Throttle Bodies

[BillS]

One of the common mods to the V6 appears to be larger throttle bodies, whether they need it or not.

With the 2.8, for example, I've seen flow bench date that indicates it makes no difference, other than lightening the owner's wallet by $200 and giving him bragging rights (at least not until you raise the engine to a much higher state of tune than the factory version).

Question - does anyone know if the same holds true for the 3.4 cast iron head engines, which already have a larger throttle body - does hogging the TB out to say 62 mm. really have any effect - does a mildly cammed engine benefit from the theoratically increase flow capability, or is this just another exercise in wallet lightening.....?

[1QUICKHATCH]

you may see some gains on a stock engine like better throttle response, but if you have some better engine mods like heads, cam the the TB will compliment them real nice! I did a set of heads for slowbird on here then we installed a 62mm TB after going to the track, we ran the car the following weekend and ran .200 faster with just doing the TB!

I know of one person on thirdgen.org that dropped a tenth or two putting a 62mmTB on a iron head 3.1 but not sure what what else they have done to it!

[SappySE107]

Given the small area of the pushrod plenums, it makes sense that a larger TB will help out.

[BMC]

3.4L Throttle body

Just make sure you port match the manifold. The casting is a bit off even for the stock TB on all L32 3.4L that i have had through the doors.
-BMC.

[BillS]

Same thing on the Fieros, plus there is a restrictive area in the 'neck' that makes properly relieving it a problem.

At least the Camaro 3.4 manifold is easy to relieve.

[BMC]

True.
Probably just like the fiero, port matching is a good idea as well at the time between the upper and lower halves, but these are usually pretty clean, just a little deburring along the edges to clean it up.... But i figure with your project, you'll probably be porting heads and manifolds.
-BMC.

[BillS]

True.
But i figure with your project, you'll probably be porting heads and manifolds.
-BMC.

You bet - nothing like free horsepower!