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New EFI Intake Manifold
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Sonic Silver View Drop Down
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Points: 7949 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Sonic Silver Quote  Post ReplyReply Direct Link To This Post Posted: Jan/31/2019 at 7:51pm
Originally posted by THE MENACE THE MENACE wrote:


Nothing new to tell. Our engine dyno's have been tied up with other projects for some time now so the new AMC EFI intake is still in the hands of the engineering Dept.   
Any idea as to why the Air Gap for AMC, Olds, Mopar, 351 W and some others have a solid divider between the 2 sides of the carb opening, while Chevy Big and Small, 289 Ford, and others have a cut down divider?
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I will to. My son Mitch pulled the 401 out of his Rebel for rebuild. It will be a nice surprise.
Did you mean GMC?
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Originally posted by Sonic Silver Sonic Silver wrote:


 Any idea as to why the Air Gap for AMC, Olds, Mopar, 351 W and some others have a solid divider between the 2 sides of the carb opening, while Chevy Big and Small, 289 Ford, and others have a cut down divider?

I'm curious about this too,
maybe even worth a thread all to itself.

I bet the answer has to do with eeking out a couple extra ponies out of intakes in the more competitive (with other manifold companies) markets.

Honestly I think they're doing us a favor by keeping the divider intact,
it's easier to remove material later if the buyer wants, than to try to add material to a cut down divider.

I like keeping the divider when possible,
 to hopefully help smooth out the idle with a high overlap cam, and increase vacuum signal strength a little to hopefully tolerate a little bigger carb.
71 P-code 4spd Javelin/AMX
some Jeeps and some Fords
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Originally posted by jpnjim jpnjim wrote:

Originally posted by Sonic Silver Sonic Silver wrote:


 Any idea as to why the Air Gap for AMC, Olds, Mopar, 351 W and some others have a solid divider between the 2 sides of the carb opening, while Chevy Big and Small, 289 Ford, and others have a cut down divider?

I'm curious about this too,
maybe even worth a thread all to itself.

I bet the answer has to do with eeking out a couple extra ponies out of intakes in the more competitive (with other manifold companies) markets.

Honestly I think they're doing us a favor by keeping the divider intact,
it's easier to remove material later if the buyer wants, than to try to add material to a cut down divider.

I like keeping the divider when possible,
 to hopefully help smooth out the idle with a high overlap cam, and increase vacuum signal strength a little to hopefully tolerate a little bigger carb.



I think that the divider helps in some situations and hurts in others. I would think that the smaller and milder the engine build is that you might want to keep it. I have seen some dyno tests that show a big difference by milling a dual plane down . One 71 454-425 horsepower LS6 Corvette, with a stock low rise intake, picked up 40 horsepower over 4,000 rpm with no other changes.

I have seen several others where it would take away 4 or 5 hp at low rpm, and add 4 or 5 up top. That wouldn't be worth doing. Who knows?
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Originally posted by Sonic Silver Sonic Silver wrote:

 Any idea as to why the Air Gap for AMC, Olds, Mopar, 351 W and some others have a solid divider between the 2 sides of the carb opening, while Chevy Big and Small, 289 Ford, and others have a cut down divider?
 
The guys in the dyno room tell me that the height difference of the plenum divider varies because some engines benefit from a taller divider to help control (smooth out) air velocity in the plenum.   
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70 AMX 416, EFI, Nash 5 speed   
70 Javelin 401, 727 (Wife's car)
72 Gremlin Autocross Project.
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A 5/8" phenolic spacer on a square bore, cast intake, 401 is much better then no spacer. Heat may be some of it but a 1/4", 1/2"and 3/4" spacer are simply not as good as the 5/8" on the same engine.
So much so you can feel it in your butt. Would like to see the difference on a dyno or flow bench.
Thinking this is why the Machine intake had 15 HP more.  
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Originally posted by Trader Trader wrote:

A 5/8" phenolic spacer on a square bore, cast intake, 401 is much better then no spacer. Heat may be some of it but a 1/4", 1/2"and 3/4" spacer are simply not as good as the 5/8" on the same engine.
So much so you can feel it in your butt. Would like to see the difference on a dyno or flow bench.
Thinking this is why the Machine intake had 15 HP more.  
I don't think that the Machine intake itself is worth 15 horsepower. The Machine exhaust manifolds also had a 2-1/4 inch opening instead of 2 inches, and no heat riser valve between the manifold and exhaust headpipe. Part of it may have been advertising. Firebirds and GTO's had different ratings for the same engines. The GTO was rated quite a bit higher, with the only difference being mufflers.

   The Machine intake was no taller than stock, and I am not positive whether or not the Machine intake had the same 4 hole spacer as the stock 390. The only difference that I can find between a stock 390 intake and a Machine intake is 2 oval holes instead of 4 round ones, and a smoother turn from the plenum into the runners.
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Dennis,

Please give us an update, the thread is running off the rails again.

Thanks,
Tom
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How does it not run off the rails in 14 months and 30 pages?
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Originally posted by PROSTOCKTOM PROSTOCKTOM wrote:

Dennis,

Please give us an update, the thread is running off the rails again.

Thanks,
Tom
 
Nothing new with the project to talk about Tom.
 
The dyno cells have all been tied up with other projects while the new EFI intake is back in Engineering.
 
Dennis  
Former Owner of:
The Craig Breedlove "AERO AMX"

Still Owner:
SS/AMX #9 replica (THE BIG MENACE)
70 AMX 416, EFI, Nash 5 speed   
70 Javelin 401, 727 (Wife's car)
72 Gremlin Autocross Project.
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