Header design, merge collectors?
#2998837
12/27/21 12:57 PM
12/27/21 12:57 PM
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Joined: Jan 2003
Posts: 9,986 Frostbitefalls MN (Rocky&Bullw...
gregsdart
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Well, pipemax gave me dimensions, with input of 6200 stall , Max hp 7400 shift 7500. 550 cubic inch, 1,000 to 1,025 hp, 2900 lb car and driver. 2.08 1st step, 2.18 second step. 14 inch each, from the valve head. I am considering merge collectors. Would like input on merge collectors and a good source for everything. It has Been a while since I have built a set. The 2 1/8 set I built in 1997, but they are showing their age. I am hoping there is power to be had in 2 step plus merge collecters, which I don, t have now.
Last edited by gregsdart; 12/27/21 01:00 PM.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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Re: Header design, merge collectors?
[Re: 440Jim]
#2998871
12/27/21 02:28 PM
12/27/21 02:28 PM
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Joined: Dec 2005
Posts: 11,531 Fulton County, PA
CMcAllister
Mr. Helpful
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Mr. Helpful
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Fulton County, PA
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I just finished a stainless set for a combo similar to yours. LIghter car, little milder engine. Same CID and RPM.
We used 16 ga. 2 1/8" primaries 30" long, with a 3 1/2 to 4" merge collector. Looking to help out a flat torque curve on a .90 car that goes in high gear on the stop.
Talk to Rich at Cone Engineering. Parts to build any configuration collector you want. Perfect, fabricated parts. No stamped out stuff. He can offer advice. Merge collectors very close to performance of a 100% fabricated part at a fraction of the price. Tell him I sent you.
Burns is top shelf stuff if you want to go there and have the budget. Would never recommend against them.
Last edited by CMcAllister; 12/27/21 02:30 PM.
If the results don't match the theory, change the theory.
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Re: Header design, merge collectors?
[Re: CMcAllister]
#2998878
12/27/21 02:41 PM
12/27/21 02:41 PM
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Joined: Jan 2003
Posts: 19,361 Las Vegas
Al_Alguire
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IMO talk to the guys at SPD. They are the best out there and know their stuff. I can tell you what I have done over the years on my stuff and my experiences, but all I will say is MOST Mopar guys have stuff thats WAY to big on their combos.
"I am not ashamed to confess I am ignorant of what I do not know."
"It's never wrong to do the right thing"
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Re: Header design, merge collectors?
[Re: Al_Alguire]
#2998895
12/27/21 03:16 PM
12/27/21 03:16 PM
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Joined: Jan 2003
Posts: 30,998 Oregon
AndyF
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I Win
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Oregon
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IMO talk to the guys at SPD. They are the best out there and know their stuff. I can tell you what I have done over the years on my stuff and my experiences, but all I will say is MOST Mopar guys have stuff thats WAY to big on their combos. I would agree with that. Calvin Elston has written a bunch on that topic. He recommends matching the tube to the exhaust port unless you have a really good reason to do otherwise. In the Mopar world it can be hard to do since the ports are usually rectangular rather than a circle.
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Re: Header design, merge collectors?
[Re: AndyF]
#2998934
12/27/21 04:39 PM
12/27/21 04:39 PM
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Joined: Jan 2003
Posts: 9,986 Frostbitefalls MN (Rocky&Bullw...
gregsdart
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My best pull was with the shops dyno headers, 2 1/4 primarys and if i recall a bit long. My 2 1/8 x 30 were down about 7 hp up top rpm. If I do ever get a set of 572/13 heads, my goal will be 1,000 to 1,025 hp. So I hope 2 1/8 to 2 1/4 step headers will be best, and what ever collecter is going to pull best in the mid range or overall. I am running a Torqueflite 2.45 low 1.45 second gears, 4.56 rear with 33 inch tall slicks. mph should be about 158, at 2900 lbs.Thanks for the input . A few calls are in order, along with taking stock of any more comments.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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Re: Header design, merge collectors?
[Re: Al_Alguire]
#2998939
12/27/21 05:02 PM
12/27/21 05:02 PM
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Joined: Dec 2005
Posts: 11,531 Fulton County, PA
CMcAllister
Mr. Helpful
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Mr. Helpful
Joined: Dec 2005
Posts: 11,531
Fulton County, PA
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IMO talk to the guys at SPD. They are the best out there and know their stuff. I can tell you what I have done over the years on my stuff and my experiences, but all I will say is MOST Mopar guys have stuff thats WAY to big on their combos. I thought about 2" on the ones we just did for this 555. Opted for 2.125. Never even considered 2.250.
If the results don't match the theory, change the theory.
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Re: Header design, merge collectors?
[Re: CMcAllister]
#2998942
12/27/21 05:12 PM
12/27/21 05:12 PM
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Joined: Dec 2005
Posts: 11,531 Fulton County, PA
CMcAllister
Mr. Helpful
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Mr. Helpful
Joined: Dec 2005
Posts: 11,531
Fulton County, PA
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Headers are such a black art. I'm not sure anyone truly completely understands what is going on inside of them when the engine is running. If the engine operated at the same RPM, under the same conditions, all the time, it would be easier. But it really is a compromise. Change one thing in the combo, and it all goes out the window.
No substitute for years of experience, trial and error, and data - especially if you're after that last couple of horsepower. I never try to second guess guys who have it.
If the results don't match the theory, change the theory.
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Re: Header design, merge collectors?
[Re: gregsdart]
#2998956
12/27/21 05:51 PM
12/27/21 05:51 PM
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Joined: Jan 2003
Posts: 16,923 NC
440Jim
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My best pull was with the shops dyno headers, 2 1/4 primarys and if i recall a bit long. My 2 1/8 x 30 were down about 7 hp up top rpm. ... If I do ever get a set of 572/13 heads, my goal will be 1,000 to 1,025 hp. So I hope 2 1/8 to 2 1/4 step headers will be best, and what ever collecter is going to pull best in the mid range or overall. I like the way you are thinking. Even if the stepped headers ended up down 5 hp at peak, if they gain enough at the converter speed (shift recovery) they may ET better.
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Re: Header design, merge collectors?
[Re: 440Jim]
#2998977
12/27/21 06:57 PM
12/27/21 06:57 PM
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Joined: Jan 2003
Posts: 9,986 Frostbitefalls MN (Rocky&Bullw...
gregsdart
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My best pull was with the shops dyno headers, 2 1/4 primarys and if i recall a bit long. My 2 1/8 x 30 were down about 7 hp up top rpm. ... If I do ever get a set of 572/13 heads, my goal will be 1,000 to 1,025 hp. So I hope 2 1/8 to 2 1/4 step headers will be best, and what ever collecter is going to pull best in the mid range or overall. I like the way you are thinking. Even if the stepped headers ended up down 5 hp at peak, if they gain enough at the converter speed (shift recovery) they may ET better. I agree. Five hp at the start of each gear is probably worth ten up top.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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Re: Header design, merge collectors?
[Re: gregsdart]
#2999028
12/27/21 09:35 PM
12/27/21 09:35 PM
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Joined: Aug 2003
Posts: 43,127 Bend,OR USA
Cab_Burge
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I Win
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Bend,OR USA
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I saw the same results on the first motor I dyno tested, it was a pump gas M.W. motor with the stock X ram and small 1962 and 1963 Carbs. We started off the testing using a set of the old Hooker BB A body 1 7/8 inch primary pipes with 3.5 inch collectors, we did jetting, ignition timing and valve lash testing and peak RPM testing for both torque and HP. This motor was the first BB Mopar that shop (Pettis Performance) had tested with their then new DTS engine dyno. The owner made up a set of Dyno headers that had 2 1/4 primary (O.D.) I think with 25 inch long pipes and a 4.0 inch collectors and we swapped them onto that motor with no other changes and it made more HP and Torque all the way from 2500 RPM to 6500 RPM That shocked all of us, we all thought it would hurt the bottom end and help the top end, WRONG All the BB Mopars I've tested and raced liked bigger exhaust , just like adding more air into the motors with more fuel Test, test and test some more to go faster and quicker
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Header design, merge collectors?
[Re: Cab_Burge]
#2999040
12/27/21 10:11 PM
12/27/21 10:11 PM
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Joined: Jan 2003
Posts: 16,923 NC
440Jim
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I Live Here
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I saw the same results on the first motor I dyno tested, it was a pump gas M.W. motor with the stock X ram and small 1962 and 1963 Carbs. We started off the testing using a set of the old Hooker BB A body 1 7/8 inch primary pipes with 3.5 inch collectors, As I recall, those Hooker A-body headers were so freakin long they never made good peak HP numbers. They were designed for a small 383 CID to help the torque moving a less than light A-body of that time.
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Re: Header design, merge collectors?
[Re: sr4440]
#2999587
12/29/21 04:43 PM
12/29/21 04:43 PM
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Joined: Jan 2003
Posts: 9,986 Frostbitefalls MN (Rocky&Bullw...
gregsdart
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Just got off the phone with Cone eng, parts on the way. Also Jericho GTX has a set of individual cylinder flanges with stubs, which I have my name on. The fact that I can build the headers and leave two or three tubes bolted up while I work ought to help welding time a bunch. R The plan is ;. 10 inch 1st step of 2 1/8 16 Ga, 14 inch 2 1/4 for second step, over all 10 inch of collector with a 3 1/2 inch merge, to 3 to 4 inch cone. Joe, what was "interesting" about the results?
Last edited by gregsdart; 12/29/21 04:44 PM.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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Re: Header design, merge collectors?
[Re: gregsdart]
#2999771
12/30/21 01:26 AM
12/30/21 01:26 AM
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Joined: Feb 2008
Posts: 714 Central TEXAS!!!!
sr4440
super stock
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super stock
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Central TEXAS!!!!
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Just got off the phone with Cone eng, parts on the way. Also Jericho GTX has a set of individual cylinder flanges with stubs, which I have my name on. The fact that I can build the headers and leave two or three tubes bolted up while I work ought to help welding time a bunch. R The plan is ;. 10 inch 1st step of 2 1/8 16 Ga, 14 inch 2 1/4 for second step, over all 10 inch of collector with a 3 1/2 inch merge, to 3 to 4 inch cone. Joe, what was "interesting" about the results? I switch from a regular 2.25 26in header to a 12in 1st step 2.125 and a 2nd 12 inch 2.25 with a 3 1/2 inch merge, to 3 to 4 inch cone. When I put the merge headers on an B1 MFI 512, the engine went dead lean. The fuel pressure was the same, the engine was just moving a lot more air or pulling the initial fuel through the cylinder. I ended up putting more fuel in it to get back the HP. Went from a .920 BSFC to 1.105 BSFC to make the same power. The cam was a 282 292 with a 112 LSA. So I ordered a new cam 282 284 112 LSA. The new came didn't make any more HP, but it did make about 20ft more torque, up to peak TQ. Has a super flat curve. LOL I wasn't expecting results like that considering how small the exhaust valve is on a b1 head. One more thing, SPD (I think) recommends that the header tubes be arranged so the firing order goes in a circle when entering the collector. Joe PS those flanges are NICE, does Jeff make them?
Last edited by sr4440; 12/30/21 01:42 AM.
Without Data, you’re just another guy with an opinion.
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Re: Header design, merge collectors?
[Re: sr4440]
#2999790
12/30/21 07:30 AM
12/30/21 07:30 AM
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Joined: Jan 2003
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gregsdart
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Jeff doesn't make them. Not sure who does. Your results were interesting all right. They back up what Rick at Come talked about. Extra torque where it does the most good . Also i Iike what happened with your cam needs. 572/13 heads have a huge exhaust valve at 1.88. my current cam is 284/296/113 and . 878 int lift.,. 796 ex lift. Less than Indy's 285/305/112(?) Recommendation.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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