What size headers
New to the group & first post. I’m running a DCI 5 combo, the guy that build my Taj Mahal intake also spec’d my headers. The trq numbers were a good bit lower than my previous build & thinking it’s a combination of huge plenum & too big of header tubes 2 1/4 to 2 3/8 5” collector. Anyone else running tubes this big on 1050-1100 hp range. My dad’s combo has 2 1/8 to 2 1/4 w/4” collector, smaller intake plenum as well & made roughly 80 ft lbs more trq.
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You say your Fathers combination has less plenum volume than yours, what about total intake track length for each combination? Stan |
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What size carb do you run?
Have you ran the dual 4bbl top? :confused: |
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That is definitely a large header. Not sure if you're trying to get the 80tq that your dad is up or what you're looking to gain. But my honest opinion is it'll take a combination of intake and header work. If the plenum is so large you're having issues on the leave that's definitely not right and you will see gains once that is fixed (I'd bet your shift recovery is bad also due to it).
One thing you could do with the headers is move to a 4 or 4.5 inch collect and lengthen it. See how that works. I'm guessing yours are removable so that would be a very easy thing to test. Fwiw, I ran 2 1/8 to 2 1/4 4" collector on my 1050hp 511ci. |
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Launch RPM?
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Mine 284/306 .954 .936 121 lobe sep |
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I would try another cam. |
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A overly large primary tube on a given race motor can sometimes be partially compensated for by a longer then needed collector extension.
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around 7800 & I pulled it to 8400. Only 7 passes on this setup & no clean runs yet but I was only crossing @ 7550-7600 @ Gainesville for the gator nationals this year. |
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What does each engine have for stall speed? Stan |
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Is your throttle stop/delay one that has you at an idle/set rpm then opens when ready to go, or on the mat and the 2 step keeps it at a set rpm until ready to go?
Nice dyno sheets! :) |
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Just a WAG using 3350# race weight. 1000 Foot ET = 8.4412 1/4 Mile ET = 9.9051 1/4 Mile MPH = 155.9576 Stan |
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Thank you for that information. 1000 Foot ET = 8.4739 1/4 Mile ET = 9.9008 1/4 Mile MPH = 160.2311 How close is my 1000 foot et? Stan |
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Good luck down in Reynolds! You guys have them Pontiacs flying! Say hi to Dave P and Kevin M for me.
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1000 Foot ET = 8.4353 1/4 Mile ET = 9.8825 1/4 Mile MPH = 157.8409 Stan |
Can you adjust the the time when the throttle 1st close? (like 1 second into launch)
Delay closed is around 2 seconds? Also actual carb being throttled or a butterfly in spacer under carb? Hope your daughter is better. |
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I lined up with Laurel on a Time run today. Sounds like the headers are too big. Try adding the extension to see what happens. Maybe after Charlotte, ask dad if you can try his intake. lol |
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Hope your daughter is feeling better.
Maybe someone else will look at this and see it as one thing. I don't know what it is, but think it has to be a combination of parts. Stan |
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Am I correct in that the 2 engines were dynoed at different places?
Stan |
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True but his is over a 2000 RPM range and yours is over a 1400 RPM range. Stan |
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When you look at dyno sheets, you need to look at all of the numbers.
These are your Father's HP curves from the 2 dyno sheets. Stan |
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Stan |
How have the Super Wedge heads turned out on big time engines ?
There does not seem to be a lot of info on them. |
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Not sure it would’ve turned out better but it sho would’ve been cheaper. I have saw tiger builds make good power & some not make good. Our 5 builds looked good on dyno but on the track I’ve yet to see a performance upgrade. We’re at Charlotte for the 4 wide so I will have a better idea tomorrow but I ran 9.90 @ 158 here in 17 with my 535 edelbrock combo that had a 1200 quick fuel. I just put a 1175 carb on my motor so we’ll see how it does. Dad ran 8.90 @ 165 with his 535 edelbrock combo & has been 8.90 @ 165 with his 5 combo. We added 30-35 cubic inch , head flow cfm went from 420s to over 500 & both got bigger cams. |
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