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Merge collectors. Do they really help? #2007506
02/07/16 06:50 PM
02/07/16 06:50 PM
Joined: Jan 2005
Posts: 4,243
Charlotte, North Carolina
sgcuda Offline OP
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Since I'm still in the rebuilding stages, I have been doing a lot of reading. I am currently running 2 1/8" primary tubes into 3 1/2" collectors. I am going to build up another set of 4" collectors for testing, since the new motor is 500". I have been thinking about trying out some merge collectors. Maybe narrow down to 3" and come back up to 4" or 4 1/2"? Has anyone seen any real improvements over a standard type collector? From what I have read, bottom end torque really increases without sacrificing top end hp.


[image][/image]
Re: Merge collectors. Do they really help? [Re: sgcuda] #2007521
02/07/16 07:26 PM
02/07/16 07:26 PM
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Oregon
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AndyF Offline
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How far are you from Elston Exhaust? Calvin can answer your question. I'm pretty sure he'll tell you that it isn't as simple as changing the collector.

Re: Merge collectors. Do they really help? [Re: sgcuda] #2007537
02/07/16 07:44 PM
02/07/16 07:44 PM
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So. Burlington, Vt.
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fast68plymouth Offline
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Ive tested them on a few motors.
They don't always work....... And they aren't all created equal.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
Re: Merge collectors. Do they really help? [Re: AndyF] #2007544
02/07/16 07:59 PM
02/07/16 07:59 PM
Joined: Jan 2005
Posts: 4,243
Charlotte, North Carolina
sgcuda Offline OP
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Originally Posted By AndyF
How far are you from Elston Exhaust? Calvin can answer your question. I'm pretty sure he'll tell you that it isn't as simple as changing the collector.

Never heard of them, but I will find out. Thanks.


[image][/image]
Re: Merge collectors. Do they really help? [Re: fast68plymouth] #2007548
02/07/16 08:05 PM
02/07/16 08:05 PM
Joined: Jan 2005
Posts: 4,243
Charlotte, North Carolina
sgcuda Offline OP
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sgcuda  Offline OP
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Originally Posted By fast68plymouth
Ive tested them on a few motors.
They don't always work....... And they aren't all created equal.


I have noticed that price varies, along with construction, which I am sure reflects function. The old saying "You get what you pay for" still applies. The cheaper ones have very short tapers back to a straight tube, while the more expensive ones will have a much more gradual, longer cone.


[image][/image]
Re: Merge collectors. Do they really help? [Re: sgcuda] #2007555
02/07/16 08:40 PM
02/07/16 08:40 PM
Joined: Jan 2003
Posts: 5,762
Hot Rod Ridge
FastmOp Offline
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I can't say for sure because I changed everything when I built my headers. Plus I went from hooker fenderwell headers.

I used them because edelbrock had them on sale lol

Re: Merge collectors. Do they really help? [Re: FastmOp] #2007605
02/07/16 10:33 PM
02/07/16 10:33 PM
Joined: Feb 2005
Posts: 20,116
PA.
pittsburghracer Offline
"Little"John
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The guy that built my header for my new car recommended Dynatech merge collectors so I ordered a set last year with a 10% off coupon. They look very nice.







1970 Duster
Edelbrock headed 408
5.984@112.52
422 Indy headed small block
5.982@112.56 mph
9.42@138.27

Livin and lovin life one day at a time




Re: Merge collectors. Do they really help? [Re: sgcuda] #2007630
02/07/16 11:26 PM
02/07/16 11:26 PM
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Australia
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ozymaxwedge Offline
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They look very nice


1963 Plymouth Max Wedge
1971 Barracuda
Re: Merge collectors. Do they really help? [Re: ozymaxwedge] #2007645
02/07/16 11:40 PM
02/07/16 11:40 PM
Joined: Feb 2005
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PA.
pittsburghracer Offline
"Little"John
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Thanks. I can't wait to give them a try.


1970 Duster
Edelbrock headed 408
5.984@112.52
422 Indy headed small block
5.982@112.56 mph
9.42@138.27

Livin and lovin life one day at a time




Re: Merge collectors. Do they really help? [Re: sgcuda] #2007806
02/08/16 05:45 AM
02/08/16 05:45 AM
Joined: Jan 2003
Posts: 2,902
A shed in England
Tig Offline
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We went from a set of horrible, home hash up 2 1/4 x 4 straight collector to a beautifully made custom set of stainless 2 1/4 with merge collectors and picked up nothing, there was no other changes. Sure looks a lot better under the hood though.


'74 Challenger..9.46 @ 145.9 1/4, 6.001 @ 118 1/8 so far. 4023lb !!! # N/A, Marsh performance 655ci, Indy Maxx, T/R, Indy 600-13 X's, Street legal, pump gas, full interior, Cal-Tracs, mufflers, 3:73's and real 10.5 radials.
9.51 @ 142.4 1/4, 6.003 @ 114 1/8 with our old mule KB, 572-13, 580 wedge.
RHD '68 Barracuda Fastback 323ci street/strip. Best ET 13.88 @ 99.03
Re: Merge collectors. Do they really help? [Re: Tig] #2007807
02/08/16 05:52 AM
02/08/16 05:52 AM
Joined: Aug 2003
Posts: 43,007
Bend,OR USA
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Cab_Burge Offline
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I think the key to merged collectors working well or not is the pipe timing in relation to the firing order and the placing of the pipes from each other based on the firing order. What little I remember about the theory is you do not want two pipes blowing into each other that are 90 degrees crankshaft firing order away from each, you shold have them side by side so the pulse from the first one helps suck the other out the collector, not blow against each other confusedMaybe not shruggy I'll try and ask my Son tomorrow about what they did and the rules they followed when he made them for Rob Muzzy racing.

Last edited by Cab_Burge; 02/08/16 02:15 PM.

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Merge collectors. Do they really help? [Re: sgcuda] #2007851
02/08/16 11:45 AM
02/08/16 11:45 AM
Joined: Jan 2003
Posts: 13,319
Marion, South Carolina [><]
an8sec70cuda Offline
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If you had a lot of time, plenty of money, and your own dyno...I'm sure you could eventually find a header primary and collector combo that would make a few more horsepower over an off the shelf set.


CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 18 spline 4 speed, Dana 60
'71 Demon, 340, low gear 904, 8.75
'73 Chrysler New Yorker, 440, 727, 8.75
'90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt
'06 GMC 2500HD LBZ Duramax
Re: Merge collectors. Do they really help? [Re: an8sec70cuda] #2007862
02/08/16 12:09 PM
02/08/16 12:09 PM
Joined: Nov 2009
Posts: 3,082
St. Paul , Mn.
tubtar Offline
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A proper merged collector will add performance , but they are not a one size fits all kind of deal.
Thinking you will get a huge difference will leave you baffled and / or disappointed unless you take all the variables into consideration when building them.
And even then , the difference won't be felt in the seat of the pants.
I could see them in a heads up , every ounce of oomph kind of deal.
Otherwise , it's more for show and tell.

Re: Merge collectors. Do they really help? [Re: sgcuda] #2007886
02/08/16 12:57 PM
02/08/16 12:57 PM
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY Offline
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Merge collectors have to be built to YOUR engine..
they are designed for a certain rpm and if you move
too far from that rpm they dont add anything.. so if
you feel you can buy a off the shelf merge and expect
to to add performance your kidding yourself... a straight
collector will do more if you make the collector 16"-18"
long... I made a few merge collectors at work to test on
the dyno... each one hurt power at most points(until it
crossed the RPM where it worked).. think a expansion
chamber on a 2 stroke.. they work on a certain engine for
a certain rpm range... I built a set of chambers for my
snowmobile.. it KILLED the top end but it turned it into
a tree puller on low end.. because I didnt have
the inlet cone and exit cone the right diameter
and length
wave

Last edited by MR_P_BODY; 02/08/16 12:59 PM.
Re: Merge collectors. Do they really help? [Re: sgcuda] #2007899
02/08/16 01:22 PM
02/08/16 01:22 PM
Joined: Jan 2003
Posts: 14,479
So. Burlington, Vt.
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fast68plymouth Offline
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There are very few "silver bullets" in the power building hobby.

The biggies are nitrous and boost of course.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
Re: Merge collectors. Do they really help? [Re: sgcuda] #2007953
02/08/16 03:26 PM
02/08/16 03:26 PM
Joined: Jan 2003
Posts: 20,149
Park Forest, IL
slantzilla Offline
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My buddy put some merge collectors on his stocker. He said it seemed to pick up .01 or so in the 60', but he said the change was so small he could not prove it one way or the other.


"Everybody funny, now you funny too."
Re: Merge collectors. Do they really help? [Re: fast68plymouth] #2007964
02/08/16 03:44 PM
02/08/16 03:44 PM
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Oregon
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AndyF Offline
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Oregon
Originally Posted By fast68plymouth
There are very few "silver bullets" in the power building hobby.

The biggies are nitrous and boost of course.


I've read most of what Calvin has posted on 4-2-1 headers and merger collectors and I think it boils down to building an effective extractor type header system which then allows the engine builder to use a smaller exhaust valve which in turn allows a larger intake valve. So not a silver bullet at all! But the NASCAR guys have used it to pick up some power and I'm pretty sure those engines are tuned now to a point where a standard off the shelf type of header would kill off a bunch of power.

The big trick seems to be cutting the primary length way down to improve high speed performance. Then the merge and choke are used to make it work on the bottom end. This is why just welding a merge collector onto a standard set of pipes doesn't do much. It doesn't start to work until the pipe length is correct which takes some math to figure out.

Re: Merge collectors. Do they really help? [Re: sgcuda] #2007972
02/08/16 04:10 PM
02/08/16 04:10 PM
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Missouri
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jwb123 Offline
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For my Dodge these make the most power Flowmaster’s retrofit-style 4-2-1 Scavenger Series. I built several sets of headers for the car, used standard 4 into one and merge type collectors. 512 wedge NSS type car. There is a program called pipemax that allows you to size your headers correctly, and give you lengths for step headers as well. http://www.maxracesoftware.com/
It also has a pretty good engine output estimator in the program as well.

Re: Merge collectors. Do they really help? [Re: jwb123] #2007976
02/08/16 04:14 PM
02/08/16 04:14 PM
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY Offline
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Originally Posted By jwb123
For my Dodge these make the most power Flowmaster’s retrofit-style 4-2-1 Scavenger Series. I built several sets of headers for the car, used standard 4 into one and merge type collectors. 512 wedge NSS type car. There is a program called pipemax that allows you to size your headers correctly, and give you lengths for step headers as well. http://www.maxracesoftware.com/
It also has a pretty good engine output estimator in the program as well.


I've used that program for YEARS
wave







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