dizwiz24

Just curious.

drove in michigan where everyone drives 80-85 and the zf6 did pretty well even in 6th (didnt have to downshift to 5th for highway passing like i do in ohio for 65-70 speeds).

back in 93, the speed limits were 55-65 in america.

Now speed limits are generally 70-85 mph.

i am wondering if gm saw this coming and thats why they geared the zf6 so low (tall), esp in 6th

FAUEE

The ZF box came from Germany, which had the autobahn, so that may be why it has long gears for the top gears.

But what's probably more accurate is the gobs of torque allowed for long highway gears for fuel economy.

Kevova

Maybe, but unlikely Michigan took away points for speeding up to the former posted interstate speed limits in 1979. In other words monatary only, driving 70-75 wasn't uncommon back then.
To meet emissions and economy standards the plan was to keep RPMs low. At 55 C4s were just above idle in overdrive. You could say the L98 was developed for the 55 MPH speed limits.

pologreen1

I agree. They are barely working at highway speeds,

Tom400CFI

^This^. CAFE. GM geared it the way they did to meet criteria.

Steves LS6

Gas mileage was the reason. I haven’t owned a C4 but my 4th gen LT1 Camaro was in the mid 1000’s at 65 with the T56 3.42 gears (30 mpg). My 3rd gen revs at 2300 when I am doing 70 with the WC T5 3.42 gear(18mpg). My C7 is at 1800 if I remember correctly in 7th with 3.42’s at 70 (36.8 mpg).

I just remembered my 79 6.6 TA with the T10 four speed and 3.23’s was 2600 at 70 mph. Don’t remember the mpg.....I do remember I would burn through 1/3 of a tank driving into the edge of the Chicago from Arlington Heights (about 24 miles round trip).