Wadoka

What 's the gear ratio in the rear end of a ZR-1?

Wondering because the cars were so strong for top-speed mph...

~Matt

DoctorV8

3.42:1. Fifth (0.75:1) is the top speed gear.


[Modified by DoctorV8, 8:13 PM 11/25/2001]

SPEEDEMON

The gear ratio for the ZR-1's is 3.45.

ZR-1DUDE

Most of them are 3.45.

Some are 3.55s. I beleive after 1991 all were 3.45 unless it was an export model - then it was 3.55. 3.55s are rare regardless.

D.
:seeya


[Modified by ZR-1DUDE, 11:47 PM 11/25/2001]

Ryan Bell

Exactly.....I've always heard 3.45 was the ratio.

gmanZR1

I am really thinking hard about changing the gearing in my car. What is the best gear to change to, and what kind of rpm are we looking at when cruising on the highway in 5th and 6th gear, at 60 and 70 mph??

I am not too concerned about gas mileage (my computer says I average around 16 any, mostly around town driving with a heavy foot!), just wondering.

BUD D'DONATO

430 are sooo much fun :yesnod: :yesnod: :yesnod: :yesnod:

Rainy99

I have a Canadian export 91, would that mean i have the 3.55s? Is there a code that would tell me this or?? Just a thought...

Brennan

USAZR1

Some of the ZR-1's used in early testing were equipped with a 3.54 ratio but supposedly all production cars came with a 3.45 gear. If Hib sees this,maybe he can offer his insight.
It's always amazing to me how many people do not realize the meaning of 6th gear's 50% overdrive. They still think a 4.10,4.30,or even a 4.56 gear will put the revs outta sight on the highway. Nothing's further than the truth. Here is the approximate rpm your ZR-1 will be spinning in 6th gear at 70mph:
3.45 gear: 1,700rpm
4.10 gear: 1,950rpm
4.30 gear: 2,100rpm
4.56 gear: 2,200rpm

DoctorV8

Sorry for the earlier mis-type. Here is some info off the ZR1-net:

"3:54 Rear Ends
The following information provided by Gordon Killebrew.

It was originally released for cars going to the European market because of low noise level requirements.
It was not an option you could order. It was automatically a 3.54 axle instead of a 3.45 when going to a Country that required this.

From the start of production in 1988 (MY89) to 01/01/89, all 6-speeds had a 3.54 axle. After 01/01/89 the ZR-1s used a 3.45 axle. The L98 6-speeds used a 3.31 axle. The 3.54 axle was not EPA certified in 90-92 because it went to the European area market. In 1990 the L98 & LT5 6-speeds used a 3.45 except the GHO code with a 8.5 ring gear.

The are no records for how many, and there were no break points. They were produced as ordered.

I doubt that any went to the country of Switzerland due to their noise level requirements. Most ZR1's did not meet their requirements. There were some sent to England."

Personally, I like cruising at 90 mph with 2000 rpm on the tach, and I like being able to hit nearly 60 mph in 1st gear....so I'm sticking with 3.45's, and just plan to add more power!

Sanjay

phrogs

I have the 3:45's :cheers:

Stan A

Food for thought!!!

The Callaway Supernatural Tw-Turbo uses 3.91:1.
Reeve figured out out this was the best gear for the power this car makes for the street driver and highway straight line runs. Not the best for the dragstrip.

Stan A :chevy

Hib Halverson

All production ZR-1 have 3.45:1 axle ratios. Also transmission ratios are 0.75:1 for fith and 0.50:1 for sixth. A few of the 89 ZR1prototypes and pilots had 3.54:1 axles but no 89 was ever sold and most were crushed.

phrogs

:cry That sucks but I love the stories of individuals finding them and restoring those cars that were supposed to be destroyed :yesnod: