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PostPosted: Fri Jan 27, 2017 8:17 am 
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Thought I'd start a thread to publish some 550 engine data that I've been gathering that may not be readily available anywhere else. Stuff like combustion chamber cc's, head flows, etc.

For example here are the combustion chamber volumes:

Right Head:
1: 16.5
2: 16.5
3: 16.6
4: 16.7
5: 16.7
6: 16.5

Left Head:
7: 17.2
8: 17.2
9: 17.1
10: 17.0
11: 16.9
12: 16.9

Looks to me as if the right head may have been shaved a tad more than the left when the machinist cleaned up the surfaces after the valve job.


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PostPosted: Sun Jan 29, 2017 10:43 am 
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Head flows at 28" WC

Cylinder 1 is the right head frontmost cylinder (when facing flywheel), and 4 is in the middle

Cylinder 7 is left head, rearmost cylinder, and 9 is in the middle

I asked them to flow one port at the extremity of the head because they're angled, and one in the middle of the head because they're straighter. Turns out there's not a big difference.


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PostPosted: Sun Jan 29, 2017 7:54 pm 
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Interesting. 225 at 28" is about 130 at 10". How is that meadured? Head with a short stack?


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PostPosted: Mon Jan 30, 2017 3:21 am 
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mk e wrote:
Interesting. 225 at 28" is about 130 at 10". How is that meadured? Head with a short stack?


Just the head with no manifold, stacks or anything else, AFAIK.

I brought the heads & cams to a specialty tech school in Houston (SAM Tech) to have their instructors do this stuff, and show the students what hipo exotic heads look like. They put the cams on their cam doctor, cc'd the heads, and flowed them.

The guy who did the cams gave me a really nice report, but it was a different guy who did the heads, and getting info out of him has been like pulling teeth. I've been over in North Africa for the better part of 3 months, so I couldn't stand over them and watch.


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PostPosted: Mon Jan 30, 2017 6:51 am 
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cribbj wrote:
mk e wrote:
Interesting. 225 at 28" is about 130 at 10". How is that measured? Head with a short stack?


Just the head with no manifold, stacks or anything else, AFAIK.


If there was no stack or any kind the numbers will normally be much lower than actual....10-20% below actual so its important to know for sure. Those numbers seem about right for that engine though so I'm thinking they used something on the entrance.


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PostPosted: Wed Feb 08, 2017 10:26 am 
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mk e wrote:
If there was no stack or any kind the numbers will normally be much lower than actual....10-20% below actual so its important to know for sure. Those numbers seem about right for that engine though so I'm thinking they used something on the entrance.


They just confirmed, no stacks or any sort of flow enhancers - only clay on the ports :)


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PostPosted: Wed Feb 08, 2017 12:11 pm 
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cribbj wrote:
mk e wrote:
If there was no stack or any kind the numbers will normally be much lower than actual....10-20% below actual so its important to know for sure. Those numbers seem about right for that engine though so I'm thinking they used something on the entrance.


They just confirmed, no stacks or any sort of flow enhancers - only clay on the ports :)


Well, whne they say only clay on the ports, that probably means they made an inlet radius from clay which in effect is a stack, just a bit of an uncontrolled stack depending how they formed it, but I use clay all the time an most heads aren't very sensative to exactly how the radius is shaped, as long as it's there and relatively large .


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PostPosted: Wed Feb 08, 2017 1:29 pm 
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mk e wrote:
Well, whne they say only clay on the ports, that probably means they made an inlet radius from clay which in effect is a stack, just a bit of an uncontrolled stack depending how they formed it, but I use clay all the time an most heads aren't very sensative to exactly how the radius is shaped, as long as it's there and relatively large .


What do you think of the flow numbers? I was a little disappointed myself....... but then big numbers don't necessarily translate directly to HP do they......


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PostPosted: Wed Feb 08, 2017 9:09 pm 
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cribbj wrote:
What do you think of the flow numbers? I was a little disappointed myself....... but then big numbers don't necessarily translate directly to HP do they......


They seem about right for what tbe engine is honestly.....you don't want more flow than you can use at the desing rpm.....or you end up with my problems.


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PostPosted: Thu Feb 09, 2017 11:58 am 
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Ferrari only rate the engine for 88 BHP/Liter, so I can appreciate conservative head flows, but the ports on these heads looked so good, and the valves were sized so generously I felt they would flow better than this.

In comparing them to some Japanese heads, I'm finding that they just barely outflow stock Supra heads on the intake side, and they well outflow the Supra on the exhaust side...... In fact, the 550 exhaust outflows a full race ported Supra exhaust.

Intake/exhaust valves on these 550 heads are 34 & 29mm respectively, while the Supra valves are 33.60 & 29mm.

The Supra engine is rated at 108 BHP/Liter, but of course it's a turbo motor too, so it's an apples & oranges comparison HP-wise.


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