3.42 or 3.73

[FuryCharger]

what mpg should i expect if i upgrade from 3.23 to 3.73? also, even if i recalibrate me speedo, my top speed will not make it past 100 like it did with my 3.23?

[Bliggida]

Recalibration allows your speedometer to be accurate. Therefore it will only allow you to go as fast as you are goverened. (115 MPH) if you remove the govenor then you will be able to attain higher speeds.

Gas mileage won't change all that much. But how you drive will play more into the MPG you'll get.

I drive as hard with 3.42's as I did 3.23's and gas mileage was nearly the same.

In order to really notice gas mileage go down you'd need to limit yourself an overdrive gear. Like my Z28. 3.42's to 3.73's or 4.10's would be a big difference in MPG. But your's with 3.42's you'll cruise at 2000 RPM at 70, with 3.73's 70 will be a 2250 RPM.

[Harry94]

For 3.4 auto's going to 3.73 gears the speedo is off by 10mph at all speeds not some percent. Your gas mileage is about the same. I top out at 105mph top end, but in the 1/4 I'm only at 82mph so that's fine. And yes my speeds were checked with radar. I have yet to recalibrate the pcm.

[camaro_dakota]

First off most 3.4L autos.. if not all came with 3.23 gears stock... it was the introduction of the 3.8L that brought about autos(not all) with 3.08 gears... Anyhoo.. I have 3.73's and an auto in a 3.4L with my pcm recalibrated and speed limiter removed.... i have been over 110 mph and it didnt want to stop... top speed is not and issue if the limiter is removed.. as previously stated.. Where do you really NEED to go over 110mph anyways.... They are a great gear and have little loss in mpg... My $.02... they are great and also with the addition of a limited slip... you get both wheels to [img]graemlins/burnout.gif[/img]
IMHO 3.73's will be fine... and if you had a 3.8 with 3.08 gears a 3.42 would be a fine mod but as for a 3.4 with 3.23's, 3.42's would almost not be noticed.... Go with what you want tho.. its your car... and if you add power later you might want a smaller gear like a 3.42.. i mean Tiago is running a 3.23 i believe with limited slip... and we all know that car is bad***.. Do what you want its your ride man [img]graemlins/thumbsup.gif[/img]

[95slowcar]

Where's a good place to buy the gears at? Is it best to order off of the internet, and then have them installed, or to buy them at a place that installs them?

[Camaro_SLP]

<blockquote>quote:</font><hr>Originally posted by 95slowcar:
Where's a good place to buy the gears at? Is it best to order off of the internet, and then have them installed, or to buy them at a place that installs them?<hr></blockquote>

Buy them new whatever you do. People will recommend purchasing used ones off of eBay, but I'd say pay alittle more for brand new ones. I don't think most shops would keep gears in stock, so ordering off the internet is your best bet.

Shop around the internet to find the cheapest deals for new gears.

[95slowcar]

Do you know of a good website, and also do I just need to buy some 3.73 gears, or are they car specific?

[Bliggida]

<blockquote>quote:</font><hr>Originally posted by camaro_dakota:
First off most 3.4L autos.. if not all came with 3.23 gears stock... it was the introduction of the 3.8L that brought about autos(not all) with 3.08 gears... <hr></blockquote>

Good info. That would explain why I didn't see it as an option. I was thinking it was a yearly model change instead of a misprint...which GM has been known to make from time to time. Good deal.

[Camaro_SLP]

<blockquote>quote:</font><hr>Originally posted by 95slowcar:
Do you know of a good website, and also do I just need to buy some 3.73 gears, or are they car specific?<hr></blockquote>

GearsRus.com
thunderracing.com
ammperformance.com
summitracing.com (?)

There are different sets of gears..look for "GM 10 Bolt 7 1/2" & 7 5/8" Doesn't have to be GM gears though. What's important is 10 bolt 7.5 rearend. Yes and no they are car specific.

Expect to pay around $170-200 for new gears. I would also strongly recommend getting a posi too. You can find a $99 one at SLPonline.com ..You will also need the install kit. Plus rear diff-fluid and an ABS reluctor ring if you want to keep your ABS.

Upgrading your your gears/rearend is going to be pretty costly in the end. It is one of the more noticeable power gains though.

[ August 09, 2003: Message edited by: Camaro_SLP ]</p>

[ellik]

i have a question about the 2 and 3-series carriers, and they havent been mentioned yet. i have 3.08's on my 97 3.8 and from my research i guess it must be a 2-series carrier. my question, is can i swap out my open differential for posi and install my 3.73 which are listed as a 3-series, or does that get more complicated than the putting in another gear that is also 2-series carrier. secondly, for $500 should i just get a 98 rear axle assemblly with the gears, lsd and upgraded rear rotor package? which install would be esaier in your driveway with limited tools?

[FuryCharger]

u guys mentioned earlier that with 3.73s, the rpm at 70mph is 2250....the sticker on my door says i have 3.23s and as far as i know my rear end has not been modified. but when im cruising at 70...my rpms are nearly 2250, and at 75 they are right on 2500....do the rpms fluctuate per car? is this normal?

[jc Kyle]

i have 308s and at 70 i'm at 1900 rpms, seriously, it's closer to 1900 then anything. Something weird though, when I bought my car, my ac caps were missing. Why would they be gone? Performance test?

Also what car would win

my car with everything in the sig, or a 2001 Olds Alero GLS with the 170hp 3.4 with alot of nice options

[staticpike]

Switching out the whole "pumpkin" is a lot easier than switching than internally pulling the gears and installing an LSD with new gears. At least it is something you could do in your garage with little problem (and doesn't require ripping the whole differential apart). Don't forget to get a speedo reaclibrator though...

My question is if you install the speedo recalibrator, will it fix the RPM miscalibration too?

[Camaro_SLP]

<blockquote>quote:</font><hr>Originally posted by staticpike:
My question is if you install the speedo recalibrator, will it fix the RPM miscalibration too?<hr></blockquote>

I don't think the tach is off after installing gears. Just the speedo would be.

[Bliggida]

<blockquote>quote:</font><hr>Originally posted by FuryCharger:
u guys mentioned earlier that with 3.73s, the rpm at 70mph is 2250....the sticker on my door says i have 3.23s and as far as i know my rear end has not been modified. but when im cruising at 70...my rpms are nearly 2250, and at 75 they are right on 2500....do the rpms fluctuate per car? is this normal?<hr></blockquote> You are dead on normal and accurate. 2250 for 70 MPH.

Dunno who gave you the other figure, but with 3.73's = 69.25 MPH is at 2,875 RPM