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Magnum intake restriction

Posted By: jefferson

Magnum intake restriction - 04/16/21 03:13 PM

This is my first post so I hope it is in the right forum. Used to own a 94 ram 1500 shortbed that was lowered and had the 5.2 in it. Best sounding truck I ever came across. It had headers and a cat back that I never was able to identify along with a big block 50 flow master. Also had the MP ecu. Never got to do some of the things I wanted to do to it as my son totaled it out and I have been without a mopar since. Onto my question.
I know the stock intake manifold on the magnum motors is much maligned. Part of the problem I see is the opening to the ports is shrouded by the close proximity of the plenum plate. My feeling is if there was room to install a spacer that would move the plate away from the intake ports it would allow more air in and they would flow better. The spacer would have to be cnc machined and if it was only an inch thick it would be a huge improvement. I'm just not sure if there would be room without interfering with the pushrods.
I wanted to throw this out there and see what people thought about the idea.
Posted By: moparx

Re: Magnum intake restriction - 04/16/21 04:53 PM

although i can't help with your question, i would like to welcome you to the board ! wave
i'm sure there are others that can help you with their knowledge.
beer
Posted By: HotRodDave

Re: Magnum intake restriction - 04/16/21 05:28 PM

I have noticed that also, I think lowering it 1/2 inch would help a ton and it fits. I ran a second plate spaced about 1/2 inch down to keep the hot oil off it and help reduce the IAT, it helped a little.
Posted By: jefferson

Re: Magnum intake restriction - 04/16/21 10:00 PM

It's nice to know there is room for at least a half inch spacer as any distance away from the port entry is going to help. More would be better if there is room. I am also intrigued by extrude honing the manifold and a flow director on the plate that I know has been done.
Posted By: RTSrunner

Re: Magnum intake restriction - 04/17/21 02:18 PM

On my '01 Ram Off-Road package truck I wanted to move the power band up to work better with the 4.10 gears.When I pulled the intake to fix the plenum oil leak,I shortened the runners about an inch & radiused the port entrance.I also ground off the raised lip above each throttle bore and radiused that as well.This made it more responsive and it did work better,less downshifting in high gear/OD when towing. This site shows some Kegger intakemods and sellls parts as well: http://utawesomeperformance.com/store/c8/Kegger_Intake_Manifold.html
Posted By: Moparite

Re: Magnum intake restriction - 04/17/21 02:49 PM

The stock kegger is good for low end torque, If you mod for more power it's better to get another intake.

https://www.allpar.com/threads/test...agnum-v8-engines.229969/#post-1085224067
Posted By: Taylor

Re: Magnum intake restriction - 04/17/21 03:01 PM

Originally Posted by RTSrunner
On my '01 Ram Off-Road package truck I wanted to move the power band up to work better with the 4.10 gears.When I pulled the intake to fix the plenum oil leak,I shortened the runners about an inch & radiused the port entrance.I also ground off the raised lip above each throttle bore and radiused that as well.This made it more responsive and it did work better,less downshifting in high gear/OD when towing. This site shows some Kegger intakemods and sellls parts as well: http://utawesomeperformance.com/store/c8/Kegger_Intake_Manifold.html



^^^^^^^^^^^^^^^^^^^^^ Good Info^^^^^^^^^^^^^^^^

On my 87 Dak , we tried a lot of different thing to get it work.....My Ex Hubby and my Uncle cut down runners and epoxied baffles... next step was buy an Airgap intake manifold......, this photo is not mine, but it's similar to the mods they did to my kegger

Attached picture Modded Kegger.jpg
Posted By: jefferson

Re: Magnum intake restriction - 04/19/21 11:02 PM

My theory on the manifold is to optimize what is there. Keep the long runners for the low end, but extrude hone the runners for more flow and move the obstruction to the intake air entering the runners by spacing the plate away from the intakes. I see the shrouding of the entrance to the runners as the main impediment to flow. I may be wrong, but I think the point is valid. Some heat resistant coatings would be good to keep the intake charge cooler as the manifold is a large aluminum heat sink.
Posted By: HotRodDave

Re: Magnum intake restriction - 04/20/21 08:37 PM

I always wanted to try milling away the entire thermostat and putting in a remote style thermostat housing. I have come to the conclusion that since it is all aluminum and there is a very large surface area to transfer heat to the air inside the plenum that removing the scalding hot water from that part of the manifold would dramatically reduce intake air temp especially for the front cylinders that always show the most evidence of detonation. Combine that with a ceramic coating on the plenum plate and I bet it would really help TQ and HP. IAT on the stock magnum is through the roof on a heat soaked engine even in very cold ambient temps, it can easily run 130 degrees on a zero degree day and 170+ on hot days.
Posted By: jefferson

Re: Magnum intake restriction - 04/22/21 12:38 AM

I think the easier way would be to coat the water passages with a thermal barrier coating as well as the entire insides of the manifold. That should get the iat's down some.
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