collector extensions and improved ET'S

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71gtdart

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I just want to see what everyones experiences have been with using collector extensions on the headers.

What have you found on the dyno or better yet on the race track?

Discuss any testing done using different lengths, or even using no collectors at all.

Just thought this could be very informative for all. Have heard many stories about what bolting on collector extensions can do for a car.

making your own is cheap, but even a set from Jegs is only around $40.

Lets hear your thoughts?
 
Had a conversation once with an VERY experienced super stock racer and he said that the perfect collectors would be one's that would fall off in high gear. On most small block cars that don't have as much torque as a big block cars collectors will help make more bottom end torque. The only real way to know what length you need is on a dyno or testing at the track with different lengths to see what your combination likes. JMO
 
Testing at the track would be the best....they used to say to mark the extension with a crayon and look for where is melts...and cut there...

i have been just adding 10 inch to a Foot.....LOl,,,,,and have never played with lengths....
 
I heard at one time to paint the extensions with some cheap paint and run it. Where the paint stops burning off that's where you should cut them back too.

Sounds like it might work.
 
remember an article years ago saying for a big block mopar that they tested 18" worked best.
 
Dart Sport 360 said:
I heard at one time to paint the extensions with some cheap paint and run it. Where the paint stops burning off that's where you should cut them back too.

Sounds like it might work.
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thats the same place you are supposed to put a crossover pipe in your exhaust.
 
I tried some 12" extensions on some cyclone unequal length fenderwell headers on a full competition 273 Valiant with absolutely no change in ET (best ET without them was 12.72 @ 108 MPH)
 
I have been reading on the subject here and there. I google something like"collector extension improved et", and start clicking on the results. most are from forums like ours.

There are some pretty interesting remarks out there about the subject. some guys saying they have picked up over a tenth by just putting on a set of collectors where they had none before.

I don't run any, but that's one thing that I had planned on doing to the car this winter. Just wondered what results or findings others in the Mopar community have had with them.
 
440 +.060", solid flat tappet a .600", 8" convertor, 4.10 gears, 850dp, ladder bars, 2900lbs, 33"x15"slicks, 2" headers with 18" collectors. added an 18" extentions and lower et by 1 and a half tenths.
 
bOb shingler said:
440 +.060", solid flat tappet a .600", 8" convertor, 4.10 gears, 850dp, ladder bars, 2900lbs, 33"x15"slicks, 2" headers with 18" collectors. added an 18" extentions and lower et by 1 and a half tenths.
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That's right in line with the kind of improvements that I've read about, Bob.

Thanks for sharing.
 
According to "Pipe Max" I need a 19.7" collector(Measured from the header collector+ bolt on collector) for best all around torque and 39.5" for max torque. I have yet to install a collector. one of the many test/changes i will be doing to my new motor this year. As i only got some good shank down run last year.
 
...........All 3 of my race only cars used 18 in collector extentions, bob is right 1-1 2/2 tenth is about right..........infact in 1 case we had to take them back off to keep the car in the 11.000 bracket............kim.......
 
oldkimmer said:
...........All 3 of my race only cars used 18 in collector extentions, bob is right 1-1 2/2 tenth is about right..........infact in 1 case we had to take them back off to keep the car in the 11.000 bracket............kim.......
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we tried them on the hemi, back in the day, didn`t do a dam thing, took them off and threw them in the trash. they usually help cars that need more low end, the hemi didn`t, always had trouble hooking it up. would go 10.40`s on those old tires back then, when hooked. be interesting to see it w/ currant upgrades-tires,convertor, cam and ect. but that probably ain`t
gonna happen,my ex partner is a little older than me, has a bad back , and is sittin on it.:sad9:
 
18'' seems to be the sweet spot for most. Worked for my Big Block and Slant Six cars.
Yep the old school way was to paint them and look for the burn "ring".The only thing that I have to add is (this dates back to the 60's) is cut at the ring for a 4 speed and 1 inch longer for a automatic.Maybe a old wive's tale ??.

Anybody remember the old Hooker adjustable headers ??
 
I think the only thing that painting the extensions does is tell you the paints thermal resistance properties. Buddy of mine tried that old "trick" and the cheap paint completely burned off. Then tried Rustoleum, didn't even phase it.
 
skrews said:
I think the only thing that painting the extensions does is tell you the paints thermal resistance properties. Buddy of mine tried that old "trick" and the cheap paint completely burned off. Then tried Rustoleum, didn't even phase it.
Click to expand...

honestly I have no opinion on the subject either way, but the paint thing - lol
 
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