squealingtires

iTrader: (14)

I'd like to start a discussion on merge collectors. I've compiled the basic designs that have distinguishable differences. Take a minute to take note of the differences. I would like this discussion to be directed towards design aspects rather than who made what and what your Mama heard. Let me now introduce the contestants from each's corner.

Corner #1: Kooks Standard Collector (older design)


Corner #2: Kooks Stamped Merge Collector (new design)


Corner #3: QTP High Velocity Merge Collector(HVMC)


Corner #4: American Racing Headers Merge Style Collector


Here are the topics that I would like covered at any time and in any order since they are all related to each other.
Round #1: Scavenging
Round #2: Higher RPM Flow
Round #3: Lower RPM Flow
Round #4: Sound
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The Alchemist

iTrader: (19)

I don't have much to add other than to add another contender, the new LPP header.

squealingtires

iTrader: (14)

That one seems very similar to the ARH merge collector. Notice how the collector is formed around the primaries and then necks down before opening back up to the outlet diameter. What do you feel makes the LPP style different?

1989GTA

Couple of thoughts.

When Joe Sherman was building his motor for the Engine Masters competition he tried all the long tube headers in Hedmans lineup. There was not 5hp difference between them.

That being said the there is probably an ideal motor for each of those headers. Put them on another motor and the results may be different.

You did not show the inside of the headers where the pipes merge. I assume they all have a cone?

2000_SS

iTrader: (24)

well i have the new style Kooks, although nothing to *really compare them to...plus my motor isn't done yet ...

but all of those designs are great. none of them will yield any more than 1-3hp difference, ALL OTHER THINGS BEING EQUAL.

if i had to bet money, i would say you might see a little more power from the ARH's or QTP's because they have a choke right before the collector. that will add some velocity to the exhaust gas and get them out quicker. all of those headers have decent merge areas where the primary tubes meet, my Kooks have a spike and i think at least the QTP's and ARH's do too...i think...

the QTP's look like they actually merge exhaust from the primaries into the collector a little better as they meet at an angle, providing a smoother transition into the choke. the other headers' primaries all stop along the same plane, with a spike in the middle, then the choke.

..just my .02

fatdave

iTrader: (6)

ARH all the way

ScottyRocket

You would see more differences in changing primary length and diameter that you will in just those collector designs.

The Alchemist

iTrader: (19)

You're right, I guess it isn't so much different as it is another option if you're looking for a good collector on a header.

xfactor_pitbulls

iTrader: (16)

I am very impressed with the ARH much more than the QTPs. Had both and the ARs in a 1 7/8 fit MUCH better than the 1 3/4 qtps. From an internal POV on the collector, the fit and finish is similar. I would have liked the AR headers even more if they werent welded out mostly with wire.

smok'nZ

iTrader: (160)

someone find the grots i cant spell the full name

squealingtires

iTrader: (14)

"GROTEYOHAN" but I can't find them

Gary Z

My understanding is that Groteyohann first developed the layout for the equal-length, long tube, F-body headers that has become generic. If you have QTP, Kooks, ... etc, you have Grots.

Sammyboy

iTrader: (9)

QTP for ME!!!

Tuner@Straightline

I went with the Kooks 1 7/8's on my recent build (new designe) with their off road pipe. I can't complain about the performance, fit, finish, quality, or sound. It's especially nice to have a spare bung in the collector for the wideband as well. Plus their Y-Pipe fitment is terrific.

blueflamespl

iTrader: (13)

I recently had my l92-402 on a superflow 902 engine dyno, at the start on the tuning session we used the shops dyno headers which I believe where 1.75 to 1.875 stepped "sprint car style" headers... very straight and efficient. Half way through the session we switched to my 1.875 ARH headers, the torque and VE went up significantly at the lower RPM and matched the dyno headers up top. On a 4k to 6.7k pull the VE started at 104% peaked at 114.4% (at peak tq of course) and was still 105.4% @6700 when we shut her down. Very pleased with the ARH headers... Fitment is excellent!

Haans249

iTrader: (24)

What intake are you running? Looks like your flow is getting lopped off at around 5800 rpms, you should be seeing 600+ fwhp.

camarojunky74

iTrader: (14)

i got some grots at home, do you guys want me to snap a few pics of the collectors and post them?

blueflamespl

iTrader: (13)

I am running a stock untouched L76 intake, I look at it this way it is making good AVERAGE horsepower that the last 1500 rpm of the pull. It will be interesting to see how it runs at the strip, If I shift it at 7k it should run pretty hard. It also has"only" a 234/244 XE cam, I kept the lobes pretty conservative to help longevity. The build is geared towards the street.

wannasupra

if that's true, there's something seriously wrong with his car.

flyinZ

iTrader: (15)

My Dynatech's have merge collectors too.