Q45 TB and FFIM question

[JesseH]

Ok, Heres the senario. Im finnishing up my mild build and one of my buddies who enjoys making parts for me (while he on the clock at work) lol is fabbing me up a FFIM for practically nothing, so of course I didnt turn down the offer. Im having him flange it for a Q45 TB even though im still on the CT26 just so its there when I go bigger not too far down the line.
Now heres the real question, after getting the TPS all wired up and I going to have to do any tuning for the TB alone?? For instance, wouldnt 20% throttle with the Q45 bring in a lot more air than 20% on the stock TB making me need to kick the fuel up a bit? Or would it not affect it that drastically?

 

[JesseH]

anyone?

 

[dbsupra90]

you could run a 100mm throttle body and it is still going to only flow as much air as available. it would be like running a garden hose with a 2" fitting on the end then swapping to a 5" fitting on the end. it isnt going to flow more water.

so no, you shouldnt have to tune anything from just a tb change.

 

[JesseH]

you could run a 100mm throttle body and it is still going to only flow as much air as available. it would be like running a garden hose with a 2" fitting on the end then swapping to a 5" fitting on the end. it isnt going to flow more water.

so no, you shouldnt have to tune anything from just a tb change.

ok, thats what I thought ( I had this argument with a local MKIII owner) I told him that im reducing back to 2.5 piping after the TB because I dont need anything bigger right now, its just there when I need it. And he insisted that I need at least a AFPR and maybe a SAFC even when reducing it back down.
Thanks for the reasurance though

 

[MK3Brent]

It's a pressurized system.

 

[need new tires]

It's a pressurized system.

its only pressurized under boost not when it is off boost.

the point is @ 15% throttle of a stock unit vs. a 30mm larger TB @ 15% throttle. i still would say to keep an eye on the a/f's. i know that my car with a stock TB wouldnt build boost under 23% throttle(or right around there) on a flat road
yet my friends car would build boost(1-3psi) on the same type road @ 15% throttle with a ffim and a q45.

both cars are on a ct similar mods minus the ffim.