Gears - to answer the questions once and for all

[Fosters]

this has all the gear ratios for every ford tranny (except for the 2004 mustang one... not gonna comment on that)
http://www.vibratesoftware.com/html_...sions_Main.htm
site w/ correct ratios:
http://www.supercarsite.net/mustang_mach_1.htm



this is a speed/gear/rpm calculator:
http://www.allfordmustangs.com/Detailed/608.shtml


EDIT: Updated using .62 gear ratio, my bad
to save you all the trouble:
80mph at gear ratio:
3.55 = 2304
3.73 = 2421
4.10 = 2661
4.30 = 2791
4.56 = 2960

top speed w/ 3.55s, 5th gear @ 6798rpm (closest w/o going over 6800) = 236mph (obviously none of us will ever see anything close to this speed, so complaining about 'losing' top speed by going w/ a higher gear is pointless)

top speed w/ 3.73s, 5th gear @ 6780 = 224mph
top speed w/ 4.10s, 5th gear @ 6787 = 204mph
top speed w/ 4.30s, 5th gear @ 6769 = 194mph
top speed w/ 4.56s, 5th gear @ 6771 = 183mph


anyway, point is, doubt anyone is gonna 'lose' top speed... at least this was the main worry w/ 96-98 gt's :p (god it feels good now that I can rag on em :p)

EDIT: I guess I should update this thread with another calculation since this seems more appropriate now for my garage queen mach...

4th gear for manuals/3rd for autos (1:1), trap speeds at 6100rpm (stock engine peak) 6500 rpm (minor bolt-ons shift point), 6800 rpm (psr/cobra cams shift point)

26" tire:
Gear	6100rpm		6500rpm		6800rpm
3.55:	133		141.7		148.2
3.73:	126.5		134.8		141.1
3.90:	121		129		134.9
4.10:	115.1		122.7		128.3
4.30:	109.8		117		122.4
4.56:	103.5		110.3		115.4

28" tire:
Gear	6100rpm		6500rpm		6800rpm
3.55:	143.2		152.6		159.6
3.73:	136.3		145.2		151.9
3.90:	130.3		138.9		145.3
4.10:	124		132.1		138.2
4.30:	118.2		126		131.8
4.56:	111.5		118.8		124.3
4.88:	104.2		111		116.1

I now prefer this calculator if anyone cares: http://www.4lo.com/calc/gearratio.php

[JeromeMach1]

Thanks for the numbers. I just installed 4.30s and love them. I did not cal my speedo yet so I was wondering about my rpm. I guessed right that 80mph is turning 3K rpm. I can live with that.

Jerome

[Ralph Greene]

Did you use a .62 for 5th for our cars? The first 3650's in Cobra's had a .67. The older 5 speed T45's had a .67. The earlier 5 speed 3550's had .68 (except for the .8 RR versions). Sorry to question this if you did.

[Fosters]

Originally posted by Ralph Greene
Did you use a .62 for 5th for our cars? The first 3650's in Cobra's had a .67. The older 5 speed T45's had a .67. The earlier 5 speed 3550's had .68 (except for the .8 RR versions). Sorry to question this if you did.

I used a .67... where did you see the .62 ratio? more reason to go 4.30s or 4.56s gonna re-run my #s soon I think... dammit, now you got me curious, i'm gonna do the test tomorrow morning w/ the digital tach and GPS going... :p

looked them up on yahoo... thanks!

[GR8 WYT]

Where's the love for 3.73's?!?!?!?

[Fosters]

Originally posted by GR8 WYT
Where's the love for 3.73's?!?!?!?

added

[Ralph Greene]

We have .62 5th. Yes you are correct. At cruising we turn fewer RPM's with 4.30's, than previous 5 speed cars with 4.10's. From .67 to .62 is a 7.5% difference. From 4.10 to 4.30 is only a 5% difference.

[JeromeMach1]

Wooohoooo. Makes me feel even better about chosing the 4.30s. Thanks for the added info Ralph.

P.S. Ralph, your sig is getting pretty long there

Jerome

[Steelhorse]

Thanks for the info Fosters , i have been wondering if i would be regretting the 4:10's i bought in case the wife and i would take a highway trip in the 100 mile range which we do sometimes. The car is a weekend driver. Feel good about e'm now.

Ralph when you going to add a set of gears to that list?

[Ralph Greene]

Ralph when you going to add a set of gears to that list? [/B][/QUOTE]

I'm not doing gears to this car. I changed rear gears 7 times on my 98 Cobra...and wound up with 4.10's. But it saw some track duty with over 500 RWHP on 15" BFG DR's. If doing again, that car would have stayed with 3.73's (which it had twice). Gears didn't really matter, car was traction limited.

I'm not drag racing this car, and think the stock 3.55's are almost perfect for all around use...with our 5 speeds (I might would prefer 3.73's for my use). If I had a 6 speed like was in the 2000R (2.97 first gear), (even if .62 6th same as our .62 5th) , I would like a little lower gear. Maybe a 3.90 or something for all around use.

Our Mach's make their power about 10% lower in the RPM range than previous 4V's, so 3.55's or 3.73's on our car feels about like 4.10's on previous 4V's, and you shifted them at higher RPM.

I'm not running race tires on this car, and no one has shown me gears make a car any faster for the way I drive this car, for my use. And even if they do make you a couple tenths faster on stock tires, that is not measureable for street use. And I like saving 5th for strictly highway cruising. I also like lazy 70-75 MPH cruising at a little over 2000. So stock 3.55's work for me.

If I were to get interested in drag racing this car with stock 5 speed, I would just jump to 4.30's, or maybe 4.56's, with a little taller than stock tire. Whatever tire/gear combo it takes to max out 4th at end of 1/4. But I will let you guys do all that stuff this time.

[MR Bulk]

"Whatever tire/gear combo it takes to max out 4th at the end of 1/4."

What a wise and sage statement...

[mach1dsg]

Originally posted by Ralph Greene

I'm not drag racing this car, and think the stock 3.55's are almost perfect for all around use...with our 5 speeds (I might would prefer 3.73's for my use). If I had a 6 speed like was in the 2000R (2.97 first gear), (even if .62 6th same as our .62 5th) , I would like a little lower gear. Maybe a 3.90 or something for all around use.

ralph, why do you think 3.73's would be better for all around use over 3.55's??, i know 4.10's or 4.30's would be the ticket for drag racing,but i haven't think about 3.73's as a replacement for the stock 3.55's until know. i know anything over 4.10s would improve acceleration in the 1/4 mile, but traction would be become an issue with street tires, specially with the ones that i was thinking to install (4.30s), i also know, dr's would cure the traction problem, but i drive 120miles every day, so i can't not afford to replace dr's every 2 months, plus i need to be able to drive in the rain.

[Ralph Greene]

Originally Posted by mach1dsg

ralph, why do you think 3.73's would be better for all around use over 3.55's??, i know 4.10's or 4.30's would be the ticket for drag racing,but i haven't think about 3.73's as a replacement for the stock 3.55's until know. i know anything over 4.10s would improve acceleration in the 1/4 mile, but traction would be become an issue with street tires, specially with the ones that i was thinking to install (4.30s), i also know, dr's would cure the traction problem, but i drive 120miles every day, so i can't not afford to replace dr's every 2 months, plus i need to be able to drive in the rain.

Well....This is how I look at it. For casual drag racing at the strip, with maybe Nitto DR's, 3.55's work pretty good. To retain stock cruising drivability, set of cheap rear 17X8 wheels with Nitto DR's cost about same as gear change. Our 3.38 first gear with a 3.55 rear gear gives a fairly low overall ratio for first gear (3.38X3.55=12-1). That ratio is lower than an 03/04 Cobra with 4.30's and 2.66 first (11.44-1). Work on getting 60' down to about 1.8 or so. You can run it out in 3rd. Cars have gone high 12's with this combo and stock power. Most cars on this forum with every bolt on mod available, 4.10's (manuals) and such, on stock type tires, don't run 12's.

For much more serious drag racing with sticky tires (BFG DR's or better) on race wheels, I would run 4.30's, and learn to launch off or near the rev limiter. But purchase race wheels. This is the hot ticket, if you wish to make your car into a race oriented car. You must get your 60' in the 1.5-1.6 area. It's all about 60' times, more so than HP. This kind of abuse requires some serious mods to drivetrain.

For cars not set up to race at the strip (been lowered etc), but where you just want a little more mechanical advantage for street acceleration, then run 3.73's, 3.90's, or 4.10's, depending on your tires and how much 4th gear speed you wish to give up, and how many extra RPM's you're willing to put up with while cruising. But these gears require an extra shift at the strip VS 3.55's, offsetting some of their advantage.

Forget what top speed could be in 5th. If you have to shift to 5th in any kind of encounter, it's all over with our extremely tall .62 5th. 5th just for cruising. We really just have a 4 speed car (manuals) plus tall overdrive.

[downsouthman1]

Originally Posted by Ralph Greene

Well....This is how I look at it. For casual drag racing at the strip, with maybe Nitto DR's, 3.55's work pretty good. To retain stock cruising drivability, set of cheap rear 17X8 wheels with Nitto DR's cost about same as gear change. Our 3.38 first gear with a 3.55 rear gear gives a fairly low overall ratio for first gear (3.38X3.55=12-1). That ratio is lower than an 03/04 Cobra with 4.30's and 2.66 first (11.44-1). Work on getting 60' down to about 1.8 or so. You can run it out in 3rd. Cars have gone high 12's with this combo and stock power. Most cars on this forum with every bolt on mod available, 4.10's (manuals) and such, on stock type tires, don't run 12's.

For much more serious drag racing with sticky tires (BFG DR's or better) on race wheels, I would run 4.30's, and learn to launch off or near the rev limiter. But purchase race wheels. This is the hot ticket, if you wish to make your car into a race oriented car. You must get your 60' in the 1.5-1.6 area. It's all about 60' times, more so than HP. This kind of abuse requires some serious mods to drivetrain.

For cars not set up to race at the strip (been lowered etc), but where you just want a little more mechanical advantage for street acceleration, then run 3.73's, 3.90's, or 4.10's, depending on your tires and how much 4th gear speed you wish to give up, and how many extra RPM's you're willing to put up with while cruising. But these gears require an extra shift at the strip VS 3.55's, offsetting some of their advantage.

Forget what top speed could be in 5th. If you have to shift to 5th in any kind of encounter, it's all over with our extremely tall .62 5th. 5th just for cruising. We really just have a 4 speed car (manuals) plus tall overdrive.

Speaking along these lines I can actually shift into 5th @ 35MPH w/ the 4.30s. To be funny last night, I shifted into each gear @ 2KRPMs. It was almost impossible to shift 1st fast enough to keep it under 2000. 2nd was almost as challenging. Once I got into 4th I was allowed to accelerate to just under 50 before needing to shift to 5th @ 2000RPMs. Just though this was interesting.

[Keith.red.mach1]

What performance gain would our cars see if adding 4.10 gears in say a 60 roll race on the freeway?

Unfortunately most of my races happen when I am commuting. I know people talk about how strong the LS1 cars are up top, but I have an amazing record against those even past 100 mph races. I don't know if the chip helped in this area that much.

I used to have 4.10s in my 97 Cobra, I know it helped when 1/4 dragging but wasn't sure if the affect was as great on 60 punch races.

[WhiteTXMach]

There sure is A LOT of extemely valuable information in this thread. Thanks to all who posted their input, whether it be simply mathmatical, or from previous race experience.

[768MPH]

Originally Posted by Keith.red.mach1

What performance gain would our cars see if adding 4.10 gears in say a 60 roll race on the freeway?

Unfortunately most of my races happen when I am commuting. I know people talk about how strong the LS1 cars are up top, but I have an amazing record against those even past 100 mph races. I don't know if the chip helped in this area that much.

I used to have 4.10s in my 97 Cobra, I know it helped when 1/4 dragging but wasn't sure if the affect was as great on 60 punch races.

I was wondering the same thing?

[torchredmach]

Originally Posted by Ralph Greene

But these gears require an extra shift at the strip VS 3.55's, offsetting some of their advantage.

Not if you are already shifting into 4th with 3.55's, which I am doing and I'm stock.

[rcodemach1]

Originally Posted by torchredmach

Not if you are already shifting into 4th with 3.55's, which I am doing and I'm stock.

Pretty nice MPH in the 1/4 for "stock"

[torchredmach]

Originally Posted by rcodemach1

Pretty nice MPH in the 1/4 for "stock"

Thanks! I did have the Cat-back though, but close enough

[SS2001]

I read somewhere that Mustangs are top speed limited, so top speed is really irrelevant. 139 or 149 mph, I can't remember which.

[wutang61]

im droping in a viper t-56 in my automatic mach this winter and the gear ratios are as follows.

1st 2.66

2nd 1.78

3rd 1.30

4th 1.00

5th .74

6th .50

i was planning on doing 4.56's.... but that equates to a 3650 with 3.73's roughly. should i go steeper? i think motive sells 4.88'sshould i go with those or the 4.56's?

[YellowMenace]

Originally Posted by wutang61

im droping in a viper t-56 in my automatic mach this winter and the gear ratios are as follows.

1st 2.66

2nd 1.78

3rd 1.30

4th 1.00

5th .74

6th .50

i was planning on doing 4.56's.... but that equates to a 3650 with 3.73's roughly. should i go steeper? i think motive sells 4.88'sshould i go with those or the 4.56's?

If you go steeper I don't know how you'll ever manage the 1-2 shift. It's already gonna come up in a hurry after launch.

[wutang61]

i think redline is 36mph in 1st w/ the 4.56's

[RotaryMagic]

No love for 3.73s.