Ported LS3 10 degree heads

[Carnut1]

1st sheet 45 seats stock, fully ported best guess style, chamber cut best guess style, this is the point I should usually stop because I am 90% of whatever I can get out of the ports. LS stuff is a different beast so I may not get 90% out of what I can.
2nd sheet stock ports and valve job.
3rd sheet honed guides, 50 degree seats 45 degree valves(forgot to face valves).

[Carnut1]

Maybe I need to explain my exhaust airspeed layout. First airspeed in top left corner is from top left corner of port flange, etc. They are usually done about max actual lift I think the head will be used at. Thanks, Charlie

Why you even consider exhaust flow is beyond me. Unless you have a kink in the bend there is no way to see the actual flow.

It is tough to see air, through use of strings, Pitot gauges and flowballs you can get a good idea that the area you have is being used at the static pressures you have. Thsnks, Charlie

[Carnut1]

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50 degree seats with 50 degree valves. 87 % intake throat, 87.5% exhaust throat, no backcuts. Notice the introduction to noisy turbulence on exhausts in mid lift where it was less pronounced on earlier tests.

[RevTheory]

The 50* seats made the exhaust cranky? Are you able to tell where?

[Carnut1]

Rev on flow sheets the "T" next to a number means noisy turbulence.

[RevTheory]

Sorry, I meant where in the port; throat, one side of the guide or the other, launch off the turn, etc. Knowing me, that could be a dumb question

[Carnut1]

Sorry, I meant where in the port; throat, one side of the guide or the other, launch off the turn, etc. Knowing me, that could be a dumb question

It is not a dumb question Rev. What I think is happening is the mass flow from the ssr part of the throat is tearing off the ssr and interupting the flow on the roof. It has to do with the geometry of valve, valve seat and throat. Shaping the chamber to add flow to the roof may also help. Now even though it sounds bad it flowed more than the ported 45 degree seat! It is still on the bench, I think I will crank the depression and see if the sound changes.Thanks, Charlie

[Carnut1]

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Exhaust noise similar at higher depression.
Changed bowl a bit which seems to lessened noise and improved exhaust flow a bit. Worked on intake ssr a bit and it worked well till it lost it, try again.

[Carnut1]

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Always good to have an extra head to work on. Obviously the intake and exhaust on this casting share a wall. So wider on ssr towards exhaust is very limited. Pic of exhaust bowl. .1" measured but the aggressive nature of the burr bulged aluminum.

[Carnut1]

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I did a bit more work yesterday and I managed the flows on the left side of this sheet. Today, I dug up my flow sheets from my first Ls3 project which is a GM copy more or less. The first project was beating these 10 degree heads badly and with a much smaller port. Did a bunch of tests with 2.165" valves with and without backcuts. I decided to cut my only 2.2" 50 degree valve with a 35 degree backcut. Right side flows and swirl are with back cut. Lifts over .6" are touchy as ssr is fast, notice two different numbers depending if ssr lets go. Thanks, Charlie

[FC-Pilot]

It would be very interesting to dyno these with and without the back cut.

Paul

[Carnut1]

It would be very interesting to dyno these with and without the back cut.

Paul

I would like that as well. I am not thrilled at how these are developing. I smelled smoke from one of my bench motors so between ot and electrical side gigs this project is paused till I run through all the brushes, check each motor. Thanks, Charlie

[Erland Cox]

On the exhaust port, can you try filling the chamber on the SSR side with clay and see what happens with the flow?
Not the corner so much as over the SSR.
Limiting flow on the SSR side usually helps but it must be just enough.
If the flow wants to separate over the turn I usually never take any material from the roof of the port, that only makes it worse.
I only make the port wider in those cases.

Erland

[Carnut1]

On the exhaust port, can you try filling the chamber on the SSR side with clay and see what happens with the flow?
Not the corner so much as over the SSR.
Limiting flow on the SSR side usually helps but it must be just enough.
If the flow wants to separate over the turn I usually never take any material from the roof of the port, that only makes it worse.
I only make the port wider in those cases.

Erland

I haven't filled the chamber but I did take some quench and shape it to add more flow to the roof. It did improve efficiency. Thanks, Charlie

[Rowdy Yates]

They're selling now. 10 degree Ls heads flow data for all makes Ls 1-3 & 7.
Carnut, keep up the work something to look over and read.
https://frankensteined.net/shop/f310/