3.45 to 4.11?

[Skant]

Would it make sense to put a lower geared axle into an LT4 vette with a 6 speed manual?

It already has a 3.45 stock. I imagine moving to the typical 3.73 wouldn't be worth it. But 4.11 seems like a good spot. It would put the freeway revs in good places... and still has good gas mileage, etc with the super low 0.5 6th gear.

But would there be much useful difference there? It's nearly 20% lower geared... therefore, 20% more acceleration through first gear. But I wonder if the tires could actually hold it. Would the car really have a quicker 0-60 time? Quarter mile?

- Skant

 

[Springer's LT4]

You may want to consider 3.90's also... traction will become an issue, but if you can hook up it's worth a .15-.2 in the 1/4. I know a lot of people who have stepped up to lower gear in the 6 spd cars and haven't heard any negitive comments, everyone seems to love them.

The 3.90's/4.10's make the car more enjoyable around town I think.

 

[Vettelt193]

the percentages really don't work quite like that with gears... you have to look at the final drive ratio.... The 4.10 or 4.11's seem to be best (the ratio varies with between makers) they will give you more acceleration, but traction may be an issue. Highway gas mileage is hardly affected though, becuase 6th gear is .5:1, so the final drive stock is 3.45 *.5 = 1.725 and with 4.10's it is 4.10 * .5 = 2.05. compare that to stock 5th gear which comes out to 2.59, and you can easily tell 4.10's will give you a very acceptable highway RPM

 

[lt4 gs]

So will the 4.56

Actual from my speedo......yours will vary a tad
rev's/mph

2000 69
2100 72
2200 75
2300 78
2400 82
2500 86
2600 89
2700 92
2800 96
2900 99
3000 102

 

[Vettelt193]

So will the 4.56

Actual from my speedo......yours will vary a tad
rev's/mph

2000 69
2100 72
2200 75
2300 78
2400 82
2500 86
2600 89
2700 92
2800 96
2900 99
3000 102

I did the math,(using a 275/40/17 tire) and checked 4.56 @ 2000, 2500, and 3000.... you are +2MPH on all of them... this brings up another question on speedo calibration? and it could be seating position too... just an FYI more than anything though

I will do a quick chart and hope this lines up
in 6th gear:

3.45 4.10 4.56
2000: 89 74 67
2500 111 93 84
3000 133 112 100


1st gear:
2000: 17 14 12
4000: 33 28 25
6000: 50 42 37

again, these are based upon a 275/40/17 rear tire and 6 speed

 

[Skant]

Wouldn't that be 285/40R17?

- Skant

 

[Vettelt193]

I run 275's on all four corners, because i have Z51... If you don't have it, you will have the 285 rear tire, and a 255/45 tire on the front... the differences between the two, as far as diameter is concerned, is hardly anything

 

[Skant]

I'm thinking about this some more. Heh. I was even just fiddling with the Gran Turismo PS2 game to setup a LT4 vette in there with a 4.10 axle. Gran Turismo is a pretty realistic simulator, so this is actually nice for just getting some idea of where the gear shifts move to and such. Drive around in a non-race fashion and see if I still like where the gear ranges are for typical road speeds.

4.10 seems like it puts them into better ranges than 3.45 does.

Just based on the simulator, I like what the 4.10 does. But how about real life? Anyone here actually have a 4.10 in their LT4?

My car is stock with FE1 suspension save for open air intake lid and it will have a CORSA exhaust. Can the tires hold it with the 4.10? If it's just gonna tend to break loose, then it won't be worth it, I think.

I understand that an LT4 would have a Dana 44 rear end. Will this accept a 4.10 gear set? Can the ratio be changed without also replacing the positraction unit?

How much should I expect the change to cost if I have it done by a reputable shop? (No way I'm gonna work on the axle myself... those require special magic lest you don't mind gear chattering).

- Skant

 

[Vettelt193]

richmond gear sells 4.10's for dana 44's. I think the gears run in the $250 range, installation will be about the same I would guess. So $500 total... I don't have a set yet, but I have been in 'vettes with them.... the car will really pull hard, and will be more fun to drive. The usual negative with a low end gear setup is gas mileage... but the 6th gear almost eliminates the problem, so it is a good mod.

The tires... well, you can spin your tires with the stock gearing, so you can spin them with the 4.10's, and it will be easier to do... you have to learn to feather the throttle off the line while racing... once you get a good hook-up, you should be able to take off like a bat outta hell... all it takes is a bit of technique, and time, to get used to launching with the 4.10's.

 

[Skant]

Off the line will obviously be more aggressive. I was wondering if the tires will hold as it revs up to 6300 after the initial launch. Sounds like they will.

Only $500 to do this? I was actually expecting like $1500-$2000. Now I'm becoming even more inclined to do it.

- Skant

 

[Vettelt193]

check on pricing where you live... i definitely can't see how it would cost more than $1000, unless you went with a whole new carrier instead of just the gears inside.

 

[No Go]

A video game??? First I've heard of that one.

Try www.fbody.org for a gearing calculator.

I highly recommend a true 4.10 gear set-like one available for the Viper from Dodge! They offer 3.73, 3.55, and the 4.10 ratio-others are also availabe but not advertised.

Last time I checked with local Dodge dealer price was $425 for retail and $325 for wholesale. The bolt in using original carrier/posi, some clearancing to the housing may be required but will be minor.

I would do the swap in a heart beat, but refuse to give up my extreme topend

 

[lt4 gs]

I run a 4.56 and it cost 1100.......installed
Also, I am pulling 7500 out of 1st and 2nd.........7300 out of 3rd.......

 

[brooks]

lt4-gs ... life may begain at 180, but ur not getting it with a 4.56 or 4.11

skant 6200 RPM with 4.11 would give you a 168 MPH top end which under normal circumstances should be plenty. 70 MPH in 6th is at approxmately 1900 RPM which provides good fuel economy.

 

[lt4 gs]

true enough...but I did with my 3.45...........now I don't need 180........it's all over at 140........heck it's all over at 100........