RDU Ratio

[Auggie]

Does anyone know what the RDU ratio of my 2015 SHO non PP is ?

    Auggie

 

[Brucelinc]

2.77.

 

[Auggie]

OK thanks. Now what is the trans OD ratio .70?

 

[Brucelinc]

.0742.

 

[SHOdded]

Wikipedia has some answers:
https://en.wikipedia.org/wiki/GM-Ford_6-speed_automatic_transmission

 

[Brucelinc]

Mediaford.com has tons of information, too.

 

[Auggie]

Hey guy's, thanks a bunch.

    Auggie

 

[ajpturbo]

2.77.

That is the final drive.....I don't think the ring and pinion in the rear needs to be the same....The focus RS is different and the clutch packs handle the torque delivery I think.

 

[Auggie]

So, if I was to attempt a top end run should I use 4th or 5th gear and what is the max RPM that these engines can reach?

    Auggie

 

[ajpturbo]

So, if I was to attempt a top end run should I use 4th or 5th gear and what is the max RPM that these engines can reach?

    Auggie

Probaly 6th....why would you think 4th or 5th

 

[FoMoCoSHO]

Ajp, we know you have a 140mph log somewhere, what gear were you in?

 

[ajpturbo]

Ajp, we know you have a 140mph log somewhere, what gear were you in?

Very end of 5th

 

[Auggie]

OK, my second question was "What is the max RPM of these engine"?

    Auggie

 

[ajpturbo]

Im sure you could rev it to 7000...i dont see much benefit to rev it much over 6k...maybe 6200

Why do you ask?

 

[Auggie]

In order to calculate the speeds of each trans gear with the 2.77 rear gear I will need to know what RPM these engines perform the best at. In other words the max RPM at each shift point. I don't think there is enough HP to pull 6th gear for top end ?

  Auggie

 

[ajpturbo]

There isnt enough power to pull top speed in top gear in most cars...and the gear before top gear is usually too short...so drag limited in top gear is usually where it happens

 

[ajpturbo]

Auggie, you can calculate all you want but if you really want to know then get out there and do it...cant change the final drive and i dont think changing the shift point will help much

 

[Auggie]

Yup AJ your right and I will do just that. But in the mean time I want to know what gear will give me the best results. If I use 6000 RPM(tach has a red line at 6500) here's what I came up with.

Engine RPM = 6000
Tire Diameter = 28.0"
Gear Ratio = 2.77
Trans Gear Ratios = 4.484, 2.872, 1.842, 1.414, 1.00

4.484 = 40.3 MPH
2.872 = 62.9
1.842 = 97.9
1.414 = 127.7
1.00 = 180.5  SO: To go 140 MPH + I would use 5th gear and have to reach at least 4800 RPM. It would be nice to change 5th gear to a 1.200 ratio at 5800 to go a 140.0 +. I wonder if the engine would be able to keep pulling past 4800 RPM in 5th gear to go 150.0 MPH + ?

    Auggie

 

[ajpturbo]

Shouldve  got a pp

 

[Auggie]

Yup, the 3.16 rear gear ratio would have been an advantage. Are there aftermarket gears available?

    Auggie