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Head flow testing.

Classic Norton Commando Motorcycles.

Re: Head flow testing.

Postby Dances with Shrapnel » Thu Oct 27, 2016 12:31 pm

comnoz wrote:Here is the resulting graph. You can only move air so fast. The white line is a 41mm big valve head and the blue line is the 44mm job. Starts out good...

Image


Did you mix up the white line and the blue line designations in this picture? It looks like the blue line plateaus as you would expect from a relatively higher lift/diameter ratio,...or is the 44mm choking elsewhere?
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Re: Head flow testing.

Postby comnoz » Thu Oct 27, 2016 1:19 pm

Dances with Shrapnel wrote:
comnoz wrote:Here is the resulting graph. You can only move air so fast. The white line is a 41mm big valve head and the blue line is the 44mm job. Starts out good...

Image


Did you mix up the white line and the blue line designations in this picture? It looks like the blue line plateaus as you would expect from a relatively higher lift/diameter ratio,...or is the 44mm choking elsewhere?


Yep it was choking, air was lifting off the floor of the port.
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Re: Head flow testing.

Postby comnoz » Tue Nov 08, 2016 3:56 pm

I finally got the new CNC ported Fullauto head on the flowbench.
I tested it back to back with a new non-CNC ported head.

Here is the non-cnc head.

Image

Here is the CNC ported head -still set up.

Image

Here is the flow graph.

The blue line is the CNC ported head. The green line is the non-cnc head.

Image

Here is the velocity graph.

NOTE- I found some inconsistencies in the first velocity test that I traced back to a loose fitting on my flow tube. The test has been repeated and now the results show there is little if any difference between the CNC ported head and the non-CNC ported head.

The blue line is the CNC ported head. The green line is the non-cnc head.

Image
Last edited by comnoz on Wed Nov 09, 2016 12:16 pm, edited 1 time in total.
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Re: Head flow testing.

Postby gortnipper » Tue Nov 08, 2016 4:02 pm

Wow, that is like a 10% drop in velocity for the same volume. Whats up?
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Re: Head flow testing.

Postby comnoz » Tue Nov 08, 2016 4:08 pm

gortnipper wrote:Wow, that is like a 10% drop in velocity for the same volume. Whats up?


After finding a problem with my measuring tube I redid the test and now the velocity reading are almost the same between the cnc and non cnc head.

With a little larger valve and some work in the seat area it should show a good improvement, both flow and velocity.
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Re: Head flow testing.

Postby comnoz » Wed Nov 09, 2016 12:23 pm

So now that I identified a problem with my prior velocity readings and corrected them -here is the flow tests with the 1.5mm oversize intake and a little work in the valve guide and bowl area.

Nice improvement for a steetbike running a .400 lift cam.

Flow
Image

Velocity
Image
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Re: Head flow testing.

Postby Fullauto » Wed Nov 09, 2016 3:00 pm

You really know how to give a guy gray hairs, don't you Jim??!!
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Re: Head flow testing.

Postby gortnipper » Wed Nov 09, 2016 3:14 pm

Fullauto wrote:You really know how to give a guy gray hairs, don't you Jim??!!


+1 as I am guessing this is my head.
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Re: Head flow testing.

Postby comnoz » Wed Nov 09, 2016 5:22 pm

Fullauto wrote:You really know how to give a guy gray hairs, don't you Jim??!!


It had me going for a bit.

I did the velocity tests twice before I posted.

After sleeping on it last night I got out the calipers and did some measuring and found that there was not enough difference in size to cause that large a drop so I got out the bench calibration tubes.

I found out all I had to do was wiggle the hoses and the reading changed dramatically. A rubber sealing ring on one of the fittings had shrunk enough to make the fitting loose.
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Re: Head flow testing.

Postby comnoz » Wed Nov 09, 2016 5:25 pm

gortnipper wrote:
Fullauto wrote:You really know how to give a guy gray hairs, don't you Jim??!!


+1 as I am guessing this is my head.


Yes. But it's all good now. [except for the new bent valve that KW is express sending me a replacement for]
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Re: Head flow testing.

Postby Fullauto » Wed Nov 09, 2016 6:18 pm

Does'nt a bent valve give better flow? Something about airflow around a curve rather than in a straight line? I dunno. You're the expert!
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Re: Head flow testing.

Postby comnoz » Wed Nov 09, 2016 6:43 pm

Fullauto wrote:Does'nt a bent valve give better flow? Something about airflow around a curve rather than in a straight line? I dunno. You're the expert!


Oh yeah, it flows great, open or closed....
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Re: Head flow testing.

Postby Fast Eddie » Sun Aug 13, 2017 4:07 am

comnoz wrote:Fast Eddies RH10 head before and after a street port job with 3mm oversized intake valves.

Image


I thought I'd post this update in Jims thread to make it easier for folk searching this topic.

More info on this topic fine build can be found here:
engine-build-prep-t18461-165.html?hilit=Cylinder%20head%20testing%20Dyno

Jim's graph is based on the following 'before and after' specs:

'Before' spec of bike was: JS1 cam/ follower/ spring kit, JS rods and pistons at 10.5:1 CR, nice squish (forget exact measurment), 35mm FCRs, cNw manaiflod, Tri spark, cNw coils and leads. Standard RH10 head and valves.

'After' spec is: as above plus, followers ground to 7/8th radius instead of 1 1/8, 3mm OS re-angled inlet valves, 1.5mm OS exhaust valves, Comnoz port job, Comnoz valve springs.

Actual peak figure was 64.6bhp @ 6300 rpm, with a very flat power graph from 6000 to 7000. This was a 9bhp (yes NINE BRAKE HORSE POWER, on the same dyno) improvement!

There was significantly more power everywhere from 3000 upwards.

I was very surprised by this to be frank, the improvement way exceeded my expectations.

The summary is that the RH10 head, reworked by Comnoz, gives an outstanding performance improvement. The BHP per $ ratio being far more favourable than most (any?) other mods that I can think of!

Sending your RH10 head to Comnoz should be a compulsory requirement of ownership...!
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Re: Head flow testing.

Postby SteveA » Sun Aug 13, 2017 2:17 pm

Fast Eddie wrote:........Sending your RH10 head to Comnoz should be a compulsory requirement of ownership...!



First find an RH10 head that hasn't already be used and abused!

Not so easy anymore....
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Re: Head flow testing.

Postby acotrel » Mon Aug 14, 2017 12:24 am

You have got about 5 airflow graphs for cylinder head porting on this page. Have you got corresponding dyno curves showing horsepower and torque when you use the head on a standardised configuration bike ?
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