happened (around 1200 miles and several oil changes, non synthetic) Let it seal and try again later.132.9 H.P. stock at 11,200 RPM and after their full system 4into2into1 with 150 main jets and pilot screws out 31/2 turns and a K&N and no screen 141.9 at 11,800 RPM.Looking for a new piston kit and some one to port match the head ETC. Let us know what happens.
|10-13-2003, 03:43 PM||#10|
Thanks guys- I know this would improve the mid-range.
I'll also take your advice on breaking -in. I currently have
1400 miles on since the 998 kit went in.
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