Reading into that, track is wrong and a stronger arb is what's in order?
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Reading into that, track is wrong and a stronger arb is what's in order?
John, not sure of point re ARB??? Please explain. Track was right when checked last week. I am sorting out this play identified at the MOT, It is minuscule hence no advisories. I have tracked down to a not tight outer wishbone bush and miniscule play on the inboard rose joint. All these have done less than 3000miles. I am getting a replacement high performance two part inner rose joint as we speak.Quote:
Originally Posted by strat24v
Craig - unless I have got it wrong the Stratos tech data indicates a standard spring rating of 330lb/in (when converting from kg/mm). I seem to read in various parts of this forum 325 is a good standard for the Hawk but I understand for an Alfa V6 Hawk nowadays folk have gone up to 350. We shall see!?
There will be no real difference in the rear spring rates whatever the kit manufacturer provided the car is fitted with strut type rear suspension. The ratio of wheel movement to damper movement will always be all but 1:1 & a car with an Alfa V6 will always have roughly the same axle weights. The front end on the other hand varies considerably due to damper angle & mounting positions.Quote:
Originally Posted by Lancialulu
I can obviously only speak from my personal experience and IMHO I find that 275lb is more than adequate for a the rear of a Stratos replica on the road, I have run the 325lb rate spring rate and it will work perfectly well but it is slightly stiffer than it needs to be for a road car but will offer a good compromise between a road car & a track day car.
Thanks Craig. We will see. At the moment Shades had run 200lb in. so I will surely see some difference. I have some roads to exercise the suspension in a controlled way so am looking forward to getting back out.
If I read it correctly the Stratos manual / tech data states that the stock spring compresses 142mm under a load of 300 - 330kg that's a spring rate of 22kg/cm or 120/130lb/in - which from my calculations is a compliant sports car ride stiffness on a strut. - so sounds about correct.
325lb/in at near 3 times the standard stiffness seems a bit on the high side - For a 1000kg car with 40/60 distribution my calculator throws out 250-275 as being in the firm sporting area.
350 lb will only have 1.75" of coil crush so if you have more than 2" of droop in roll or bounce the spring will be unrestrained. Stiff springs are all well and good but you also need to take into account the suspension travel you have on the strut and the bounce and droop you want to have. Having a wheel in roll unsupported and just bouncing against a loose spring is not good.
I always want to have at least 3" of bounce and droop with the spring restrained in that movement - for 3" of coil crush - and no preload on the strut - assuming adjustable platform of course - you need a spring of 220lb/in range - the coil free length etc will depend on the open and closed lengths of the strut and position of the bump stop.
Big subject
Hi Andrew. Yes I got the wrong page - how irritating is that! Calculated for front ARGHHHH. Having said that looking at the Stratos rear spec the spring is c12" whereas the LEDA strut takes a 9". The Factory spring is as you say c 125lb in....
Strange thing is the LEDA guy thought the 325 spring was in the right area and said other Hawk users were going a little bit higher.
I calculate I will get 2+inches of crush (625+kg rear axle when loaded) if I set the spring with zero preload. (Wonder what the ride height will go to...Need to aim for 175mm). The LEDA strut has 7 inches of travel. Looking at the Stratos tech book it seems the rear damper only has 5.75" travel. Not sure what to make of this other than wheels will dangle as early as my set up??? The setup I got for a Gp4 ashphalt Stratos works car (from Gianni Tonti) had a spec for "Molle" of 17 to 14 % for the rear and 40 to 35% for the front. Can anyone interpret this??
I am aiming to set the car up as sporting rather than comfort (I have other Lancias that fit that GTouring bill!!!) We will see but if I have to go softer its not big deal. The debate goes on.
Have you considered CV joint articulation with 7" of damper travel?Quote:
Originally Posted by Lancialulu
The Stratos had a central differential so the drive shafts were much longer & consequently the angles the CV joints ran through were less. An Alfa V6 is quite wide across the drive flanges and therefore has much shorter shafts which leads to more extreme CV joint angles. If you have too much droop on the suspension then you will run out of motion on the CV at full droop or at the very least the CV boot could pull off of the cage. 5.75" of travel is more than adequate for a tarmac car even taking into account the bumpstop. Too much bump & you'll be rubbing the arches before you hit the bumpstops. 7" of travel will be fine for a full gravel spec car but I am struggling to see how you can use all that travel knowing the limits on the CV joints & wheel arches. You have got a smaller tyre than some which will certainly help with bump travel.
175mm is quite high for the ride height but does help with the rear geometry & camber gain.
Obviously its fine for Roger to give out advice on springs and travel but unless he's actually owned or driven a car then there is only so much theory & calculation you can apply. There is no substitute for bum in seat testing. 325lb or 350lb springs will yield quite a high spring frequency. A 325lb will be around 2.2Hz, a 350lb will be more like 2.3Hz.
I have this issue!!! At least one drive shaft has just pulled through the circlip retainer when I have "drooped" the suspension on a jack. Will have to think about this. What does a Hawk Gaz strut travel??Quote:
Originally Posted by Strat Fan
That one I can't answer I'm afraid, you'll have to find a Hawk owner with current spec dampers to check for you.Quote:
Originally Posted by Lancialulu
Cheap solution is to fit some sort of limiting strap; a droop limiting cable from lower spring pan to chassis or (depending on spring length) tie wrap the springs to lower and upper pans.
If damper if correctly determined ; its the shock absorber piston to be the stop to full extended stroke (to prevent CV and spherical bearings issues)?????
And probably as soon as springs are becoming stiffer and stiffer some "spring helper" will be need to leave residual pressure on main spring for centering it
As stated choice of springs have been always a "compromise" and a scratch head in beetwen "calculations"( so many sophisticated formulas existing )and "realty" ( only test can seriuosly help)
I think I will be going for a correct damper extension. My research says the Gaz dampers have a 6 inch extension. I have spent the afternoon checking and measuring. Beyond 6 inches the drive shaft has no further play and starts to pull out of the inner CV joint at 7 inches it is possible to pull it right out due to the free movement gained in the inner joint. I am quite satisfied the installation of the engine is correct with shafts being horizontal with weight on the axle, and angled slightly back from the engine to rotate the cv ball bearing.Quote:
Originally Posted by colin artus
With 325 lb in springs they compress 2.5inches laden but without driver/passenger. I am happy with this as approximately the midpoint on a 5.75inch suspension travel.
After 2 months rebuild of of steering and suspension Shades finally came out of the workshop and into sunshine. A short test drive of some 20 miles showed that she is Transformed and has much nicer steering feel than previously.
I can sense self-centring which was not there before.
So what did I do:
Found minuscule play in steering rack track rod (replaced with new/remanufacured unit from Rimmer Bros
Found play in the bottom steering shaft/rack knuckle (bolt loose)
Found adjuster seized on front Spax coil overs (replaced with Gaz coil-over 325 lb units)
Had LEDA shocks rebuilt by LEDA and fitted higher rate 325lb springs.
Set bump steer to mild toe in on both compression and droop (<.6mm over max travel)
Set corner weights
Set Caster to 5degrees
Set rear camber -0.3deg
Set Front camber -1.0
Front toe-in 1.5mm per side
Rear toe-in 1.0 mm per side
Tyre pressures 24psi
Adjusted ARB push rods as they had changed after all this adjusting.
Ground clearance measured at front back of tub 178mm Rear 168mm front.
Happy with this as a starting point!
A long time since I posted but another hurdle navigated.
David
Sent you a PM.
Tim
Its over 2 years since I thought I had sorted the handling of Shades, but a few drives early this year made me think something was still not right.
Then I happened (by accident as I was fiddling with the oil temperature sensor) to find the offside rear wheel had some lateral play (ie it could be wobbled from side to side giving variable toe- in). Nothing in the vertical plane.
The culprit was (were) the 2 41/2 inch 7/16 UNF bolts holding the base of the hub carrier to the inverted uprated inverse wishbone. Both had worked loose by virtue of the movement of the suspension.
A couple of MOTs ago this looseness had been picked up and I had tightened it all up. But obviously it had come loose again. And it was similarly loose on the nearside too!
As one of the bolts seemed to have a poor thread I replaced all the bolts with new 7/16 Grade 5 self coloured and new nylock nuts. Gerry suggested using lockitite as well which I did.
I torqued to 50 ftlb. I checked today after a 150mile run and they are still tight. More importantly the car ran as stable as I can remember. Lets hope it lasts...
Sad day as Shades is now destined for France under new ownership and duties.
This should not mean another Strato’s project will turn up in Colchester sooner or later.....
'Glad to hear that Tim.Quote:
Originally Posted by Lancialulu
Did you get a lot of interest on Car and Classic?, and where do see secondhand Hawk prices these days?
Obviously without disclosing any actual selling prices.
C&C was quite until end Jan then went a bit mad. Most but not all interest from EU including far away places. I think my price was realistic for the quality of the car. This is always the subjective part of pricing especially when there are few on the market. I could have got more if I converted to LHD but not necessarily more than the cost of doing so. My philosophy is to always leave something for future purchasers (of anything).Quote:
Originally Posted by ProtoTipo
Glad to see you've finally got shot of the old nail. Maybe get a decent one next time, eh? ;)
I am, of course, kidding....I know you said you enjoyed driving the Hawk the most out of your fleet, so methinks another Stratos will be finding its way onto your drive at some point! Congrats on the sale, and good to see people willing to pay proper money for proper cars, meaning money spent on keeping them in good order will never be wasted.
I agree, it is a particularly nicely detailed example. I think its age has an appeal, because it's been well cared for.Quote:
Originally Posted by Lancialulu