5.0 MPG

I just installed a GT 40 upper and lower intake, what size TB should I go with and which should be bigger the TB or MAF I can remember.

boss429

the MAF should be bigger.

65mm TB should be good, your car isnt real modded to hell
and around a 70-75mm MAS should do the trick.

thats my little diddy for ya

5.0 MPG

I heard somewhere its not a good idea to go too big on the TB, any idea why?

OJMiles

I wanna say because it can reduce your low-end torque... but i've been known to be wrong before.

94GT5.0

When you go too big with your throttle body, it can become so big that it overcomes you intake port where it is connected to the throttle body. The intake port, being smaller, creates a lip inside of the throttle body. When air passes through your intake, some of the air hits this lip and bounces back creating drag on the perimeter of the port. This drag will effect all of the air going into the manifold, slowing it down, and reducing airflow, which in hand reduced performance.

Mustangkiler

+ 1, but if your going to do anything big within a year, your going to need the 70 mm tb... its a give and take

FiveLiterRiceEater

just slap a 90 mm maf on there and a 80 mm tb

boss429

you could do that,
but if your tb is bigger than the mouth of your intake then your going to have to do some machining to make them match up
ive heard of some guys on here just using s dremel tool and matching them so there no lip to cause drag.

FiveLiterRiceEater

shhhhhhh

92hatchLX

I'm running a 70mm TB and a 75mm MAF, my set up works great.