AT vs ST chassis differences? Options

[Nespeed]

Just looking for info on the major to minor differences between a AT and ST chassis.

[Special_Edy]

Thanks for all the info, this will save me a lot of time. I had looked over the car and notice ill have to find a different gas tank or run a cell, and fab up mounts for the carrier bearing for the drive shaft. If I have a rear AWD subframe that should bolt up, correct? So next step is to find me a GT4 clip!

If you read my previous post you will see that I have already answered this question. Slightly frustrating considering I type all my posts out on a cell phone.

AT = A series engine
ST = S series engine

The GT(ST204) and ST(AT200) are an identical chassis, the ST(AT200) has different engine/transmission mounts that are designed for the A series engine, whereas the GT(ST204) SSII/SSIII(ST202) and GT4(ST205) are all equipped to accept S series engines(3sfe, 3sge, 3sgte and 5sfe)

The GT4(ST205) has a different floorpan than all the other models of celicas, from the firewall back, so that it can fit the rear differential and driveshaft. It should also be noted that the GT4 has an E series transmission instead of an S series, so the mounts are slightly different.

But to answer your question more directly everything from the GT4 front clip will bolt directly into your AT200, with the exception of the rear differential(if you want AWD) and the Passengerside engine mount(not sure but Ive heard AT200 owners have to drill out some premarked holes)
You will need either an S54 transmission from a GT(ST204) or an E153 from a camry, mr2 turbo, or solara to name a few. The AT200 transmission will not bolt directly to the 3sgte motor. The E153 is the transmission you want behind a 3sgte though, the S54 has weaker internals.

You can either get the rear floorpans from a GT4 and weld them in, or you can weld mounts for the differential and driveshaft(you also must mount an aftermarket fuel cell with this route). The FWD celica has the fuel tank where the rear differential sits on the AWD, The AWD has a shallower trunk with the fuel tank mounted underneath.

This post has been edited by Special_Edy: Jan 7, 2013 - 10:29 PM