Anyone out there using these 4-2-1 collectors and are they worth any power/torque increase as the ad says. I picked a pair up cheap at a meet during the summer and want to know if it would be worth my while fitting them into my headers/exhaust. Motor is typical 500hp recipe running good iron heads and 2'' TA headers. Thanks in advance,
Surprised none of you guys have tried these. Would have thought just their extra volume would have yeilded a small improvement. Just guess I'm gonna have to try them and report my findings, before and after. Although this may take a while.......still building my car.
I saw a dyno test on them by ( I think) Rob C. From what I remember , they didn't do anything but boost the mid-range slightly and take a way a few numbers from the peak and upper HP numbers. To optimize the scavangers, the primary pipe needs to be shortened and the pipes need to be pair together properly. It's worth a try, but the idea works better on a custom 4-2-1 header. I personally like the merge collectors better for a little HP pickup on a existing 4-1 collector setups.
Thanks for the replay Rick. The torque increase may be good for my set-up. I'll do a little more gas-flow research before taking a saw to my headers.
If I recall correctly Tom Rix didn't get much to nothing out of them on the dyno. Properly sized merge collectors are probably the only way to go.
Hi Jeff, It's quite amazing how much weight two words carry. But if the 'The Man' didn't get much from them that's good enough for me. Sounds like I'd better do that gas flow research and size those collectors best for my application. Thanks,:Smarty:
Merge collectors help if your headers are a little big for your combo like your 500hp 2" primary header.I'm running around 600 +hp w 1-7/8 primaries which is a bit small so i would not use them.
Thanks for the pointer. Merge collectors it will be. BTW, That is one nice car you have. That all on the motor?
Ian, Tried to find all my dyno sheets from some extensive dyno work we did about 4 years ago. Tried on 530 HP small valve low compression 455 Super Stock motor, 600 HP iron head Stage 2 and 650+ HP aluminum Stage 2 Top Stock motors. Headers on Stage 2 were 2 1/8" and on small valve iron head they were a custom set of stepped headers, 1 7/8" into 2" into 2 1/8". Results were close to same on all combinations. The 4-2-1 picked up Hp and torque below 4800 rpm but lost it and more above that rpm versus stock collectors. Part of the issue was that you couldn't "pair" the correct 2 cylinders on one side. The Hooker merge collectors with tapered point in collector was worth a couple of HP all the way to 6500 rpm. Tried several sets of the true "necked down" merge collectors and both were worth 15+ HP through the whole power band. The set that merges four 2 1/8" pipes down to one 2 3/4" pipe and megaphone was best. Cost was +$550/pair but first time in my racing career that the true performance of a purchase EXCEEDED my expectations. Best bolt on part I ever tested, including carb spacers. These were all open exhaust comparisons so not sure how they would be on a muffled car. Might try that next. Tom
Hi Tom, Thanks for taking time to reply. With the Flowmasters, my concern was the firing order link up, and with a production Buick header it was not going to happen. The pairing of the pipes is wrong. From your information, sounds as though I'm gonna have to get me some of these merge collectors. Originally built my exhaust with more power in mind,.....2" primaries into 3.5" collectors and on into X-pipe and then down to 3" for mufflers and tailpipes. Amazing how much money building, preping and painting a body can take! Thanks again, can you recall the manufacturer of your collectors? If I could get some specs, could probably fabricate some.:TU:
Is anyone familiar with headerdesigns.com or had any experience with their design program? Was wondering how close they are to actual operating systems. Jay
Yep Tom, that's me! Rusty & I haven't run since the late 90's - ended up destroying a couple of short blocks due to a defective high-end torque convertor (too much oil in-not enough out!) and on that problem correction, we dropped a valve destroying yet another engine including a head this time so the old white car languishes in the barn until finances allow a complete new engine but for now I'm really enjoy spending other guy's money! Jay
