Header extensions / torque tubes?

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Demonx2

Demonx2

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We get a couple months in summer in Florida to do the projects/upgrades on your car getting ready for the "season" to start again in September. I've got one such idea I'd like to hear some input on.

The basics: the avatar is a street/strip car that has run a best of 11.10@119+ mph. Guesstimated 3350#'s at the line. 408 engine, 4.10 gear. Footbrake car staged at 2000 rpm that then flashes to 5000 rpm when the loud pedal is mashed. Shift at 6150-ish that crosses the stripe at 6150-6200. Engine has 1-3/4" Hooker Super Comp headers that have 3-1/2" collectors.

Does anyone run torque tubes attached to their headers? I could go 3" or 3-1/2" x whatever length. 12" or 18" or ?? I'm just not sure with the 5000 rpm launch if they would help or hurt.

Interested to hear of anyone's experience or what they run and why. Thx!!
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I run 2 inch primaries with 3 1/2 collectors. I gained MPH and more torque through a 3 1/2 H pipe and mufflers. 10.67 @128 through Mufflers 3650 lbs. without driver.

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From the engine masters test, collector extensions make huge torque increases, but in the midrange 3000-4000.
It looks like your car never sees less than 5000, (except for maybe the first ten feet) so, not sure they would help.
Still, extensions aren't expensive (I scrounged some diesel exhaust tubing, and made flanges for my four bolt collectors). A couple collector rings and some tubing and a couple welds. I'd sure give em a try.
 
On both my cars with 2"-3 1/2" headers, I ran 3 1/2 tubing and mufflers. Whether they helped or hurt, I have no idea (not counting the system weight). I never ran uncorked.
 
Demonx2 said:
We get a couple months in summer in Florida to do the projects/upgrades on your car getting ready for the "season" to start again in September. I've got one such idea I'd like to hear some input on.

The basics: the avatar is a street/strip car that has run a best of 11.10@119+ mph. Guesstimated 3350#'s at the line. 408 engine, 4.10 gear. Footbrake car staged at 2000 rpm that then flashes to 5000 rpm when the loud pedal is mashed. Shift at 6150-ish that crosses the stripe at 6150-6200. Engine has 1-3/4" Hooker Super Comp headers that have 3-1/2" collectors.

Does anyone run torque tubes attached to their headers? I could go 3" or 3-1/2" x whatever length. 12" or 18" or ?? I'm just not sure with the 5000 rpm launch if they would help or hurt.

Interested to hear of anyone's experience or what they run and why. Thx!!
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I feel you'd definitly gain with an extension on the collectors! You are benefitting from 3.5" collectors and 3" would be an improvement but you can transition to 3" with an extension.
 
Dave!! I have always lived by the old school way of learning how to make them the proper length.
I used 3 1/2" x 18" "Collectors/torque tubes" whatever term is used.....
I used a low temp paint and put a single coat on, took 5-6 runs and wherever the paint is burnt off to, cut them off - Mine ended up about 16", then had them jet-hot ceramic coated.
Supposedly this is where the exhaust is coming out at its peak temp/flow.
My dad did this back in the 60's on his S/S cars, I assume it still works? Maybe someone can chime in and update this old way or "fine tune it" - pun intended!
 
I don’t think with your weight of car that 3.5 collectors are doing you any good. Years ago I swapped to 3.5 collectors from 3 inch collectors and saw nothing. This on a 13 to 1 422 inch W5 motor that ran well into the 9’s at the same weight as yours. Surprised me a bit.
I am a believer that “ Torque Tubes” or header extensions, whatever you call them can be beneficial.
That is why I basically always race with very low restriction mufflers on my cars, currently Kooks, previously dynomax bullets, which can serve a similar purpose based on length used.
If you run open headers at the track, I would experiment with one or both of the above.
I have found these to be ultra trick…. They come in 3.5 too

3” Round Muffler 10” Long Body. Polished Stainless Steel. | Kooks Headers & Exhaust

FWIW.. I also leave at 2k off the foot and vert hits at 4900-5000, shift couple hundred rpm higher than you( I think..lol)
I never look at the tach when I shift, always by feel, that way I can be more consistent run to run, car tells me when to shift it
 
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The Engine Masters dyno guy (Steve Brule)said he has never seen collector extensions not make more power.

Also the heat check mentioned above is how I learned to determine extension length.
 
Oldmanmopar said:
I run 2 inch primaries with 3 1/2 collectors. I gained MPH and more torque through a 3 1/2 H pipe and mufflers. 10.67 @128 through Mufflers 3650 lbs. without driver.

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I'm always amazed at you guys that run through mufflers and the performance you get. Just the added weight of the exhaust system alone says you've got some serious Wheaties under the hood. Those are also some great pictures of how you routed things. Very neat and clean as usual - thx for sharing. I know Don (@B3422w5 ) runs exhausts as well and runs very hard. I run a 3" duals on the street but can't really tell about performance as the car is a smoke show with even mildly hammering it.

Wally (@wkroncke17 ) - thx for reminding me of how I was taught of this trick probably 35 years ago. I had forgotten!!

I appreciate all of your guys input - that's why this forum is so useful for to me. Gain insight from others that "been there, done that." I'm just not sure if, given the stall speed of the TC, whether any increase in low-spped torque will help. This 408 really doesn't need help in the low speed area that my buttometer can detect but perhaps this might be an easy thing to try. I would likely go for a 3"x18" tube to start and shorten them from there if it seems warranted. And as Oldmanmopar shows, I'd want them to run through the trans xmember in the right locations so length may play a role there as well. Thx again for sharing your inputs!
 
wkroncke17 said:
Dave!! I have always lived by the old school way of learning how to make them the proper length.
I used 3 1/2" x 18" "Collectors/torque tubes" whatever term is used.....
I used a low temp paint and put a single coat on, took 5-6 runs and wherever the paint is burnt off to, cut them off - Mine ended up about 16", then had them jet-hot ceramic coated.
Supposedly this is where the exhaust is coming out at its peak temp/flow.
My dad did this back in the 60's on his S/S cars, I assume it still works? Maybe someone can chime in and update this old way or "fine tune it" - pun intended!
Click to expand...
I used the paint also. I put my cut outs for racing at that location. I never have to drop my exhaust when racing. Just open up them up and go.
 
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