FR500 Intake Manifold

wildturkey

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I have a FR500 intake and need some assistance from other members that have been exposed to the characteristics and set up of these jewels.
1. Below 3500 RPM is it normal for the IMRC plates to rattle? Actually the rods are loose and causes the plates to rattle when they are closed.
2. Is there a bushing kit to quite the snake?
3. I notice there is adjustment screws for the plates. How are the to be set?

Any help would be appreciated.

Read ya later, Nick
 

old01cobra

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I ended up deleting the flaps. They’re pretty much useless as they become a restriction above 3500 rpm and the little bit they helped wasn’t worth it for the loss they caused from 3500 up. The intake when you look at the dyno naturally flows the long and short runners. You can see a dip when the airflow switches it’s weird.

There are little bearings in the front by the linkage on the shaft if I remember correctly when I pulled them. I don’t ever recall seeing anything in the back part it’s just rods that pull straight out when you take all the butterflies out. I’m not really sure how it could rattle with the cause being from the actual intake as the butterflies pretty much hold it in and they have no physical stop it’s like the throttle body. The machined parts the rods pass through for each cylinder would need to be worn unless the butterflies are loose.

If the cables going too the actuating motor has slack that hold them shut that could cause a rattle.
 

wildturkey

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Thanks for the reply. We put mine on the dyno and noticed the dip at 3500RPM, so we took it to 4500 and the dip was less pronounced. Then we went to 5000 and settled at 4700 RPM. The rattling seems to be the shaft when the butterflies are closed. I'm going to check out a Lincoln Aviator intake pretty soon, to check the similarities. I know they are quite, but they fail closed where the FR500 intake fails open. The Aviator engine may have less cam and degree to run smoother. At this time I have disconnected the window switch and left the butterflies open.

Read ya later, Nick
 

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