3.73 gears too much?

Loco5.0

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Apr 2, 2005

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Mar 24, 2008

#1

• Mar 24, 2008

• #1

My car has 3.73 gears & a 2500 stall. I'm adding a single T76 turbo setup
C4 3 speed trans
26" tires
shift at 6k

Are the 3.73s too much?

 

QDRHRSE

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Dec 31, 2002

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Mar 24, 2008

#2

• Mar 24, 2008

• #2

Should be perfect with an AOD.

 

Fast63

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Sep 20, 2007

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Mar 25, 2008

#3

• Mar 25, 2008

• #3

He has a C4, not an AOD...

at 6000 rpm in 3rd, you'll be able to go 124.48mph, so if you plan on going faster than that in the quarter mile, then they are too much.

So at 3000 rpm, you'll be cruising at 62.24mph, or 3133rpm at 65. If that cruising rpm bothers you, then you need a different gear.

Hope that helps

 

strtrcr50

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Jun 21, 2006

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Previously from Dirty Jerzey exit 7a

Mar 25, 2008

#4

• Mar 25, 2008

• #4

Turbo cars also like a load against them. I'd go to a 3:55 or 3:08. can you get a lockup converter for your trans?

 

Loco5.0

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Mar 25, 2008

#5

• Mar 25, 2008

• #5

Fast63 said:

He has a C4, not an AOD...

at 6000 rpm in 3rd, you'll be able to go 124.48mph, so if you plan on going faster than that in the quarter mile, then they are too much.

So at 3000 rpm, you'll be cruising at 62.24mph, or 3133rpm at 65. If that cruising rpm bothers you, then you need a different gear.

Hope that helps

Click to expand...

No, I am around 3200 RPM when I am doing 75-80.

 

J

Jmunk

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Sep 30, 2007

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Mar 25, 2008

#6

• Mar 25, 2008

• #6

Those gears would not bother me with your setup.

 

NKau

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Mar 25, 2008

#7

• Mar 25, 2008

• #7

Loco5.0 said:

No, I am around 3200 RPM when I am doing 75-80.

Click to expand...

Then either you don't have 3.73's, your tach or speedo are way off, or you have an overdrive transmission and don't know it

 

M

mavmavv

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Mar 25, 2008

#8

• Mar 25, 2008

• #8

Personally, id go 3.55.

 

Loco5.0

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Mar 25, 2008

#9

• Mar 25, 2008

• #9

NKau said:

Then either you don't have 3.73's, your tach or speedo are way off, or you have an overdrive transmission and don't know it

Click to expand...

It's a C4 3 speed w/manual valve body. No OD. Tach could be off, but then so would my Auto Meter tach since they read about the same.

 

Fast63

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Mar 25, 2008

#10

• Mar 25, 2008

• #10

Loco5.0 said:

It's a C4 3 speed w/manual valve body. No OD. Tach could be off, but then so would my Auto Meter tach since they read about the same.

Click to expand...

Then you've exhausted the only other option. Your speedometer is off.

Unless your tires really are not 26 inches in diameter.

The formula doesn't lie my friend.

 

Loco5.0

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Mar 25, 2008

#11

• Mar 25, 2008

• #11

Fast63 said:

Then you've exhausted the only other option. Your speedometer is off.

Unless your tires really are not 26 inches in diameter.

The formula doesn't lie my friend.

Click to expand...

The speedo very well could be off. I don't have anything to test it. The tires definitely are 26" though. I wasn't saying you're wrong. You could be right, but I can only go by what I see & what info I have.

 

NKau

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Mar 25, 2008

#12

• Mar 25, 2008

• #12

Loco5.0 said:

The speedo very well could be off. I don't have anything to test it. The tires definitely are 26" though. I wasn't saying you're wrong. You could be right, but I can only go by what I see & what info I have.

Click to expand...

If you know your tire height, gear ratio, and RPM, you can calculate what speed you are running at various RPM's by plugging in some different RPM numbers. If I had the formula, I'd give it to you......but I don't

 

SuperStang83

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Mar 25, 2008

#13

• Mar 25, 2008

• #13

I'd go with higher gears if you are going turbo. 3.27s would be a good choice.

 

Fast63

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Mar 25, 2008

#14

• Mar 25, 2008

• #14

There are different formulas, but the one I like the most is this:

RPM = MPH x 88 divide by the circumference of your tires in feet x Transmission gear ratio x rearend gear ratio.