I am about to buy a used 98-99 z28, formula or TA, but have a few questions that I need help with. I don't know which to go with as far as trannies go. The 6sp or the auto w/ 3.23 gears?

1) When stock, which one is faster? The 6sp w/ 3.42 or the a4 with 3.23?

2) Am I right by saying all automatic f-bods that have a 150mph speedo have 3.23 rear gears?

3) In the future, I plan on adding free flowing exhaust and a shot of nitrous. Which one holds up better?

Any help would be greatly appreciated!

 

m6....
definetly get a 6 speed
and they have 155mph gauge speed...
well i think all have the same rear end gears stock

 

autos get 2.73's (gu2) OR 3.23's (gu5)

manuals get 3.42's (gu6)

at the track its my belief that an automatic tranny is the way to go, i have yet to see a man shift faster than a computer.

i love my auto, i get so tired of shifting! i have a shift kit. the tires smoke when i floor it <can do that stock, howeever> and i can spin going into 2nd and 3rd!

 

Yeah well I can spin my tires going 2nd to 3rd too.

1) They are both about the same. The engines vary in hp and the gears don't play a huge role. An auto with 3.23s will have very similar times to the manual with 3.42s. An auto with 2.73s will be a tad bit slower than the others. This is just a comparison. Some engines are stronger than others, like I said. I've seen a stock auto go 13.1. I've seen a stock M6 go 13.3. And vice-versa. There is no definate determining factor for the car.

2) No. All the cars came with 155 speedos. There were limiters on some cars. I *think* the limiters came on the cars without the factory performance tires. The limiter was 118 mph I think because the tires were only rated to 122 mph (forgot the letter). I don't know how to tell on your car other than seeing if you can hit above 118, if you can't there is a way to bypass it so don't worry. Don't take my word for all this info though, hopefully someone will correct me or verify me.

3) Depends what nitrous kit you go with, wet/dry, and how you plan to use it. I think they will both hold up just fine if you don't abuse your car.

The M6 always has the fun factor, but like Corey said, shifting gets tiring and boring sometimes. I wish I had gotten an auto when I'm sitting in traffic sometimes, but when I get the chance to open it up some and/or race, I'm glad I got a manual. The autos produce more consistant results at the track and are generally considered better for the strip.

edit: Added a little more. Good luck with your search too! You won't be disappointed with either one you get.

 

Thanks guys, I did remember that a friend of mine bought a 98z28 when they first came out and he did have the z rated tires with 2.73 gears. After doing a little more research, I did find out how to tell the difference between a 3.23 rear and a 2.73 rear. Instead of running 118+mph, I just need to drive on the highway in third gear and check the rpms at 60mph. If it reads 2100+/-, it's 2.73's. If it's 2500+/-, then it's got 3.23's. Thanks again for the help, but still undecided on 6M or 4A w/3.23's. I guess it'll come down to price and which one I can find.

 

I have a 99 T/A that did not come with Z rated tires although it has them now, and there is no speed limitter on it.

 

I'd go with the M6!! Especially if your puttin power into it!!!! The M6 will hold up a lot better, it's a stronger tranny than the auto!! Plus it's more fun with a manual, and if you can drive it, you can shift quicker than an auto, on the contrary to what someone else said!!!

 

It is true that some came with a speed limiter, you can tell by checking the sticker in the driver side door jam to see if the car came with z rated tires. if so then you know the car tops out the same as all the rest.

 

So far, I've test driven a 98 T/A 6M and a 98 Z28 w/3.23's (I tested the revs @ 60 in my 94 Formula w/2.73's on the way to test drive the Z and tached 1900 rpm's, and on the Z's test drive the Z tached around 2500-2600 rpm's). So I'm torn between the two so far. The T/A is silver, has chrome 5 spoke wheels, grey leather and 75000 miles and the Z is white, has chrome 5 spoke wheels, tan leather and 58000 miles. I also know where a platinum 99 T/A, 6sp, grey leather, chrome 5 spokes w/ 55000 miles.
I used to own a 97 T/A w/6M and I currently have a 94 Formula w/4A & 2.73's, so I have experience with both 6M's and 4A's. I bought the T/A brand new and the stock clutch started slipping a little at around 30,000 miles and now my 94 4A is starting to slip, but it started around 100,000 miles.
I'm leaning toward the Z because it has less miles, but still haven't worked out the price yet. It will probably be the one that works out to be the best price.

Thanks again for the help.

 

Do all LS1s w/o Z rated tires come with 2.73s and w/Zs with 3.23s? Just wondering?

 

Tires had nothing to do with it, all M6s came with 3.42s, you didn't have a choice. A4s came standard with 2.73s and there was an option (GU5) for 3.23s.