'83 GTV 2.0 track project - suspension and keeping it roadworthy

[peter.b]

Hi all,

I've decided that since I drive my GTV once a month (at best) it should definitely be on the track. As such, I've slowly accumulated upgraded parts:

• Koni Yellows all round
• GTV6 discs and calipers
• 15x7" wheels (with tyres to follow)

My questions are:

• What diameter torsion bars would suit for spirited track performance without jarring my spine to and from the track and on the occasional Sunday drive; and do I need to buy new springs for the rear or can I just have them cut?
• With all these modifications, how can I ensure that the car will still be roadworthy, as I plan to drive it to and from the track; what are the don'ts?

Any help would be greatly appreciated!

Thanks very much,

Pete

[GTVeloce]

Hi Pete.

I have an 83 GTV which has been extensively modified but is still thoroughly a road car. However, I built it with the idea of it still being competitive on the track. Whilst i'm sure everyone will have their own idea of what works best, I think my set-up is fairly normal for what you are trying to achieve. So, my specs are;

Torsion bars - 28mm from PACE engineering. I haven't tried going bigger but I never felt like I was under sprung on the track
Rear springs - King springs. These are a progressive spring that are 95-155lb. Some race cars have stiffer rear springs, around the 180lb mark but again, the Kings are much better for the street and felt very capable on the track. Plus they are fairly cheap.
Bilstein B6 shocks - these are fantastic and I prefer them to Koni's but I know many are very satisfied with the Koni's so either way.
PACE upper ball joints - these are essential to improve the roll centre issue with these cars and well worth the extra few hundred.
A/R bars - I am just using stock 75 TS bars at this stage (slightly bigger than yours) but plan on installing an adjustable rear bar in the future. The front is 22mm and the rear I can't remember! That said, when I used stock road tyres I removed the front bar whilst on the track. Track tyres would be different.
Finally I used a mixture of rubber and poly bushes but mostly rubber. The only poly I have left is watts linkage and rear A/R bar drop links.

As far as roadworthiness goes, I cannot see any reason why your roadworthiness should be affected by these modification except for ground clearance (depending how low you go) and maybe the upper ball joints but I'm not sure about them.

The only don't I would say is go crazy with poly bushes. Maybe for a dedicated track car but otherwise you will have far too much harshness for road use.

With this set-up I drive it as a daily and am quite comfortable, plus it is a fun drive to work! The only issue is speed bumps as I have lowered it.

[peter.b]

Hi GTVeloce,

Thanks so much for the detailed response! I'll look into the bushes and A/R bars and potentially the upper ball joints at a later stage, as I neglected to mention that I'm trying to do it on a bit of a budget! So I might try and source some older GTV6 long torsion bars - anybody have some that they don't need??

I'll consult my mechanic too about the road worthiness of the upper ball joints.

Either way, it's coming along slowly but surely, and with the help of the kind folk like yourself on the forum, it will be done properly!

Thanks again,

Pete


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[DHDamo]

With the budget in mind: have you extracted its potential in the current setup?

[peter.b]

Hi DHDamo,

The current setup is completely stock and I've done a few track days with it in this trim. That was enough for me to get excited about modifying it for the track specifically. I'm yet to fit the parts I mentioned in my first post, but will do so when I've acquired new rear springs and torsion bars.

Upgraded brakes and suspension were most important upgrades for me before I went further. 

The bushes and A/R bars will wait, I think.

Pete

[DHDamo]

I see Peter, that makes sense. Im sorta doing the same thing with mine - have done a handful of track sprints this year. Am picking it up tomorrow after a tune and some minor front end work but mines essentially stock plus bilsteins, aftermarket 15" wheels and front sway bar. New tyres go on thurs and im ready for the track on sat. Will be watching your thread with interest. I have a fair wishlist.

[peter.b]

Same - it gets pretty dangerous! Although I think once I acquire what I've mentioned, with the addition of the rear springs, I'll be set for a while, and focus on having fun. Oh, some sticky tyres for my new 15" wheels would be good too!


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[peter.b]

GTVeloce, just had one question regarding the king springs - did you go for the 30mm lowered springs, or just cut the standard height stiffer springs?

Thanks!

[Duk]

I can also recommend PACE top balljoints.
Knowing what I know now, I would have loved to have added some to my old Guilietta.
They do add some significant bump steer (toe in with bump, or 'bump over-steer'), but it's not to bad.
You'll notice a significant improvement to turn in and mid corner grip, if you use them.
Tyre wear should also be more even, without having to use silly camber angles.

[GTVeloce]

I went with the lowered King Springs. I am happy with the choice although have considered getting the adjustable spring plates sometime down the track so that I can fine tune the rear height. Not looking to go any lower but for road use a little higher wouldn't go astray.

[peter.b]

Thanks very much Duk and GTVeloce. I'll keep you all posted with the project as I hope for it to progress steadily! Cheers.

[MD]

Peter,

Once you are satisfied with your street/track car set up, you should consider joining the G.E.A.R. Club http://gear.org.au/# if there is one in your state as it is specifically intended for these types of car applications .

It is very cost effective and you can compare your pace with other like minded guys of a whole variety of car makes and models.

[peter.b]

Hi MD,

Thanks for the suggestion - I don't believe there's a club in Melbourne though unless I'm mistaken!

On another note, I've recent had time to assess whether the wheels and new GTV6 brakes and calipers are compatible. I've come to the conclusion that I'm going to need extended studs and a pretty decent spacer (35-40mm). Has anyone had experience with any particular spacers and whether they'd be suitable for track applications?

I was looking at the Serpent Autosport spacers in case you were wondering.

http://www.serpentautosport.com/HTML/Hub%20Adapters%20and%20Spacers.html

Thanks!

Pete

[MD]

Peter,
Please check with you local road worthy certificate inspection outlet regarding a potential 40mm offset. It is unlikely to comply for road use.

You have come to the first hurdle of road and track.

[peter.b]

Dang it. Thanks MD. I'll do some reading and maybe have to find myself some more appropriate wheels.