SBF / TFS R Head Issue
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SBF / TFS R Head Issue
A friend of mine is working on a set of SBF - Twisted Wedge R heads. He has raised the intake port about half an inch and modified an intake manifold to match. Low lift numbers are very good, but the port really drops off at .500" lift compared to similar heads.
2.10 Intake valve.
Here are the current intake numbers - 4.100" bore fixture, 28" H2O:
.200 - 185
.300 - 237
.400 - 286
.500 - 300
.600 - 314
.700 - 320
Anyone worked on these heads? Any thoughts?
The biggest issue I see is these heads have not short turn radius as do other standard SBF heads.
2.10 Intake valve.
Here are the current intake numbers - 4.100" bore fixture, 28" H2O:
.200 - 185
.300 - 237
.400 - 286
.500 - 300
.600 - 314
.700 - 320
Anyone worked on these heads? Any thoughts?
The biggest issue I see is these heads have not short turn radius as do other standard SBF heads.
Brian,
Maybe I'm misunderstanding you. Did you mean 200 cfm @ .200 lift on the Dart heads in your previous note?? That is indeed impressive if so. I have never seen a SB head go 200 cfm @ .200 lift.
The heads I mentioned above are 237 cfm @ .300 lift which from what I have seen is nearing Yates territory (~240cfm @ .300). In fact they are comparable to a Yates up to .400 lift. After that, no comparison. I believe there are folks out there that are getting this head into the 360 - 370 cfm range in the upper lifts. We are missing something.
Thanks,
Jason
Maybe I'm misunderstanding you. Did you mean 200 cfm @ .200 lift on the Dart heads in your previous note?? That is indeed impressive if so. I have never seen a SB head go 200 cfm @ .200 lift.
The heads I mentioned above are 237 cfm @ .300 lift which from what I have seen is nearing Yates territory (~240cfm @ .300). In fact they are comparable to a Yates up to .400 lift. After that, no comparison. I believe there are folks out there that are getting this head into the 360 - 370 cfm range in the upper lifts. We are missing something.
Thanks,
Jason
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I'm willing to bet you just need to slow the air down in the bowl area so it's not moving over the SST as fast. You might need to re-profile your short side turn some more if the radius is too tight. If you've moved the port around that much, you may also want to make a mold and section it, that would tell you where it's too small or large. There's a ton of velocity probe conversation in previous posts which may help you also.
SWB
SWB
I must apologize for my post...I posted after BRIEFLY looking at you numbers and thoght they started at .300 lift!!!! That should teach me to not post after 10:00! Sorry for that. Now that I see them, they are very good. Reminds me of doing a set of Brodix chevy heads, the 867 heads, after some seat work but keeping the bowl small the heads would flow huge down low and then taper off at the top. I finally opened the bowls up more, about .060 and laid back the short turn. I also lowered the turn after the apex, in the middle, and seemed to help the port hang on up into .700 lift.
Hope this helps, and sorry again for my dumb post
Brian
Hope this helps, and sorry again for my dumb post
Brian
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Sorry I haven't gotten back on this topic, but I haven't been able to post for some reason.
Brian - I figured that was the case
Bo - Yes, I was comparing to TEA and Foxlake. I'll try to get some pictures.
SWB - My first thought is that the short turn on this head is aweful. We basically have a Yates port with a standard SBF short turn which is very short. We built up the short turn and tried various shapes with no change. At this point the only thing left is the valve job or lack there of.
Airflow - We've raised the roof about 1/2", profiled the guide boss, layed back the chamber, and reworked the short turn. Once we got to the point we are currently, nothing seems to pick up the top end. We are going to start working on the valve job next.
Any suggestions on the valve job?
Brian - I figured that was the case
Bo - Yes, I was comparing to TEA and Foxlake. I'll try to get some pictures.
SWB - My first thought is that the short turn on this head is aweful. We basically have a Yates port with a standard SBF short turn which is very short. We built up the short turn and tried various shapes with no change. At this point the only thing left is the valve job or lack there of.
Airflow - We've raised the roof about 1/2", profiled the guide boss, layed back the chamber, and reworked the short turn. Once we got to the point we are currently, nothing seems to pick up the top end. We are going to start working on the valve job next.
Any suggestions on the valve job?
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what is your current valve job angles and widths? what is your venturi diameter? what is your valve profile, angles, and widths? Is the head turbulent or smooth at the upper lifts? I've seen some of those tw style heads not like the chamber being laid back too much. We've got a twr port with a 2.12 valve that is high 360's to 370 at .700.