wideopen85

What does the Z51 package all include? Is there a noticeable difference between a base suspension car?

QZRBLU

My '90 has the Z51 option plus FX3 adjustable suspension. I found this:

what the book says about it is: "Z51 included RPO KC4 (engine cooler), heavy-duty front and rear springs, larger front brakes, and heavy-duty front and rear stabilizer bars. Available with manual transmission coupes only."

And this: http://www.buyavette.net/suspension%20packages.php

I understand the combination of Z51 and FX3 got the standard leaf springs NOT the heavy duty ones.

Mick

blackozvet

'90 - 115.5/659 lbs front 57.2/326 lbs 30/26 rear
R9G 115.5/659 57.2/326 30/26
2 mm more in the rear bar from '89

FRONT 88-96
FHA 93.1
FHB 115.5
FHC 93.1
AA 96.2
FSK 90.1
FSM 75.4
FSS 90.1
FSR 73.2
HA 60
JA 60

REAR 84-96
BMF 72
BMH 87.5
NYU 57.2
NYR 39.9
RCA 39.9
RHY 39.9
RHZ 39.9
RR 26

93Rubie

Is there a difference between night and day?

Yes the difference is very noticeable. Base is for the country club/boulevard cruiser type. Z51 is for those who like to drive there Corvettes...HARD!

QZRBLU

Thanks Sean!

blackozvet

no worries mate !

3JsVette

Perfect analogy!

Supermutt

Ressurectiing thread #2 thanks in advance for any help and advice.
ive been googling the threads and you tubing a lot to find my own answers but sometimes better clarification is needed (don't know options, codes, differences)

So i got this 90 w/ zf 6spd, kc4 oil cooler(adapter on filter pad w/ coolant hoses), fx3 shocks & No rpo sticker

First Q. shocks the attached link is asking with or without z51, and mentions 17 inch rims
this thread post 2, i think means it has the z51.
(believe fx3 inop & looking to replace w/ non fx3 shocks)

https://www.shockwarehouse.com/search?vendor/Bilstein

Q 2. Bigger brakes! If thats true than- 90, corvette, brakes, front, from the autoparts store are wrong and there was no option other than base and zr1
is there different front brakes.

I was going to start a service/maintenance/fix thread after the initial service, but maybe i should do it now and attach threads in that instead of ressurecting.

Swear to god i'm cramming like it it's finals week to save you guys from the dumb questions
thanks

Fiberbundle

The J55 front brakes (bigger brakes) are 13 inch rotors rather than the base 12 inch rotors. They are also the ones on the ZR1 cars.

The Z51 cars had 17”x9.5” wheels at all four corners.

Measure the front sway bar and if it is 30mm you are a Z51 car.

Also the Z51 package included a quicker steering ratio.

Supermutt

Thank you, front sway bar measures 26mm, also found this chart when outside crawling under it, settles it for me but i'll measure again since it goes up in the air tomorrow for brakes, bearings and rims go to the shop for tires. Guess i better get the shocks ordered up.
thanks again

https://www.corvetteactioncenter.com...uspension.html

WVZR-1

If you have a '90 that's missing the SPID on the console door you can take your VIN to a GM Dealer and they can supply you with an RPO list of 'as built' - NOT A LABEL - but a list of RPO/Description that they can print and hand to you. There shouldn't be any charges under most circumstances. If $$ are mentioned ask exactly why!

Dacer Spears

RPO KC4 Engine Oil Cooler, heavy duty suspension and brakes.

jts90vette

All 1990's were equipped with 17x9.5 wheels and 275/40/17 Gatorback tires, Z51 or not, except the mighty ZR1 which had the 17x11 wheels on the rear, but still had the 9.5's on the front.