105 Headers Comparison/shootout! - Page 7 - Alfa Romeo Bulletin Board & Forums
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post #91 of 126 (permalink) Old 02-25-2019, 06:56 AM
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I thought the shankles were loud and you lost a little torque down low by the seat of the pants.

im not sure since it was never dynoed back to back with a stock 74 exhaust mani. it may be an illusion of losing low end just because the top end was noticeably stronger. from my experience top end motors dont feel as fast as they are and low end torquey motors feel fast though they might not be.


it wasnt as smooth as the stock mani since there was such a loud racket coming from the engine compartment. it was a worthwhile addition if one was looking for more performance and a lighter system. they used to be pretty affordable to just try out of curiosity
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post #92 of 126 (permalink) Old 02-25-2019, 07:12 AM
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I think unless you building a race engine the stock cast exhaust works well, the money can be spent elsewhere, IMHO ...that said,its whatever blows your hair back ...

The older I get.. the faster I was....
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post #93 of 126 (permalink) Old 02-25-2019, 08:04 AM
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...and now for something completely different, https://www.okp.de/xtc2/105/115-Bert...15::24362.html

Cars ruined my life! 😱
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post #94 of 126 (permalink) Old 02-25-2019, 08:18 AM
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Looks like an overpriced Spruell hybrid to me, as was previously posted converting from the single to 2 piece cast manifold is the most beneficial and cheapest way to get alot of bang for the buck. they are cheap, and as stated IMHO unless you have a screamer race engine and need the weight loss-a waste on the street.

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post #95 of 126 (permalink) Old 02-25-2019, 10:09 AM
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Looks like an overpriced Spruell hybrid to me
Those are some nice welds on stainless, though. It's very pretty.

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[...] as was previously posted converting from the single to 2 piece cast manifold is the most beneficial and cheapest way to get alot of bang for the buck. they are cheap, and as stated IMHO unless you have a screamer race engine and need the weight loss-a waste on the street.
Hold it! I am sure they are the value option, but this is the point where we could use some objective data, like, ya know, dyno results.

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post #96 of 126 (permalink) Old 02-25-2019, 11:25 AM
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Hold it! I am sure they are the value option, but this is the point where we could use some objective data, like, ya know, dyno results
.
Looks like a good project for someone who really wants an accurate number.
The drop in performance when Alfa switched to the one piece manifold and the dyno results published by Shankle for his headers points to a difference of about 10 HP.
That is also backed up by theory - length of header tubes, speed of sound in the pipes, rpm.

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post #97 of 126 (permalink) Old 02-25-2019, 11:57 AM
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My top secret header will increase power by up to 300% over stock.*






















*Important snail-like accessory not shown.
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post #98 of 126 (permalink) Old 02-25-2019, 12:31 PM
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The problem with objective data is it is rarely on YOUR motor. The best headers for you depends GREATLY on the exact specs of your motor and how you drive the car. Takes experimentation to get it right.

The stock (early) header is pretty good and doesn’t crack like a significant number of aftermarket ones.
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post #99 of 126 (permalink) Old 02-25-2019, 12:38 PM
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Looks like an overpriced Spruell hybrid to me, as was previously posted converting from the single to 2 piece cast manifold is the most beneficial and cheapest way to get alot of bang for the buck. they are cheap, and as stated IMHO unless you have a screamer race engine and need the weight loss-a waste on the street.

Good points, although I won't rule out the street-cred derived from a cool looking engine. In terms of effectiveness headers can offer incremental horsepower advantages. You may see some small benefit on a stock engine but where these kinds of incremental contributing factors come into play is when you are building a fully-built motor. With the right combinations of head-work, cams, high-comp pistons, ignition, carb mods, lightweight flywheel, balanced bottom end, etc., etc. you can build a very decent 160-170hp 2 liter Alfa Nord engine that will be a real blast to drive. It won't be a state-of-the-art race engine but you'll nonetheless have a very satisfying increase in hp that will nonetheless run quite happily on pump gas and return 21-22mpg.

Several years ago I think George Willet commented that slightly modified stock, cast-iron headers were entirely good---up to about 140-150hp when, along with other required mods, proper headers came into play. This seems about right to me.

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. . . still i get a kick at seeing all you BB'ers trying to get blood out of this stone :-)
Well, we're all lookin' for that secret sauce ingredient!

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post #100 of 126 (permalink) Old 02-25-2019, 12:41 PM
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Looks like a good project for someone who really wants an accurate number.
The drop in performance when Alfa switched to the one piece manifold and the dyno results published by Shankle for his headers points to a difference of about 10 HP.
That is also backed up by theory - length of header tubes, speed of sound in the pipes, rpm.
Hmmmm... Maybe I can do something about that

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post #101 of 126 (permalink) Old 02-25-2019, 01:02 PM
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Good points, although I won't rule out the street-cred derived from a cool looking engine. In terms of effectiveness headers can offer incremental horsepower advantages. You may see some small benefit on a stock engine but where these kinds of incremental contributing factors come into play is when you are building a fully-built motor. With the right combinations of head-work, cams, high-comp pistons, ignition, carb mods, lightweight flywheel, balanced bottom end, etc., etc. you can build a very decent 160-170hp 2 liter Alfa Nord engine that will be a real blast to drive. It won't be a state-of-the-art race engine but you'll nonetheless have a very satisfying increase in hp that will nonetheless run quite happily on pump gas and return 21-22mpg.

Several years ago I think George Willet commented that slightly modified stock, cast-iron headers were entirely good---up to about 140-150hp when, along with other required mods, proper headers came into play. This seems about right to me.

Well, we're all lookin' for that secret sauce ingredient!
awhile during the early years of the BB, simon anthony and big thanks to peter for setting up the magnaflow alfa dyno days at his facility.

somebody that was keeping track said it was the highest powered nord of the day. spica on stock manifold, 133whp depending on how you want to calculated the losses 155 to 165hp at the crank. note the car car was not dialed in yet as you can see by the A/F readings. Ive later added the SS exhaust since the vid.

you can hear how much smoother the cast irons sound over the tubular headers of the others


dyno graph, off the shelf specs and my own secret sauce porting. here:

https://www.alfabb.com/bb/forums/gt-...o-results.html
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post #102 of 126 (permalink) Old 02-25-2019, 02:23 PM
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Here are some header HP numbers from "The Vandenberg Papers" published in the Alfa Romeo Owners Club Technical Notes from the early 1970's. There were many dyno tests run by Dave Vandenberg Import service in Belmont California using the Hasselgren Engines dyno.

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.
Looks like a good project for someone who really wants an accurate number.
The drop in performance when Alfa switched to the one piece manifold and the dyno results published by Shankle for his headers points to a difference of about 10 HP.
That is also backed up by theory - length of header tubes, speed of sound in the pipes, rpm.
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post #103 of 126 (permalink) Old 02-25-2019, 02:57 PM
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Here are some header HP numbers from "The Vandenberg Papers" published in the Alfa Romeo Owners Club Technical Notes from the early 1970's. There were many dyno tests run by Dave Vandenberg Import service in Belmont California using the Hasselgren Engines dyno.
anyone notice what happens on the technical notes by replacing the spica with webers? :-)
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post #104 of 126 (permalink) Old 02-25-2019, 03:05 PM
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At the end of the day.... when god judges you, to tell the truth ....can you really differentiate the difference in a street drive?

The older I get.. the faster I was....
Tom
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post #105 of 126 (permalink) Old 02-25-2019, 03:26 PM
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anyone notice what happens on the technical notes by replacing the spica with webers? :-)
How about that removal of the engine fan?
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