stock 3.4 TB on a 3.1?

[1992grandam]

ok well inknow the TB off the 3.4s are 56mm right? and the ones in our 3.1s is 52mm....so wouldnt i see a gain if i converted over and used a 3.4 TB and would it be a direct bolt on? or would it not fit?

[voyager]

it fits. you need to use the linkage from the 3100. it bolts up directly, except for the heater line, which you won't use. your TB bore won't match your plenum anymore, so you should port out the plenum to match.

gains? maybe 1-2hp peak, combined with intake and exhaust, and a small increase in throttle response. large bore TB's don't make much power in any case.

you can either use a new 3100 TB gasket and cut it to match, or use a new 3400 TB gasket. good oppourtunity to clean the EGR valve and upper intake manifold while you have the TB off..

[ChevelleSSLS6]

I thought the stock TB on the 3400s were "tiny" for the engine. Am I wrong?:roll2:

[1992grandam]

they are 56 mm.....which may be small for that engine but its bigger than my midget 52mm...

[jayhawk]

Originally posted by voyager

gains? maybe 1-2hp peak, combined with intake and exhaust, and a small increase in throttle response. large bore TB's don't make much power in any case.


Yes they do, IF also air flow is increased before the T/B and in the exhaust.