Gear and pinion question

[AtlasMK5s]

Has anyone tried 3.73 gears in an ecoboost yet? I'm thinking about swapping from 3.31 but wanted to know how it affects drivability and power band.

Sponsored

 

[dragonacc]

The gearing is pretty low on both the manual and auto. I probably wouldn't change unless you plan to go big turbo and also increase the factory rev limit.

 

[Bomicino]

I've also been curious about 3.73s. Although the gears are short, I run 285/40r19s, 28" tall. The couple seconds it takes to get into boost sometimes feels like forever. Gears would probably help with the instant gratification, with the trade off of shifting quicker, less time in each gear. There's also the debate of the benefits of low gears helping put more of a load on the turbo, helping power production, but not accelerating as quicky. I'm not an expert on the topic by any means. I did go from 3.27 to 3.90s in a fox body in high school, and it was a great seat of the pants improvement. I'd bet it's a decent option on the big turbo cars that get an extra 1500 rpm of power production.

 

[dragonacc]

Go big or go home, 4.10s all the way... lol

I don't think gears are a bad idea, but its a lot more work changing them on the new IRS.

 

[Bomicino]

Thats too wimpy actually, I used to have an rx8, and MAZDASPEED sells 5.12s!

 

[dragonacc]

Thats too wimpy actually, I used to have an rx8, and MAZDASPEED sells 5.12s!

When you have 10,000 rpms to play with 5.12s are probably no big deal.

 

[Fast64ranchero]

With 3.55's in mine, I'm already to the point I need to shift to 5 to stay in the curve in the 1/4 mile. I've been thinking about going the other way (from 3.55 to 3.33) to keep from shifting to 5th..

 

[Bomicino]

Are you on stock size tires?

 

[dragonacc]

With 3.55's in mine, I'm already to the point I need to shift to 5 to stay in the curve in the 1/4 mile. I've been thinking about going the other way (from 3.55 to 3.33) to keep from shifting to 5th..

Stock rev limit?

 

[AtlasMK5s]

I'm still debating the gear change. I spent Friday night at the track and learned a good bit about my car. My best time was 14.0 at 92 mph and a 1.9 60, would have been faster but at the top of the track I missed 4th. Every other run was 95-96mph with little to no spinning. The car needs to be launched hard at high rpms, my best run I left at 4300 rpms. That's what makes me think 3.73 would help by increasing torque in first and second so I can launch at a lower rpm.

 

[neodark]

I'm still debating the gear change. I spent Friday night at the track and learned a good bit about my car. My best time was 14.0 at 92 mph and a 1.9 60, would have been faster but at the top of the track I missed 4th. Every other run was 95-96mph with little to no spinning. The car needs to be launched hard at high rpms, my best run I left at 4300 rpms. That's what makes me think 3.73 would help by increasing torque in first and second so I can launch at a lower rpm.

I have no idea how you're not just spinning your tires launching that high. Do you have TC ON?

 

[AtlasMK5s]

I have no idea how you're not just spinning your tires launching that high. Do you have TC ON?

No that was with advance tc off. Without a high rpm launch the power band fell on its face.

 

[Fast64ranchero]

Are you on stock size tires?

Yes stock tire diameter

Stock rev limit?

6,800 rpm limiter, I short shift and that is past the curve, better then shifting at this point, but still past the power curve. When I make more power, I'll have to shift, or make the curve move to the right on the rpm scale.

 

[Bomicino]

Ranchero, I'll pull my 3.31 center section out before I go on vacation august 3rd, send it your way for a trade?

 

[dragonacc]

Yes stock tire diameter



6,800 rpm limiter, I short shift and that is past the curve, better then shifting at this point, but still past the power curve. When I make more power, I'll have to shift, or make the curve move to the right on the rpm scale.

I think if you go big turbo in the future you will regret changing to 3.31s, but if its going to be a while go for it.

Sponsored