Re: Throttle Body
I rather doubt the computer will care, but you can.
Really the only time the airflow is increased with the larger
bore is at Wide Open Throttle. The rest of the time the
butterfly's closed enough to limit the airflow to it's
Someday when I get a chance I want to make dyno comparisons
with the spacers, smooth vs the spiral bores. More than
likely the spiral types give a better atomization at mid
range, and may inhibit top end a bit, but if it's big enough
it won't matter that much.
And - it depends on where you want the added "poop."
Matching the TB bore to the manifold bore probably will be
the biggest improvement in yours, since you said the difference
is a 1/4" mismatch. That makes a ledge causing turbulence.
But then, who knows, maybe that mismatch turbulence was
intentional by the designers.
Another improvement is matching the flow rates of the injectors.
Straight out of the box they are often mismatched, causing one
side to be leaner than the other. The computer "averages"
the two, leaving some cylinders slightly lean while others
are slightly rich - neither side is at peak performance
Depending on the engine and how far off they are, significant
improvements can be made by matching them.
Do a search on the internet for matching services, or call
your local speed shops, they should know someone that does
it locally. It's not all that expensive, as they do it on
an exchange basis.
Let us know how it comes out with the larger bore.