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Discussion Starter #1
Will the 3.27 rear gears from a Supra turbo fit in my '02 5 speed LSD rear end? I have an "I think so" answer but I am looking to comfirm that. I think the car is geared too low. I mean, I can shift into 5th gear at 38 mph, which is ridiculous. My old GSR was geared to 160 in fifth with a four cylinder and my '85 Mustang GT's theoretical top speed was OVER 200 mph (yes, I know it wouldn't go that fast). My point is that a top gear speed of 140 for a 6 cyl is little low. I don't know how to do the calculation but I bet the swap from the 3.5x gears to 3.27 will get me closer to 180 top speed, which will increase mileage. I will make up for the taller gears with some power mods. This might also be a good mod for those people with FI. Thanks.
 

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with lots of fabrication, not without. when i say fabrication, i don't mean bending a few things, i mean custom mounts, tig welding, machining, plasma cutting and a lift.

btw, the american supra final drive was 3.13, supposedly the japanese final drive was 3.27.

-gte






ckIS300 said:
Will the 3.27 rear gears from a Supra turbo fit in my '02 5 speed LSD rear end? I have an "I think so" answer but I am looking to comfirm that. I think the car is geared too low. I mean, I can shift into 5th gear at 38 mph, which is ridiculous. My old GSR was geared to 160 in fifth with a four cylinder and my '85 Mustang GT's theoretical top speed was OVER 200 mph (yes, I know it wouldn't go that fast). My point is that a top gear speed of 140 for a 6 cyl is little low. I don't know how to do the calculation but I bet the swap from the 3.5x gears to 3.27 will get me closer to 180 top speed, which will increase mileage. I will make up for the taller gears with some power mods. This might also be a good mod for those people with FI. Thanks.
 

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Discussion Starter #3
To clarify: you're saying the gears themselves cannot be swapped into the existing diff without major mods, correct?
 

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as far as i know, the ring/pinion setup is not interchangable. i haven't had them side by side, but the housing configuration and sizing is different to the plain eye

-gte





ckIS300 said:
To clarify: you're saying the gears themselves cannot be swapped into the existing diff without major mods, correct?
 

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Discussion Starter #5
:x Aaaarrrrgggghh! Another brilliant idea goes up in flames. How would I get the definitive answer? Call the parts guy at my local Lexus dealership?
For the benefit of the FI guys some one needs to make some taller rear gears. The car will start without too much fuss in 2nd gear right now; I can only imagine how bad it is with 300+ HP.
 

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its not bad at all with the stock trans, check out the gearing of the supra trans combined with the stock rear.

you can pretty much assume that it isn't going to fit period. i have an idea on what might, but i won't be talking about it until i do some testing ;)

-gte






ckIS300 said:
:x Aaaarrrrgggghh! Another brilliant idea goes up in flames. How would I get the definitive answer? Call the parts guy at my local Lexus dealership?
For the benefit of the FI guys some one needs to make some taller rear gears. The car will start without too much fuss in 2nd gear right now; I can only imagine how bad it is with 300+ HP.
 

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Discussion Starter #7
I know the six speed is a great option and I could afford it but my wife would shoot me. This car should have had a six speed all along.

Can't wait to find out what might fit! :p
 

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You might think about changing out the whole rear end of the car. I'm sure it can be done with some custom work. You might need some custom mounts, some controle arm work, and a new drive shaft but I think the rest is just plug and play. The down side to this option is that you might not have an LSD if you choose the wrong rear, not to mention the cost of it all if you dont have the tools to do it your self.

In my opinion, this is still a good option. You might be able to get a whole diff out of an old es300 or sc300 to match up quite well, but as for using a supra ring and pinion I cant say because Ive never looked.

On a side note, I remember hearing something about the Is300 trans being the same as a toyota truck or some crap like that. That might be one thing you might wana look into for gears, and if thats true you might be able to find a new type of swap for the trans.
 

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is carrollton texas near dallas or plano? are you the ebay seller?




is300tx said:
You might think about changing out the whole rear end of the car. I'm sure it can be done with some custom work. You might need some custom mounts, some controle arm work, and a new drive shaft but I think the rest is just plug and play. The down side to this option is that you might not have an LSD if you choose the wrong rear, not to mention the cost of it all if you dont have the tools to do it your self.

In my opinion, this is still a good option. You might be able to get a whole diff out of an old es300 or sc300 to match up quite well, but as for using a supra ring and pinion I cant say because Ive never looked.

On a side note, I remember hearing something about the Is300 trans being the same as a toyota truck or some crap like that. That might be one thing you might wana look into for gears, and if thats true you might be able to find a new type of swap for the trans.
 

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Discussion Starter #10
You mean that there is a sister tranny to the IS3? That would be plan B. I think 1,2, &3 gears are ok but 4 and especially 5 are a little too short. It would be great to find the equivalent of 4.5 to use as fourth gear and a little more overdrive for fifth.
 

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Discussion Starter #11
Aha! So, the Aussie IS has a 3.58 final drive ratio. Would that fit in my diff? Any other foreign iterations of our car with taller final drives?
 

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You need to find out what type of differential the IS has first.

Once you know that, find out which cars have the same type.

Then find out if they have different final drive ratios.
 

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ckIS300 said:
OK, where do I find this info? At my dealership? Any other good sources?
One way to go would be to call the dealer's parts department and ask them...
 

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Aubie83 said:
Yeah, but do they make differenc gears for the IS300? :-?
My understanding is that they don't make a different final drive for the IS300.

However, if the differential in the IS300 is used in other cars, it may have a different gearing in those applications.

So, you'd have access to different gearing that way.

Make sense?
 

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Discussion Starter #17
Hmmm, the Tacoma truck comes with 3.58 and 3.72 final drive ratios. I wonder what gears are in that tranny....? I also want to know what the final drive is for the GS series.
 

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ckIS300 said:
Hmmm, the Tacoma truck comes with 3.58 and 3.72 final drive ratios. I wonder what gears are in that tranny....? I also want to know what the final drive is for the GS series.
You need to find out if the differentials have swappable components before you do anything else.

Otherwise it doesn't matter.
 

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quick said:
Aubie83 said:
Yeah, but do they make differenc gears for the IS300? :-?
My understanding is that they don't make a different final drive for the IS300.

However, if the differential in the IS300 is used in other cars, it may have a different gearing in those applications.

So, you'd have access to different gearing that way.

Make sense?
Yep, I wonder which ones though :)
 

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Discussion Starter #20
I'm leaning towards changing 4th and 5th gears. The car is short geared in 1-3 but it does pay benefits with respect to acceleration. I just looked up the gearing in a Golf GTI 1.8; it has a 3.65:1 final drive and 4th is .9x and 5th is .75. This is taller than the IS and this is a 4 banger, albeit with turbo.
 
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