FR500 intake IMRC rattle

[afeod03]

Howdy. New here.

I intstalled a new FR500 intake manifold a while back, and my engine immediately started making more noise than usual. I thought it was a head tick at first. I can hear it from the driver's seat through the firewall. Turns out it's either the butterflies in the intake knocking against the runners, or the rod they're mounted on rattling around. It only occurs with the valves closed, and it's much louder on the passenger side than the driver side.

Has anyone else had similar issues? Any suggestions on how to quiet it? Maybe it'll go away as the intake--uh--"breaks in"? I haven't driven the car at all since I installed it for fear of damaging something, and my beater car just isn't cutting it any more.

It's actually a Mach 1, but there aren't too many Machs with this intake. So I figured I'd post here for a wider audience.

Thanks for any help you can offer.

 

[Nazman]

Howdy. New here.

I intstalled a new FR500 intake manifold a while back, and my engine immediately started making more noise than usual. I thought it was a head tick at first. I can hear it from the driver's seat through the firewall. Turns out it's either the butterflies in the intake knocking against the runners, or the rod they're mounted on rattling around. It only occurs with the valves closed, and it's much louder on the passenger side than the driver side.

Has anyone else had similar issues? Any suggestions on how to quiet it? Maybe it'll go away as the intake--uh--"breaks in"? I haven't driven the car at all since I installed it for fear of damaging something, and my beater car just isn't cutting it any more.

It's actually a Mach 1, but there aren't too many Machs with this intake. So I figured I'd post here for a wider audience.

Thanks for any help you can offer.

That rattle is caused by the intake air resonance. Its the air at low speeds goes down and hits the intake valves it "bounces" back up-to the runners hitting the blades. This causes the noise.

The problem is easily fixed:

Set the Window Switch to have the blades open from idle to ~2000RPMs, then have the WS close the valves at 2000RPMs. This will allow you to run on the long runners at idle and up to 2000 RPMs (no worries it will not hurt anything and not have any detrimental stuff to performance), then from 2000RPMs up to ~5000RPMs on the long runners, then have the WS open the runner again at ~5000RPM and transition to the short runners for sick top end performance.

Trust me, I have a crap load of dyno pulls with the FR500 intake (~20 of them) when I was running one on my motor. I know where the RPMs needs to be.

Also, have your tuner add a few degress of timing at the transition point, so @~5000RPMs have him add about 3 degrees of timing on at about .7+ load at only that RPM range. Then continue to tune as normal. That along with the RPM transition point of 5000RPMs will be the best and eliminate the dip of ~300 RPMs in the power band lots of people experience with the FR500 intake.

Let me know if you need anything else.

Naz

 

[afeod03]

Thanks. I was starting to worry I had made a mistake with this purchase (FI guys would probably argue it was a mistake anyway...). I should be able to post a dyno slip in a month or so, depending on when I can get it tuned. :banana: