Cylinder head dyno shoot out
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NC Engine Builder
Grumpy Old Man
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Std old moly top ring, nothing trick
Earlie A
Well-Known Member
Looks like chamber volume is going to be 67cc which will give us about 11:25/1 compression. Stock TF on the left and 67cc on the right. Exhaust ports on these heads are tiny. Not going crazy, but this one has been opened.
PRH
Well-Known Member
Any changes to the flow curve by opening up that chamber?
Exhaust flow improvements with the clean up?
Exhaust flow improvements with the clean up?
Earlie A
Well-Known Member
Opening the chamber helps mid lift flow a fair bit, both on intake and exhaust. That's where the TF head shines. High lift flow and high depression flow is where the TF falls apart. Put in a 2.08 valve and open the pinch and the high lift flow suffers even more. Opening up the chamber can make it even worse. I have one port with the ant-swirl vein removed, and one with it existing. For the dyno test it will most likely remain.
Stock exhaust flow with no pipe peaked about 188 cfm. With a little work on the port that increased to 202-203 with a port velocity in the 330 fps range. I would actually like to see a little more flow, maybe 215, but the velocity is good and the port is quiet except for a little bouncing at 0.250 lift. It may just stay the way it is.
PRH
Well-Known Member
I’ve had a few heads where unshrouding the intake valve created some high lift flow problems.
For me, it seems like if the high lift flow stability is iffy, moving the chamber wall away from the valve hasn’t shown to improve that.
For me, it seems like if the high lift flow stability is iffy, moving the chamber wall away from the valve hasn’t shown to improve that.
Earlie A
Well-Known Member
In another thread Brian Hafliger talked about a port being 'out of balance'. I've thought a lot about that. I think this TF head is the perfect example. Opening up the pushrod pinch and the chamber make both areas more efficient, or capable of flowing more air with less pressure drop through that section. That really exposes or puts additional pressure on the short turn. With the larger valve I've seen velocity above 500 fps in the center of the apex. Even a stock TF with a 2.02 valve has apex velocity in the 460-470 range.
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PRH
Well-Known Member
I say this as someone who has never put a set of TF190’s on anything myself, and/or dyno tested an engine that had them.
But, I feel like the best use of TF SBM heads is an application that can use them as they come right ootb.
The cost effectiveness goes down quickly if you’re paying someone to rework them.
But, I feel like the best use of TF SBM heads is an application that can use them as they come right ootb.
The cost effectiveness goes down quickly if you’re paying someone to rework them.
NC Engine Builder
Grumpy Old Man
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Welp, we got an assembled short block.
Has the short block been spoken for?
NC Engine Builder
Grumpy Old Man
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Yes @Earlie A is buying the shortblock at the conclusion of the dyno testing
RAMM
Well-Known Member
Earlie A
Well-Known Member
But if by 'deshrouding' and creating the ideal shape for mid lift flow results in curve A, and intentionally leaving the chamber shrouded results in curve B, which one would you choose? I don't know the answer. That's one of the big reasons I'm spending so much time on these heads.
RAMM
Well-Known Member
I guess what I was trying to say is the "Ideal distance/shape" will yield the best of all worlds, and therein lies the challenge and why serious R&D gets expensive--ruining cylinder heads in the quest for perfection. I know-not the answer you wanted and I'm not even sure this is achievable with these heads as I've never used them. J.Rob
Earlie A
Well-Known Member
Could not agree more.
Newbomb Turk
Well-Known Member
Have you tested A and B with an intake manifold on the head?
That would answer the questions right there.
My experience is A every time as long as the dip in the curve is the port and not the valve or the valve job or both.
Mike Jones and I discussed this on the phone at length in 2013.
It’s why I didn’t by a cam from him.
Put an intake on the head and test it. The best equalizer is a tunnel ram. A single plane is second best and a DP is the toughest to test with for stuff like this.
The different length runners and multiple curves can skew the results of the test.
Earlie A
Well-Known Member
I have tested with Vic 340 and with Super Vic. I have tested at 28" and 33". I have tested inner ports and outer ports because of pushrod location and swirl directions. Sometimes the dip comes out completely, sometimes it does not. But it always improves.
The TF head is the worst for flow back up. Part of that is because of the anti-swirl design of the port and part of it is because water under the short side limits the porting options. The anti-swirl features help the mid lift flow numbers, but when the flow jumps the valve the ported crashes hard. The TF needs the pushrod pinch opened up to make power, in my opinion. Opening the PRP makes the flow separation/crash worse. One of the 'tricks' to making a head flow well on the bench is to use the size of the PRP to limit flow separation and jack the flow numbers up. Works for flow numbers, hurts power.
I have not done it, but if I flowed the assembly at 10" there would probably be no dip. At 28" there may be a slight dip. At 33" the dip may or may not be more pronounced. I've been thinking about the correlation between high lift, high test depression flow and a head's ability to carry HP beyond peak TQ. On the flow bench, if we try to put a head in a high lift, high flow condition and try to create flow separation, can we SOMEWHAT predict performance of the head in a past-peak-torque high rpm 'choked' condition?
The TF head is the worst for flow back up. Part of that is because of the anti-swirl design of the port and part of it is because water under the short side limits the porting options. The anti-swirl features help the mid lift flow numbers, but when the flow jumps the valve the ported crashes hard. The TF needs the pushrod pinch opened up to make power, in my opinion. Opening the PRP makes the flow separation/crash worse. One of the 'tricks' to making a head flow well on the bench is to use the size of the PRP to limit flow separation and jack the flow numbers up. Works for flow numbers, hurts power.
I have not done it, but if I flowed the assembly at 10" there would probably be no dip. At 28" there may be a slight dip. At 33" the dip may or may not be more pronounced. I've been thinking about the correlation between high lift, high test depression flow and a head's ability to carry HP beyond peak TQ. On the flow bench, if we try to put a head in a high lift, high flow condition and try to create flow separation, can we SOMEWHAT predict performance of the head in a past-peak-torque high rpm 'choked' condition?
Earlie A
Well-Known Member
I realize this is somewhat connected but it is also a derail of @NC Engine Builder thread. I'll try to keep the head posts more directly connected to the dyno test and address the hypothetical elsewhere.
rmchrgr
Skate And Destroy
Thanks for saying that. The theory is interesting but IMO once you get into this type of discussion you’re essentially beyond the main purpose of these replacement-type heads anyway. Plus it’s only one aspect of the equation.
Sure, anything can be made to perform better with enough effort but frankly it makes little sense to start from point A and then put in whatever work it takes to get to point B when you can just start at point B instead.
Earlie A
Well-Known Member
Then you will never find point C.
Edit: A little more explanation here. The Speedmaster, ProMaxx and TF heads all have their unique features. Enough so that I think it's worthwhile to do some dyno testing to compare the platforms and to test flow bench results vs dyno results. In the end it will prove nothing, but it should provide some interesting information.
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PRH
Well-Known Member
Here’s an early prediction…….
If the testing goes reasonably smoothly, it should be possible to have/claim a “winner”.
However, I feel the testing will be condensed enough to where there will still be many unanswered questions at the conclusion.
If the testing goes reasonably smoothly, it should be possible to have/claim a “winner”.
However, I feel the testing will be condensed enough to where there will still be many unanswered questions at the conclusion.
rmchrgr
Skate And Destroy
That's basically what I'm saying. From a practicality standpoint, it's easier to achieve your goals by starting with parts that have had their inherent flaws solved already.
It's probably safe to say that most TF users are not hardcore racers. I'm sure there will be a few who get a set of those in the 9s or whatever but for 95% of TF build ups the OOTB flow/performance potential is probably sufficient.
Do I agree with most of this statement but it seems to me the term hardcore racer is somewhat vague, anyone approaching Max effort on a small block Mopar would never begin with a standard location push rod head would they?
9secRR
Well-Known Member
I did think this until I seen the proof with the Bloomer head. No other head comes close to it for stock push rod location.
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