Wesmanw02

iTrader: (4)

My car is an M6 with 4.10 gears. Its had the 4.10's since I bought it 3 years ago, so I've never known any different.

I put the car away for the winter and haven't driven it in about 2 months. In the meantime, I picked up a new daily driver, a '08 Cobalt SS T/C. Fun car.

Anyway, I took the T/A out yesterday to blow the dust off, and I realized how extremely short my gearing is with 4.10's. I mean I knew it was short before, but after driving the Cobalt for 2 months, I realized that I actually have taller gears in my 4 cylinder Cobalt than I do in my T/A. There is something wrong with that picture, especially since the T/A has twice the cylinders and 140ft/lbs more torque. Its just not necessary. And its not like my 1/4 mile times are that great, I end up spinning the entire way through 2nd gear.

Maybe its just me, but the gears are obnoxiously short. I take off from a stop, and by the time the car is moving, time to shift to 2nd. Then immediately 3rd, 4th, and I'm in 6th by 40MPH. I'm running 26" tires on 18" rims BTW, which is about the same as stock.

I've decided I'm going back to 3.42's. I need a new differential while I'm at it, because the cone-clutches in the Auburn are shot, causing ridiculous axle endplay on the driver's side.

Anyone else agree, or am I alone in this realization lol??

I also need to decide whether to get a set of 3.42's and a new diff and install it in my rear, or just get a used 10 bolt from someone that already has 3.42's and a Torsen diff installed.

massconfusion

iTrader: (18)

you sure you have 4.10s. sounds like 4.56 to me. I cant touch 6th at 40 in my car or it boggs

Wesmanw02

iTrader: (4)

Yep, the gearset was stamped 4.10 when I had it apart. At 40MPH it runs about 1200RPM, as long as its flat ground it will just cruise along.

bigj2717

iTrader: (15)

Yeah that sounds like my car. You get spoiled with the cobalts they have really long gears

Wesmanw02

iTrader: (4)

Time to go back to 3.42's.

The thing is people really hype up gear swaps, but often without merit. Having shorter gears such as 4.10's allow the car to reach its powerband quicker in 1st gear, but other than that they don't do much of anything.

So if you're having trouble with bogging on the launch (cammed cars, ect) then 4.10's might help you. But for me, they just mean lack of traction in 1st and 2nd gear, lots of extra shifting, and shitty fuel economy.

kidcamaro98

iTrader: (8)

I went from 3.42's (stock) to recently having 4.10's installed. Although they are short, I love them more then the 3.42's especially being a MS3 cammed car.

I learned very very quickly that instead of going through every single gear like you would with 3.42's, with 4.10's you skip gears...

for example...

your going from a stop, revv out first to 3500rpms, then shift too 3rd. You will fall down to around 1800-2k....get up to 3200-3500 in 3rd, shift too 5th etc...get my drift? BTW, I get better gas mileage doing this now with the 4.10's then with the 3.42's but I am not sure how you can go into 6th at 40mph and be at 1200rpms and complain about it. Even on the stock motor, thats lugging it. I cant even touch 6th until 60 or so.

Wesmanw02

iTrader: (4)

Since you are cammed, the 4.10's are more beneficial. Revving my car out to 3500RPM in daily driving is nothing more than an exercise in wasting 93 octane.

Typically I shift at 2K when I'm just cruising, or in traffic. With the torque available, there is really no need to shift any higher. By the time I'm at a cruising speed of 40-45MPH, I'm already in 5th or 6th gear. Those are both overdrives. This just results in a lot of unneccessary shifting.

As I stated, my 346 ci V8 car should not have shorter gears than my 4 cylinder Cobalt. That tells me right there that something is wrong.

00pooterSS

iTrader: (40)

Well if you have that much low end, try taking off in second and going to fourth, see how you like that before taking them out. I did it in a 3:42 car and it wasn't bad at all.

kidcamaro98

iTrader: (8)

Not really. You are talking about two completely different cars that have completely different reasons why they are geared the way they are. You do realize that your T/C Cobalts gears are so long because TURBO cars benefit from long gears. Long gears on a T/C car (lower gear ratio cars) put a load on the motor, which helps spool the turbo faster,sooner etc...You cant compare your Turbo Cobalt too a N/A 4.10 car.

BlackScreaminMachine

iTrader: (17)

Agreed here,

As to the OP. Whom I have had some debates with.

The 1st gear in a Fbody Spec'ed T-56 NEEDs a 4.10 gear to help get it's self out of it's own way. Do a simple search on Torque Multiplcation.

http://www.team-integra.net/sections...?ArticleID=708

This is a great example how people relate Engine power and how it is applied. Gearing, be it changed in the transmission or rear end (final drive) will effect the power made.

I will use my car and my dyno graph for an example.

I make 363 RWTQ @ 5,000 RPM's with a 3.42 rear gear and a 2.66 1st gear ratio and a Launch @ 5k yeilds 3,302 FT Lbs of Torque. 3.42 x 2.66 = 9.0972 (over all gear ratio) x 363 = 3,302.

Now if I put in a 4.10 gear (which I do have now). 4.10 x 2.66 = 10.906 x 363 = 3959 RWTQ at launch and finally if I put a m12 Transmission (GTO/Z06) and left the 4.10 gears in there 4.10 x 2.97 = 12.177 = 4420 RWTQ which with match with a proper tire/suspension set up helps heavy cars like these to leave hard off the line and run good times.

Over simplified but for arguement sake, I always notice a difference when driving any other car after driving my T/A for a week at a time.

Having a steeper gear helps car leave the line quicker as well has help with clutch life on the street.

The 09 T/C Coblat has a 3.84 Final Axle Ratio, I do not know what the trans ratio is but I bet its similar to your car now but just that the Cobalt does not make as much power and thus the "feel" is different.

**EDIT**

I did find the gear ratios for the newer cobalts....
http://en.wikipedia.org/wiki/F35_(MU3)_transmission

Find a dyno graph and you can play with this!

01ssreda4

iTrader: (96)

You M6 guys are sure cry babies. Try driving around with a 4K+ converter and see where your precious 93 octane goes.

Wesmanw02

iTrader: (4)

That sounds good in theory, but your theory does not hold up.

Look at the Subaru STI. 4 cylinder, turbo, 6 speed. It has extremely short gearing. Its 1st gear tops out at 35MPH, and 5th gear tops out at 119. Redline in 6th is only 158MPH.

You can compare any car to any car when it comes to gearing. The LS1's generous and flat torque curve are what allow it to have seemingly tall gears and still be fast, it doesn't struggle in the lower RPM's like smaller engines do.

Short gears are needed in cars like the Mazda RX-8 and Honda S2000, which struggle on the low end and need short gearing in order to get respectable acceleration and not bog down as badly. An LS1 F-body is not one of those cars.

Wesmanw02

iTrader: (4)

Stock these cars will do 0-60MPH in as little as 4.8 seconds. I don't think it is anything close to NEEDING shorter gears. You may like shorter gears, but it doesn't need them.

Look at the C6 Z06. EXACT same gear ratios 1st through 6th as the LS1 F-body T56, and same exact rear end ratio as well (3.42). Yet it still run 0-60 in 3.4 seconds and runs low 11's in the 1/4, bone stock. It ain't going any faster with 4.10's, despite what you might believe. All shorter gears would do is promote more traction issues and more shifting through the 1/4 mile.

Gear ratios do not affect power. In any case. Period.

You don't need all that extra torque at the wheels to get the car off the line. Its not a dumptruck, its a 3500lb car. So most of that torque ends up wasted through spinning tires. Once again, look at my Z06 example. It doesn't do 0-60MPH in 3.4 because its lacking torque.

You also neglect to calculate the physics behind your arguement. Its not as simple as you make it seem. Although you can multiply the torque at the wheels through gearing, the fact that you cover less distance with each shift negates the fact that the engine accelerates faster.

The bottom line is that gearing is one of those things that you either have right or you don't. A car like an A4 2.73 F-body is hindered in acceleration by its gearing, so its beneficial to put some shorter gears in it. A car with an M6 and stock 3.42's is not hindered by its gearing, its limited mostly by horsepower, and the addition of shorter gears really doesn't add much in terms of performance. It may feel faster, but the physics of it is that it can't be faster, because the HP hasn't changed. The only benefit to shorter gears like 4.10's is that they allow you to get off the line quicker if you have slicks, so you can get into the powerband. Other than that, the car will not be faster.

I think any addition to clutch life is negated by the fact that I have to constantly shift, meaning constant engagement and disengagement of the clutch pedal, pressure plate, and hydraulics.

I compared the cars in an excel graph based on trans ratios, tire size, and final drive ratio. Cobalt has taller gears, period.

LS1_Sean

iTrader: (1)

Then why with pretty much every muscle car the first things that people change are the exhaust and gears?

edwardzracing

iTrader: (59)

Couldn't the term "better acceleration" also mean "faster." I mean if it gets from one point to the other much faster than it used to, it could be because the car accelerates better, right? Now, the last time I checked, a gear change will help the car to accelerate better. Thus getting you from one point (the starting line) to another (the end of the 1/4 mile) a lot faster. I would agree with what Wesman has to say, but a gear change can most definitely result in better 1/4 mile times... it's been proven over and over again. And I wouldn't be surprised if people started pooring into this thread to post proven results. There's my two cents on a topic that has gone way off track from the original posters questions. To the OP, why not try a 3.73? Good luck to you, whatever you decide.

Wesmanw02

iTrader: (4)

Thanks.

As for 1/4 mile times, let me clarify.

Given sufficient of traction for a hard launch, 4.10 gears should definitely cut down on your 1/4 mile ET. Which means the car is quicker.

However, the car is not faster. If you go through the traps at 108MPH with 3.42's, you should end up going through the traps at the same 108MPH with 4.10's.

FirstYrLS1Z

iTrader: (4)

This is turning into one of those 'endless debates'. When we get an f-bod(or any other rear wheel drive car),it is up to us,as the owner/user,to decide on any mod,if any,to attain how we want the car to handle,accelerate,use fuel efficiently,and on and on.Some want more acceleration ability or more top speed or better gas mileage or less shifting,we each have to choose what we want. We seek input from other members,isn't that what this forum is for,and then we decide.If someone wants less shifting,that's their decision.If someone wants a more wicked acceleration rate,that's their decision.
When I put 4.56s' with my A4,my sole purpose was a 'light to light streetfighter',the hell with mpg and low rpm,I attained what I wanted.If I'm going somewhere and want good mpg,I'll drive my Cavalier.
If someone likes their 2.73s',3.23s',3.42s' and doesn't want 3.73s',4.10s',it's still a GM late model muslecar.

chavez885

iTrader: (12)

Obviously gears do not affect power, but they do affect acceleration and getting you into the power band. Plenty of people have picked up 3-4 tenths and a couple MPH out of gear swaps alone. Just because you don't THINK so there are time slips to prove your theory wrong.

A z06 runs 3.4 to 60MPH because it has 500horsepower and weights 3100 pounds. This is why you can't compare cars like a cobalt, z06 and a fbody.

If you seriously think putting 4.10's in a car with 500bhp and a 7200RPM red line isn't going to drop ET and pick up MPH you are very wrong.

edwardzracing

iTrader: (59)

I've got to agree... besides there is nothing wrong with a friendly endless debate, lol. With traction, 4.10's in that Z06 turns those low 11's you were talking about into high 10's real quick, and yes I do believe an increase in MPH would occur as well. To Wesman, I'm not sure I can agree with the "Quicker" statement about how the MPH would be the same with a 3.42 and a 4.10. If that theory is correct, that should mean that the same car with a 2.73 gear will also trap 108. I don't see that happening because a quarter mile is still a quarter mile. The 2.73 car will eventually reach 108, but not in a quarter of a mile from a dead stop... I think it will run out of room. I'd like to hear your view on this. Let the friendly debate continue.

FirstYrLS1Z

iTrader: (4)

When I changed from 3.23s' to 4.56s',1/4 mile improved by .5,1/8 mile improved by .4(the 4.56s' changed the 1/8 the most),trap speed increased by 3mph.
The results were with 2 seasons with the 4.56s' and 3 seasons with the 3.23s'.
Also 2 different tracks provided identical results.