For those with A4's that went from a 2.73 to a 3.42 did you notice a nice sized gain with the 3.42's or was it minimal? I was told I will spin off the line more but my new rear has LCA brackets and Spohn LCA's so I know that will help. My old 86 Camaro has 3.42's but it was a 2.8 and a one wheel wonder car so I am hoping to notice some sort of gain in the swap since I now have a car with some power My motor is also pretty much stock right now, mo cam or anything.

 

I had a hotcam heads/cam setup with 2.73s for awhile. At the track I couldn't do better than 2.3 or 2.4 60ft on slicks.

I changed the gears to 3.42 and picked up 3-4mph and went from 13.5 to 12.9. With some more practice I got it down to a 12.5 on 1.9 60ft time.

For an 4l60E, I personally believe it is one of the best mods. If not the best mod for the money.

 

The 3.42 is a great all around gear for the 4L60E. The 3.06 first gear combined with the 3.42 rear gear makes for great first gear drive ratio...better than 4.10s with a TH350 (2.52 first gear)...I pull consistent 1.70s to 60' with some 1.60s with good track prep on BFG DRs with 3.42s and it takes lots of finesse to launchit without spinning. You may also want to look at 3.73s depending on what your plans are for the car. If you can hook 3.73s they may pull harder in the 1/4 by providing more engine speed. I currently trap around 5500rpm, but max power is at 5800-5900. So, I may benefit from the swap...

Generally, on this board its 3.73s for A4s and 4.10s for M6s.
--Alan

 

Well the rear is in the car now along with the Spohn LCA and brackets along with the Spohn PHR.
I think for next season I will stick with the 3.42's then if I decide to, go with 3.73's and slicks next winter.
Since I am pulling some things this winter I am going to go ahead and get Ion to get me a tune so a tune with the 3.42's should give the car a big punch over the 2.73's

 

you will definetly feel the difference I went from 2.73 to 3.73 and it was a different car! and on street tires I droped 3 tenths!

 

Well I know I will at least feel it in first. I had it in the driveway in the snow (moving it) and with the new suspension parts and rear in I could tell it was going to be a fun summer coming up and then I got stuck.... hahahaha, glad I have a beater...

 

I am about to do the same thing. LT1/ A4(700R4) going from 2.73 to 3.42. I have several engine mods already including a custom tune chip in my 93LT1 Z28. I have some Nitto 555DRs so I hope they will help me get some added traction also this spring for bracket racing.

 

How much will it hurt gas milage going form a 2.73 to the 3.42 gear ratio?

 

I asked the same question in another forum 2 days ago. I was told it will be little or no difference in town but on the highway it will decrease some.
I am gonna be trying to run quicker with 3.42s, so I already know my mileage will be less.

 

It made a huge differance on my car stock. As for gas consumption, hehe, yeah it dose that

Faded

 

My 96z vert is currently mildy modded..catback,airfoil,induction,maft.small stuff .I absoluted hated those stock 2.73 gears.The car was very doggy barely turned the tires and just felt slow as a slug around town.
At the track it did some 15.0s at 94mph or so before catback on street tires with around 2.4 60fts.
I swapped in some 3.42 and they were a night and day difference .I knew they would be have done similar things in my other cars.Around town the car is way way nicer and can burn the tires much easier.

At the track the car ran a new best of 14.3 at 96 with 2.18 best 60ft but even with a 2.4 60ft it ran a 14.4 something.Now I am sure the catback helped a few tenths but the gears had to help out too.I did have nitto drag radials on the car for the track run but really didn't even bother heating them up as most of the cars I was up against were plus 16 second imports and didn't want to use up my brand new tires.And on comparable 60fts to my street tires the car was still faster. I have no idea why some mags seem to get no improvements from going up gears.They also seemed to knock off at least 3 tenths or so going from 3.08 to 3.42 in my 80 400 engine trans am.

3.73 might be fine too a lot of guys do them in autos.But for a 99% street car to me the 3.42 are perfect in an lt1 and sure when combined with a nice 2800 converter they will be even more perfect.Find out this summer hopefully.

I got real gm gears out of like a newer ls1 and got carrier at same time so the swap was really simple.And gm gears are usually much quieter than aftermarkets.And stay the heck away from richmonds and I had some bad experiences with gm motives too.

3.42 gm grears are dirt cheap used.

 

Well I beat a 94 Formula pretty good when I was close to stock and he was stock and beat an 04 GT auto and a manual so I know its running pretty good good as is.
I am going to have MSD wires, plugs, STB, A/C delete, front sway bar, rear seats, spare and jack and I have the 3.42 in there with the LCA's and relocaters. I am also going to have a tune before it hits the road so I am HOPING for a mid 13. I think the next mod is going to be a 2800. I thought about a full exhaust next but I think it might be better for the 2800 next.

 

But can you put 3.42s into a rear end that came stock with the 2.73s without upgrading to a 3 series carrier?

Specifically, on a 93 with an A4. Man what a slug!

Thanks

 

You can buy some gears in 2 series but most guys get another carrier to run the 3.42.I got carrier and gears for cheap enough made for a real easy install.
The 2.73 gears should be illegal they suck so bad around town. Gm should have offered 3.23,3.42 and 3.73 on the autos and 3.42,3.73 and 4.10 on the manuals.And if they would have given us an 8.5 10 bolt we would likely have been ok and not needed 12 bolts near as much.

 

Well I got the car out last night to test it out with the SLP eaton 3.42 rear, LCA and relocaters and PHR. It was about 10 degrees and it felt A LOT stronger off the line and the ground was so cold that I kept breaking the tires loose but even in the cold I could see a noticable gain from the stock peices.