a newer gear head question

[Mace1647545504]

I've have decided to go with a v-8 after looking at several cars. More than likely a mustang gt as they are cheap and I want to teach my son how to drive a stick.

So I look around and see several of them. But what perplexes me is the fairly stock ones with the 78mm tb on it. I could see doing something like that if you camed the car and had headers on it but a car with just a few bolt ons. It doesn't make sense to me.

Back in the day..yes i am old..we put a bigger carb, high rise manifold ,cam and headers so we could get more fuel inside the more efficient engine

So what am i massing??

Thanks

Mace

[twistedfocus1647545489]

On an multi-point EFI system, adding a larger throttle body doesn't change the fuel delivery at all. All it really does is reduce intake restriction. They also will typically boost throttle response a bit because the TB is effectively "more open" at the same throttle input. I assume you're looking at 4.6 cars, because 78mm is a common size for aftermarket TB on them.

 

On a basically stock car you really don't need that large of a throttle body, but there is little to no downside to overshooting it. This is why most manufacturers only make very large throttle bodies for the newer cars (also they are fairly large from the factory anyway in many cases). It doesn't make much sense for them to offer a 65mm, 70mm, 75mm, etc when they can just sell the big one and it works for mildly modded cars and highly modded or supercharged cars about as well.

[Mace1647545504]

Thanks twisted