mjr46

I put 3.50's in my 66 and honestly it could use more cause at 65 mph rpms =2100 mine would really benifit from a 3.73 or 3.89 since it now has overdrive

Gun Jam

okay okay ignore the cobra comment lets just call it a 1352-249

It shifts great into first with no grind at all.

According to your inputs it sounds like it working as it should.

-mjr46 do you have a diff ratio calculator that accounts for overdirive or a formula? All the ones I have seen assume 1:1
With 3.50 what would be my rpm at 90? what about with 3.73s? with a 25" rear wheel and probably a .63 overdrive.

Thanks for your help guys

-Gun

mjr46

4 th gear on the t-5 is 1 to 1 but if I understand your question right and most t-5's the overdrive is .68?? ...I don't have a diff calculator bu my guess is around 90 mph rpm's would be closer to 3000 with my old t-10 and 3.50's rpm's at highway speed were 3000 easy = to much for me so that's why I DID the t-5 conversion

Gun Jam

is there anyway to figure out if my t5 is .63 or .68 based on the tag number?

thanks

-Gun

mjr46

YES!! according to the number you gave me you have the 1352-249 = 2.95 first gear ratio t-5 = world class 330 ft lbs rated and according to my decoder here are the ratios starting with rev 1, 2 , 3 , 4 , 5,





1352-249
Ford Mustang All 5.0 V8 WC
U
2.76
2.95
1.94
1.34
1.00
0.63

mjr46

that's why it may not be as peppy in 1st and has flat spots when climbing to another gear..I have a 3.35 t-5 first and it's ample...but coupled with your 3.00 gears your ratios are not prudent to achieve what you desire......with a .2.95 t-5 and a .063 overdrive you might wanna think about at least a 3.73 gear

Gun Jam

Yeah I knew it had the high nickel alloy gears and was the "badass" t5

so now that we know 5th is a .63 ratio does anyone know how to calculate rpm at 90 mph with a with 3.73 gears? I havent found a formula that allows for overdrive do i just take the 1:1 rpm and x by .63???

Thanks

-Gun

bighungrymatt

yeah I never downshift in any of my manualvehiclesinto first unless I am barely rolling or at a complete stop

golden_eye

Using the spreadsheet I made in excel (I was really bored [8D]) it's looking like you should be around 2600rpm in 5th at that speed. I just used 255/45/17 as the tire since you didn't specify that but it shouldn't changeby too much.

I autocross my car and sometimes I have to downshift into 1st if I don't want to bog coming out of some of the sharper turns. As long as I rev match it (still working on my heel-toe) it goes in without grinding or skidding the back tires but I usually am not looking at my speedometer when I'm doing that so I don't really know what speed I'm doing. Probably more than 10 mph though .

Gun Jam

total wheel height is 25"

so with a 25" wheel height 3.73 gears 90 mph with .63 overdrive what would you calculate rpm at now?

Thank you for your help

-Gun