Vtsuby's cylinder head development thread

I finally got the heads rigged up on the flow bench today. We have had issues calibrating the software for the bench but for an initial test I lifted the valves to .450" and saw 235cfm. Does anyone have anything to compare this to? I started adding some clay to the floor of the port building it up so far the cfm hasn't decreased. I'm flowing the heads without the velocity stack right now just with a clay donut. I suspect alot of the stack will fill in without effecting cfm with things the way they are now. The head has a nasty short side turn which is inhibiting flow at some level. By filling the floor in the port is being raised vertically making a smoother radius down to the valve decreasing the restriction. Another scenario would be its just dead right there. The pitot is also screwed up somewhere in the program and is preventing further investigation hopefully the bench will get sorted out tommorow. The over all plan is to increase the angle of the port and give the short side a much smother radius. The next thing I'am going to try is grinding the part of the combustion chamber near the valve back some to try to deshroud the valve a bit. I'll post some numbers and pictures when the bench is working properly

[SVXRide]

Originally Posted by VTsuby

I finally got the heads rigged up on the flow bench today. We have had issues calibrating the software for the bench but for an initial test I lifted the valves to .450" and saw 235cfm. Does anyone have anything to compare this to? I started adding some clay to the floor of the port building it up so far the cfm hasn't decreased. I'm flowing the heads without the velocity stack right now just with a clay donut. I suspect alot of the stack will fill in without effecting cfm with things the way they are now. The head has a nasty short side turn which is inhibiting flow at some level. By filling the floor in the port is being raised vertically making a smoother radius down to the valve decreasing the restriction. Another scenario would be its just dead right there. The pitot is also screwed up somewhere in the program and is preventing further investigation hopefully the bench will get sorted out tommorow. The over all plan is to increase the angle of the port and give the short side a much smother radius. The next thing I'am going to try is grinding the part of the combustion chamber near the valve back some to try to deshroud the valve a bit. I'll post some numbers and pictures when the bench is working properly

Nice! I've got a head already fixtured on a SuperFlow bench - without the injector stack. Just haven't gotten around to starting to flow it yet.
-Bill

[TomsSVX]

so how much lift can we acheive with stock compnents without bottoming out the stock springs?? please make measurements in metric

Tom

My fixture can't handle that pressure which would be the most convient way to answer that. I don't intend on using the springs.

[SilverSpear]

Good luck VT with that project, with your experience and tools I foresee you will be achieving the fastest N/A SVX...

[SVXRide]

Originally Posted by TomsSVX

so how much lift can we acheive with stock compnents without bottoming out the stock springs?? please make measurements in metric

Tom

Gee, Tom, and why would you want to know this info?
I'll see if my machinist can rig up a fixture to take this measurement. If we can't make something work, I'll see if I can't get a feeler gauge in between the coils while using the "upgraded" intake cam at max lift.
-Bill

you could put spring in a compressor measure that subtract installed height then put retainer on valve with buket on top measure the displacement in the head and compare the difference which would bottom out first

Fastest na impreza is my goal. I like the svx especially the room but its got 600 pound easy on the impreza.

[SVXRide]

Originally Posted by VTsuby

you could put spring in a compressor measure that subtract installed height then put retainer on valve with buket on top measure the displacement in the head and compare the difference which would bottom out first

yep, I was thinking the same thing....
-Bill

[oab_au]

Originally Posted by SVXRide

Gee, Tom, and why would you want to know this info?
I'll see if my machinist can rig up a fixture to take this measurement. If we can't make something work, I'll see if I can't get a feeler gauge in between the coils while using the "upgraded" intake cam at max lift.
-Bill

Bill if you have a head on the bench, just pull the inlet valve open till the spring is coilbound, and measure it, can't be too hard

Harvey.

[SVXRide]

Originally Posted by oab_au

Bill if you have a head on the bench, just pull the inlet valve open till the spring is coilbound, and measure it, can't be too hard

Harvey.

Harvey,
Just got back from business travel, so I'll see if we can't make some progress in the next week!
-Bill

[mbtoloczko]

Originally Posted by VTsuby

I finally got the heads rigged up on the flow bench today. We have had issues calibrating the software for the bench but for an initial test I lifted the valves to .450" and saw 235cfm. ...

Were the springs still installed when you lifted the (intake?) valves to 0.450"?