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Discussion Starter · #1 ·
I've been thinking about doing a gear swap for my auto tC... Mostly just to get better ratio's, but maybe if I could to throw in a 5th gear...


has anyone seen/heard talk of this before? I don't want to take it down to a shop to have them look at it and go "yeah, we can do it." just to tell them I don't have any cash right now. That brings up another point...how much does that type of thing usually cost? This is the first car I've had a chance to do mod's to and I have no idea how much something like that might cost...
 

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I would be very cautious about regearing the final drive on a tC or adding a ratio. Either will upset the On Board Diagnostics (OBDII) because the diagnostics are expecting certain values for speed vs. rpm. If you change them without changing the ECM's programming, you could have a constant Malfunction Indicator Lamp (MIL) glowing to remind you it is unhappy.

Adding a gear to an existing transmission is next to impossible unless there is a clever way to do this with software manipulating an overdrive component (Toyco did this with the A340E in a Lexus model to make a 4 speed a 5 speed). Again this would be a mod to the ECM, not the gearbox.

I seriously doubt you'll have anyone say, "Yeah, we can do that" with any truth in the statement.
 

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Discussion Starter · #3 ·
well, if I'm ever going to do it, I know I'll do it/have it done "right." I refuse to ever do anything halfassed. I'm basicly trying to come up with a list of things to take note of if I had it done to talk about with any shops I go to. I'm less concerned with adding a gear as I would be changing the current ratio(s) to something more like the manual's, or possibly better.

All in all, my plans are to hit 250whp through supercharger, massaging out what I can, and possibly a piggyback chip. After that, I want to look into the gear ratio thing a lot more, which would be my next step. After that...I have no real plans. Yet.
 

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You'd spend a lot less money buying a used TT Supra. It does all that stock and passes smog without issues.

There are no piggyback "chips" for a Toyota. They don't do their ECM like GM. You'll need at least an F-Con V in a piggyback configuration to control the engine, and that's after you completely redesign and rebuild the fuel system. Since no one has done this yet, you will also be experimenting with the durability of the stock block's open deck. Not something I'd want to do without a lot of cash to fix things when they break.

Expect to spend arount $10k + a lot of personal hours tuning to get 250 hp out of the 2AZ, and don't expect stock drivability. There is very little from the stock set up you will be able to keep, and a LOT you will need to re-engineer.
 
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