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kbraun94 · 04-10-2017, 11:01 PM

You know that feeling you get when you're given a ton of options and can't choose between them? Yeah, that's where I'm at right now.

I'm trying to decide on a final drive ratio for a brz. It's driving me crazy, cause I can't go out there and test them individually... xD

So...can I get your opinions on what a good fdr might be for me?

My situation looks something like this: Manual transmission, daily driver, no plans for FI, the car will never see speeds over 80, infrequent interstate trips (30 mins to 2 hours), and not interested in 0-60 times. I'm trying to give the car a very clear sense of urgency. I want to make it feel like it's hauling buttocks without it actually hauling buttocks.

My options are as follows: 4.56, 4.67, 4.88

Stock 2017 brz has a 4.3 fdr, and based on a number of videos, people driving the updated model can feel the 4.3's difference over earlier models' 4.1. They basically said that the fdr woke the car up a little. It's a little more eager to push. With this in mind, 4.3 still seems to tall. So, looking at the other three options, the "pull feeling" of 4.56 should be twice that of 4.3; the "pull feeling" of 4.67 should be just under thrice that of 4.3; and 4.88 should be fourfold that of 4.3. Assuming my maths are correct, 4.88 seems best.

But, I've seen it mentioned a couple times (there are FAR more final drive posts for ATs, which makes sense, but still...) that fuel economy on highways becomes abysmal. If you think about it, traveling stock at 70 is 3k, and that yields 29mpg. With 4.88, 70 is at 3600. 3000/3600 = 0.83, 0.83 * 29 = 24. And 80 would be 22. So, I'd be placed right up there with V8s. Go 'Murica! This, in and of itself, isn't so bad, so long as there aren't any other powertrain-related downsides apart from natural wear.

I've also heard that the first gear becomes useless and that, in manual applications, it's really only used to tailor cars to specific tracks. How true is this?

In all, I obviously favor the 4.88 'cause of the mechanical torque gain. But, if it's too impractical for daily driving, there's also the 4.67. And if that's still too impractical, there's 4.56. What do you all think?

04-10-2017, 11:01 PM	#1
kbraun94 Junior Member Join Date: Apr 2017 Drives: brz Location: GA Posts: 4 Thanks: 0 Thanked 1 Time in 1 Post Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Final Drive Ratio Help You know that feeling you get when you're given a ton of options and can't choose between them? Yeah, that's where I'm at right now. I'm trying to decide on a final drive ratio for a brz. It's driving me crazy, cause I can't go out there and test them individually... xD So...can I get your opinions on what a good fdr might be for me? My situation looks something like this: Manual transmission, daily driver, no plans for FI, the car will never see speeds over 80, infrequent interstate trips (30 mins to 2 hours), and not interested in 0-60 times. I'm trying to give the car a very clear sense of urgency. I want to make it feel like it's hauling buttocks without it actually hauling buttocks. My options are as follows: 4.56, 4.67, 4.88 Stock 2017 brz has a 4.3 fdr, and based on a number of videos, people driving the updated model can feel the 4.3's difference over earlier models' 4.1. They basically said that the fdr woke the car up a little. It's a little more eager to push. With this in mind, 4.3 still seems to tall. So, looking at the other three options, the "pull feeling" of 4.56 should be twice that of 4.3; the "pull feeling" of 4.67 should be just under thrice that of 4.3; and 4.88 should be fourfold that of 4.3. Assuming my maths are correct, 4.88 seems best. But, I've seen it mentioned a couple times (there are FAR more final drive posts for ATs, which makes sense, but still...) that fuel economy on highways becomes abysmal. If you think about it, traveling stock at 70 is 3k, and that yields 29mpg. With 4.88, 70 is at 3600. 3000/3600 = 0.83, 0.83 * 29 = 24. And 80 would be 22. So, I'd be placed right up there with V8s. Go 'Murica! This, in and of itself, isn't so bad, so long as there aren't any other powertrain-related downsides apart from natural wear. I've also heard that the first gear becomes useless and that, in manual applications, it's really only used to tailor cars to specific tracks. How true is this? In all, I obviously favor the 4.88 'cause of the mechanical torque gain. But, if it's too impractical for daily driving, there's also the 4.67. And if that's still too impractical, there's 4.56. What do you all think?