Gears - to answer the questions once and for all
 

this has all the gear ratios for every ford tranny (except for the 2004 mustang one... :rolleyes: 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 :D
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)
I now prefer this calculator if anyone cares: http://www.4lo.com/calc/gearratio.php

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

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 :COOL: 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! :)

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

added :)

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.

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

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 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.

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

What a wise and sage statement...

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.

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

No love for 3.73s.:o

:LAUGH:

The Mach1 A/T is electronically speed limited in the 120+ mph range, the M/T @ 151 mph. (Doesn't mean they have to stay that way)

...and gears will help you attain them faster...

Wonder why the difference??

Well, IIRC the auto redline is @ 5800 rpm and the manual is @ 6800 rpm. I don't know what the gear ratios are for the A/T but I'm pretty sure that would come into play too.

There are a few people here who can answer this much better than I can since I don't know much about the auto's... I'd like a good explanation for this too. :CHEERS:

Good stuff!!

Would love to see those RPM's at 80 for the Mach's auto, as well as the top speed with each, but am uncertain how to figure that based on those links.

Got to think though that with the top speed being 120 with the 3.73's the 4.30's or 4.56's would have the car nearing or hitting it's top speed in the quarter.

find the gear ratios for the tranny, plug them in, plug your rear end ratio and play with the speed...

i have to go to work or i'd look the ratios up for you...i'll do it when i get back :)

Got bored :rolleyes: :D

Are the Mach1 4R70W ratios as follows???: :confused:
2.84
1.55
1.00
0.70 (OD)


Manual
.62 ratio, 80mph, at X.XX:1 rear gear ratio

3.55 = 2304 rpm
3.73 = 2421 rpm
4.10 = 2661 rpm
4.30 = 2791 rpm
4.56 = 2960 rpm

top speed w/ 3.55s, 5th gear @ 6798 rpm = 236 mph
top speed w/ 3.73s, 5th gear @ 6780 rpm = 224 mph
top speed w/ 4.10s, 5th gear @ 6787 rpm = 204 mph
top speed w/ 4.30s, 5th gear @ 6769 rpm = 194 mph
top speed w/ 4.56s, 5th gear @ 6771 rpm = 183 mph

Auto
.70 ratio, 80mph, at X.XX:1 rear gear ratio

3.55 = 2602 rpm
3.73 = 2733 rpm
4.10 = 3005 rpm
4.30 = 3151 rpm
4.56 = 3342 rpm

top speed w/ 3.55, @ 5789 rpm = 178 mph
top speed w/ 3.73, @ 5775 rpm = 169 mph
top speed w/ 4.10, @ 5784 rpm = 154 mph
top speed w/ 4.30, @ 5791 rpm = 147 mph
top speed w/ 4.56, @ 5765 rpm = 138 mph

Re: Gears - to answer the questions once and for all
 

The auto data would be more interesting in 3rd gear since we don't race (or even make full throttle runs) in OD.

Re: Gears - to answer the questions once and for all
 

I think that Ford set the speed limiter to 126 on the automatics to prevent a wide open throttle shift into overdrive. The shift with stock gears happens somewhere around 130MPH.

Why wouldn't you do a full throttle run in overdrive to get top speed? I bet it would be around 160+. I know you don't need overdrive on the drag strip.

I removed my speed limiter. I did have a chance to run to 135, but I let up on it around 125 and let it ease into overdrive. Once it shifted into overdrive I stomped it and it went from 125 to 135 so fast I couldn't believe it.

Re: Gears - to answer the questions once and for all
 

Awesome information! I have been looking for this because I am considering a gear change for my automatic. BUT I like top speed.

The rev-limiter is set to 6250 on automatics, so that's where we need to calculate top speed. Can you re-calculate for us?

Actually, 5800RPM is ok for 1'st, 2'nd, 3'rd, if you let the trans shift automatically, but 4'th will go all the way to 6250RPM.

Re: Gears - to answer the questions once and for all
 

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.

Re: Gears - to answer the questions once and for all
 

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.

Re: Gears - to answer the questions once and for all
 

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.

Re: Gears - to answer the questions once and for all
 

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.

Re: Gears - to answer the questions once and for all
 

If this is to become the official gears sticky, may I suggest adding info about what degree of rebuild kits would be needed at various mileage, what misc parts are needed (I recall some sort of special pin or grinding needed with 4.56+), etc.

Re: Gears - to answer the questions once and for all
 

with 31 spline differentials, you get a thicker cross pin; and also, with steeper gears, the ring gear will be thicker, to the point the teeth of the gear will cover up some of the real estate needed to put in/take out the cross pin. I don't believe all 31 spline differentials offer similar thickness pins, so you might be able to slide by with some.

The Ford 31 spline traklok needs to have the pin ground to be able to fit 4.30s or higher on there. I believe same is the case with the Torsen differentials. Not sure about the eaton or auburn ones.

Re: Gears - to answer the questions once and for all
 

I Need Some Advice About What Gears To Get. I Have A 02 Gt 5spd And I Am Looking Into Getting Some Gears Soon, What Should I Get?

Re: Gears - to answer the questions once and for all
 

:worship: "This IS a tasty burger".... Thanks for all the info, in this thread... I just took the 4:30s out of my car, in favor of the 3:55s. I think every owner has to analyze their individual use, and gear-up/down accordingly. The fuel economy with the 4:30s sucked. I hope to see better economy :3: when I can keep my foot out of it...

Re: Gears - to answer the questions once and for all
 

I dont care much about top speed, I just want acceleration, but I heard having the lower gears like 4.10 or 4.30 are harder on the engine. Is this true? Plus I would like to have reasonable gas mileage still so I was thinking maybe 3.73s would be the best gears for me, or should i stay stock?

Re: Gears - to answer the questions once and for all
 

Im either going 3.73's or 4.10's I just wanted to know if I switch to 4.10's how bad of a spinning problem am I gonna have ?. I mean right now im street tires I had the et streets on the car but they didn't last to long

Re: Gears - to answer the questions once and for all
 

If I'm reading this correctly, would 4.10's in an auto tranmission be roughly equal to 4.56's in an manual transmission? Or am I backwards?

Michael

Re: Gears - to answer the questions once and for all
 

right now im thinking about getting 3.90 or 4.10 gears but its my every days driver. if i have a k&n cai, bbk long tube headers,slp loundmouth cat backs, diablo preditor tune and put one of these 2 gears on will i be having trouble with spinning the tires off of every take off? my car is loud as hell with my slp loudmoths and cops love to mess with me now, so im just trying to see if ill have to baby my take offs as to not get more cops to pull me over for something.

Re: Gears - to answer the questions once and for all
 

You'll spin only if you peform sprited take offs, so don't let that hold you back. As fars as the gears, again that depends on your transmission, remember 410's in a auto is like having 456's in manual. If your car is a 5 speed, you'll love the 410,'s. If your an auto go with the 390's.

Michael

Re: Gears - to answer the questions once and for all
 

thanks for the information. if i take my car to the track on occasion would i have any troubles with the stock rear axle with 4.10 gears in a manual? should i get 28 or 31 spline axles or am i good with as little upgrades that i have.

Re: Gears - to answer the questions once and for all
 

If you plan on doing lots or 1/4 miles stuff the safe bet is to go with 31 spline axles.

JMO

Michael

Re: Gears - to answer the questions once and for all
 

thank you for your help

Re: Gears - to answer the questions once and for all
 

Does anybody know anything about these guys?

Pro50 Gears

Re: Gears - to answer the questions once and for all
 

you guys can see the difference in max speed (MPH) in every gear with different final drive ratios. i used 6800rpm as max rpm in any gear.

Re: Gears - to answer the questions once and for all
 

I still dont know if i should go with 4.10s or 3.90s? i have a manual.

Re: Gears - to answer the questions once and for all
 

If you had an auto I'd say 4.10s...with a manual, I'd say 4.10s aren't enough. go with 4.30s

Re: Gears - to answer the questions once and for all
 

I am not sure if this question is answered yet and I thought I have seen it before... can't seem to find it right now. I have a blown auto mach with stock gears. Which gears would be the best for me? I do a ton of driving and see some track. How well do you guys think the car will hook up on the street with 285 drag nittos with the gears? I don't have the 285s on the car yet and I have 245s that spin like crazy with the blower. I cruise at 120 a lot right now and race til 150 or so usually; but I guess I can let the high MPH go for some quickness.

Re: Gears - to answer the questions once and for all
 

I see that you are in Houston. I have 2 sets of Nitto Drags 275/40 17 and 305/35/18s. If you want to meet up one day we can mount a set and take it for a drive. I would like to feel that blown Mach so I would be happy to see what you think of the bigger drag radials.

Keith

Re: Gears - to answer the questions once and for all
 

You wanna sell the 275s? I live in Tomball, we go out everyday Tuesday to a Lowes off 249, tons of cars go out there and we do some street racing. I also go out to 1960 an 45 to sonic every friday night. If you ever go I have a red mach 1 with black fr500s with a BLOWN emblem on the back.

Re: Gears - to answer the questions once and for all
 

Street racing ain't too smart but posting when and where on the Internet is even worse.

Re: Gears - to answer the questions once and for all
 

We don't race there...usually go up there just to talk and sit around. People drive 30 miles away to go race if they want to.