How to make RPMs drop faster

Dog bite

Founding Member
Sep 25, 2002
Can someone direct me to the thread... can't seem to find that thread that explained how to get the RPMs to drop faster. Something about emissions and Ford making the RPMs drop so slowly to reduce polution.

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I did this mod too. I noticed right away the "burbally"(sp) note to the exhaust. No loss in mpg(seemed to improve, but I have not verified)the rpm drop is better. It does make more intake noise at startup, but after that, I don't notice it.
I get the tracing of the gasket onto the sheet metal and then cutting the IAC hole a bit smaller in the sheet metal to reduce flow of air through the IAC. However, whats this stuff about copper plugs ?

Also, anyone with automatics who've tried this mod, please, share your comments. I do notice that "hanging" effect of rpms on the interstate though some of it is my 4.30 gears I'm sure.
Give Me TP said:
Somebody in the V6 forums on another site did this mod on an '04 manual and liked the results as well. I haven't heard yet about automatics, but surely someone has done it.

what mod are you guys talking about?? sorry but i dont get it :bang:
more explanation please :hail2:
9646gt said:
Basically the mod is a way of restricting aif flow from the IAC restricting this flow the rpms drop fast between shifts or when power braking...instead of the all to common slow dropping rpms in stangs

why do we want RPS to drop faster?? dont we want to keep the rpm's in the high range?? :stupid: i feel stupid for asking this , but seriously
If you are a beginner to a manual the hanging rpm help smooth out the shifts so the car doesn't jerk.

When you upshift the revs will drop to match the new gear, but may require a little feed in of throttle to smooth it out.

Is it a mod the EVERYONE needs to do? No, just people who are used to driving carbed cars and want that feel again with a newer car.

Doesn't add any performance benfit.
Newbie143 said:
why do we want RPS to drop faster?? dont we want to keep the rpm's in the high range?? :stupid: i feel stupid for asking this , but seriously

It helps to engine brake if the RPMs drop faster...this also give you more control to rev match your shifts when racing also..I personally htink its the best cheap mod you can do ..but thats jsut me
You can do this mod to an auto, but won't notice it as much. You'd mainly notice a difference at start up or when reving it in neutral/park. Not a whole not of difference when it shifts, maybe a little more when coasting down to idle.
I made the hole 1/4" and the car was idling like I had radical cams. I don't think its supposed to do that. So I made the hole just a little bigger and its idling normally. Don't feel a difference whatsoever but I'm curious which side the small hole goes. One person said the drivers side and someone else said passenger side.