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03-13-2001, 03:07 AM

Well, actually, the IMRC's (Intake Manifold Runner Control) open the secondaries at 3250 rpms. You can actually hear this function everytime you cross 3250 rpms from the kickpanel where CPU is located. The exhaust gets a deeper tone also and it pulls harder. You can also see this jump on any 96-98 Cobra dyno graph.

I just keep it above 4500 rpms because my only purpose in life is to run 11's on that stock motor and I am just below max torque and right in the heart of the HP powerband pull back to 7000 rpms where I make my next shift. The 4.56's get me up there quickly and keep me up thru-out the run.

FYI, the 99/01 Cobras do not use IMRC. They have a different head design (tumbleport) which promotes more low-end torque, enough where Ford decided not to use them on these.

There are also IMRC delete kits sold by FRPP to take them off of the 96-98 Cobras, but unless it is supercharged or some straight-up N/A race application, low-end torque will really suffer. There is also finally a new aftermarket intake coming out for the 96-98 Cobra which bolts directly to the heads and does not use the IMRC. But, this intake kills torque but raises HP significantly. 5.13+ gears minumum will be needed to take full advantage of this new intake. Stay Tuned!!!

Later, Jason

------------------
N/A 1997 Cobra

1/8 mile - 7.83 @ 90.08 MPH
1/4 mile - 12.26 @ 114.02 MPH
1.64 60 ft.

03-13-2001, 03:07 AM	#14
jmeiers Guest Posts: n/a	Well, actually, the IMRC's (Intake Manifold Runner Control) open the secondaries at 3250 rpms. You can actually hear this function everytime you cross 3250 rpms from the kickpanel where CPU is located. The exhaust gets a deeper tone also and it pulls harder. You can also see this jump on any 96-98 Cobra dyno graph. I just keep it above 4500 rpms because my only purpose in life is to run 11's on that stock motor and I am just below max torque and right in the heart of the HP powerband pull back to 7000 rpms where I make my next shift. The 4.56's get me up there quickly and keep me up thru-out the run. FYI, the 99/01 Cobras do not use IMRC. They have a different head design (tumbleport) which promotes more low-end torque, enough where Ford decided not to use them on these. There are also IMRC delete kits sold by FRPP to take them off of the 96-98 Cobras, but unless it is supercharged or some straight-up N/A race application, low-end torque will really suffer. There is also finally a new aftermarket intake coming out for the 96-98 Cobra which bolts directly to the heads and does not use the IMRC. But, this intake kills torque but raises HP significantly. 5.13+ gears minumum will be needed to take full advantage of this new intake. Stay Tuned!!! Later, Jason ------------------ N/A 1997 Cobra 1/8 mile - 7.83 @ 90.08 MPH 1/4 mile - 12.26 @ 114.02 MPH 1.64 60 ft.