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Discussion Starter #1 (Edited)
Star Racing head work on ZX-10 UPDATES

If you recall I am the one working on the bike for the magazine article on the ZX-10. After reading all the posts on head work, cam, head gasket etc I decided that was the most common route and the one that I would take for my project.

Here is the original post about that

http://zx-10r.net/forum/showthread.php?t=7264


For a quick review the bike now has a full Hindle race exhaust and a PCUSB and with MR9 gas it makes 163hp as is.

So I got the race cam from Kawasaki and then had to decide who to port the head. After a lot of talking to everyone that does head work it seemed that most of them just grab an air grinder or chuck it up in a mill and rather randomly start grinding and cutting.

When I talked to Star Racing/G2 motorsports I could instantly tell their whole approach was different. First they insisted on me sending them not only the head but the stock cam and the new race cam. The also had a lot of questions on rpm range of the bike and power output as is.They even noted the diameter of the exhaust pipe. They measured both cams and also included the lift figures in the calculations.

With all that info they said they could then properly test and improve the bikes power. So I sent it to them. First they flow tested the head, measured spring pressure etc. The flow was tested at 4 different valve openings too. Intake and exhaust

Then using one valve hole as the test they started trying different valve seat cuts until they got the flow they wanted. Then did the rest of them the same way.

After that they did the port shape the same way. Flow test it first, make changes and re measure until they were happy. Then they ported them all that way. This was done on the intake and exhaust side.

The of course it was flow tested at the end as a comparison to see true before and after. Total CFM on the intake was increased by 15.17% and on the exhaust side it was about a 5% increase.

They also tested valve seat pressure which was pretty low at 28lbs. Or at least I thought it was low.

Over the years I have had a bunch of engines built as a lot of respected shops but NEVER have I seen this tyle of a technical approach before.

The worksheet they sent me back had all kinds of formulas and calculations on it showing the work that went into this head port. The amazine thing is that the price was $1200 which is the same as most every performance shop I called. Even though they did not have this level of expertise.

I will have the engine back together next week and see how much power the head makes, then we will add the race cam and see what that does.

I am really hopeful of this and will keep you all posted.

Don
 

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Supercharged Mod
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There are a few engine simulation software packages out there, that are supposed to fairly accurately predict the results of various modifications provided that the base information is correct. From the request to have the camshafts (so that they can accurately measure the profile and use it as input data) and to have the exhaust header diameter (which is an important factor!) it's likely that they are doing something like this. It's the right way to do the job these days ... but few people actually do it.

The closest I've come to one of these was help someone optimize a camshaft profile for an automotive engine. The best overall result was a lot more conservative than a lot of people might expect. I wasn't surprised, but the guy I was helping was. Bigger isn't always better when it comes to camshafts ...
 

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I definatly would like to hear the outcome f'sho!
 

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I want to know what the flow chart says.
 

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Discussion Starter #6
1killer1liter said:
I want to know what the flow chart says.

As mentioned earlier the chart reveals a near 15% increase on the intake side and 5% on the exhaust side at .400 lift.

I have the whole sheet but those details will be in the article so I better hold some of it back for now. The main thing will be what the dyno says and what the top speed changes are.

I am a lot more interested in going fast than just what the flow is. Hopefully they will be related !!

Don
 

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How much CFM do the heads flow before and after. What is the lift/duration of the factory cams vs. the bigger cams. Man I need some info. Hurry up with the article already!
 

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Discussion Starter #10
1killer1liter said:
How much CFM do the heads flow before and after. What is the lift/duration of the factory cams vs. the bigger cams. Man I need some info. Hurry up with the article already!

The article will be months away so here goes what I have now. Still no dyno until next week.

At .400 lift and 10 inches of water on the flow bench the stock intake flowed 112 cfm stock. After porting and valve job it increased to 129 cfm. I think that is only one cylinder but dont quote me there.

The stock intake cam has a lift of .353" vs the race cam of .376" looks like duration was the same on both but I am having trouble decyfering all these formulas from the sheets they sent me so I am not 100% sure on the duration yet. I will confirm that later.
 

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Thank you for the info. Please keep us updated. We all might be going to star for some head work. How long did it take for them to get the heads back to you?
 

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Discussion Starter #12
Normal turn around they claim is 2-3 weeks. Of course that can vary during the race season etc mine was actually on the short side of that scale so I am very pleased with that.

The builder has my head and promises to install this week with stock and race cam to see what we get !!

I cant wait to see how all this technology does.


Don
 

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Discussion Starter #14
Sorry guys I am still waiting on my engine to be put back together and I am going out of the country for a week. So it looks like it may be 26-27th before I know anything for sure on the head and cams.

Sorry for the delay and false alarm


don
 

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Discussion Starter #17
I just got back home from Canada last night late. He was supposed to be on the dyno today. It never goes as planned you know. Hopefully I will have an update soon

Don
 

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I'm giving you a dead line. I want this article on my desk by tomorrow morning! Those of us holding our breath can't.......hold...........it..............much.............longer. < Face is some shade of blue-purple-red.
 

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Green with envy and kawi blood.
 
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