SBF / TFS R Head Issue

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Jason G
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SBF / TFS R Head Issue

Post by Jason G » Fri Apr 01, 2005 10:51 pm

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.

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Post by ou812 » Sat Apr 02, 2005 2:55 am

Actually your low lift numbers are kinda low...I can get 200 cfm @ .300 lift from a dart 195 cc ford head and a 2.02 valve. The top cut on your valve seat should be steep (around 33-35 degrees) and run into the aluminum and the angle should continue up and smoothly radius into the chamber.
Brian

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Post by Jason G » Sat Apr 02, 2005 5:45 am

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

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Post by Bos's5.0 » Sat Apr 02, 2005 1:44 pm

according to Fletch's page, those numbers are better than any TFS TW R head on there. Who's getting the big numbers..
TEA does pruduce better numbers on THEIR flow bench at higher lift, but your low lift blows them in the weeds.
Any possibility of getting some pics?????

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Post by bill jones » Sat Apr 02, 2005 3:22 pm

-You guys are good.

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Post by SWB » Sat Apr 02, 2005 7:53 pm

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

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Post by ou812 » Sat Apr 02, 2005 11:07 pm

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 :lol:
Brian

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Post by airflowdevelop » Mon Apr 04, 2005 11:51 am

WOW!

the only way I can get those hot numbers on the bottom, is with material added to the floor and a huge chamber!




Dennis

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Post by Jason G » Thu Apr 14, 2005 7:25 pm

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 :wink:

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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Post by ou812 » Thu Apr 14, 2005 10:19 pm

Did you raise the roof where the valve guide is and above the short turn? I wonder if you maybe raised it too much and slowed the air down too much? Just a thought...
Brian

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Post by EngineTech1 » Thu Apr 14, 2005 10:23 pm

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.

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