how much does stock rear gearing hold back my 89 RS 305? i believe its got 2.73's open differentail. it would be niece to replace it with limited slip, i hate one wheel tire spin, and it really sucks in the rain. i just wondered how much this ratio hurts my cars performance? i would like to have a little more acceleration but need to maintain fuel millage. i think part of why this car delivers such great gas millage is becuase of the rear end. can you get a 2.73 limited slip or make mine into a limited slip? how much does your gas millage suffer with a change in rear gear ratio?

 

I do believe, and don't quote me on this, you'd need a new differential case to go with a limited slip, which if you're doing, you might as well do the whole job. Best recommendation? Find a totaled 4th gen, and take it's rearend. There's an article on it in the technical articles off of the mainpage. You'll get better gearing, a posi, and better brakes, and a direct bolt in, at a used parts price. At least that'd be my recommendation.

 

a 4th gen rear would be a good place to start, but remember they're also 3 inches wider. If you used regular 3rd gen backspacing, your wheels will stick out a little farther.

If you decide to just replace your carrier, look for something in the 7 5/8ths size, w/ 28 spline axles. 2 series for 2.73-3.08, or 3 series for 3.23+

3.42s are considered to be the middle of the road gears, all around good gas mileage and acceleration. swapping from 2.73's to 3.42's should result in about a 40% increase in torque/acceleration IIRC.

good luck either way!

back to my cereal!
brandon

 

I thought it was two inches wider? At two inches, I could see the nice mean stance mentioned in the article. Three seems a bit excessive.

 

are all 4th gen's limited slip. i kinda doubt a v6 4th gen has limited slip. i think what im really looking for would be a junk iroc, right. i know where there is one that has been for sale for almost 2 years. i think the guy is asking too much the car its in poor shape. i looks like a salt monster and it has sat roadside collecting all of the crap in the winter. if tax refund time comes i think ill offer him 500. i dont have the money right now but it would be great if it was a 5.7, i could pull the engine rebuild it and into the rs it would go. also i could use the rear end, its also a T5 so if i wanted i could make my car a manual. i could also use the iroc wheels. as i said its a pretty trashed car but there is an awful lot of good parts still on any of these cars. only if my job paid better. i dont make much at $11. just about all of my extra money goes into my car.

 

i was under the impression it was 1.5 inches extra each side. i'll look it up.

 

It's about 1-5/8" per side.

Gives the car that "mean" rĄcer stance; you know, the skateboard wheel look. Ultimately goofy and bogus looking IMO (narrow wheels stuck out past the fender lip.... yuck). On the other hand, 4th gen or Corvette wheels, will go right on and fit perfect. Then you'd need 1ž" spacers for the front to run the matching fronts. Or use C5 or C6 wheels, with 2" or 2ź" spacers on the front and ˝" ones on the rear (otherwise they'll rub the fender well at the front, right about where a frame would be if these cars had one).

 

not all of any gen are posi,

i had a list that a member here gave me of what the good 4th gen axles with posi are but it is on my HD somewhere i would have to search for it

maybe someone who has it will show it before i can find mine

 

I wouldn't do the swap for the extended wheels. But I'd live with them for everything else. Personally I'm saving for a big nine inch.