03redGT

is it necessary to get a plenum with the TB?

MustangMafia

I think average gain for a plenum + t-body is like 5 hp.... Its not a bad bolton to do....

70 MACH I

The whistle is NORMAL! Ford does alot of things in the stock plenum to prevent noise. Take a look at the EGR port in the stocker, there is a raised triangular bump in the casting above the port, you guessed it, for noise. The aftermarket does nothing to reduce/eliminate it. I can fix mine by grinding into the ports and rounding the edges , but I can't be bothered.
John

marcuslee842

I wish I could tell you if that is normal, I installed a K&N CAI, 75mmTB, and plenum but my car dosen't run. The bolts that go on the rear of the plenum were in bad shape so I had to throw them away. If I start my car it sounds like a turbo lol, but it won't stay on because of the idle air leak code.[&o]

rbstang

Its a good mod if your going with a supercharger. More airflow to the engine to compensate with those huge 42 pound injectors the blower is using.

01yellowgt

With a Centrifical S/C you will see more from a plenum & t/b than if you was N/A. Now if you are getting a KB the plenum will not be needed.

WAG03GT

I noticed some pretty good gains from my TB and Plenum but who knows that might just be me. After i added the tb and plenum along the o/r h i droped .5 sec off my 1/4 time

WAG03GT

woops

2k1gt

My mac 75mm TB makes a whistle sound at 1/2 throttle. Every mac TB I have ever hear sounded like that. My friends GT with an accufab didnt whistle as much as my mac did.