93Rubie

In theory you should a touch more understeer than I have with my 93 Z07, you'll have a slightly stiffer front bar and spring but not much.

Don't forget the front sway can be "salted to taste" to get the car where you want it. I prefer a car that is just barely pushy.

HandsomeMike

I would have thought that stiffening the rear with the spring would loosen it a bit thus reducing some of the push I have now. Can you explain how it'll cause a touch more push? I'm running the "what you do to one end effects the other" scenario through my head trying to understand. I too prefer a pinch of push vs oversteer. Thanks for your help! I think I'll go ahead and put the spring in and see how it feels. When you say I can salt to taste on the front bar, do you mean by swapping it out or shimming it, etc?

93Rubie

Ok, I had to re-read that.

Yeah, FE1 stuff with the 32/combination, then you put the rear NYU spring on WITHOUT changing the front.

It might be ok, but I suspect it will be loose. Too much rear stiffness compared to the front but you DO have a larger front bar so....who knows.

Now the 93.1 AND the NYU bar, yes that would be a good close to Z07 combination.


Shimming front bar mounts.

HandsomeMike

I agree, the 93.1 front spring I have now with NYU rear, bilstein sports and 32/24 bars should get me pretty balanced and make me essentially a Z07 car suspension wise. That and a proper autox alignment should satisfy me for at least a year before I start wanting to mess with something else! Thanks for your input!

93Rubie

Yeah, that setup might be a touch pushier than a true Z07 but not much, especially when salted to taste.

Alignments are good.

blackozvet

A FHA / NYU combination is pretty close to a Z07/Z51 combo.

the 32 front sway bar is 2mm larger than any z51 so that could give an understeer tendancy, but can be tuned out with tire pressures.

My prediction would be that combo would work fine.

https://www.corvetteforum.com/forums...84-96-z51.html

HandsomeMike

Thanks blackozvet. I'm pretty pumped to see how it handles after install.

ddahlgren

83?????

blackozvet

dont forget to update us after you have run the z51 setup.

you might need better tires too !

l98tpi

Handsome- here is my $.02. First, if you are going to Autox the car you will want to have a touch of oversteer to rotate around decreasing radius corners and tight 180 degree corners. Second, with the car lowered, you could be bottoming the shocks out on the front. With a lowered C4 look for C3 front shocks; they have the same mounts as the C4 on the front. I would work toward getting adjustable shocks next, preferably double, but Koni Sports are pretty nice too. Once you get the new spring in, have the car aligned and corner balanced. Lastly, the most important suspension component is tires; get some good tires for the class you want to run. Just research and see what the faster cars or the National guys are running. HAVE FUN

3JsVette

Not referencing model year......production number.

69427

Slight disagreement here. Both the C4 and C5 have two fixed length lateral rear suspension links (at each corner) that determine the camber curve (the halfshaft and strut rod on a C4, and the upper and lower control arms on a C5). And both models are designed to change camber as the wheel moves up and down to counteract the effect on tire vertical positioning when the vehicle/"frame" leans during cornering. It's the angles of the links that determine the amount of camber gain during suspension movement. And, there's rarely a free lunch in this world. If you get the suspension camber curve to perfectly cancel out the "frame" lean-induced camber change during cornering, you then end up with measurable camber change during straight line acceleration squat (thankfully the anti-squat geometry in both these suspensions reduces this effect).

FWIW, I'm running the '84 Z51 rear suspension in both my '84 and my '69. I like the handling (I do mostly track days, and autocross on rare occasions), and the ride is quite acceptable to me.

blackozvet

good point about the shocks, most c4 front shocks are around 9.5" to 10" compressed, if your going to lower your front you should get no longer than 9.5" compressed length shocks. Try for 8.5" if you can, Flaming river do make one of those. QA1 make a 9.5"

in this pic with a couple of typical c4 shocks you can see the effective shaft length can be quite a bit different too.

HandsomeMike

Thanks for the info guys. I'm just an occasional autox'er not looking to win my regional championship. I want to be competitive when I do race but overall just want a great handling Vette. I race in CAM class and was 8th out of 13 the last time out (beat a Viper by .1!). I won't be changing out the Bilstein sports that I bought new and put in a few years ago. The NYU rear spring is going in tomorrow. My neighbor who owns a shop and is also a Vette fan (he has a built C6 GS) is taking care of the job. This will conclude my suspension upgrades other than getting a more aggressive alignment. Tires are Continental Extreme DW. I'll go softer once these wear out. Next up, long tube headers!

shotime123

thank you very much great article

HandsomeMike

It's was raining when I picked up the Red Dragon from the shop today so I didn't get to drive it hard to feel the difference the spring made. That and the passenger rear is much higher than the driver side so I need to adjust it. Can't tell by looking but I measured from floor to frame on each side. Hoping to have an update for you guys about handling changes on Friday. Just driving home though cruising in a straight line it does feel noticeably more planted and solid.

HandsomeMike

Signed up for a HPDE today at NCM Motorsports Park for Aug 13th. I'll really have some good feedback for you after that!

blackozvet

measure from the jacking points (you will see the little indicators in the plastic) to the ground. make sure you measure from the steel behind the plastic.
that will give you a basis to see where your chassis heights are.

good luck with your autocross !

HandsomeMike

I adjusted the ride height yesterday using the jacking points as references (metal frame). It was way off! I then drove the car and made a few entry and exits from my steep driveway at different angles to make the suspension travel through its full geometry.

The HPDE will be on the race track, not an autocross. I have autocrossed on their autocross pad though and it is sooo nice and smooth!

blackozvet

its tough to get some level measurements with a leaf front, do you have the longer bolts in the rear ?
thats where coilovers are so good, its a dream to adjust the chassis wherever you want it.