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Discussion Starter #1
Has anybody ever tried a set of merge collectors before and after to see what power or E.T.difference it really makes? I built a set of regular collector headers with 2 3/8 to 2 1/2 w/5''collectors and I've seem to have lost some E.T.(mostly 60 ft) from when I had the 2 1/4'' straight tubes w/4 1/2'' collectors! Would merge collectors bring
up the torque?
 

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Has anybody ever tried a set of merge collectors before and after to see what power or E.T.difference it really makes? I built a set of regular collector headers with 2 3/8 to 2 1/2 w/5''collectors and I've seem to have lost some E.T.(mostly 60 ft) from when I had the 2 1/4'' straight tubes w/4 1/2'' collectors! Would merge collectors bring
up the torque?
Take a close look at some NHRA pstk comp or aussie psk headers...also some "low-buck" sportsman racers like most of us usually have a well designed set of headers from flange to exit.
My only pointer based on my experience is to favor the small side on primaries and choke, than to have everything too big and the result is what your running into..
 

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Discussion Starter #3 (Edited)
Would putting Merge Collectors on help or hurt ? Are they worth the money? Has Anybody ever dyno'ed a engine without and with Merge collectors ?
 

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Discussion Starter #6
I'm hoping someone with a dyno will give us a clear answer ! I know somebody out there has got to have done testing with & without !!
 

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Call Tim @ The Fab Shop he can tell you more about headers than you ever wanted to know. There has been extensive testing done on collectors. His first word will be why did you build such a big set of pipes!!!
 

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why did you build such a big set of pipes!!!
i dont think the merge will do what you are wanting with the torque.

pipe max program works great on building headers if you was starting a new set to get what size and length's needed, thats what i use to build mine
 

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According to my builder, we lost 7 hp with merge collectors. Love the headers though, and have lots of torque.
 

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http://www.perfweldheaders.com/compmerg.html

Take a look at what these folks have to say. I know that all Nascar teams were running 4 into 1 merge collectors and have now switched to 4-2-1 tri-y merge collectors. I am sure specific applications require maybe one or the other but these guys are also building tri-y's for drag applications. I would think your gains would be minimal at best but if they increase your average power (over a broad spectrum) they might be worth a look. They are expensive...
 

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you went from 2-1/4" headers to 2-3/8 t o2-1/2 step headers. unless you are going to spray it, those are to large. that is prob why you killed power. if you dont have a merge collector, then that might help. maybe even doing something little smaller in merge like a 4" or 4-1/2" merge collector
 

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Racers frequently build their headers with tubes and collectors that are too large. A real sharp engine guy from Kansas told a friend of mine that a 4.5" collector was better than a 5" one.
 

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I have'nt used the merge collectors ,but have tried 4.5" and 5" collectors on a dyno with the same size tubes you have . I lost almost 95hp with the 5" collector vs the 4.5". If your going to us a lot of nitrous ,i would use the 5" for >400 shot.
 
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