Sheet metal Tunnel ram - The AMC Forum

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tsanchez

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Topic: Sheet metal Tunnel ram
Posted: Jul/24/2010 at 10:40am

http://www.swartzracingmanifolds.com/tech/index.htm

Aljav

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Posted: Jul/24/2010 at 12:37pm

Thanks for your info,,I have been on the Swartz site so many times I can't tell you...LOL And a many other sites.

Your total number appears to be big by the number presented below.. they call for half of total CI
http://www.grapeaperacing.com/tech/inductionsystems.pdf
But I have hear as much as the total CI. But I was also under the impression when they talked plenum I thought they were talking about just the plenum not the runners included.

I keep running into 4 cylinder guy who mention even large plenums.

Yours numbers give me at least some clue where I need to be..I think

Thanks, Allan

Edited by Aljav - Jul/24/2010 at 12:38pm

69 AMX 10.24 129 mph 71 JAV/AMX and 69 Javelin, trying to work on it and go to college at same time.. NAMDRA member #1106

tsanchez

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Posted: Jul/24/2010 at 1:54pm

Remember that that would be for a dry intake in a fi application. TR would be different look at the link I provided for the big ford at 500 inches and the one I posted for a small block. Those are from pipe max.

Small chevy:

3rd Harmonic= 12.830 (ProStock or Comp SheetMetal Intake)

Plenum Runner Minimum Recommended Entry Area = 2.632 to 2.961 Sq.Inch
Plenum Runner Average Recommended Entry Area = 3.026 Sq.Inch
Plenum Runner Maximum Recommended Entry Area = 3.091 to 3.657 Sq.Inch

Minimum Plenum Volume CID= 58.8 [typically for Single-Plane Intakes]
Maximum Plenum Volume CID= 355.1 [typically for Tunnel Ram Intakes]

500 ford:

3rd Harmonic= 13.787 (ProStock or Comp SheetMetal Intake)

Plenum Runner Minimum Recommended Entry Area = 3.056 to 3.438 Sq.Inch
Plenum Runner Average Recommended Entry Area = 3.513 Sq.Inch
Plenum Runner Maximum Recommended Entry Area = 3.589 to 4.247 Sq.Inch

Minimum Plenum Volume CID= 68 [typically for Single-Plane Intakes]
Maximum Plenum Volume CID= 502 [typically for Tunnel Ram Intakes]

Aljav

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Posted: Jul/25/2010 at 1:28am

Plenum volume..TR- same as engine CI.. without Runner or with runner volume?

Allan

69 AMX 10.24 129 mph 71 JAV/AMX and 69 Javelin, trying to work on it and go to college at same time.. NAMDRA member #1106

tsanchez

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Posted: Jul/25/2010 at 11:04am

Without runners. The plenum doesn't start until runners end. And that is max volume, you can make it smaller up to the point that it is individual runner. Smaller the plenum the larger the carb you need to run, we used to run a cleveland on the street with a tunnel ram without the top and bolted 1150s to it individual runner and it ran great.

Edited by tsanchez - Jul/25/2010 at 11:13am

Aljav

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Posted: Jul/25/2010 at 11:32pm

THANKS!!

You made me finalize what I was thinking. Pretty much what I was thinking was the same I appreciate the input.. Now time to finish my ideas and get our fabricator to get going on the intake!! Thumbs Up

Thanks
Allan

Edited by Aljav - Jul/25/2010 at 11:33pm

69 AMX 10.24 129 mph 71 JAV/AMX and 69 Javelin, trying to work on it and go to college at same time.. NAMDRA member #1106

Paul Swartz View Drop Down

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Posted: Jul/28/2010 at 11:04am

Originally posted by Ken_Parkman

...Unfortunately you will have a rough time making that square to the port so you will have an angle between the head and the intake runners.

Another option would be the 4th harmonic with a total length of 10.9", or 5.4" intake manifold runner. That will package easier, but be down in power from the longer runner.

This is a common problem on OEM style (as opposed to raised-port race heads). The trajectory of the runner is VERY important. Tilting the runner up is not a good idea. I just delivered a short "4th harmonic" tunnel ram (my first), but I can't say for sure if that's the right way to go either. I should have dyno numbers by next week.

I've had good luck with plenum sizes from 70% to 120% on V-8's. If you keep it small, you can add height with spacers under the top to find what it likes.

Sorry to interrupt, but I saw some web traffic coming from this thread. I used to own an all-original 4 speed Rebel Machine. and I wrenched on a '69 AMX drag car in high school (my first wheelie in a car!)...always had a soft spot for AMC's.

www.swartzracingmanifolds.com

tsanchez

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Posted: Jul/28/2010 at 11:19am

Welcome Paul, thanks for the insight!! Have you built any AMC stuff?