I've only seen them for v6 or v8 cars. I know Modified Mag did a dyno for a manifold spacer on a 350Z and it gave them +8 or so hp near the top end. I don't know exactly how they work so I'm kinda in the dark.
i had outlaw engineering phenolic spacers for the IM and the TB on my mx6 that i had. never had a dyno comparison...but even after a long hot day of beating up the car, you could hold your hand on the intake mani and not get burned.
Spacer on an intake manifold make some sense. they are designed to thermally insulate a metal intake manifold from the metal head. This reduces heat transfer significantly and thus reduces heating of the intake air/fuel charge while it passes through the intake runners. It does however push the torque band further down the RPM range as it increases running length to some degree (of course a 1/8" spacer might only move it down a few dozen rpms).
A TB spacer on a fuel injected vehicle really doesn't do a dang thing other then increase the IM plenum volume slightly...which increases throttle lag slightly...but also changes the resonation in the intake manifold to a degree...not necessarily positively or negatively. On a carburated vehicle it does allow additional mixing of the A/F charge...that doesn't occur on a fuel injected vehicle unless it is a throttle body injected car, which the 3 most certainly is not.
What does a Throttle Body Spacer Do? A throttle body spacer is designed to increase speed and volume to the incoming intake air, and atomize the fuel more efficiently increasing HP, and MPG. A throttle body spacer is a fairly simple modification to add to your vehicle, installation time is less than 30 minutes with very basic hand tools.
[quote author=Hindi link=topic=68503.msg1193752#msg1193752 date=1170903736]
i think the tb spacers are pretty point less. its just like adding length to you intake
What are you talking about? It works to "atomize the fuel" increasing HP and MPG. With a word like atomize it HAS to be effective.
Okay, sarcasm aside, I really don't understand how this would work at all. Anyone have an idea about the physics behind this and how it could possibly work on our cars? It doesn't seem like it would do anything at all, as though it is in the realm of a Turbonator...
In the case of a carb spacer it places the carb further from the intake ports. When the air flows through the carb the fuel is sucked from the carb into the ingoing air stream. This causes mixing of the air and fuel. However it is not instantenous. The more 'time' the air and fuel spend together in a high velocity stream...especially with some swirling or turbulence the more they mix. To much time and the fuel can percipitate on the intake runner walls, not enough time and you are sucking in a poorly mixed grouping of fuel and air making the burn rate slower and less likely to properly burn all of the fuel.
For a throttle body spacer you get just about jack. The only thing it does is add volume to the plenum chamber (and not that much unless it is like a 6" thick spacer).
Read this article from my Almamater. It does an excellent job describing the effect of plenum on power production.
If you read through it you can see that a larger plenum might not get you the power where you want it (if a big plenum was so damn hot why the heck would individual runner throttle bodies be 'the thing'?)
PS don't forget to keep in mind looking at the information this is also an engine that revs EXTREMELY high. I forget the exact numbers, but the generally accepted volume you want is 50-60% of the displacement of the engine to generate peak torque in the range of 5000-6000rpms. This means that on a 2.0L engine you want about 1000-1200cc of plenum displacement.
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