? gearratio c-4 dailydriver

mg man

Member
Jun 24, 2006
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Trying to decide on gear ratio of 89 Mustang 2.3 turbo c-4 intercooled. Still has original 3.73 gears. Approx 3000 rpm at 55 to 60. needest to say not good on gas. This is daily driver for wife. Tire size p225/60r15. Shifting is between 3300 to 3700rpm. The way I read I need to stay under 3000 to stay out of when computer changes loop modes. Don't want to do this several times. Have done several search but most comments are for 5 speed or dragracing with a c-4. What do you recommend.
 
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Stinger

Founding Member
Jul 7, 2001
7,753
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Shawnee, KS
Search on google for a gear ratio calculator...Then you can plug in your 1:1 trans gear, tire size, and different gear ratios to find one that creates a good rpm.

Most likely, you'll have to drop clear to a 3.08 or something if you want to be able to go 75-80 at under 3 grand...which will make the car dangerously slow.

BTW, it changes loop at about 2800rpm.
 

mg man

Member
Jun 24, 2006
142
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Thanks Stinger I found that calculator. But didn't know motor would do at differant gear ratio's. Thought changed at 3000 been reading Turboford I've been wrong before. I won't be running no 75-80 if I am I want care about fuel mileage. I was thinking of 3.08 but with your advice forget that. Would something around 3.27 or 3.45 be good? Wife drives speedlimit . We live within 5 miles of work and not too much out of town.New at the 2.3 t but trying to learn. Definitely has a learning curve.Thanks alot save from one gearchange and money. I respect your opion
 

Stinger

Founding Member
Jul 7, 2001
7,753
24
118
Shawnee, KS
Come on now...

According to this gear ratio calculator (tire diameter 25.6" according to an online tire size calculator): http://www.et-studios.com/motorsports/gears/gears.html

It says 3.27's will go 70mph @ 3 grand...with converter slip though it's probably closer to 65-67mph. It says 3.08's will go 74mph which is probably more like 70-72mph...

If it's turbo, it would be ok, if it's n/a...that's too much gear...