TF & Speedmaster Flow Tests

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PRH said:
I missed this earlier:

What I meant was any port form that has some obvious separation issues vs one that doesn’t.

I’d say the change in sound you hear at .400 up is the signal “something” isn’t as happy as it was before the sound changed.
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I knew what you meant, just couldn't let the moment go by quietly.

Yeah, I think it is the flow separation/turbulence getting progressively worse as the valve is opened. The valve is actually containing the separation and giving 'walls' or structure to the flow. When the valve is out of the way enough it becomes a free for all.

Here's one more chart that compares the SM to the TF. Same thing happens at the same time on both heads.

You mentioned earlier and perhaps you are correct that the best I can hope for is to minimize the zeros on the flow charts. It may be impossible to eliminate them, even on a head that does not back up.

BTW, the circles on these charts do not represent the valve. It's the computer's way of storing and displaying data. The top number is the pitot reading at the seat, then going clockwise each number is another pitot reading at 0.100" further distance from the seat.

IMG_2394.jpg
 
You mentioned earlier and perhaps you are correct that the best I can hope for is to minimize the zeros on the flow charts. It may be impossible to eliminate them, even on a head that does not back up.
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That’s my suspicion…….. but I’ve never done any testing to confirm or deny it.
 
All of you guys digging deep into the TrickFlow heads are awesome and much appreciated! These threads really get a guy thinking and learning. With that said I'm curious what the actual expectation is for the TF heads? We are finding theres definitely room for improvement or places they are lacking but the few racier type combos we've seen seem to run pretty good for something that doesn't need sent out for port work right?
 
19DUSTER73 said:
All of you guys digging deep into the TrickFlow heads are awesome and much appreciated! These threads really get a guy thinking and learning. With that said I'm curious what the actual expectation is for the TF heads? We are finding theres definitely room for improvement or places they are lacking but the few racier type combos we've seen seem to run pretty good for something that doesn't need sent out for port work right?
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I can't wait to get my Trick Flows back from CFM Performance. We should see what these things really are all about.... lol
 
-Boosted- said:
I can't wait to get my Trick Flows back from CFM Performance. We should see what these things really are all about.... lol
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I am excited too lol. Let me know when ya have it out this year I'll come watch ya run. Heck I may even be there with mine.
 
This is a test I've been wanting to try for a while, but just getting to it. This test is in a Speedmaster head with 50 degree seats and 35 degree top cut. Valves were sunk 0.090" to acheive the top cut.

I have been struggling with flow backing up in the port starting at 0.550-0.600 lift. Pitot testing revealed that the flow is separating from the SS starting at 0.400 lift (380 fps SS floor velocity) and getting progressively worse as lift increases.

I will stop here and say that PBR told me a couple of months ago to increase the area at the apex and get the velocity down and that is probably the real solution, but I don't listen so here we are. Momma always said if I had been her first child I would have been her last.

I have been thinking of other ways to keep the flow attached to the SS at higher lifts. I have been wondering how a tulip valve would help on the short side. It's not easy to find tulip intake valves, so I ended up fabricating one with epoxy. Now I know that overall a tulip valve is not the way to go, but I am looking for a solution that helps one localized area, not the entire port. This is a learning exercise. Look at the drawing below. Surely air coming over the short side would benefit from a tulip shape to help it make the turn. Surely. Air would ease around the turn and not hit the brick wall straight on.

But, as can be seen from the flow results, the tulip is the overall loser. Even when I measured localized velocities around the perimeter of the valve from the combustion chamber side, the tulip never clearly helped. I thought there would be somewhere in the flow curve and some localized area that significantly benefitted from the shape of the tulip. Not really. There are a few areas around the valve that respond favorably at some lift points, but there are no real positive trends for the tulip.

This is just another case of the flow bench proving my intuition to be wrong. It happens frequently. Guess I should have known since it was so hard to find a tulip valve.

IMG_2407.jpg


IMG_2406.jpg


IMG_2408.jpg
 
Earlie A said:
I will stop here and say that PBR told me a couple of months ago to increase the area at the apex and get the velocity down and that is probably the real solution, but I don't listen so here we are. Momma always said if I had been her first child I would have been her last.
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Just curious what is your Cross section area is here ?

I've seen Eric say he finds it's generally around peak flow # when he's done, so 300 cfm = around 3.00", 275 cfm = 2.75" etc..
 
I saw that video as well and thought that was an interesting correlation, but it’s also not a SBM head. In both of the examples you gave, the average velocity at the area you specified would be 240 fps. That would certainly help air get around a corner. I don’t think there is enough metal in the SM head to open it up to 3 sq in to get 300 cfm, so we have to live with a higher velocity. It’s a little hard to define exactly where the apex area is located, but my port is somewhere in the 2.4-2.5 sq in range at the apex. My average velocity at the apex area is in the 290-300 fps range. Port floor velocity exceeds 400 fps (in the center) at 0.600 lift before falling off.
 
A couple of random thoughts……
- lowering the seat .090” takes away what I feel is valuable length on the floor from the apex to the seat
-I don’t feel you can actually fix the SSR by playing with the seat angles.
The seat angles are more about pressure recovery as the air moves thru/past the seat.
-the tulip valve reduces the port area around the whole valve.
While it’s blocking air moving over the SSR, it’s also blocking the air at other locations in the port.
That air is trying to find somewhere else to go……which then taxes the SSR again.

I’d try a “normal” valve seat profile on a different port, nothing else, while sinking the valve the least amount possible, and ending up with a 30* top cut that’s around .040” wide.
No chamber mods.
Flow that, then start addressing the SSR……..and see where that ends up.

-FWIW, I’ve never tested any ported SBM std port head that didn’t have some turbulence issues at higher lifts.
-While I’m comfortable working on them, I also don’t consider myself as someone who has them “all figured out”.
 
PRH said:
A couple of random thoughts……
- lowering the seat .090” takes away what I feel is valuable length on the floor from the apex to the seat
-I don’t feel you can actually fix the SSR by playing with the seat angles.
The seat angles are more about pressure recovery as the air moves thru/past the seat.
-the tulip valve reduces the port area around the whole valve.
While it’s blocking air moving over the SSR, it’s also blocking the air at other locations in the port.
That air is trying to find somewhere else to go……which then taxes the SSR again.

I’d try a “normal” valve seat profile on a different port, nothing else, while sinking the valve the least amount possible, and ending up with a 30* top cut that’s around .040” wide.
No chamber mods.
Flow that, then start addressing the SSR……..and see where that ends up.

-FWIW, I’ve never tested any ported SBM std port head that didn’t have some turbulence issues at higher lifts.
-While I’m comfortable working on them, I also don’t consider myself as someone who has them “all figured out”.
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Thanks for the insight, the detailed response and the recommendations. I think you are correct that sinking the valves that much may have made a bad situation worse on the SSR. I'll keep slowly plugging away at it.
 
Back on the Speedmaster head with a few changes. I increased the width of the port on the cyl center side at the apex which brough the velocity at the apex of the SS down to 360-380 range. It was almost 410 at peak. Flow did not change much, maybe down 5 cfm from previously. I also undercut the chamber a little where most shrouded, but stayed with the 4.07 bore circle. Flow increased a little in the 0.200-0.400 range, but decreased a little after that. Test 495 shows the result of those modifications. Seat was still 50 deg, throat remained in the 91-91.5% range.

Next, the throat was epoxied up and the valve job redone at 35/45/60/75 and blended to 88% wide and 89% SS to long side. Seat angle is now 45 deg. This was mostly a loser, but the throat is still a little small and I'm not happy with the shape yet. Test 497.

Before enlarging the throat and eventually going back to 50 deg seats, I decided to lay back the center of the SSR. I probably removed 0.020" at the center and blended it into the existing sides. I also did some very minor touch up to the cyl wall side of the throat which increased the throat size to 89% in both directions. Laying back the SSR did help a little at higher lifts, and I noticed that flow was trending upward at 0.750, which is the point I usually stop testing. This time I went to as high a lift as the valve would allow, which was 0.950. The flow continued to be stable and slowly increased with increasing lift.

I'm not exactly sure what this means, but I think it is a positive trend. I would still like to get the dip at 0.600-0.700 out of the curve.

IMG_2416.jpg


IMG_2417.jpg
 
Earlie A said:
Back on the Speedmaster head with a few changes. I increased the width of the port on the cyl center side at the apex which brough the velocity at the apex of the SS down to 360-380 range. It was almost 410 at peak. Flow did not change much, maybe down 5 cfm from previously. I also undercut the chamber a little where most shrouded, but stayed with the 4.07 bore circle. Flow increased a little in the 0.200-0.400 range, but decreased a little after that. Test 495 shows the result of those modifications. Seat was still 50 deg, throat remained in the 91-91.5% range.

Next, the throat was epoxied up and the valve job redone at 35/45/60/75 and blended to 88% wide and 89% SS to long side. Seat angle is now 45 deg. This was mostly a loser, but the throat is still a little small and I'm not happy with the shape yet. Test 497.

Before enlarging the throat and eventually going back to 50 deg seats, I decided to lay back the center of the SSR. I probably removed 0.020" at the center and blended it into the existing sides. I also did some very minor touch up to the cyl wall side of the throat which increased the throat size to 89% in both directions. Laying back the SSR did help a little at higher lifts, and I noticed that flow was trending upward at 0.750, which is the point I usually stop testing. This time I went to as high a lift as the valve would allow, which was 0.950. The flow continued to be stable and slowly increased with increasing lift.

I'm not exactly sure what this means, but I think it is a positive trend. I would still like to get the dip at 0.600-0.700 out of the curve.

View attachment 1716215997

View attachment 1716215999
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What size are the bowls?
 
PRH said:
For comparison……..what is the bowl diameter of the TF head?
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TF bowl is 1.996 or 98.8% at the tip of the bronze guide. That is the widest point and it tapers toward the throat.

Factory CNC Speedmaster is 1.904, 94.3% at the guide and 1.923, 95.2% between the guide and the throat.

I would enjoy the opinions and theories on bowl sizes. I have several conflicting thoughts bouncing around in my head.
 
Earlier in this post we discussed the purpose of the vein in the TF head. Eric touches on it a little in this video:

 
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