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Discussion Starter #1 (Edited)
Hey guys,

I was just wondering has anyone used or heard of using progressive spring in a GTV? I understand this will give me a good compromise between a reasonable ride and track sessions.

I think Apex and Pi make a set for the GTV.

As this is the first suspension modification I am making I'm not changing the front roll bar just yet. Its 1 inch (2.54mm) std isn't it?

most ppl go for 27mm and few go for the 29mm. EB Spares sell the 29mm with their springs as a 'kit'?

Thoughts? ideas? I orginally wanted to just cut the original springs (to lower the car 2.5 inches front and 1 inch rear to level it out) as i was very happy with the handling and balance. I remain skeptical if an after mkt company get the difference between the back and front rate just right?!

and it drops the height by 40mm

Sorry if its hard to understand. Thanks in advance for any advice.
 

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Whatever you decide, one of the biggest improvements to the balance of the car is to get it corner weighed and corrected.

This will make the car balanced and thus brake real straight under pressure, etc. This is why race cars have adjustable spring platforms, so they can move weight around by jacking up a corner, etc.

With the front suspension design it is possible to lower the spring and thus move more weight forward (er, probably do not want to do this ... ) by simply adding spacers between the wishbone and spring plate.

Anyway the most important thing is to get the weight with the driver in the car even on both sides, ie. each front wheel carries the same weight and ditto for the rear. As explained above the front is easy to do ... but the rear (with the standard setup) is not.

Pete
 

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Discussion Starter #3
Ride Heights

On a similar note...

By lowering a GTV or any other similar car by approx 1-2inches, how much is gained in terms of handling, and brake dive?

What is the weight distribution of a 105 gtv? does lowering a car tighten the roll significantly? or is all just aesthetics?

The way I'm imagining the whole thing is that the CoM is sitting a little lower inbetween the geometry of the chasis/suspension.

mmm....
 

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My advice would be go with the setups developed by the people who've been doing this for a long time. Harvey Bailey (who used to race GTAs) in Europe and I think the Ward and Dean setup is similar.

I have copied the Harvey Bailey setup - 600 lb front springs, 30mm lower and 180 lb rear springs, 35mm lower - with a 27mm front anti roll bar and the handling is superb. Great on track and fine for the road. Ride suffers slightly but still quite acceptable for long drives.

Then you have to choose tyres.....

Oh, and throw away the rear anti roll bar.
 

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Discussion Starter #5
Springs Rates

me again

From AlfaCentro:

My favorite spring set up for a competition GTV is a set that I had wound at 1150 front and 160 rear.

Thats amost double your 600lb rates? does this mean anything or have I misunderstood somthing? How come they are so different? This is for a 'competition' (track only?) GTV though so maybe it can be that hard. but that seems way too different!?


what are the stock rates? as these might put everything in perspective? Does anyone know?:confused:
 

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My understanding (don't quote me) is that the standard spring rates are 400 lbs front and 90 lbs rear. I got the Harvey Bailey rates by talking to them myself so I'm pretty confident of those. 1150 lbs fronts does sound a lot but I'm not a spring expert.....
 

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those spring rates djone 101 state sound a little to soft. Everyone I have spoken to have always suggested a spring rate between 1150 -1300 front ,150-190 rear.I know centerline rates there front as 1150 and rear as 160.International rate there front as 1300 and rear as 180.I am now a little confused can anyone shed some light on the subject.
 

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1150 front, 160 rear spring rate sounds about right. 105 series alfa's have a 6:1 spring to wheel rate up front. So work this out with f/r weight distribution to figure out spring rates.

Example: 1150 spring rate front would be 191 wheel rate. With a rear rate of 160, this set up would probably work for a car with f/r weight distribution around 54/46%
 

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Springs are an interesting topic. When I acquired my track car, it seemed very soft in the front when I first drove it. I didn’t know what springs it had, only that they were painted bright red. However, there is an equation for calculating spring rates. I’ve seen it in engineering texts, books on car setup and handling, and on several websites. I tend to believe it should produce a useful value. It says:

SR = (11.5x10^6 x WD^4) / (8 x NC x CD^3)

where SR is the spring rate in lb/in, WD is the wire diameter, NC is the number of active coils and CD is the coil diameter, all in inches. The constant is good for springs made from most any type of steel. The NC value is the number of coils or fractional coils that actually bend when force is applied. This means any coil or portion of a coil that is not in contact with another coil or that does not rest in a support saddle. Also, CD is the distance from the wire center on one side to the wire center on the opposite side.

Anyway, I grabbed every front spring I could find that I knew anything about and started measuring. Here are the rates I calculated:

Stock ’78 Spider 385 lb/in
Mystery red spring 485
Ward & Dean 878
IAP 898
Centerline 922

I haven’t seen a stock Alfa spring rate spec but I’ve seen AR Ricambi claim to have springs that are 19, 20, 40, 48 and 75% stiffer than stock depending on what document I look at. My mystery red spring is 26% stiffer than stock so I haven’t learned what it is. However, compared with the IAP springs I had on my last track car, I can see why the red ones felt soft. I don’t know why the W&D, IAP and Centerline springs have calculated rates that are so different from their claimed values. Maybe I count active coils differently than they do. However, I would have to be off by about a whole coil to account for the differences. I also have no idea what the batch-to-batch differences might be with any of these springs, especially if they come from different initial suppliers.

It would be very interesting to know whether of not anyone has actually compressed some of these springs with known weights to measure the rates.
 

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Springs

Does anybody know what the red springs come from/
I have seen them on a lot of Alfas.
And what about the rocwell testing for them are that all the same as far as use?
PSB
 

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Both IAP and AR Ricambi sell red springs and I would assume they are different.

FWIW, the Ricambi springs are the same as the old Shankle Engineering springs - they were silver when sold by John Shankle and red now but he same springs.

Joe
 

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Red Ricambi springs.

Hello,

On my 73" GTV I have Red springs that I remember were purchased from Ricambi when they were still in Glendale, CA. I would like to find out more information about what they really are in terms of specs. If I remember correctly Ricambi sold several springs. Not sure if they were all red? Ours do not seem to lower the car too much (unless there are some spacers that would rise the car) but I don't think so.
Does anyone know the differen't springs and the colors of thsoe springs that were offerd by Ricambi?

Currently the car also has front and rear Ricambi anti-roll bars, red Koni's, and these mystery red Ricambi springs.

Any help would be appreciated.


JoeCab said:
Both IAP and AR Ricambi sell red springs and I would assume they are different.

FWIW, the Ricambi springs are the same as the old Shankle Engineering springs - they were silver when sold by John Shankle and red now but he same springs.

Joe
 

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Hello, all. I'm relatively new here but I am learning a lot form this BB and think that it's top notch!
I am coming from a different discipline of vehicle (Ford Mustangs, oh no!) but the ideas about springs and their engineering is the same. I have mentioned in another post of two that I am in the midst of acquiring a 1972 GTV 2000 and I am trying to learn as much as possible about the chassis and suspensions on the Alfa's and what is available for them. First off, I have not seen anyone mention much about what shock they are using with their springs. That will make a difference, as I am sure most of you are aware. I will start out by saying that I am a HUGE proponent for Bilstein dampers. I have had several sets on my SN95 Mustang and have been pleased with their performance. I have ridden in a 1971 Buick Skylark convertible with Bilstein's and they made the car ride like a million bucks! I'm not saying I will want my Alfa to ride like a Cadillac or Mercedes, (becasue its a sports car ;) ) , but I want to have some comfort. I have driven and ridden in several cars with Koni dampers and they have a much harder ride quality. Koni's are not bad by any means, but they have an inherent harder ride quality and in my opinion are great for track applications so the driver can fine-tune the rebound and compression qualities to their liking. These spring rates that have been mentioned in the 1100lb/in and 1300lb/in range is astonishing to me because of the weight of the cars. I used springs only slightly heavier on a car that was over 1000lbs. heavier! Anyway, I guess what I am after, is who is using what dampers on their cars and in what manner are you using the cars? I'm almost certain I will go with Bilstein, but I want to make sure they will match the spring rates I decide to go with for a high performance street car, as far as the handling is concerned. I’m not looking to make a rocket out of my car, just to enjoy weekend drives on the coast and through the country. Thank you for any input, have a great day.
:D
 

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Welcome aboard Matt, by using the search facility you'll see that spring rates and damper choices have been covered extensively and continue to be so. One thread is called something like "Brits vs Yankies in spring weights" or something like that, it makes for good reading.

I'd actually like to get some input from everyone about the original topic of this thread. Why don't I see progressive-wound springs on 105 cars, is it simply because the fronts seem too short anyway?

Alex.
 

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Hi Matt-

Welcome. It's great to have new enthusiastic faces(?) around the place. There was a great thread about spring rates last summer. If you search for "British vs. Yankee spring weights" or something similar, you'll find it. I think the bottom line is that the Brits pay lots of attention to roll centers, which lets them run more reasonable spring rates. If you lower your Alfa in front without making geometry changes, the roll center dives fast. Then you need to run such stiff springs that the twisting of the car itself becomes a meaningful part of the suspension equation.

As for the 1100 lb springs, the Alfa geometry gives a 2:1-ish mechanical advantage, so the wheel would move an inch under a 550 lb load in this example.

Some folks consider Bilstein shocks too stiff for old Alfa. Search the forums some more for lots of discussion on this.

-df
 

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Gentlemen,
I apologize, I should have spent more time trying to dig things up. I will search the "British vs. Yankee spring weights" thread, thank you! :)

It will be interesting to see what the rate of the mechanical advantage is...
 

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Not to highjack the thread, I guess this may be off text a bit but...

I have heard some stories that too heavy spring/shock combo can cause stress fractures in the front end, is there any real world proof of this, or just guys talking. I am close to suspension overhaul on my GT, this is something of a concern to me. In a stock 35 year old car, metal fatigue could be a possibility, I know lots of track cars have shock mounts reinforced. As my car buddies would say, how does the metal know its 35 years old?

Again, not to change topic, but if this is the case, should I be concerned about getting the suspension to stiff. Any one experience this problem?
 

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The motion ratio is probably closer to 3:1. A 1200 pound spring gives you a 400 pound(ish) wheel rate. In general, you don't need to worry about chassis cracks due to heavier spring rates. A monster sway bar could cause cracks around the mounts, but that is more a problem with the 750/101 cars.

Erik
 

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Great! now we have 3:1! I'm not flaming your input genericwood, from everything else I have read of yours, you have a wealth of knowledge. It's just that for new guys like us, there are now 4 different statements about what the front suspension ratio is.

Mr. genericwood, can you provide us with info about why you believe that to be the case. Much thanks
 
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