I have a 91 RS 3.1 auto.

Im willing to upgrade my rearend gears
to higher ratio maybe 3.73 or 3.43.

now what im not sure is what would i have as a stock? 2.73?
all I know is its never been swapped,
and I dont want to open it up until i actually have it swapped by a shop..

is this upgrade possible without getting a whole new rearend?
or is there some upgrade gears for our stock rearend?

in advance for any info I reallty want to know what gear ratio im running.(and yes i searched and couldnt find it)

 

https://www.thirdgen.org/1991-chevy-camaro

 

aww i guess i didnt have to search the forum.. lol

thanks!!

so if its a 3.23 already.. will 3.73 make lot of difference in acceleration?

 

You bet it will .especially off the line ..will suffer on top end though..if you drive on them CAL freeways a lot I wouldnt go over that 3.73 gear..fuel mileage will also suffer some.It all depends on where and how you drive your car.I was considering a 3.42 but doing 80 MPH at 2000-2500 is awesome,probably just stick with what I have.

 

you can check the rpo codes in the glove box for the axle ratio

 

i went from the 3:42's to 4:56's and it made a huge difference,except i do alot of driving so my gas milage was suffering alot.since then ive switched to 4:10's and gas milage is pretty good as long as u dont drive liek a manic,cruising @ 65 im just over 2,400 rpms

 

Yeah, I did a smaller jump than Dave did... I went from a 3.42 open rear to a 3.73 posi rear- WOW, what a difference! Even nicer since I had the special B&M 4-3 kickdown sleeve in my transmission... I could really pull strong in overdrive on the highway.

If you search this forum for posts by me (TomP) and the words "3.73", I think I had posted my RPM changes. I don't quite remember (that was back in 2001 or something like that!) but it was only an extra 200-400 RPM at 60 MPH.

So if you go from 3.23 to 3.73, yes you'll notice a BIG difference- and yes you'll use more gas.

 

3:23 to 3:42 = 190 rpm increase
3:23 to 3:73 = 500 rpm increase
3:23 to 4:10 = 870 rpm increase
3:23 to 4:56 = 1330 rpm increase

 

is the gas mileage loss very noticable?

caz i dont run tracks,
and i just want to have my car a bit faster
on off-the-line so that when im taking off the red light
im not behind all the stock looking honda cars

i know swapping ring/pinion isnt a easy DIY, so ill have a shop do it for me

but as for recalibrating speedometer is that a easy task?

thanks for any info in adnvace

 

if u go with 3:73's u will notice a good diff in acceleration.gas milage wont be that big of a idfference depending on how u drive.u have a 91 which has a electronic speed sensor so im not sure what u would have to do to calibrate the speedo with th enew gears.with a non vss car alls u have to do is swap out the speedo gears in the transmission

oh btw expect to pay around 600+ for a reputable rear end shop to install a new ring and pinion.parts are about 300 and genrally the labor for setting up a rear is about 300+

 

Mine is a 91 and all you have to do is swap the speedo gears in the tranny, still. I went from 3.23s to 3.73s...pretty nice improvement. My mileage still isnt bad either...with lots of engine mods, I still get 16 or so city and 25-26 hwy. I had 4.10s in it for a while but I felt that they were too much for it and the 1/4 mile.

 

And I ask this.....WHAT GLOVE BOX?????????

 

thanks for all the info guys.

just flipping around summit catalog i thought i seen ring and pinion for maybe
180$ or so.. but i could be wrong.

and is 300$ labor including all the flushing and refilling of the gear fluid too?

o well ill get a quote on that.. thanks!

 

buy all the parts urself and u will save money.gearsets run 160-200 from summit
and u also need a install kit(i.e bearings and seals) also 80-115 from summit.2 quarts of gear oil like 3-6$ a quart,th3 300 for labor is just an estimate.my shop charges 350$'s labor to set up a rear + cost of parts/oil etc

 

thanks for the info dave,
is that 350bux including the speedo recalibration?
caz i do not know what it takes to calibrate my speedo
after changing gears.. as mine is 91 and it's electrical speedo or something..

 

i know with the firebird electronic speedos there are gears in the trannsmission that need to be changed. these gears drive a cable on the old mechanical ones, and turn a censory wheel inside the VSS on the electronic ones. once you change these gears in your tranny your cars speedo will act as though it was in a car originally equiped with X.xx gear ratio.