156 v6 spring rates vs gta - Alfa Romeo Forum
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156 v6 spring rates vs gta

Hi there,

Been thinking for a while now that the front of my yr 2000 v6 is a little soft.
So first off, i'm after the sp3 spring rates, and want to know if the gta ones are compatible and stiffer, also the gta spring rates.

I'm thinking if i get new standard front dampers with slightly stiffer springs, but keeping the same ride height, will this improve things? Also thinking of upgrading to gta front roll bar, as car rolls quite a bit in corners.

Not interested in koni kits and stuff like that, as i can get springs made if required.
Don't want to mess with ride height, as that is MAX POWER stuff.

So just want to improve the front end stiffness and roll control if poss.

Any advice welcome.

Cheers

Richard Yeo
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I have spring data for the GT V6 which has the same front springs as the 156 and 147 GTA’s. The spring part number is 60674405. The spring part number for the 156 2.5 v6 is 60668437.

Standard front springs GT V6, 147GTA, 156GTA.
12.1 Wire Diameter
7.8 coils
Original length 365mm
At 198.5mm load is 564daN
Compressed by 166.5mm
Spring rate = 564daN/166.5mm = 33.8N/mm

For comparison the 1.8, 2.0 petrol and 1.9JTD is 28.8N/mm, as you can see there is not much difference and I imagine the 2.5v6 springs are about the same.

Us GT and GTA owners also complain about the front end softness which shows upgrading to GTA springs will not help. Upgrading the dampers has been successful so my advice is to go that route first.

I run the Bilstein coilover kit and the front spring rate on them is 90 N/mm. I find them too hard for road use. I’ve already lowered the rear spring rate once and I’m now looking to lower front and the back rate again.
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Quote:
Originally Posted by Brynd View Post
I run the Bilstein coilover kit and the front spring rate on them is 90 N/mm. I find them too hard for road use. Iíve already lowered the rear spring rate once and Iím now looking to lower front and the back rate again.
I am just installing KW V3 and the front is 70N/mm and rear is progressive starting at 24N/mm. I think this range might be OK for your Bilstein as well.
I used Intrax HDA before with 130N/mm front and progressive 42,5 to 60N/mm rear and this was just too stiff for road.
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I am just installing KW V3 and the front is 70N/mm and rear is progressive starting at 24N/mm. I think this range might be OK for your Bilstein as well.
I used Intrax HDA before with 130N/mm front and progressive 42,5 to 60N/mm rear and this was just too stiff for road.
I had researched the KW rates and have 70N/mm front and 30N/mm rear on order. These rates also match the rates I had on my last car a MG ZS 180, 2.5 v6 with standard springs and that was the best handling car Iíve had so far. A good benchmark. If these rates don't fix it for me I know its the damping that needs adjusting.
I can imagine how hard those Intrax would have felt as the Bilstein rears were 60N/mm before I lowered them to 40N/mm.
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So if I try a 70nm front spring with a new sport pack damper that would be a good place to start? And a gta roll bar. I think the rear feels ok for the road.

Any ideas where I can get 70nm springs off the shelf as well?

cheers
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buy koni street kit or sport kit and enjoy
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Unfortunately you will not be able to buy off the shelf springs of differing rates that will fit on your Alfa. The only way to custom your own spring rates without getting custom springs made is to go the coilover damper route so you can use off the shelf racing springs.

Going the coilover route will also mean lowering the car as off the shelf coilovers do lower on there highest setting. As you don’t want to lower your car you’re a bit stuck with the only option of a damper upgrade. Which with reading other peoples experience may do the trick for you.
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Hi!
Does anyone knows the specs for the rear spings for 156 GTA and GT 3.2?
reagrds
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Hi!
Does anyone knows the specs for the rear spings for 156 GTA and GT 3.2?
reagrds
Don't have the specs, but they are different.
The GT 3.2 used the same rear springs as later 156 Veloce/Ti.
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Quote:
Originally Posted by Brynd View Post
I have spring data for the GT V6 which has the same front springs as the 156 and 147 GTAís. The spring part number is 60674405. The spring part number for the 156 2.5 v6 is 60668437.

Standard front springs GT V6, 147GTA, 156GTA.
12.1 Wire Diameter
7.8 coils
Original length 365mm
At 198.5mm load is 564daN
Compressed by 166.5mm
Spring rate = 564daN/166.5mm = 33.8N/mm

For comparison the 1.8, 2.0 petrol and 1.9JTD is 28.8N/mm, as you can see there is not much difference and I imagine the 2.5v6 springs are about the same.

Us GT and GTA owners also complain about the front end softness which shows upgrading to GTA springs will not help. Upgrading the dampers has been successful so my advice is to go that route first.

I run the Bilstein coilover kit and the front spring rate on them is 90 N/mm. I find them too hard for road use. Iíve already lowered the rear spring rate once and Iím now looking to lower front and the back rate again.
damping rate of bilsteins may be your problem being too firm
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Quote:
Originally Posted by Toivonen View Post
Hi!
Does anyone knows the specs for the rear spings for 156 GTA and GT 3.2?
reagrds
Rear GT V6
12.4 Wire Diameter
3.33 coils
Original length 280mm
At 180mm load is 259daN
Compressed 100
Spring rate = 259/100 = 25.9N/mm
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Quote:
Originally Posted by davealfa11 View Post
damping rate of bilsteins may be your problem being too firm
Changing the springs to 70N/mm front and 30 N/mm rear made the difference I was after with the Bilsteins, can now take speed bumps in comfort. Been running the car with these for 4 months now. There is still some crashy-ness between 20 and 35 mph over pot holes so after a little more softness now. Thinking of lowering the front rates to 60 N/mm. Canít lower the rear rates anymore as there arenít any softer springs available and itís almost back to standard spring rate anyway. The damping does feel soft at low speeds soaking up the driveway cobbles and cat eyes and at high speed it floats along nicely so donít think the damping is too high.
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You thought about looking at veloce springs dampers???

I have a 156 JTD 20v mutijet and gotta say it's a lot stiffer and better handling than my 1.8TS

Also seen it said that on std dampers and springs the JTD bottoms out and risks grounding but on the slightly lower Veloce ones it doesn't do that.

Anyway not a lot of experience with the 156 V6 but thought may be worth looking a veloce kit to stiffen up the car a bit. fair enough you may get something better aftermarket but if you can find some veloce spec items off a low mile breaker it may be worth a look.

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You thought about looking at veloce springs dampers???

I have a 156 JTD 20v mutijet and gotta say it's a lot stiffer and better handling than my 1.8TS

Also seen it said that on std dampers and springs the JTD bottoms out and risks grounding but on the slightly lower Veloce ones it doesn't do that.

Anyway not a lot of experience with the 156 V6 but thought may be worth looking a veloce kit to stiffen up the car a bit. fair enough you may get something better aftermarket but if you can find some veloce spec items off a low mile breaker it may be worth a look. Plus a slight lower ride on they veloce springs I guess would do no harm to the V6 with the weight being up high in the engine bay.

In fact would later 20v veloce struts fit??? The 5 cyl diesel is a heavy lump so the same setup should work nicely with the V6 if it gives the front end of the diesel minimal body roll and a nice stiff setup.

John

Last edited by mr-mac; 20-01-12 at 20:11.
 
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Originally Posted by Brynd View Post
Changing the springs to 70N/mm front and 30 N/mm rear made the difference I was after with the Bilsteins, can now take speed bumps in comfort. Been running the car with these for 4 months now. There is still some crashy-ness between 20 and 35 mph over pot holes so after a little more softness now. Thinking of lowering the front rates to 60 N/mm. Canít lower the rear rates anymore as there arenít any softer springs available and itís almost back to standard spring rate anyway. The damping does feel soft at low speeds soaking up the driveway cobbles and cat eyes and at high speed it floats along nicely so donít think the damping is too high.
Rather than going softer and softer you thought of asking bilstein if they can provide a stiff main spring and a tender spring setup. This would give you a more progressive setup that would allow a nice soft start to ride to soak up the potholes and other bumps but keep the stiff low roll performance of a stiffer spring for track days and fast road? Seems like a logical progression if too stiff.

You could then have a shorter hard spring say of spec they originally come with and a small tender spring which is quite soft. Best of both worlds and provides a more progressive and comfortable ride without sacrificing performance as much as continually moving to softer springs. You could tailor the bump removal and fads road performance without compromise of one or the other.

John
 
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Ah, the perennial problem of soggy dampers rears its ugly muzzle once again. The standard sportpack springs are fine, it is the dampers which are the problem leading to nose dive over speed bumps and juddery ride at speed. They need a higher compression value at low speed and more compliance at high speed. Bin them and put some decent ones on. I personally rate Bilsteins but there are some much cheaper Koni's which are also rated. Anyway, check this post on the 2.4 vs. GTA, it's all in there:
https://www.alfaowner.com/Forum/alfa-...ml#post5043277

Best,
Nick

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