3:73 in 5 speed

RedSC

Registered User
does anyone have this setup? also, which speedo gear is the right one? or do they even make it? I couldn't get the ford dealer to look for it. just wondering

thanks.

Brian
 
3.27s are the best all around gears for a 5 speed. You will regret going to 3.73s b/c 1st will be useless and forget about going on the highway.
 
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I don't know why everybody says 3:73s are too high for a 5 speed.

1st question HOW MANY PEOPLE HAVE ACTUALLY EXPERIENCED IT? and not just heard about it?

My SC is not my daily driver, and even if it was, it handles the highway just fine. It sets at about 2500 in 5th at 60-65. not the quietest ride, but not too bad at all.

1st gear isn't wasted, it'll break your neck though.

and I like the Idea of a losing traction in 3rd gear.

and getting completely sideways in second .....well, all the way through second....

but I just need wider tires.

I just need to get the speedo calibrated so I can see if I can hit 100 in 4th gear. that's the only problem I can see with the gears is getting through the 1/4 in fourth because I sure as hell don't want to shift to 5th.
 
with 3:73s on mine the 1/4 mile and 0-60 was about .5 sec slower and unpredictable(at the launch it sometimes hopped or spun up), with no slicks. I have 3:08s now, I dont like those either:D .
 
I have them in my SC. I used a 21 tooth speedo gear, but the speedometer is still off. When I am doing 60 the speedo says about 70. I have given up on trying to fix this, I know its off. If I could have done it again I would have gone with the 3.27s, but I will say the 3.73s are a lot of fun especially when you want to pass someone.:D

Nick
 
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OK, say I do go to the track, and find that 1st gear is unusable?

even with drag 10.5" drag radials, I just can't hook up. what about starting in second gear?

I can lay a patch of rubber as long as I want to until I let off in second gear right now, so wouldn't a good second gear launch be possible?


also... 1st gear becomes useless with 3:73s due to traction loss and the shortness of the gear correct?

wouldnt a car with 500 Hp and 700 lb ft of torque experience the same problem??

that's why I say traction is the key. more rubber, more grip, more go??

if not, why? just because the gear is so short? but if you COULD get traction all the way through 1st, wouldn't it be ok if it's still short?
 
I think that you would need a 23-tooth speedo gear to get you close with 3.73s in a 5-speed ... and no, I wouldn't recommend that ratio either !! :p

cheers
Ed Nicholson
SCCoO
 
That size gear works real well with a high rpm engine but our cars create power down low plus you will top out to early.
I do know what your saying about having fun spinning the tires.
I put a 411 in a 68 goat years ago. no top end but could lite em
up in any gear.
 
BAD IDEA

i had 3:55's in mine and they sucked. Sure they were snappy and they made the car feel really fast, the problem was that the car wasn't really fast, it just felt that way. I raced my buddy and his SC had the stock 2:73's and we launced and I pulled 1 car length ahead of him in first but as I was shifting from 1st to second he was going right by me still in first gear and i could never catch him. Same on the interstate I pulled really hard until I redlined in fifth and he went right by me. The 3:73's would really suck, and 1st gear with the 3:55's was only good for about ten feet. And on the highway they were crappy, 3,000 RPMS to run 70MPH or so. That is horrible. I could launch in second gear and still smolder the tires then chirp into third. They suck, don't do it. .If you are going to do a lot of mods go with 3:08's they are great all around, good top end and they will be better all around than the 3:27's once you get some mods behind them, although the 3:27's aren't that bad either. Just don't use the 3:73's
 
You'd pretty much have to start in 2nd with 3.73's your total ratio in 1st gear is just shy of 14:1 (3.75 1st). I guess if you planned on running a 4 spd it would be okay, lol. The M5R2 gear ratios from 2-5 are almost the same as the AOD 1-4 (+/- .01) and I doubt any auto owners with 3.73 would want a lower gear. This isn't a mustang with a 3.35 1st.
 
well, I already have this setup right now.

because I had the 3:73s with my auto, and then I did the 5 speed swap.

I have a friend that will swap his stock auto rear end with me if I need to, but I was really hoping this would work out.

I'm still not taking them out until I hit the track.

I really dont think first gear is all that bad though.

I raced my friend in his stock 5 speed mustang a couple days ago and when I hit 3rd I almost hit his rear bumper.

(and I took off after him from the side of the road.
 
Re: BAD IDEA

1BADSC said:
i had 3:55's in mine and they sucked. Sure they were snappy and they made the car feel really fast, the problem was that the car wasn't really fast, it just felt that way. I raced my buddy and his SC had the stock 2:73's and we launced and I pulled 1 car length ahead of him in first but as I was shifting from 1st to second he was going right by me still in first gear and i could never catch him. Same on the interstate I pulled really hard until I redlined in fifth and he went right by me. The 3:73's would really suck, and 1st gear with the 3:55's was only good for about ten feet. And on the highway they were crappy, 3,000 RPMS to run 70MPH or so. That is horrible. I could launch in second gear and still smolder the tires then chirp into third. They suck, don't do it. .If you are going to do a lot of mods go with 3:08's they are great all around, good top end and they will be better all around than the 3:27's once you get some mods behind them, although the 3:27's aren't that bad either. Just don't use the 3:73's

exactly:D , feels like you're hauling from all that shifting, but you're not. Yes once you find out you slowed the car down from changing the gears it pisses the hell out of you:rolleyes:

I've only had like 4 different ratios in mine, till I figured out almost the stock ratio is best for street tires(beats me about slicks)
 
I thought that for a 5 speed, the 3.27's were supposed to be a big improvement and knock a good bit off the 1/4 mile times?
 
3:27's

3:27's are a nice gear for racing. It has been said by a few others though, including myself, that if you don't plan on a bunch of mods then go with the 3:27's. But if you plan on doing a lot of mods to the car then you should go with 3:08's. The 3:08's work really nicely with 245-50-16's. They pull very hard and you aren't shifting like crazy, and you can still really push the needle past 120. When I had 3:55's the car topped out at like 120 -130 MPH, and that was clear into red line like 5300 RPM's. I love the 3:08's and would suggest them to anyone who wants to do a lot of mods to the car. If you are just going to little mods then go with the 3:27's... Just do not use the 3:55's or 3:73's on anything other than an automatic.
 
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so what about the old Chevelles, etc. that are running 4:88 tail gears, or 5:13s?

Is that just because their first gear is long enough?? due to the 4 speeds that are normally used?
 
I don't know anything about Chevelle's, but what is their first gear ratio?

You can't look just at the rear gear overall ratio. You have to look at all of the variables together.

Dale
 
???

It is the same reason why the Mustangs can run 4:11's. They are not using a truck transmission like the SC. So the gearing in the tranny is not as steep
 
There is a little bit of truth in just about everyone's posts above, but I will add a couple of things that may help clear the mud (or not?!).

First of all, you can get a speedometer calibration unit made by Cyberdyne and sold by Summit. It allows you to pace a car with the correct speedometer, and the set yours to the same reading. I think it is about $70. Some people around here have used them.

Regarding 3.73's, well there are good reasons why you wouldn't want them in an SC. For one thing, a stock SC peaks power at 4500 rpm. A highly modified one peaks at 5500. In either case, you will find yourself past your HP peak in 4th by the end of the 1/4. Not good for 1/4 times. Shifting into 5th is gonna cost you a good 10 rwhp due to internal transmission losses, again not beneficial. Say nothing of the extra time lost for shifting.

That being said, I have 3.55's in my 5spd. It runs very well at the track, and I don't have traction problems. It does get monotonous on the highway running 3000rpm for long trips - and yes, I've done cross country several times with them. They also cause the motor to run a significantly hotter than it used to.

Finally, there is a big difference in the power curve of a pressurized motor than an N/A one. Check what the turbocharged 5.0's are running for gears. Did I see 3.27's? Yup I did. See, we have a broad, flat torque curve and a HP curve that really doesn't curve much at all. Compare it to the curve on an N/A motor, especially a high HP one, and you will see that even for racing, a tall rear gear that forces the motor to rev to redline quickly is not helpful for us like it is for an N/A motor.

:)
 
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