merge collectors

[hoffman900]

Funny how the tight merge has all of a sudden loosened up at the choke area as the years continue.

Why are you digging your heals in the mud? As far as people on this site go, Clint probably has the best data on this outside of Elston.

Can you provide examples of this, what changes in choke size (and at what power levels)? If there has been a change, it's probably because they're making more power than they were as R&D has continued

[tenxal]

Funny how the tight merge has all of a sudden loosened up at the choke area as the years continue.

A look at what current Comp Eliminator cars are running will show otherwise. In fact, many are now using a reducing 'cone' at the end of the collector.

Collectors...any style of collectors...are simply another piece to tune with. -tenxal

[hoffman900]

Funny how the tight merge has all of a sudden loosened up at the choke area as the years continue.

A look at what current Comp Eliminator cars are running will show otherwise. In fact, many are now using a reducing 'cone' at the end of the collector.

Collectors...any style of collectors...are simply another piece to tune with. -tenxal

Rich Houser's SS/AH car. Most of the other cars are running something similar (some without the reverse cone, some with).

[nitro2]

Most of what I build are what I call the street racer type.. What I try to advise most guys is to spend the money on things that give the most bang for the buck. This has been my basic idea all my life.. So many guys WASTE money on things that have VERY LITTLE affect on making MORE HP.


JOE SHERMAN RACING.

That's good sensible advice for street racers, though many will fight it However, taking the most "bang for the buck" literally would mean steering clear of NA V8s . People will tend to do whatever it is that interests them.

[englertracing]

To everyone who disagrees with merges
Are we talking about cross plane crank engines?
Or flat plane crank engines ?

[900HP]

Biggest eye opener for me was when Calvin asked me, "only one cylinder fires at a time, why do people insist on running such large collectors?"

One the Comp headers pictured above, those headers have interchangeable chokes so they can change out chokes quickly as a tuning aid.

[900HP]

[quote="Strange Magic"] It happens all the time, and it happens because many are so oblivious to the average and how to read the average. quote]

LOL. What do you think 4-2-1 headers and merge collectors are all about? It's all about making more AVERAGE power, not necessarily more PEAK power.

[Strange Magic]

A look at what current Comp Eliminator cars are running will show otherwise. In fact, many are now using a reducing 'cone' at the end of the collector.

Case in point and this right here is the problem. As I mention time and time again, it is a monkey see monkey do. Comp eliminator is a strict rule book class, of which 90 percent of comp are small inch engine with large manifolds and very large carbs. Many are also backed with 8 to 12k transmissions with multiple gears so they can run within a 450-650 rpm range the whole way down the race track. Comp eliminator represents less than 0.5 percent of the actual drag race vehicles that actually participate week in and week out, and that is a over estimated percentage that I just gave. There are little to no sportman classes whereas you will see an engine that is 265-292 inches, or even 305 inches or even 338 inches. Your average engine now is 582 and greater. You know it and I know it. 6 years ago the average engine was 565 inches. You think your really going to find a comp car that pulls to the line with 565 inches. Even A/D or A/A is not that much cubic inches. Monkey see monkey do. everyone is looking at a select few that go fast.

LOL. What do you think 4-2-1 headers and merge collectors are all about? It's all about making more AVERAGE power, not necessarily more PEAK power.

Go put a one of those on a 598 or 632 that makes 1275hp and let me know how you make out. That is your average engine now. they run 6.95 to 7.05 in a 1980 to 2050 pound dragster.

This is your average deal pictured below. It's 26 degree, 548 (4.6 x 4.125). cast manifold, single 1150 carb, brodix heads, bow tie block, 4 link dragster. I've tested lots of headers and different collectors as well. The initial primary's where between 25.5 to 27.0. The can is a scavenge. I increased the primary length by a net of 3.5 and the gains where pretty substaintal. The 60ft's went from 1.038-1.041 to a 1.017-1.021. The increased length of your typical produced header was not enough, and I have been working with increased primary's since the 80's, and all have significantly helped broaden that torque curve. The header company's never issues enough primary, and they do not because they don't build engines and what's most important is that they don't test really enough down the race track. I have had merges on as well on 548 to 640 inch stuff and I keep going back to the scavange with increased primary, or shall we say the correct primary length.

[Warp Speed]

[Strange Magic]

Come take a test. Put your money where your mouth is. Show up with a 565, 582, 598 or 632 and we'll test right down the race track with headers. Longer primary's with a scavenge vs any fuckin thing you desire with a merge. Do not show up with an engine that is not your average application that gets bracket raced.

Whats a test without a wager? Show up with a G.

Not interested in an engine that is a minority, meaning a 315 inch with a sheet metal manifold in a body car, because that shyt your not going to find on an average weekend.

[piston guy]

Strange Magic
Old picture? ( No wing)

I have to agree with you that the race track is not as smart as the dyno! I saw several times with a C/ED where more dyno power went down the track SLOWER. Comp is certainly monkey see, monkey do . Upswept headers, down headers, scoops, spacers, 302ci ,305,310 ci , two speeds, three speeds etc. ET slips hardly changed from the rock soild base line combination. Just more money wasted. Now days they don't even get a full field unless it's Indy.
Bracket racing for me now.

[dirtracr5]

It's really a tale of 2 worlds. Petty basic stuff gets you by in bracket/street racing. In my world of circle track (especially 2bbl stuff) you need to really be on the ball to make good power and win races.

I built a bracket 406 for a guy this past winter. Did well on the dyno but was kinda boring for me. If it had make 40 more or less hp the guy didnt really care. Just needs to be consistent. Kinda lame IMO.

To me it's fun trying to get the most out of a given rules package. Seeing what works and what doesn't on the dyno and on the track.

[dirtracr5]

Show up with a G.

I assume you are an "older" gentleman?

[CREngines]

All of my experience has been bad. On several occasions a jet boat racer has come to test headers on my dyno . He always brings several sets of Burns headers/collectors. They never show any gains- this is the same Burns guy who sells these very high dollar merge collectors. So far, no good. I still get emails and phone calls about them though


JOE SHERMAN RACING

Joe,

Calvin Elston told you a couple years ago that the merge collectors allow you to run shorter primaries, while still protecting the bottom end some, thus allowing you to make more power. He said in the same post adding them to an existing header and doing nothing else will probably hurt the top end.

When I get a moment, I'll dig up the thread and post.

Why dont we talk about measuring something other then what is currently being measured. I have a question for Mr. Elston, Mr. Meaux or anyone that has some input. Concerning the merge collectors, if they work better with a shorter primary, how much shorter? If we have X Engine that has the 3rd harmonic at 29 inches, and 4th harmonic at 20 inches. Are we talking about setting up that header with the merge to tune at 20 inches? Or are we talking about shortening that 29 inches up until it is 29 inches from header flange to the choke in the merge? The primaries have more length with the merge then a standard collector. Now if we are running this X engine what happens when we bump it to the next size diameter primary and retain the tuned length that the merge works with?

[buddy rawls]

the ability of a choke point on the exhaust (or intake for that matter) to show gains or losses is critically related to the engines flow parameters (qualities and quantity), as complete systems, valve events, and displaced volumetric flow of the cylinder.

a restriction at the collector might show gains in situations where the motor had too much exhaust valve activity for the flow parameters and rpm region, where as a motor with reduced and delayed exhaust activity (relative to the inlet needs) may show losses.


Its a testing and experimentation situation that is related specifically to the engine combination that it is being tested on. global assumptions concerning flow increases or decreases or nozzle or venturi-type on the outlet side of the cylinder are not going to be a rule of thumb. they may be touted as that, but they arent. There is simply too many other key pieces in the puzzle to 'globally' hang gains or losses on a collector design.

Nearly everytime I have seen them show gains, a quick reverse engineering of the engine combination and valve events indicated the motor had too much exhaust activity and were looking for a little restriction on the exhaust side to recoup the proper flow relationship.