C3 Suspesion mods.

C3 Suspesion mods.

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Discussion

ZR1427

Original Poster:

17,999 posts

249 months

Wednesday 25th February 2004
quotequote all
Ive often heard that the C3 suspension wasnt the best to be had on a performance car ,was it that bad?,and how could you modify the suspension for performance.
What is a 'Gymkhana kit'?

mickn

89 posts

242 months

Wednesday 25th February 2004
quotequote all

Knowing bugger all about cars mechanically, perhaps someone could give me a reason as to why my C3 seems to sit high compared to others. I know nothing about the current suspension set up on my car, which is incidently a very original 1973 convertible 350 auto.

LuS1fer

41,135 posts

245 months

Wednesday 25th February 2004
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The "FE7 Gymkhana" suspension offered higher rate springs and firmer shocks giving tighter handling. It says here "Gymkhanas weren't recommended for general driving". This refers to the 1974 Vette but not sure when the option was available.

As for sitting high, all Vettes have a transverse leafspring suspension. One option was a Z07 "Off Road Suspension & Brake package", presumably for increased ground clearance in Dukes Of Hazzard country.

vetteheadracer

8,271 posts

253 months

Wednesday 25th February 2004
quotequote all
:Lucyfur said:
"Gymkhanas weren't recommended for general driving"


....that is because it was difficult to get the pony behind the seats and the hard hat and riding crop make you look silly driving the vette....althought the jodpers might be fun!

LuS1fer

41,135 posts

245 months

Wednesday 25th February 2004
quotequote all
Hi Nigel. I've spoken to Fred and am currently looking for a nice red Z06. Just got gazzumped on a red one dagnabbit! Don't fancy half the colours they do. What colour is yours?

Don't think I don't know where you nicked half your forum name from. LOL.

SunnyZR1

48 posts

244 months

Wednesday 25th February 2004
quotequote all
I love the c3 looks, specially the 1980-82 models. Please have a look at VetteBrakes (I guess they have a web site, do a search in the internet), I have their latest catalogue and they offer several improvements to the c3 suspension.

L81

314 posts

247 months

Wednesday 25th February 2004
quotequote all
ZR1427 said:
Ive often heard that the C3 suspension wasnt the best to be had on a performance car ,was it that bad?,and how could you modify the suspension for performance.
What is a 'Gymkhana kit'?

As said, the Gymkhana kit was basically stronger springs (& sway bars?), which gave a much firmer ride.
The suspension definately isn't anything to shout about for a performance car.... these days. Go back to the 60's & 70's and it was a different story. I find my Vettes handling to be better than our MGB (chrome bumper version, so no factory frigs to get it past US safety laws). Both cars were built as cheap sports cars for the masses, so shouldn't be compared to Ferraris, etc.
One thing definately wrong is the rear suspension as the wheels move in an arc throughout the travel of the suspension. This reduces the footprint of the tyre as the suspension compresses/extends. VB&P sell 'Smart Struts' which are just new rear strut rods & a bracket to mount the inboard ends lower. THis kit then ensures that the tyres stay parallel to the road as the suspension moves. The stock design can't be that bad as I've never noticed any problem with it - maybe I need to drive faster?
One thing with C3's that I've noticed, & is a PITA, is bump steer. This is due to the front suspension & steering geometry. As one front wheel hits a bump/hole, that wheel will either move up or down. This suspension movement turns the wheel very slightly in or out due to some sort of design c-up regarding the tie rods (as the wheel moves up or down the geometry on the tie rod means that it pushes or pulls the rear of the wheel in or out). This is a PITA, especially on our non-smooth roads. People fit R'n'P steering & all sorts of other expensive fixes to reduce it, but other people do a simple mod to cure it. They drop/raise the tie rod ends so that the geometry is correct. What happens with bump steer is that on very rough surfaces you can feel the car dart slightly to one side on the really bad bumps/holes.
Easiest handling improvement for a C3 is to put some decent tyres on it. Big difference. Even better is to put 17" wheels & low profile tyres on. Don't matter how good the suspension is, if the tyres are crap then corners are going to get messy!
The feel of the suspension can be modified by different size sway bars (anti roll bars). Mine has a 1 1/8" front one & no rear. A heavy front bar (&/or front springs) will reduce bump steer as suspension travel will be reduced for a given bump. A very popular combination is a 1 1/8" front & a 3/4" rear. The car with balanced front & rear bars will corner very flat & faster than mine could, but there's always a drawback: with no rear (or a small rear) sway bar, then pushing it to far on a corner will get the rear tyres slipping earlier due to the rear body roll (and change in rear wheel camber if you've not got Smart Struts!). With matched front & rear bars the rear tyres will let go at around the same time as the front ones do. Balanced sway bars will give you faster, flatter cornering, but if you push it to far you don't get a nice gentle warning.
Another mod is uprated springs. 460lb front & 330 composite rear are a good combination for normal use (or popular, at least). Decent shoks are a must. Bilsteins are highly rated, but I reckon my Spax ones are excellent. A composite rear spring gives much better suspension reaction at the rear & also drops 44lb of weight (or something like that) compared to the stock steel leaf spring, but will need different damping on the shoks to compensate for the different action. There's also more than one manufacturer of these springs & it seems that one type, at least, greatly increases ride height (check with other owners b4 parting with your cash). A lot of people swap to a composite rear spring & still keep the original rear shoks in place. They don't get the results they wanted!
I think the handling on mine is great, it just goes where you point it & if you start driving to fast for the corners you're on then it gets to be fun & (so far) the handling has been very predictable with no sudden, nasty surprises (unlike a couple of previous cars I've owned ). A stock suspension IN GOOD CONDITION isn't as bad as people make out. You won't stay with Porsches, Ferraris, etc, but there's plenty of stuff you can do to improve it, if you decide you want to. When I've had the occasional mad 5 mins my C3 has surprised me by the way it's stayed with, or beaten, modern cars on the twisty bits. Whatever the std of the suspension is compared to modern sports cars, it's good enough to put a grin on your face & that's what matters to me
Your best bet, for a totally unbiased opinion(!), is to go to:
http://forums.corvetteforum.com/zeroforum?id=3
It's a very informative C3 forum, most people are helpful & there's bags of stuff in the archives on suspension, etc. I've just read that this forum isn't really for C3's, so I'm gonna clear off back over to that other one. And I'm taking my ball with me

malc350

1,035 posts

246 months

Wednesday 25th February 2004
quotequote all
L81 said:

A stock suspension IN GOOD CONDITION


I think that's the key. Maybe people who own C3s that don't drive very well should consider a suspension overhaul with all new bushes, etc.

I've been in two C2s (basically the same suspension and chassis as a C3), one a 1966 4-speed 327 and also a 1967 427 4-speed and it would shock you how ell they rode and drove (shame about the cr*p skinny steering wheel but that's what they had in those days).

My thoughts at the time were: If only a C4 could ride that well...!

jaytee368

2,058 posts

244 months

Thursday 26th February 2004
quotequote all
LuS1fer said:
Hi Nigel. I've spoken to Fred and am currently looking for a nice red Z06. Just got gazzumped on a red one dagnabbit! Don't fancy half the colours they do. What colour is yours?

Nige's is banana.
When you get your C5 are you intending to keep the Z28?

LuS1fer

41,135 posts

245 months

Thursday 26th February 2004
quotequote all
I'm keeping the Z28, I've spent far too much on it to sell it and I need 4 seats a lot of the time and it's such a good car, I'd be lost without it. If I sold it, I could buy a brand new Z06 (they're being advertised for $43000)but if truth be told, the Corvette is a total impracticality and sometimes you need a choice of V8.

vetteheadracer

8,271 posts

253 months

Thursday 26th February 2004
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Don't listen to JT....it is Millenium Yellow....not BANANA!

Black interior.

For 2003 they only did 5 exterior colours and 2 interiors. Inside you got black or modified red, which is black with red inserts (wanted one of these until I saw it in the flesh).
Exterior colours were Black, Yellow, Red, Electron Blue (only until Jan 2003) and Silver/Pewter.

They did Speedway white for 2001 and some different silvers for 2001 / 2002 but basically the options list ain't exactly long on a Z06. I think there were about 4 options to choose when looking for my one.

I wanted the memory package which includes the electrochromatic rear and drivers door mirror, I didn't want the Body Side Mouldings, I bought the $15 front license frame which somebody kindly stole from the car during shipping.

Hope Fred gets you sorted with one soon!

jaytee368

2,058 posts

244 months

Thursday 26th February 2004
quotequote all
Wayne - that'll be the basis of one helluva stable then buddy, good luck with the search.

Nige - okay, I give, minnellium yellow, it does look very nice.

roscobbc

3,367 posts

242 months

Thursday 26th February 2004
quotequote all
I have factory spec 'gymkana' suspension on my '68 big block. It rattles and crashes around a bit on poor surfaced road at lower speeds.I think is it really quite good at higher speeds with no wallowing or grounding. It rides close to what one would reasonably expect from a european sports car from that period.

LuS1fer

41,135 posts

245 months

Thursday 26th February 2004
quotequote all
jaytee368 said:
Wayne - that'll be the basis of one helluva stable then buddy, good luck with the search.

Nige - okay, I give, minnellium yellow, it does look very nice.


Just gotta persuade my fiancee to swop her Astra for a trans Am then...she likes the idea but isn't convinced about the practicality of 3 V8's. I'd insure her for the Zed but it's modified. Once we're married, we'll try the spouse argument with the insurers.

jaytee368

2,058 posts

244 months

Thursday 26th February 2004
quotequote all
Way to go dude... then you'd have over 15 litres of displacement in 24 cyls and somewhere around the 1,000 HP mark, cumulatively speaking of course.

ZR1427

Original Poster:

17,999 posts

249 months

Thursday 26th February 2004
quotequote all
jaytee368 said:
Way to go dude... then you'd have over 15 litres of displacement in 24 cyls and somewhere around the 1,000 HP mark, cumulatively speaking of course.


Lu51fer now needs to post on the TOTB3 thread

LuS1fer

41,135 posts

245 months

Thursday 26th February 2004
quotequote all
Been meaning to ask...what is TOTB?

vetteheadracer

8,271 posts

253 months

Friday 27th February 2004
quotequote all
It is the chance for us Corvette owners to beat those pseky Snakes and Japanese wher it matters...at the track!

Checkout www.totb.co.uk for all the details.

P.S. Cliffy and I do personal appearances on the DVD for TOTB II! As do all of the Corvettes!

LuS1fer

41,135 posts

245 months

Friday 27th February 2004
quotequote all
I'll have a look at that later.

In the meantime, you will be very interested in this which gives some hot tips on launching your Corvette off the line.

http://forums.corvetteforum.com/zerothread?id=759802