ALFAGTV6.COM

[PietereQ]

I'm finally about to take my gtv6 to new step in evolution - namely throw in front coilovers I have found out that GAZ shocks, appear to have good value for money, yet they don't have any bolt-on kits for alfa transaxle. OK. So I took out my old junk konis and took measurements:






To my layman reasoning the 170/100/B12 (open length 17" closed length 11" stroke 6") shock should be the closest (best?) solution. And even with spring it should clear the upper control arm (though I'll be enlarging it anyway for more castor)

Here's the link to the catalogue:
http://www.gaz-shocks.co.uk/gazcatalogue.pdf (page 15 )

Ok so the questions:

1) Is the beforementioned shock the way to go or not? If no any other suggestions?
2) What springrates should I use? I want to run coilover torsion bar combo. My gtv6 is inevitably going to be a racecar, basically for the time being I want it to be road legal trackday car. (Have just few kms to the racetrack, so ride comfort is unimportant)
3) Seam welding. Absolutely necessary or only when I'll be running coilovers only?
4) I have read somewhere that you need to lower suspension (via torsion bars) before installing coilovers. Is there any fixed figure for that? Or trial and error?



Thanks in advance and waiting for your input guys

[Greg Gordon]

I can answer questions #3 and #4, at least partially.

3. Seam welding is not needed for a coil over torsion bar combination, at least not with the spring rates normally included with the RS racing kits. At some point it's probably needed, but when that point is, I don't know. I suspect that with coil overs only (i.e. no torsion bars) and really stiff springs it would be needed.

4. You will need to set the ride height with torsion bars via the normal method here: http://hiperformancestore.com/AlfaSuspension.htm . The coilovers can provide some adjustment to ride height, but obviously they can't lower the car beyond the torsion bar setting, so those have to be set first.

Greg Gordon,
www.hiperformancestore.com

[mjr]

my two cents worth.

setting the ride height via the torsion bars first will not always get you the desired ride height before you fit the coil over kit. it depends on what year your car is, as to how much adustment you may get on the torsion bars. you will need to count the number of splines on the torsion bars, to see how much you can lower on the torsion bars, and how much you will need the coil overs to give you. I think the later cars give you more splines, than the early ones (in europe anyway). for instance my euro 83, would only give 30mm lowering max, before the torsion bars maxed out. knowing this, I lowered some on the torsion bars, and the coil overs the rest to get 45mm total, otherwise the torsion bars end up doing nothing, and according to RS, the front coil over set up works best IN conjuction with the torsion bars. What wheel set up are you going to run on the streets? note that front coil over kit will significantly load up your steering, making it very heavy, so if you can, i would stick to a max of 195 15's. if you are going wider, and bigger, then IMO power steering is needed. i find the steering with 205 16s up front schwarzennegger esq, especially on the twisties.

[MD]

I know this will cause some angst around the place but I gots to say what I gots to say..

The notion of making a road car a race car at the same time is simply delusional crap.

Make your mind up. You wanna go racing? Make a race car. You would like a quick road car then do that. These things are like night and day.

You cannot make a quick race car carrying all the original stuff including airconditiong and coffe cup holders so who are you kidding besides yourself. Neither is it safely possible to use a race specification car on the road cause the first time you applied your cold brakes in an emergency stop you'd wind up somebody's arse in a tailender without listing other problems. You would automatically be in breach of your insurance cover to say the least and it would never pass machinery inspection anyhow.

Seriously, I thought we were a tad smarter on this forum.

Pete, not aiming this broadside specifically at you 'cause I see this type of activity all the time and the logic of it scares me.

OK let the shitfight start. I'm ready..

[MR2 Zig]

I'm hiding on this one and I ain't even involved

[Greg Gordon]

mjr: What are you talking about when you say "my euro 83, would only give 30mm lowering max, before the torsion bars maxed out". The torsion bar adjustment doesn't limit the rideheight on these cars in any way. They can raise or lower the car all the way until some other part of the suspension hits a physical stop.

MD: I think everyone on this forum, including me agrees with you. However in this case he only wants to go a few miles to the track without putting the car on a trailer. Depending on where you live and how far you have to go, it might not be a big deal. Now, on the other hand if you want the car to be competitive at the track, but still a nice daily driver, then that's a tall order with any car, especially something from the 80's.

Greg Gordon,
www.hiperformancestore.com

[PietereQ]

First off thanks everyone for their thoughts. I guess I should have posted in racing section, or put a "racecar" in the topic, or shouldn't have written anythig about driving to the track to avoid confusion. My car is going to be driven on the track only.
I thought my questions were clear enuough not to get into any offtopic talk. As Greg pointed out, depending where you live, driving a racer on roads (commuting to track or autoX events etc) isn't a big deal, provided you have stone balls
For instance here you can drive a car with full rollcage, all the racing stuff you might have dreamed of, in return you only have to put road legal tyres, all your lights must be working, horn etc, and 95dB exhaust that's all. Just like rallycars, in terms of daily driving they are crap, but they are road legal machines. No point arguing about that.
And Mike I'm not that nuts, to take all effort with the driveshaft conversion for a mere road car


Back to topic, since it takes from 2 to 3 for the GAZ to make the shocks, anyone who could give any idea on springrates, (and the rest of my questions) I would much appericiate it.

Cheers chaps!
Pete

[mjr]

greg. yeah but many preople over here lower infinately by simply adjusting the front of the torsion bar only, to achieve 40-50mm. Bad.I did not want it done that way.

As far as I know according to my alfa mechanic, the euro 83's and 84's had torsion bars with a different numbers of splines on them, and mine could only be lowered by 30mm (doing it the proper way front and back) before the bars become ineffective to the point of slapping the bump stops all the time. I wanted mine lowered a year before I got the RS kit. The 84 he had in the shop had a greater number of splines on the bar front and back than my 83 does, which according to him allowed you to lower another 10mm without issues. it was news to me, I had never heard of this, but i saw it in the flesh so to speak. i ended up waiting until I got the RS kit.

[Giuliettaevo2]

Your mechanic has some strange stories to tell.....

I've had a few models off transaxles in the past yeas and they were all lowered more than that. The Alfetta sedan from '74 was lowered at least 60mm and so were all of my 75's and the '81 GTV2000.

the difference in the torsionbars is in the lenght, the 75 and late model GTV6 use different length (forgot if they were longer or shorter.. ) that at the end rest in the main chassis of the car rather then in a loose mount as on the earlier cars.

The lower wishbones can also be interchanged between early and late cars, so no difference there...

[MD]

Have to agree. Never seen/heard of different splines only lenghts and diameters on genuine Alfa parts.

Advice to me is that a standard 23mm GTV6 torsion bar has an equivalent spring rate of 280lbs.
This would be your starting point depending on how much spring rate you wanted up front. Early Oz gtv6 racers had up to 1200lbs. Now if you are even remotely thinking along the later lines, seam welding and reinforcement is the order of the day if you want the suspension to flex instead of the car.

Unless you are an experienced chassis tuner, the chances of getting it right by experimentation will be costly. A better alternative would be to obtain a full set of specs from a successful dedicated race car in your neck of the woods and replicate that. To do that, you will need to :-

Match its total weight
Match the corner weights
Have the same body stiffening
Use the same tyres and rim sizes
Have the same roll centre
Use the same suspension settings

...only then start experimenting for your preferences.

[Duk]

Advice to me is that a standard 23mm GTV6 torsion bar has an equivalent spring rate of 280lbs.

You get a smigin under 62% of the spring rate at the wheel, when a coil spring is mounted over the shock.

http://www.miracerros.com/mustang/t_wheel_rate.htm

The 75s have a front wheel rate of 93lb/in. So that would be equal to 150lb/in spring. Soft, aint it?

I added some 105lb/in, 1 7/8" diameter springs over my Koni Yellows (standard TB). This would be way to soft for track work but upgrades are easy. Wheel rate is 158lb/in.
If I used a 160lb/in spring would give the same rate as a 27mm TB.

A 30mm TB bar has a wheel rate of 278lb/in. You would need a 298lb/in spring used with a standard TB.

A 33mm TB bar has a wheel rate of 408lb/in. You would need a 508lb/in spring used with a standard TB.

A 36mm TB bar has a wheel rate of 578lb/in. You would need a 782lb/in spring used with a standard TB.

*This is using the longer torsion bars.

[PietereQ]

Thanks for the idea on the spring/wheel rates that's a start. Mike, believe me if I had an opportunity to copy and paste settings of any successful transaxle racers here I would have done it long time ago, and wouldn't be bothering you guys here. Thing is there are NO alfa transaxle racecars here. Zero, null, not to mention lack of any "know-how" here bout these cars. Given the fact that this is the country of beemer and lancer evo wankers, it's quite unlikely that I will see any transaxle racecar exept for mine (I hope!), and my friends who are just as rookie as me. That's why I'm asking all those silly questions

[MD]

OK Pete, I am getting the picture now.
The fact remains that you need to have a target and preferably a known weight for your car to start with that you intend to race. Now if this is going to include street trim and stuff it will make your job so much harder. For instance you just can't go and start welding up roll cage components to stiffen up the suspension without setting all the trim on fire. If you don't tie everything into a roll cage the car will never perform at its best so right there you are at the crossroads of choices.

Now I could simply just give you my complete chassis specs from the Brick but that would be futile
because its a 4 cylinder and has a different weight distribution to what you will likely be using.

I guess the real problem at the end of the day comes down to money. I am sure there are plenty of chassis tuners in Holland for Alfas and so what would it take to hand the car over with a simple request, make some racing suspension for it ! The answer comes back- money.!

Sometimes you just have to pay for services you cannot do yourself or don't have the combination of skills and equipment to do the job. This is what I had to do. I knew what I wanted and worked with some guys who fabricate open wheel racers as a rule and they made the parts for my car and carefully set up its corner weights, geometry, spring rates, roll centre and damper control setting. In twelve months of racing, we only backed off the bound rates on the dampers once a few % and it has remained that way and doing a great job.

Failing all that, there is always the suck it and see approach if you are prepared to start with a ballpark rate for front and rear and experiment using second hand springs from the motor wreckers?

I am reluctant to specify actual rates cause it will start another bun fight just like the one about my rear rotors being bigger than my front rotors that most people said that doesn't work but It certainly works for me.

Send me a PM if you need to..

[PietereQ]

Thanks for understanding. I'm rather sentenced to buy few sets of springs to fiddle with. Fortunately they are not too expensive.

Thing that keeps me bothering though is the stroke of the coilover. I now when I think of it there's no need to copy huge stock stroke since car will be lowered.
Anyone has by chance stroke, and lenghts for RSR coilovers? Otherwise what would you suggest?

[MD]

Once you set up the car for around 80mm ground clearance and the correct spring rates, the actual suspension travel may be in the order of 35mm so it's not like a road car that needs to have a lot of movement to cater for. Therefore it should not be that hard to work out the stroke length.