What gears??

[98_ls1maro]

What ratio gears do I have? I own a '99 Z28 Auto. At 70mph I am at 2100rpm's. What's the best gear for an auto?

[2001NBMZ28]

Looks like 3.23 to me, that was the performance axle option over the 2.73. www.f-body.org/gears/

[Pyromaniacal]

A good ratio for auto is 3.73.

I've driven a car with a built 4L60E and 3.73 gears, that thing would MOVE if you even pushed that shit down too hard. It cruised 80 at 2700-2900 approx according to memory. If you plan on going fully built, the car I drove was a Procharged 383 LT1 Stroker and it was an absolute beast at any speed. It was fresh so the suspension was stock, that thing would shred rubber 'cause of this at nearly any speed so it got scary sometimes, haha.

[kebie05]

subscribed to check it out, i am thinking of gears also. thanks

[Z28Thunder]

As far as I can recall all Z28's came with 2.73's factory. The 3.23 was a opition for the SS. I dont think you could get the 3.23's in a Z but could be wrong. What gear also dpeneds on what you want. 3.73's here behind a 4000 stall. Unless you have driven a stall a 4000 will seem unreal loose. I did have a 3500 stall when I had the 2.73's and enjoyed the heck out of it. I would think a 3500 and 3.23 or 3.42's would be great. 3.73's might be fine with a 3500 but the stall may be to little for the gears.

[67CamaroRSSS]

Here we go again. Z28's with an A4 had 2.73's with 3.23's as an option. All A4 SS's were 3.23. All M6 cars (Z28 & SS) were 3.42's.

I changed my A4 car from a 2.73 to a 3.73. Car seems to work well with these gears. Deep enough for decent acceleration and not so deep I can't drive the freeway.

[Z28Thunder]

Here we go again. Z28's with an A4 had 2.73's with 3.23's as an option. All A4 SS's were 3.23. All M6 cars (Z28 & SS) were 3.42's.

I changed my A4 car from a 2.73 to a 3.73. Car seems to work well with these gears. Deep enough for decent acceleration and not so deep I can't drive the freeway.

Okay well I didnt know the 3.23's were and option. And yes with 3.73's at 65 on the highway I sit at about 2100 rpm. At 75 its around 2500 or 2600.

[98_ls1maro]

I have 3.23's. Thanks for your help ya'll.

[Kup98ss]

Okay well I didnt know the 3.23's were and option. And yes with 3.73's at 65 on the highway I sit at about 2100 rpm. At 75 its around 2500 or 2600.

What's your MPG.

[greatwhiteZ28]

i think GU8 is the code on door for 3.23, and gu6 for 2.73

[Z28Thunder]

i think GU8 is the code on door for 3.23, and gu6 for 2.73

GU2 - 2.73
GU4 - 3.23
GU6 - 3.42 (Manual Tranny only)

[Y2KPewterSS]

GU2 - 2.73
GU4 - 3.23
GU6 - 3.42 (Manual Tranny only)

GU2=2:73
GU4=3:08
GU5=3:23
GU6=3:42

[Z28Thunder]

What's your MPG.

I would say 17/20 ish highway only.. I didnt build the car for good MPG. If your going to build your daily only car its a good question. My daily is a Acura that gets 34/37 mpg. If you dont have a daily and it is your only vehicle you may not want to mod to much. It will and does effectt mpg. I do drive the Z daily sometimes like I did all last week. The 3.73's and cam kill the mpg. I could get better mpg with a better cam and go back to 2.73's but enjoy what I have built...

[Z28Thunder]

GU2=2:73
GU4=3:08
GU5=3:23
GU6=3:42

Didnt know 3:08's were an option. Hmm And yes I meant GU5 for the 3:23's.

[Y2KPewterSS]

Didnt know 3:08's were an option. Hmm And yes I meant GU5 for the 3:23's.

3:08s were for the V6s

[greatwhiteZ28]

GU2=2:73
GU4=3:08
GU5=3:23
GU6=3:42

get em LOL, but i did knew it was bu5 ,, ( damm coronas)

but any other codes to be sieferd heres the site

http://www.lonestarthunder.com/m_rpo.php

[mtb01z28]

I went to 4.10 in my a4 car went from 13.2 at 106 to a 12.55 at 110. I had to go back to the stock 2.73 it was un drivable whith out drag radials plus it is over a hundred miles to the track.

[greatwhiteZ28]

thats what stopping me getting them. but only 75 miles for me

what was your 60' times for both

[kebie05]

what do you mean undriveable?

[greatwhiteZ28]

probley caseu hes at high rpm s on cruising speeds