mr gtx
Active Member
what i recall is the guy that did the test was going to put headers on his car and sell the HP manifolds to his friend but after the test his friend didn't want them lol
Max wedge vs HP manifolds vs Headers Test!!
- Thread starter 69monaco
- Start date
mr gtx
Active Member
believe what you want. just trying to save some guys time and money chasing HP manifolds like i use to do. for one or two HP that it said as i recall.
A lot depends on level of build vs stock HP, $, cu inches, etc.
Also I haven’t seen a build showing a comparison of stock HP, then various mods for performance gains, where all 3 are tested apples to apples, I.e. log, HP manifolds, the headers where everything is exactly equalized to max efficiency (jet and timing changes) and tested throughout.
Normally they either take a really hot 440 and test all on the heavily modified or stroked engine running higher RPMs
OR
Start making mods then quickly stop testing log or magnum manifolds almost immediately.
In the later a non drag racer can’t tell how much he’s giving up at any given power level, and if he could he may well be okay with giving up some and build to a happy median for best magnum manifold engine for a nice street cruiser.
I agree to each his own but I haven’t seen an apples to apples comparison that showed that 2 HP for example on a stock HP engine in the same test/conditions.
Probably will give it to you that magnum manifolds won’t gain much over logs on a purely stock NON HP 383, 400, or 440 with no other changes.
mr gtx
Active Member
i will find what i read when i have time. it was apples to apples. do you think i made it up about the test and the tester selling them to his friend.
Thanks
mr gtx
Active Member
it had to be the same article i posted that the guy read
Okay I couldn’t find it from that screenshot
And I’m pretty sure I’ve read their work and seen a video shootout with him and what’s his name from roadkill.
And wasn’t convinced
And I’m pretty sure I’ve read their work and seen a video shootout with him and what’s his name from roadkill.
And wasn’t convinced
Well . . . when you get past the multiple layers of head shielding on the Chevy 5.7L LT1 motor in the 1990s Caprices and Buick Roadmasters it came in, you'll find cast iron exhaust manifolds that look like "Honey! I shrunk the Chrysler 383/440 HP exhaust manifolds" under there. When I saw those, I laughed at GM (once again!) copying something that Chrysler did. Anything to make an internal combustion engine a better "air pump" will result in more power out of the engine, no matter the compression ratio. Might not be a massinve increase, but an increase over the log style factory manifolds.
Understand that GM could have designed any kind of exhaust manifold for that LT1 V-8 of the 1990s. The fact that they used a design very similar to what Chrysler used on the B/RB HP engines no doubt helped those motors attain the iconic level they did.
Enjoy!
CBODY67
Understand that GM could have designed any kind of exhaust manifold for that LT1 V-8 of the 1990s. The fact that they used a design very similar to what Chrysler used on the B/RB HP engines no doubt helped those motors attain the iconic level they did.
Enjoy!
CBODY67
mr gtx
Active Member
this is not the same dyno test that i read, still looking.
Can you post the link/url to the pages instead of pictures please?
Dyno testing a stock(?) 1972 440
It’s a test IQ52 did in 2013. There’s a thread here about it too, as well as FBBO.
It’s a test IQ52 did in 2013. There’s a thread here about it too, as well as FBBO.
He's awesome for sharing his findings, I love the RV 440 build he did, over 500hp with a low compression engine. Showed every change on the Dyno, very cool.
I was thinking of that one earlier
70bigblockdodge
Old Man with a Hat
I believe if you ported a stock set of log manifolds and opened the outlet flange to the same diameter as the HP manifolds you would see no noticable gain with the HP manifolds.
Headers rule.
Headers rule.
mr gtx
Active Member
thanks for posting, 4 HP and 2 lbs more TQ.
mr gtx
Active Member
now can anyone post HP manifold dyno test showing a big increase in horsepower or torque? over the log manifolds.
Doubtful as I don’t think a full apples to apples test has been done on a full exhaust 440 HP engine with full exhaust has been done with both sets of manifolds.
Id be happy to see it if it has. Maybe Nick?
Id be happy to see it if it has. Maybe Nick?
70bigblockdodge
Old Man with a Hat
No, they still dump exhaust pulses into a common chamber from different directions, that is how to kill flow.
Think of a header like a water wheel in a old 1800s grinding mill. There is usually a long run of viaduct that takes the width of the creek and narrows it down increasing velocity while still maintaining original volume. Then it spills out in the same direction to fill the cups quickly while imparting the velocity of the water to the cups along with the weight of the water. Efficient.
A manifold is like putting the wheel in a the middle or maybe slightly biased to one side of a waterfall. Some water goes directly into the cups albeit at a slow speed, but allowing the water weight to move the wheel. The rest is splashing on the sides and on the back sides of the cups, in general not helping out at all.
So you say you do not want to move a wheel with your exhaust(turbo), fine. Getting your air all lined up and headed in the same direction to shoot down the exhaust pipes is efficient, blowing exhaust pulses at each other, letting them bang around till the eventually fine the way out is not efficient. Efficient equals power and fuel economy period at any engine speed or load.
Now I understand that packaging is attractive, but trying to justify manifolds over headers for anything but packaging is a waste of breath.
mr gtx
Active Member
i will be happy to sell you a c-body drivers side exhaust manifold i have laying around.lol
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