Cascade Crew

91RSVert · Posted: Thu Apr 10, 2008 7:28 am Post subject: Rear Axle debate.

So when I got this vert I swapped in the rear axle from my v6 that I THOUGHT had a 3.23 peg leg. I noticed no difference in power that everyone speaks of when swapping gears. hum....

So while trying to correct my speedo, I have figured out that is still a 2.73 axle ( Confused

on how that got put in a v6 car).

So now I have some thoughts bouncing around in the brain... my biggest obstical is money and tools.

1. Install the used set of 3.42's I have with my slp LSD.(dont have tools, knowledge, 3.42 may be to steep for my intended use)
2. Get junkyard unit/drum for 200+core and swap.
3. Wait, hunt, find v8 rear disk and pay more cash. Swap hoses, cables, etc.

Also, what years did they change the splines and to the better rear disk?

blue89 · Posted: Thu Apr 10, 2008 7:37 am Post subject:

All the V6 camaro's I've ever hunted down in the 86-89 era have all had open 3.42 rear gears. There should be any difference between V6 and V8 rear ends except for one, 26 or 28 spline axles. With 28 supposedly being stronger. So if you have a limited slip unit (I assume cone/clutch Auburn?) count the teeth on the spider gears. The 28's are also a bit thicker and don't physically fit into the 26 spline case. Fortunatly I lucked out on mine and found a 26 spline auburn 2 series to match my 26 spline axles.

3.42 is a pretty low gear when doing performance stuff. 3.73 would be a minimum. Do a little math and figure out what RPM you'll be at with a given rear gear. My V6 is only at 2500-2700 at 70mph with 4.11's and lots of people put 4.11's behind their V8's. Not to mention gears are cheap. $150 from Richmond.

91RSVert · Posted: Thu Apr 10, 2008 8:01 am Post subject:

I knew the splines were different depending upon the year. Didnt know when they changed though.

Gears from my readings..
v8's had 2.73/auto or 3.08/t5
v6 91/92 was 3.23/auto or 3.42/t5
v6 pre 89 was 3.42/auto/trans

I want to beable to cruise down the highway and not kill my milage. I'm thinking 3.42 may be to much for that. The 3.23 was just one step above what the car should have. Then also later if/when I kill this t5, I want to go back to 4l65e or 4l80e... so then I "should" go back down to 2.73.

Whats the formula to figure rpms out???
tire dia... 26.18
axle gear... ??
trans gear.... .73 od?

blue89 · Posted: Thu Apr 10, 2008 8:48 am Post subject:

http://www.wallaceracing.com/gear-speed.php

Do a quick search for WC-T5 ratios, I think I just posted them up somewhere. Initial calculations for a 4.11 with 0.70 rear has the engine at about 2500. And you'll have low 60' times!

My initial views of rear end ratios has been skewed by having automatics. The torque converter makes the engine always spin at a minimum of 2-3k, no matter what rear is in the back. Messes with your head man!

91RSVert · Posted: Thu Apr 10, 2008 9:07 am Post subject:

Cool link. Thanks!

Confirms I do infact have a 2.73. That is so close its scary! Shocked

Confirms 3.42 is to much for the interstate. So its gonna have to be 3.23 or 3.08.

Also searching, I have found...

3.08 lower is series 2. So basically 95% of v8's had series 2
3.23 higher is series 3. So all v6s were series 3

90+ is 28 spline
pre88 is 26 spline

Slp's/zexel pull out is series 3 28spline.

So I'm back to where I am now. No matter what axle, I'll have to pay someone to swap gears n carriers. Unless I can just "happen" to find a 3.08 posi/disk and just be happy with stock.

blue89 · Posted: Thu Apr 10, 2008 9:17 am Post subject:

damn dude, what RPM do you want to be pushing at 70mph? At a 3.08 you'lll barely be idling? I have 3.08's in my LT1 and its too low. I'd much rather 3.42 or 3.73 at a minimum. Just for fun I might put my 4.11's in it for a day or two Very Happy

I have other useful calculator pages if you want them. Maybe we should all start a bookmarks thread? I have tons and they're all organized. If you want jay, I'll send you mine.

91RSVert · Posted: Thu Apr 10, 2008 9:32 am Post subject:

I was aiming for 60 and 80mph Cool

3.42/80mph is est 2600/2700mph. That is going to suck my gas.

3.23/80mph is est 2300/2400. Better, but still pushing. This would be nice around town though... which is most of my driving. 70 would be 2200, which may be what I have to settle for.

3.08/80mph is 2100/2200. Nice, but not great for around town. But better then the 2.73 I got now.

there is a 92 model disk/posi on ebay right now.. 4hrs way, likely 2.73 though Sad

. finger....... is........ twitching.....

blue89 · Posted: Thu Apr 10, 2008 10:03 am Post subject:

2.73 would be a 2 series carrier that you could bring up to your 3.08 with new gears. Just putting that out there.....

91RSVert · Posted: Thu Apr 10, 2008 10:24 am Post subject:

yea, but gotta pay someone to do it Sad

blue89 · Posted: Thu Apr 10, 2008 11:08 am Post subject:

That part can get expensive. If you get a new axle though they would probably drop the price down if you brought it in a truck bed. They tend to be happier and more inclined to be cheaper if they can set the gears on a bench instead of the ground.

rjmcgee · The Hammer Joined: 08 Jan 2004 Posts: 2328

Your going to see almost no performance gain going from 2.73 to 3.08, it's just a real small change for the $'s you will shell out.

I think 3.42's would be a nice trade of performance and $'s.

Do you know what overdrive ratio your T5 is? Both Jenn and I have the .63 5th gear. I cruise 2000 rpm @ 60ish with 4.10 gears.

On Jenn's Firebird we went from a LG4/700R4/2.73 combo to a LG4/T5/3.73 combo and she was still getting 22-24 mpg on the freeway when we drove up to Washington for Cows last summer.

Dewey316 · Posted: Thu Apr 10, 2008 5:17 pm Post subject:

yeah, I agree, its not worth bothering with 3.08's. I have 3.42s in my car, and I got 32mpg on a trip last summer. 3.42's are a pretty good mix, it will give you a gain, but isn't so steep that you can't cruise and still get good gas milage.

91RSVert · Posted: Thu Apr 10, 2008 5:29 pm Post subject:

Ok, the axle I found is mine Very Happy

, gotta go get it sunday.

GU5/G80, with disk and booster. So I'm going to be upgrading in every way possible