nik1703

Okay, I've been told from multiple people on this forum that if I put 4.10 gears on my M6, I'll be spinning 2200-2300 RPM @ 80MPH in 6th gear. How is this possible? I am spinning 2200 in 6th gear currently with stock gears...

SoxXpupPeT

iTrader: (34)

maybe you dont have stock gears ? @ 80 in 6th im around 2k with stock gears

nik1703

4.10 gears from stock only makes a 200rpm difference @80mph in 6th??? seriously?

How can i tell if i don't have stock gears? I'm pretty sure i do - 2nd will take me almost to 60mph

ryle

iTrader: (19)

Not to be a dick or anything... But... Did you even try researching before posting??

https://ls1tech.com/forums/gears-axl...ere-first.html

Here's the calculator that will help you out the most.
http://www.f-body.org/gears/

BTW at 80 MPH you will be around 2600-2700 RPM

nik1703

thanks for the link, that was helpful.

according to the chart i will be 82 in 6th @ 2200 with 4.10's, but that's what im doing now. that chart seems off, or i dont know.. maybe i need one of you local guys to come check out my car. lol.

ryle

iTrader: (19)

I put in the info for a 93 bird M6 and came up with 81 @ 2700 RPM, how are you getting 82 @ 2200?
Did you remember to change the ratio from 3.23 to 4.10?

nik1703

whoops!!! okay yeah you are right. lol. okay so that is a pretty big difference... is it safe to cruise at RPM for long?

ryle

iTrader: (19)

regardless, I can tell you from personal experience that you will be closer to 2700 @ 80. I just swapped over to my 4.11's from a 3.23 and I can tell you that my camaro works a lot harder at highway speeds than it used to

ryle

iTrader: (19)

I was a little uncomfortable doing it at first, but as long as you have good oil pressure I can't see what the problem would be. I know a few people who have done the 4.10 swap in an auto and they cruise at 2500-3000 rpm all the time with no issues

The only problem I can see is worse gas milage.

nik1703

I feel like 3.73's would be the best overall. still good on the 1/4th times and reasonable RPMs.. 4.10 just seems extreme cruising at 2700.

ryle

iTrader: (19)

You get used to it. It's not really that bad. I was thinking about goin with 3.73's and I almost did. then I got a good deal on the 4.11 gear and I'm glad I did. I love my 4.11's! We'll see how the 10 bolt likes them once I get some DR's though

MTN-DEW

3.42
5th at 65 mph = 2,156rpm
6th at 65mph = 1,457rpm

5th at 70mph = 2,322rpm
6th at 70mph = 1,569rpm

3:73 (Multiply 3.42 rpm's by 1.091)
5th at 65 mph = 2,351rpm
6th at 65mph = 1,589rpm

5th at 70mph = 2,532rpm
6th at 70mph = 1,711rpm

3:89 (Multiply 3.42 rpm's by 1.137)
5th at 65 mph = 2,452rpm
6th at 65mph = 1,657rpm

5th at 70mph = 2,641rpm
6th at 70mph = 1,784rpm

4:10 (Multiply 3.42 rpm's by 1.199)
5th at 65mph = 2,584rpm
6th at 65mph = 1,746rpm

5th at 70mph = 2,783rpm
6th at 70mph = 1,881rpm

i don't know if that will help you out any but you can see what would be better for the slower driving conditions.

nik1703

what kind of 1/4th times are you doing with your current setup?

acammer

iTrader: (1)

To the OP - if you can't blast past 60mph in second, you've got a lot of error in your stock tach (very likely - have you ever hit the limiter? At what rpm?) or, you don't have stock gears. If you can't pass 60mph in second, you've got 4.10's already, or bad instrumentation on your tach or speedo. Stock gears will pull just about 67-69mph in second, with a stock rev limiter.

96capricemgr

iTrader: (1)

Before the early 80s everything automatic had 3 speed non-lockup trannies. Parts were lower quality than today. What sort of rpms do you think they saw? They still managed to travel on highways.

za355tx

iTrader: (108)

True that. 4.10's are a blast to drive. OP how often are you really going to cruise at 80? 4.10's are the only way to go with a 6 speed.

nik1703

i have an aftermarket tune (installed by previous owner) so i imagine there is no rev limiter. However i never said i could blast past 60mph in 2nd, i did say that 2nd will take me to 60 though (or pretty close +/-). I really do hope my tach isn't off though.

next semester i'll be doing about 40 miles freeway everyday.. so.. ill be cruising at 80 pretty often, lol

acammer

iTrader: (1)

I thought almost to 60mph meant not all the way to, not past...

I may have confused things in my post, I first said if you can blast past 60mph in second, you have a problem, and later in the same post said if you can't, you have a problem. What I meant was (and I corrected it above - meant can't, not can) that if you cannot go past 60mph in second, you don't have stock gears. 4.10's at 5700rpm would be about 60mph in second.

Sounds like you should get your instrumentation checked out - 2200rpm in 6th at 60mph would require about a 5.5:1 rear gear ratio.

legendarysouls

wait so help me out a little i got a 95 lt1 m6

If my 2nd gear red lines at 60 i have 4.10's

acammer

iTrader: (1)

Or your gauges are way off. What is your cruise rpm at 60mph.