1st trip w/ T5

R

Rapid

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Mar 31, 2005

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Columbia, SC

Mar 3, 2007

#1

• Mar 3, 2007

• #1

I drove my 65 coupe with the new T5 Z to see my daughter about 80 miles away.

80 MPH at 1700 RPM, 21.8 MPG. Is this comprable to other T5 set ups? I feel like I may have some room for a little taller diff now.

Sure is cool to slip into 5th!

 

mdjay

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Dec 9, 2003

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Las Vegas, NV

Mar 5, 2007

#2

• Mar 5, 2007

• #2

Rapid said:

I drove my 65 coupe with the new T5 Z to see my daughter about 80 miles away.

80 MPH at 1700 RPM, 21.8 MPG. Is this comprable to other T5 set ups? I feel like I may have some room for a little taller diff now.

Sure is cool to slip into 5th!

Click to expand...

You must have highway gears in the rear and a .64 top gear on your trans. Nice numbers for a 42 year old car

You have some room now to add some rear end gears without too much loss up top.

 

dlf

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Nov 14, 2005

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Rincon, Georgia

Mar 5, 2007

#3

• Mar 5, 2007

• #3

Your results are very comparable to mine. My 66 coupe has a 3.00 differential gear and your rpms appear to be very close to what I'm getting at 70 mph. I'm planning to put a new pumkin in the 8" rear this weekend with a 3.55 and trac loc. I felt that the 3.00 was a bit tall for my engine/trans setup and after much consideration, I decided to go with the 3.55.

 

ratio411

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Apr 21, 2002

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109

Pensacola FL

Mar 7, 2007

#4

• Mar 7, 2007

• #4

I had 3.42s with a .50 OD on a previous car, and it did 2000 rpm at 80.
1700 at 80 is crazy low.
You must have 2.79s, right? (and maybe some tall tires too...)

I would think you could jump up to 3.25-3.55 and still get decent mpg.
Dave

 

R

Rapid

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Mar 31, 2005

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Columbia, SC

Mar 8, 2007

#5

• Mar 8, 2007

• #5

ratio411 said:

I had 3.42s with a .50 OD on a previous car, and it did 2000 rpm at 80.
1700 at 80 is crazy low.
You must have 2.79s, right? (and maybe some tall tires too...)

I would think you could jump up to 3.25-3.55 and still get decent mpg.
Dave

Click to expand...

Thanks, My diif does not have its tag but I do believe that it is a 2.79. I am running 70 series soon to be 60 so that will help and I plan a Tru-track with 3.25 gears as the next project. I have always enjoyed my car but it has really come alive with the new tranny!

 

iskwezm

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May 24, 2005

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Rowland Heights,California

Mar 8, 2007

#6

• Mar 8, 2007

• #6

Rapid said:

I plan a Tru-track with 3.25 gears as the next project. I have always enjoyed my car but it has really come alive with the new tranny!

Click to expand...

Put some 3.55's or 3.80's and youll think it was new engine you slapped it.

I have 3.80s(soon 4.11's) and drive mine pretty far distances sometimes, but im not worried about gas mileage

 

R

Rapid

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Mar 31, 2005

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Columbia, SC

Mar 8, 2007

#7

• Mar 8, 2007

• #7

blkfrd said:

I agree. Don't put 3.25s in. At least 3.50s or 3.73s or 3.80s. I went from a C4 crap-o-matic to a T5z and I have 3.50 rear gears. The T5z make the 3.50s equivalent to 4.10s in 1st gear as compared to the C4's 1st gear. If you go much higher than 3.80s though, you'll have a very short 1st gear.

My gas mileage went from 11.5 with the C4 to 17 with the T5z. Overdrive is wonderful!

Click to expand...

How would the 3.50s affect the rpm? If I am turning 1500 at 70 mph with the 2.79
what would I turn with the 3.50? Is there a formula? It is a daily driver with mixed city and highway use and I would like to stay flexable.

Thanks

 

ratio411

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Apr 21, 2002

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Pensacola FL

Mar 8, 2007

#8

• Mar 8, 2007

• #8

Rapid said:

How would the 3.50s affect the rpm? If I am turning 1500 at 70 mph with the 2.79
what would I turn with the 3.50? Is there a formula? It is a daily driver with mixed city and highway use and I would like to stay flexable.

Thanks

Click to expand...

Here, you need to know your tire size and such...

http://www.f-body.org/gears/

I was playing around on there...

If you are running 1700 rpm at 80 mph, and your engine is capable of 6000 rpm...
Then your theoretical top speed is 280 mph!!!
You need more gear...

 

R

Rapid

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Mar 31, 2005

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Columbia, SC

Mar 8, 2007

#9

• Mar 8, 2007

• #9

ratio411 said:

Here, you need to know your tire size and such...

http://www.f-body.org/gears/

I was playing around on there...

If you are running 1700 rpm at 80 mph, and your engine is capable of 6000 rpm...
Then your theoretical top speed is 280 mph!!!
You need more gear...

Click to expand...

I might need a spoiler at that speed...

The calculator is good stuff.

 

8

86bluecobra

Advanced Member

Dec 20, 2004

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B.C. Canada

Mar 8, 2007

#10

• Mar 8, 2007

• #10

personally i like this calculator. http://www.mustangworks.com/analyzer.html
if you scroll down there is a gear with tire diameter calculator. It is for the t-5's. I know there are different 1st and 5th ratio's but it gives you a ballpark if you want to enter different rear gear ratio's. Personally i believe the 3.73 rear gear with the t-5 is an awesome combo. so at 80 mph withh 3.73's you would be turning 2600 rpm.

 

67 Evil Eleanor

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Nov 22, 2006

66

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SW Virginia

Mar 8, 2007

#11

• Mar 8, 2007

• #11

You need more gear, why not a 4+ with that final drive of .63 or so. I personally like a .82 final and perfer a 370 or 350 (I have both and have learned thru the wallet). The .67 with a 370 is still sluggish in 5th unless you plan to change at about 130 or 140. But thats just me.

 

iskwezm

10 Year Member

May 24, 2005

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Rowland Heights,California

Mar 8, 2007

#12

• Mar 8, 2007

• #12

67 Evil Eleanor said:

The .67 with a 370 is still sluggish in 5th

Click to expand...

i agree

 

blown65

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Jul 7, 1999

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Queen Creek Arizona

Mar 8, 2007

#13

• Mar 8, 2007

• #13

I'm seriously thinking of ditching my C4 and doing a T5. 3100 rpm at 60 sux.

 

R

Rapid

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Mar 31, 2005

297

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Columbia, SC

Mar 9, 2007

#14

• Mar 9, 2007

• #14

Thanks guys, this gives me a lot to work with.