WillMarquis

Can I throw this on my 4.6 without having to mess with the ECM?

WillMarquis

And...is it worth it? I believe the stock is 68 mm.
Thanks again in advance.

CatSkinner

The ECM is measuring the air flow and the CO2 of the exhaust, it has no idea what size throttle body as long as the necessary parts (IAC, etc.) are still there. On the flip side, are you doing anything to the 4.6 that would require that much more air? A decent after market CAI will probably give a stock engine plenty of air.

__________________
Prius repellant, just add gas.

WillMarquis

ECM...lol...sorry about that- I meant the ECU- the chip, etc.
I'm not really doing anything internally to the engine, (cam, injectors) but do want to add the CAI kit and run a superchip program on it.
I'm not looking to go nuts- just a little more kick.
Main question is it it really worth it?

CatSkinner

With a super chip, the 75mm may give a little more advantage, however, the heads and exhaust may restrict anything the intake can add. A bigger throttle body allows more air in, competition cams hold the valves open a little further and longer, headers and a bigger exhaust allows the emissions to flow away with less restriction. In old school talk, if you had an 800 cfm carb, but your exhaust would only allow 55 to move freely, the engine would have to work harder to port away the exhaust, so any advantage gained by the intake was taken away by the engine having to work harder to pump out the exhaust. Fuel injection and throttle bodies work the same way.

__________________
Prius repellant, just add gas.

Bajarider

As Catskinner say's, you will not get a noticeable gain without exhaust mods. Intake mods need to be coordinated with exhaust and cam timing/overlap. Oftentimes, the heads are the bottleneck and need to be changed too. You cannot pump more air into an engine without getting it out, and then you will need to program the ECM to the fuel and ignition curve that produces the most HP and torque to get the most from the mods. You may [I]think[I] you are getting more HP, but dynos don't lie. I used a 75mm throttle body on a 5.4, with Trick flow heads, in a CV with good results, but a stock 4.6 will not benefit from a larger throttle body.

Also keep in mind what kind of power you are looking for. Big HP numbers high in the rev range might impress some, but big mid-range torque is what moves a 4,000 pound CV on the street.

WillMarquis

Right- thanks for the input.
I got a great deal on a new MAC TB and thought I'd try it so I did put it on there yesterday and do notice a slight difference at mid range...
I am about to do the exhaust next- upgrading to 2.25" pipes and have a tuner coming in a couple of weeks.
Again- I'm not trying to go crazy with it but just have a little more fun with what the car can do....It may be heavy but the thing sure likes to move!

Bajarider

Have fun, that's what our hobby is all about!