So I just pulled the throttle body off of my 4.0L and I just donÆt understand all of this talk about spacers, larger throttle bodies and what not. Let alone the whole concept about what they are intended to do (high RPM performance increase), but the hole throttle body is already larger than the hole in the intake manifold, so unless people are going to the trouble to machine out the inlet to the manifold, it really doesnÆt make sense, not that it ever made sense in the first place.

Just my 2 cents.

Sean

Venturi effect, This speeds up the air entering the manifold and allows better fuel atomization.
Sounded good didn't it... <img src="/forums/images/graemlins/drunk.gif" alt="" />

The venturi is in the trottle body, right below the throttle plate. This was probably about a 1/8" "step" all the way around. I could not see that helping flow out at all. LOL

Sean

Venturi effect is localized to the minimilization of diameter, after if passes the "bottle neck" it slows back down.

A TB spacer works on the principle of tuning the intake harmonic like a 2 stroke has an expansion chamber. It doesn't work, it's a gimmick to get your money.

A larger bore TB works off the idea that your TB is not flowing enough for your engine.

If you were running a race engine or an engine with a fat cam, a larger TB might help. But for those of us with a stock motor, it doesn't do anything noticeable.

It's not like the engine designers wanted to get a low performance out of an EFI motor. They put on parts that will get good mileage power and emissions. If you modify the intake tract or exhaust system with someone elseÆs idea of a performance part, you will sacrifice cleanliness, drivability, and mileage.
If you were to build a high performance motor, you wouldnÆt run stock intake, stock exhaust or stock computer. The "high performance" parts people bolt on work well for engine making more power than stock, but they are not the cause of more power than stock. If you rebuild your motor with more compression and a more aggressive cam than stock and port your heads, the stock TB will not flow enough nor will the stock exhaust or intake handle the flow, once you have a built motor, then buy the high flow stuff.

here is a good example.a coworkers friend just bought a new acura ,a tl i belive.anyway he installed a stanless steel exaust and "cold air" intake system.the exaust and intake made it sound awful and run poorly.We all know how much better japanease cars are compared to ours,so why would you want to change it.im sure his gas milage and power will suffer,in the attemt to make more.i have to say though that exaust is really purty. <img src="/forums/images/graemlins/lol.gif" alt="" />

We do??

The new ones breathe fairly well, but I think some of the older (pre 94) Honda's do have a restrictive exhaust and intake tract.