Is going from a 68mm to at 92mm throttle body safe. (calais vy 2003)

[Wee_Man]

dont know if i have the right forum, im now to the site. I have a Calais 2003 V6 VY. i have just got in to the modifying and want to do it right. im looking in to getting some extra bhp. im is looking in to throttle bodys and was wondering if its safe to go to a 92mm from a 68mm standard. i have no mods on the car yet but will have a sports preformance exhaust and a cold air feed induction kit by next week. (no idea if that will make much of a difference).

[TMM]

It'll need to be tuned, otherwise it will potentially run lean at part throttle, or the transmission will play funny buggers with gear selection (gear is decided according to the throttle position sensor and the speed). That is because the bigger throttle will flow more air at part throttle, but is unlikely to be a restriction at WOT.

It's probably not the best idea to go and put such a large throttle on an otherwise stock engine, because without other mods all it will do is make the throttle response more savage, and half throttle will probably be the same as full throttle.

[DUK13Y]

Before you go looking into wider throttle bodies for first mods, I'd take a look at Mace's website (sponsor section). I've heard great stories about their spacers in particular. Or just save a bit of money and go the upgraded roller rockers. As far as first mods, I don't think throttle body is high on the priority list.

[Surfwagon]

Unless your car is turboed or supercharged then going a bigger TB is just throwing money away as the std TB never becomes a restriction on NA V6's unless running a huge cam.
On a NA V6 you would be lucky to gain 1-2hp (not kw) and then only right at the top of the rev range and if your car is auto you'll never really see any benefit.
Some people say they are quicker with bigger TB's but what is actually happening is that for the same opening (foot travel) the bigger TB is letting in more air so feels like it is reacting quicker but in reality nothing is different at low revs.