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Discussion Starter #1
I often hear about people swap their 1zz or 2zz MR2s to a 6 speed transmission. Probably a silly question, but why would one do this? If you were to get a 2zz would you do this. I've only every driven a 5 speed, so I've been like 'wish I had more gears here'. If you were to get a 2zz would you consider this necessary?
 

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You can stay in lift on a 5 speed if you lower the lift point down and increase your rpm limit using something like an Apexi PFC.

I'd only do it if you can get one cheap(junkyard) and do the swap yourself. I've had both on a 2zz and the 5spd was fine. 6 speed does help, but not much IMO. I tell people not to go out of their way to do the 6 speed swap. If you're fine pulling transmissions from a junkyard and doing the swap yourself, I say do it. If you can at least do the swap yourself but can't find one at a junkyard I'd say flip a coin. If you can't do the swap yourself and are paying more than $500 for the trans, no way.

-G
 

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With a 1ZZ, the Euro 6 speed has a lower numeric final drive than the US 5 speed (3.94 Euro vs 4.31 5 speed) so the RPMS are lower at highway speeds and the top speed in each gear is higher. The SMT 6 speed is sometimes converted to manual and has the same first 5 gears and final drive as the stock 5 speed with an overdrive 6th, so the speeds in each gear are the same, but 6th drops RPM.

The 2ZZ seems to work best with the C60 as it has a higher numerical final drive at 4.529, so the RPMs are higher in each of the first 5 gears at any speed with an overdrive 6th. Since the 2ZZ powerband is at higher RPM than the 1ZZ, it is better matched to the C60

Examples of typical RPM at 70 in top gear (tire size dependent)
US 5 speed: 3,600
Euro 6 speed: 2,950
SMT 6 speed: 3,200
C60 6 speed: 3,400

Personally, with a 1ZZ, the Euro 6 speed is the nicest combination for more open roads and highways, but the converted SMT 6 speed is the nicest on tight roads with the same first 5 gears as stock and the overdrive 6th to drop the RPM on the highway. Most people with a 2ZZ use the C60.
 

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The Corolla 5th gear ratio (.725) is exactly the same as the SMT 6th gear. In effect it would behave the same as the SMT 6 speed if you skipped 5th on the shifts. We have a Spyder with a converted SMT 6 speed and still use 5th quite a lot, so I wouldn't want to give it up. But the swap is a pretty easy way to get a taller highway gear.

If you ran a taller rear tire with about a 24" diameter like 225/45-16 or 205/55-15 and had the Euro 6 speed you would be down to about 3,200 at 80. That would be around a 800 rpm drop from stock at that speed, which is significant
 

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What do you use 5th for? Just curious. On my Euro 6 speed I skip 5th, it's 200 RPM off from 6th or so.
It seems top me that the "sweet" spot for a basically stock engine is between 3,000 and 4,500 RPM. This is in the "fat" of the torque curve for decent acceleration and yet not running running the engine hard. On some moderately fast back roads (50-70 mph), 4th is near the top of that range, and 6th is a bit below that range so 4th and 5th get used quite a lot, even with the converted SMT. With a Euro 6 speed, we mostly only use 6th on the highway, and 3rd and 4th get used more on the back roads.

On normal highway driving, I often skip 5th and go 4th to 6th. I do that a lot with other cars we have owned with 6 speeds.
 

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I find the idea of a Corolla 5th gear intriguing.
I have spent a lot of time thinking about the Corolla 5th gear vs a 6sp. I have yet to pull the trigger on either as I am pretty happy with the 5sp and it isn't broke. A 400rpm drop would be great at interstate speeds.
 

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I am quite satisfied with the gearing on my 1zz with lsd for all but freeway driving, which really isn't even all that bad. But, if the SMT would be an easy swap, I would welcome the 400 rpm drop at 70 MPH. I understand the advantage of the Euro 6sp but they seem rare and expensive, while the SMT 6 with LSD might be more plentiful and doesn't change my current 1-5 gearing. Assuming I could find a good one, where can I find info on swapping an SMT 6 into my already-manual-configured chassis?
 

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It is probably easier to source a Euro 6 speed than a SMT. Most used SMT are going to be high mileage parts. If you find a used SMT 6 speed, it needs to be converted to manual. The easiest solution is the MWR Kit. But it isn't cheap. You could buy the required parts from Toyota and build you own kit using some of the SMT shifter parts, but won't save much. The required parts are almost $500 list, but can be found online discounted. You can usually get the Euro 6 speed from Mike V, although he doesn't show any available at the moment. Both will be used, and a SMT with conversion parts may actually cost more. If you want LSD, most of the Euro 6 speeds with have it, while most SMT do not.

The 6 speed is slightly longer than the 5 speed, so clearance during install is a bit tight, but not a problem. Otherwise, the transmissions are direct replacements for the 5 speed and can use the original shifter, axles, and shift linkage. If you want a "stock" looking 6 speed shift knob, you can get the Celica GTS knob, which isn't cheap (0ver $100).
 

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Discussion Starter #19
Simple answer. If you've ever driven the Spyder over 80mph, you know why.
Im not sure I have! its not really enjoyable at that range (so why go fast if its not that fun). But from what Im sensing, it is to drop the RPMs at higher speeds.

as my friend said below, I find that the car is most fun between 3-4.5k RPMs, does that means with a 6 spead ill get similarly zippy performance at higher speeds due to lower rpms?
 
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