Top Gear - 5 Auto vs 6 Manual

S

stripmonkey

Member
Just a quick question for you tech guys that I've been wondering about for a while...

My Zed is a 2.5 auto with 5 forward gears. How does top gear in this compare to the 6 speed manual boxes? Is it the same ratio, with the lower gears spread through the range? Or is manual 6th a 'faster / extra' gear that the auto doesn't have? In 5th mine does about 2,500 RPM at 65ish :driving:
 
I think my 6th gear is a little longer than that. On an unused airfield *ahem* I was doing 80mph, and if I remember correctly, that's about 3,000rpm

I'm sure someone who uses their zed daily will be able to help more :thumbsup:
 
Hard to do a direct comparison because the 2.5i auto and 3.0 manual also have different final drive ratios as well, as does the 2.5i manual. Your final drive would mean that even with an identical gearbox to the 3.0 your engine would be revving higher in any given gear.
 
I got all exicted about the title of this thread.
I thought the show Top Gear was doing an article on our cars
Oh well never mind :rofl:
 
Looks like the 2.5 auto .74:1 with 3.64:1 final drive, With 255/35/18 tires = 165 @ 6000 revs
six speed 2.5 si, .85:1 with 3.38:1 final drive, With 255/35/18 tires = 155 @ 6000 revs

Link to formula. http://www.apexgarage.com/tech/gear_ratios.shtml
 
To complete the comparison, doing bigdog's calc on the other end...
2.5 auto 1st gear 3.67 with 3.64 final drive with 255/35/18 tires = 33mph @ 6000 revs
2.5 manual 1st gear 4.35 with 3.38 final drive with 255/35/18 tires = 30mph @ 6000 revs

Thus auto is 10% taller in first, down to 6% taller in top gear, which means a corresponding decrease in torque at the wheels with auto trans. Interesting. Good question stripmonkey.
 
Gear ratios 1 through 5 are the same on both boxes, the 6 is an overdrive gear. but they final drive ratio will be different so they tend to cruise at the same RPM from my knowledge.
I cruise at around 2700~ in 6th at 70, 3000 at 75. wish it were lower though.
 
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