Throttle Body?

[Mixedpuppy]

I talked to a co-worker today that told me I would need to get a 85mm Throttle Body vs the stock 70mm Throttle body. I guess the stock is 70mm. Would this be necessary to help out the car?

He also mentioned if I got a "Shift Kit" for my 1998 automatic T/A, it should help a little more with performance, like 5 HP.

Is it just me or does every company with a nick nack here and there state their product gives your car "5HP" just to buy it and to find out it really doesn't make a difference at all?

Just curious on your guys thoughts.

[Rob B (shoebox)]

If you don't have any engine modifications (your post does not say), you sure don't need to change the throttle body.

[FRMLAV8]

I haven't done as much research on the LS1 in this area, but I know on the LT1's the larger TB is usaully overkill.

Normally you won't need to change theTB until you have ported and polished heads, w/ a larger cam, and other more serious mods.
So I would assume the same is true for the LS1. There are cheaper more effective ways of making power.

The shift kit, basically just causes the tranny to shift firmer and faster. You won't pick up any HP, but you may pick up a tenth or so in the quarter, because the tranny is shifting better.
You can actually do most of that with a computer and editting software because the tranny in your car is controlled by the PCM in the car.

[BillWS6Formula]

Stock TB size on LS1's is 70mm. A popular (and cheaper) way to go is to have your stocker ported to match the 75mm TB plate (there is a built in restriction in the stock TB to reduce intake noise).

Here's a couple pics of mine...(done by Bauer)