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Zoomies vs collector headers

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Roger:
In a current thread there’s been a conversation about collector headers and zoomies on FEDs. I agree with most, zoomies belong on FEDs and I think they also belong on altereds. With that said, has anyone out there done an actual comparison between the two? I’ve been studying, or trying to, the difference in performance between the two. The only actual dyno test information I’ve been able to find is one conducted by Joe Sherman in which he stated “have seen as much as 55 or 56 HP (less) on a 1000 HP engine“ compared with collector headers. Now zoomies won’t have the inertial scavenging of a correct length and diameter pipe (roughly 28” to 34” long) because they are to short and it won’t have the wave scavenging of the collector because there’s no collector to share the wave with other cylinders. But what a set of zoomies have working for them while hanging out in the breeze at 180mph is the Bernoulli principle effect on drawing exhaust out of the cylinder. That’s the same effect that draws fuel out of a carburetor bowl and draws a crankcase vacuum with a pan-evac system. Any comparative tests out there of zoomies vs headers or any thoughts?

dreracecar:
7 seconds is not enough time to worry about scavanging
On a blown car the collector outlet area is restrictive vs open pipes
For what I have seen, the dyno shop has headers set up to use in their room with all the hook-ups, and there might be a difference between those and the headers that fit the vehical, also consider that open zoomies in the dyno room without someway of collecting the exhaust, contaminate the air in the room, which hurts performance.
NASCAR teams spend $100,000's on header designs and dyno testing because the runs are longer and take advantage of every  single 1 hp gain, If they change cams, it might also need a header swap. We on the other hand are happy if they just fit right off the shelf

coupemerc:
I know that Bill (masracingtd1167) has run his FED with both header types. His engine is a normally aspirated SBC on methanol. It used to be quicker with the 4 into 1 collector headers but recently he made some changes to the car and ran his best et ever. I think he had the zoomies on it. Maybe Bill will chime in on this thread.
I agree with what Sherman said. Recently I went to the dyno with my injected, methanol SBC. I run zoomies on the car and I did not want the scavenging effect of collector headers to give me bogus (higher) dyno numbers. I ended up using custom dyno headers that are basically 12" long zoomies that dump into an 8 inch "log". They were more representative to what I run on the car. The idea came from Scott Parks.

masracingtd1167:
I can't honestly say witch one is quicker ! I have been using a collector header on my cars for a long time and we always ran quicker with them ! When I built the zoomie headers for my current car my plan was to slow the car down for 7.50 racing and I did not notice much difference in performance at all ! Back when we started running the collector headers we were also running on gasoline and the headers were worth a solid tenth !I think the only way to really tell the difference is with an a to b to a test . Also about 10 lbs lighter with the zoomie header . This picture is from the early seventies   

JrFuel Hayden:
My experience with dragster pipes has been it depends on the fuel, head flow, and RPM. When we were running a non-raised runner 23° Iron SBC, we used 1 5/8 pipe zoomies, on alky, then as we started running raised runner heads, we increased the pipe size 1 3/4, then 1 7/8, then 2" and now with the bigger cam, and 10,000 RPM, we have 2 1/8" zoomies.
On my 1'st 1962 dragster, C/D on gas we tried different pipes based on formulas , we didn't learn enough, since it broke allot and only race it a year. Next dragster I ran for 5 years [63-68] it was a real nitro JrFueler, again we tried long pipes, short pipes, different pipe sizes, For us none of the formula pipes seemed to make a difference burning nitro. I ended up with just about 8" zoomies, because they were just lighter, and out of the way to work on the valves, etc.  The other thing is we always aimed the traditional zoomies back toward the slicks. Remember the big deal on the funny cars zoomie angles last year, action/ reaction, helps moves the car forward. I had a B/ND motor in a car and I put my angled zoomies on it and took the mostly upright zoomies off. The car picked up MPH.
I don't know any team that has found any improvement while burning injected alky. I know of one team that runs collectors on his injected alky, and he said he just picked 4-1 because he just wanted to look different and he runs the 7.60 class, and not looking for max performance. 
Good Luck
Jon

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