4AGZE throttle body upgrade to 4AG

[gerkn]

While doing basic research I discovered that the 4AGZE intake manifold is insanely restrictive and can be replaced with a 4AGE small port intake manifold with some modification (but no grinding/drilling etc) but a great start is to replace the throttle body with that of a 4AGE small or big port which I happen to have laying around. I found the official walkthrough thread for doing this swap, but its so old that the link is dead.

Trying to figure this out on my own, I hijacked a picture from google to find out what all needs to be eliminated, bypassed, or rigged up with the new throttle body install. I am aware that the pipe after the throttle body must be ground out to accommodate the larger butterfly during WOT and there will be issues with cold starting, and the TPS should be rotated 180* then adjusted accordingly for idle, AND I SHOULD make a PCV catch can system into the the new intake piping (replacing the J-pipe).

First off, I have no idea what this sensor is for, can anyone tell me?? It is marked in yellow.



Second, when eliminating the J-pipe (before throttle body) can I just block off all the vacuum lines going to it or do they need to be rigged into the intake? (A/C VSV, Air control valve, etc)

Third, on 4AG T/B I'm planning on connecting the power steering vacuum lines and TPS sensor but blocking off everything else. I'm not sure what these 4 vacuum lines are for on the back side, can I just keep these blocked off?? Should I connect the A/C VSV from where it went to the J-Pipe on 4agze?

[Davegt27]

Idle speed control valve


http://www.mr2oc.com/showthread.php?t=4 ... light=iscv


On the top photo those are water line connection for the ISCV

[jdm86gtz]

The T/B from a ST185 GT4 Celica are 55mm and have an ISCV similar to a 4AGZE. They also bolt up to the J pipe.
I haven't done anything with the one I have yet but the throttle cable crank might need to be swapped over from the 4AGZE T/B.

[Mr2swift]

The 4ag tb is a decent upgrade, but quite frankly its not enough. Futhermore, after 25 years we all continue to misunderstand our terrible stock 4agze inlet track starting with a 48mm tb on all 4agze platforms. 4agze manifold is not even close to your worries as it has been proven to make 300rwhp. If your not going to completely open up the inlet side of the blower then using an n/a manifold is probably the easiest way to eliminate the stock piping I guess. At that point however I would surely consider going bigger then the n/a throttle body.

Ron