Posted By: sixpacksteve
Header extentions? - 03/08/13 04:00 PM
maybe this was asked before, does anyone know how much better performance this will give you? if you paint a line on it,and cut off where it stops.curious if someone has stats.
Header extentions?
Posted By: Jamie McGrath
Re: Header extentions? - 03/08/13 04:07 PM
I remember years ago that 18in seemed too work best and the gain was something in the order of 15-20ftlbs, HP was unchanged. FWIW
Posted By: MR_P_BODY
Re: Header extentions? - 03/08/13 04:11 PM
Quote:
maybe this was asked before, does anyone know how much better performance this will give you? if you paint a line on it,and cut off where it stops.curious if someone has stats.
Being that I was in the exhaust lab at Chrysler for
YEARS I played that game... its not a good way to do
it.. just for info.... it doesnt know if the engine
is fat or lean and different colors burn at different
temps... but i you make them 16" to 18" from rhe end
of the primaries you will be real close
Posted By: Cab_Burge
Re: Header extentions? - 03/08/13 07:13 PM
This is one of the tests that need to be doen at the track on a back to back basis, hard to do in todays world unless your at a test and tune day where you can do run real close to each other 
We use to use a 18 inch, 12 inch and 6 ich colleteor extensions on both of the Hemi Stockers, 727 and 4 speeds, and the 18 inch was always faster 
After discusing our results with a SS/A 4 speed racer he had some big, 4 inch diameter, 18 inch long H pipe and extenions made up for his car, it went faster also 
We use to use a 18 inch, 12 inch and 6 ich colleteor extensions on both of the Hemi Stockers, 727 and 4 speeds, and the 18 inch was always faster After discusing our results with a SS/A 4 speed racer he had some big, 4 inch diameter, 18 inch long H pipe and extenions made up for his car, it went faster also
Posted By: 10.90 Racer
Re: Header extentions? - 03/08/13 07:18 PM
Now there are these............ http://www.perfweldheaders.com/compmerg.html
Posted By: Todd
Re: Header extentions? - 03/08/13 09:07 PM
I had a similar question a while back. Here is the link.
https://board.moparts.org/ubbthreads/show...&PHPSESSID=
https://board.moparts.org/ubbthreads/show...&PHPSESSID=
Posted By: sixpacksteve
Re: Header extentions? - 03/09/13 04:47 PM
cab burge, what were the results,big-small? i guess its like indexing plugs, guys are not sure but still do it!
Posted By: Cab_Burge
Re: Header extentions? - 03/09/13 06:11 PM
Quote:.12 to .18 ET pick up in the 1/4
cab burge, what were the results,big-small? i guess its like indexing plugs, guys are not sure but still do it!
Posted By: 52savoy
Re: Header extentions? - 03/09/13 07:20 PM
Quote:Quote:.12 to .18 ET pick up in the 1/4
cab burge, what were the results,big-small? i guess its like indexing plugs, guys are not sure but still do it!
That's pretty close to what I found in running them on a Hemi.
Posted By: emarine01
Re: Header extentions? - 03/09/13 07:29 PM
Does a header extention have any value if its curved... say 45*
Posted By: Cab_Burge
Re: Header extentions? - 03/09/13 07:33 PM
Quote:
Does a header extention have any value if its curved... say 45*
Try it and see 
Posted By: emarine01
Re: Header extentions? - 03/09/13 07:37 PM
Cheep answer Cab... I'm talkin theory here 
Posted By: Cab_Burge
Re: Header extentions? - 03/10/13 05:49 AM
I have new car that has a set if short 90 degree turn outs, the fomer onwer put them on to get away from blowing dust and dirt up under the car from the straight out headers, he siad his motor slowed down by adding them years ago I put a set of 14x 3.5 inch Bullit racing mufflers on my old 440 Dart that had a set of Hooker 1 7/8 inch fenderwell headers on it, no extensions, those muffs slowed that combination down I had convinced myself that they would act just like collector extensions, they didn't 
Test, test and tset some more for real world results
years ago I put a set of 14x 3.5 inch Bullit racing mufflers on my old 440 Dart that had a set of Hooker 1 7/8 inch fenderwell headers on it, no extensions, those muffs slowed that combination down I had convinced myself that they would act just like collector extensions, they didn't Test, test and tset some more for real world results
Posted By: MR_P_BODY
Re: Header extentions? - 03/10/13 02:43 PM
Quote:
Does a header extention have any value if its curved... say 45*
Normally we talk centerline length but on a curve you
might want to take the outside radius as the length
and try that... so if you figure the outside radius
you would be long, so try figuring that in