Historic Forest Stage Rally 124 Spider

Non-engine, eg: aerodynamics, gearboxes, brakes, suspension
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Guy Croft
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Re: Historic Forest Stage Rally 124 Spider

Post by Guy Croft » Sun Feb 10, 2013 1:45 pm

MODEL THREAD!

Beautifully illustrated and photographed, keep up the excellent & important work.

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miro-1980
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Re: Historic Forest Stage Rally 124 Spider

Post by miro-1980 » Sat Mar 23, 2013 11:22 pm

I kept my 124 spider CS0 pretty much original so far , though had some ideas before.

Your thread makes me thinking of some rally modifications. Very tempting !

Great project and very interesting reading !

Miro
www.131abarth.pl
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Rallyroller
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Re: Historic Forest Stage Rally 124 Spider

Post by Rallyroller » Tue Apr 02, 2013 7:47 pm

Work on the car has slowed due to other commitments. The front caliper mounting plates have arrived, and a trial fit seems to prove they will work well.
The cross member is on so when the shocks arrive everything can be fitted.

I do have a question. I need some negative camber on the front. I have some plates made up to replace some of the spacing washers that space out the lower. My question is - what is the standard dimension for the lower wishbone mounts? Is there a distance between the wishbones? Obviously the washers are used to get exact dimensions on what is a fabricated assembly. I cannot find any info anywhere regarding dimensions. Also is there any info regarding general adjustment. ( ie 1mm spacer = x deg adjustment). Obviously everything will be checked when the car is complete, ( castor, camber etc) but getting it somewhere near to begin with will save a lot of work.

Nigel.
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Re: Historic Forest Stage Rally 124 Spider

Post by miro-1980 » Wed Apr 03, 2013 11:32 pm

Nigel,

I have all kinds of service manuals fro many cars including 124 spider and none of that offers such data ( i.e. 1mm spacer = x deg adjustment). It seems to work the reverse way "put a spacer of sufficient thickness to obtain required degree of correction.

Incidentally lowering 124 spider on a standard ( non-abarth) suspension is a tricky business, many have tried and very few succeeded. By succeeding I mean lowering the car and achieving increased handling and stability and good steering at high speeds, in curve acceleration, and especially hard, performance braking on curves. I know of instances that people after near accidents caused by unexpected car behavior on a track or during a rally stage dumped all modifications and went back of almost a standard factory setup. stages went back to standard suspension setup. There appears a point you can easily and successfully lower 124 spider , but when you go beyond this pint all inappropriate starts to brake loose.

Here are two of a series of pictures documenting such unhappy ending :
1.jpg
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It looks like the car was a bit too fast on the curve and did not respond well to attempted correction mixed with hard braking. It seems that the car decided to drive itself regardless of what the driver does and chose to continue turning right where there was no more track - only a concrete retention barrier.
32.jpg
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I have done quite a bit of research on handling of a 124 spider with modified suspension. This seems quite typical of whet this model does when one tries to lower it beyond the limit ti tolerates. Incidentally 124 spider - from mu experience even with most standard suspension setup is exceptionally predictable , and tolerates drivers mistakes offering him a chance to correct before it is too late and the car starts spinning out of control. With this experience on the track I have found that mild adjustment can improve its great handling and stability, but too much quickly turns the car into a Porsche ( Note: in my mouth this is no complement !)

We have made several attempts to radically lower the car and failed so we ended up with only mild height adjustment, and even this has forced us go beyond factory limits of caster to keep and ultimately even improve handling . The effect is excellent , but the number of test runs on a very wide airfield strip we had to do was just shocking. We used a 360 deg G- force measuring device which registered G-force of the moment we lost control (and started spinning). Ultimately it was a "trail and error" approach which brought us out ultimate setting. Please note that this setting apples to a specific tire type and specific wheels ONLY .

Actually I just realized I do not even have the geometry data of this setting. It probably is a good idea to go to a geometry place just to measure it and record it, so we can adjust it back to the same in the future.

The picture below shows the car in mixed surface (tarmac/gravel) rally setting. wheels are CD 66 & inch front / 8 inch rear, tires Falken Ziex ZE 502 205x60x13
124 low rally setting 3.jpg
124 low rally setting 3.jpg (46.25 KiB) Viewed 1684 times
I do not want to discourage you but just suggest a lot of caution. 124 spider is tricky to lower and please remember that whatever looks good does not necessarily drives well....

Miro
www.131abarth.pl
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Urbancamo
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Re: Historic Forest Stage Rally 124 Spider

Post by Urbancamo » Thu Apr 04, 2013 4:55 pm

Hi Nigel
Shims.JPG
Shims.JPG (84.01 KiB) Viewed 1665 times
Here's the picture taken from Lada factory repair manual for camber/caster adjustments wich I believe can be used here because the front suspension is the same. +1 or -1 means ONE 0,5 mm thick shim.
I kindly translated the words from Finnish to English.
So if you add lets say two 1 mm shims to existing stack, one on the front and one on the rear you will increase camber by 14' to 20' minutes wich is approx. 1/3 of a degree.
IMG_6600 (Small).JPG
IMG_6600 (Small).JPG (31.31 KiB) Viewed 1665 times
Here the photo of factory fine adjustment shims, they are either 0,5 mm or 1 mm thick.
Wheel angles.jpg
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Speaking about RADICAL front end settings in Fiat 124 based rally car can be found in our garage.


Ride height: -30 mm from and -50 mm at he rear, same as original Fiat 124
Camber; enough, more than -2 degrees
Caster: more than stock, both lower control arms moved towards front by 20 mm
Toe-in: 1 mm or 0,5 mm/side
Ackermann steering: almost zero
Bump steering: almost zero
Steering ratio: just under 2,5 turns from lock to lock, very short steering knuckles
Steering effort: more than stock but has great feeling and feedback

Handling compared to stock at any surface? SUPERB. Understeering is almost non-existent thing with this setup.
I have no clue how hard you can take a corner in tarmac, it's freaking scary...!! When stock car starts to squeel the outer front tyre, this just yells at you "TURN MORE PLEASE or DRIVE HARDER to corner"
Maybe this is the difference between stock car and properly adjusted rally car. :)

T
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miro-1980
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Re: Historic Forest Stage Rally 124 Spider

Post by miro-1980 » Fri Apr 05, 2013 12:13 am

Hi Tommi

Outstanding !!!!

I really envy you the radical setup in your garage.

I know this os possble with 131 , because we have done this.

The 131 speaks to me and says: TURN MORE PLEASE or DRIVE HARDER to corner"

As the 124 spider we have is less performance oriented we have not made such radical changes and even with what we did the handling and traction improved so radically it wil take me some time before I take the car to the limit. Having driven my car for several years on standard setup I have learned where the limit was. Now it seems so much further I need to learn the car anew.

Incidentally what made a large difference with our setup was was adjustable shocks , and significant change (well beyond factory limits) of both caster and camber.

By the way Tommi, are you on standard or Abarth suspension?

I share your view there is a difference between a sock and sports prepared car and setting up suspension and geometry is an art which is real key to handling on a stage !

Very interesting and most informative. Smart use of Lada data - they typically produced more detailed technical /adjustment data than Fiat ever did , but thall work was conducted in private garages rather than authorized dealers anyway so this data was in real demand,

I am sure Nigel will find it very useful !

I did !

Miro
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Re: Historic Forest Stage Rally 124 Spider

Post by Rallyroller » Fri Apr 05, 2013 11:07 am

Hi Gents.

Many thanks for the detailed information and also (of great importance) information on your own experiences and technical knowhow.
My experience on my previous 2 rally cars is similar. My original spider had 2 sets of springs, one for forest, one for tarmac. The forest front springs raised the suspension slightly, and the tarmac springs gave standard height at the front with slightly lower at the rear. (maybe 25mm lower than standard.) As I only did 2 tarmac events, I did not really get into it. ( I do remember an air field stage in East Anglia- cornering on full opposite lock at 130km per hour certainly got the adrenalin going, as did the resulting spin and flat spotted tyres!!. ). I was young then though.

The ST was transformed with very stiff front springs. ( Advice from the Lada boys). Talking to the Escort guys, they say such hard springs (basically tarmac spec) would ruin the handling of an Escort. Just goes to show you need to know your car and its technicalities.

The springs I have are similar in spec to the Lada ones, with a slightly shorter length. The length is the same as my original Spider Forest spring, so should be somewhere near. (Perhaps raising the hi-light slightly if they are much stiffer.) Certainly the stanard Spider front suspension is a weak point, probably why they changed it so much for the Abarth. I Think the 131 had a better starting point. The rear suspension on the standard Spider is very good for a live axle car. Again, indepenent (as Abarth) is better and allows more adjustment and fine tuning.

Certainly the feel of the car should be to the drivers taste. I remember the Spider being far more controllable than the ST. Perhaps due to the setup, and perhaps due to the weight distribution. The one thing about a rally car ( in the forest) is that it should be controllable. Out right road holding is not as important as handling. ( ie the car should be able to change directions quickly, rather than having the ultimate speed around any one corner. This is slightly different requirement than say circuit racing or even tarmac rally with pace notes and repeated stages.

The comments you guys have made are taken on board, and I don’t underestimate the work needed to get it totally correct. ( G Meters on a airfield- impressive stuff.)
Once the car is up and running I am considering a “Forest” test day rather than a rally. A similar cost, but it allows you to go around the same corner a few times, so adjusting things will hopefully give feed back straight away.

Hopefully in the next month I will get around to more work on the car. New bathroom and business keep getting in the way.
Nigel.
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Urbancamo
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Re: Historic Forest Stage Rally 124 Spider

Post by Urbancamo » Fri Apr 05, 2013 12:41 pm

Miro: no fancy Abarth stuff here. Just standard parts modified to rally use, everything is heavily reinforced. No professional parts anywhere, just parts you can buy cheaply and replace if needed. In the old days many national level RWD rally cars were just like this, but novadays they are beyond imagination. If you fit Volvo 1031 rear axle to Ford Escort RS2000 with Öhlins/Reiger/Proflex suspension (€€€€), Volvo gear box with Ford bellhousing and many many things you cannot even imagine, is that a Ford Escort anymore?
Rallying has gone far away from that what it was.

And for the comparison the springs in this car are:

Front: Mercedes-Benz W123 front springs, the softest ones, coil thickness 14,5 mm
Rear: some real thin and short Nissan Sunny springs I heard, coil thickness only 11 mm, rear end is very soft.
Dampers: Koni Sport's

And I cannot highligh enough how important is to have RWD car's rear end really close to ground. You won't see dragster-like RWD rally cars, they are pretty low today. It's todays trend wich seems really working.

-----

In the overall handling of this car in loose surfaces is very neutral and balanced. It doesn't make any awkward movements like stock car does when speeds are increasing. Neither understeering or oversteering is the dominating character.
I'm not expert by any means, but I think handling like this is preferable.

Of course the body rigidity is also the key. These are pretty durable cars if they are not rusted, but they still need plenty of reinforcements to suit them to rally use.
Especially at both front and rear ends.
If some one ever needs pics how to reinfore some parts, just ask, I can take photos.

Nigel: thanks for the feedback and interesting story. Looking forward to hear more about this build.
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miro-1980
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Re: Historic Forest Stage Rally 124 Spider

Post by miro-1980 » Fri Apr 05, 2013 6:03 pm

Rallyroller wrote: Nigel: Certainly the feel of the car should be to the drivers taste.
The one thing about a rally car (in the forest) is that it should be controllable. Out right road holding is not as important as handling. ( i.e. the car should be able to change directions quickly, rather than having the ultimate speed around any one corner. This is slightly different requirement than say circuit racing or even tarmac rally with pace notes and repeated stages.
Exactly !

When I think of a forest rally stage I see in my mind the Finish rally stages through on wet gravel /dirt. It seems to me these cars flow over the surface being in constant drift rather than just drive. In a sense it is like a canoe boat ride down the rapids or flying a small airplane in 2 (& a half) dimensional reality with a crosswind, rather than tarmac type o traction control. In Forest it looks as if traction/friction /attrition means keeping the tires in contact with the ground allowing the balancing their slide/drift all the time. To make a point: just imagine Finish rally driving with traction control system switched on ! This would be a total disaster and look real funny !

Whereas on tarmac, control is more like hockey ice skating , where keeping the car going a path chosen by the driver is the key and sliding means controlling the swings of the rear not so much to negotiate a single turn as fast as possible, but allowing the car to negotiate a series of turns smoothly - which yields the best stage time.

In both cases physics is everything. Fortunately there is no mathematical algorithm that would allow building of a perfect rally car or perfect setup for each surface type. Differences of each stretch of forest or tarmac surface: viscosity, density, temperature, water content, traction, attrition, friction, etc., etc., etc. are so vast that no such algorithm can be built. This makes performance driving a combination of art and craftsmanship. Nothing that can be described by a mathematical formula. For this reason whereas the cars become more and more robotized it takes a human to drive a rally car. Only a human equipped with a human mind can deal with so many variables at the same time. Thus drivers are not in danger of being replaced by robots.

The point is : the more one gets into it the better one understand why some drivers are better on dry tarmac, some on wet tarmac dry, some on ice, some on fluffy snow and some on gravel. No one is equally good on all surfaces. The differences between required car suspension, tire traction and geometry setup for each of these surfaces are worlds apart, and each of setup is different for each driver. So even if you are looking at a team of ex factory cars for the same rally there are no two cars exactly the same.

Fortunately, we are not professional drivers rallying for money, and thus we represent the true spirit of this sport. Mastering our cars is a sincere expression of our passion for motorsport tradition not motivated by a drive to be rich and famous but have fun in the process. It is amazing how much talent and dedication this hobby brings together here at GCRE.

Fascinating thread !

Thanks

Miro
www.131abarth.pl
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Re: Historic Forest Stage Rally 124 Spider

Post by miro-1980 » Fri Apr 05, 2013 8:37 pm

Urbancamo wrote:Miro: no fancy Abarth stuff here. Just standard parts modified to rally use, everything is heavily reinforced. No professional parts anywhere, just parts you can buy cheaply and replace if needed. In the old days many national level RWD rally cars were just like this, but nowadays they are beyond imagination.

Tommi,

This is something many people do not know or understand any more. Basic & cheap was the real “rally way” of doing things. In fact when I talked to Poliosh rally drivers of the 60’s 70’s and 80’s they all stressed exactly what you put so simply but eloquently: cheap standard parts heavily reinforced. People do not seem to realize how basic it really it was. One of the champions told me for instance that on a stage the best tool to care of the bodywork was a hammer and a can of paint with a paint brush. Who cared it looked ugly up close as long s it won rallies!

Urbancamo wrote:Of course the body rigidity is also the key. These are pretty durable cars if they are not rusted, but they still need plenty of reinforcements to suit them to rally use.
Especially at both front and rear ends.
After all this has a cabrio chassis with the whole front and the whole back are kept together by an almost flat piece of steel holding it together ( It sometimes looks to me as of it were not for the doors the car could fold on any bump). The car however is sufficiently rigid for road use and very predictable in handling. You are absolutely right that reinforcing the chases as well as heavy reinforcement of the front and the rear is absolutely necessary to make it fit for a rally.

The jumps Marku Allen made in 1000 Lakes ...
markku big jump .jpg
markku big jump .jpg (53.55 KiB) Viewed 1569 times
takes more than a standard chassis...

Miro
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Re: Historic Forest Stage Rally 124 Spider

Post by Rallyroller » Tue May 28, 2013 4:45 pm

As explained in my last post, work on the car has been held up due to business and the wife demanding a new bathroom.
Anyway getting back to the car now, so a little work has been done.
The dash has been “overhauled”. The 2 dash boards I had were both poor. The one from my original spider had a good top, but the lower rail was shot ( After mods to convert to RH Drive). The second was from a USA car, so was in one piece but cracked and bent.


I managed to salvage it by removing most of the plastic covering, modifying the lower rail, then recovering with foam and “suede” look leather cloth. The finish is acceptable for a rally car, although I think I used the wrong glue as some has come through the material in a couple of places. The folds around the edges were difficult, and fortunately will be hidden by the roll cage legs.
The instrument panel is made from 3mm alloy. I have used 1 sheet for the centre and drivers side. The rev counter is directly in line with the driver and the speedo moved over a bit. The alloy is covered with matt black sticky backed plastic. ( more scratch resistant than matt black paint.) The panel in front of the co driver will be completed later.
Another one of those time consuming areas was the heater. I have 4 heater units, all of which show signs of leaking from various areas. The cost of a new heater assembly/core/control seems quite high so I looked at other options. I did consider electric, but I found a new modern aluminium heater matix that would fit into the original plastic casing for £15.00 on the internet. This is also very light. The problem was controlling the flow and the pipe work. As it is a rally car, it tends to get hot inside ( well I get hot, not really bothered about the co driver, he can put an extra coat on if he is cold). The heater is only used to demist the windows. For that reason “control” is not really needed, just on and off. So a suitable stainless ball valve is being used, mounted next to the fan assembly. The pipe work was sorted with silicon hoses and some aluminium pipe.
The lower flap of the heater box will have a small extension made to enable it to be raised and lowered, so this only leaves the main air flap under the front scuttle that requires cable operation, so removing all of the cable and controls from by the handbrake.
As I am sure many of you know, this is not the “sexy” part of car preparation, but it has to be done. Hopefully in the next week or so I can finish it off and get the dash installed. I can then work on connecting the wiring and the centre console.
Ah well perhaps I wont be rallying this year!!!. Still we can hope.
Attachments
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Before
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dash in 1.jpg
And After
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heater 1 c.jpg
Heater Matrix
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Re: Historic Forest Stage Rally 124 Spider

Post by Rallyroller » Tue May 28, 2013 4:52 pm

Hi Guys

Sorry about the pictures. I will learn how to use this computer thing soon.


Nigel.



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miro-1980
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Re: Historic Forest Stage Rally 124 Spider

Post by miro-1980 » Sun Jun 02, 2013 8:12 pm

miro-1980 wrote:I kept my 124 spider CS0 pretty much original so far , though had some ideas before.

Your thread makes me thinking of some rally modifications. Very tempting !

Great project and very interesting reading !

Miro
Do not get too tempted or you'll sink in .. as I did and one modification leads to another soon enough you have a full gr 4 car....

Miro
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Simon
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Re: Historic Forest Stage Rally 124 Spider

Post by Simon » Sun Jun 02, 2013 11:11 pm

That's coming along very nicely Nigel. I have a similar tangle of 'spaghetti' to sort out under my dash too!
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Re: Historic Forest Stage Rally 124 Spider

Post by Rallyroller » Mon Jun 03, 2013 8:36 am

Hi Miro
Hi Simon

I agree with both of your comments. I am now starting to draw a line at what mods are being carried out in the first build of the car. I need to get out there in it before I get too old!!!.

Re the wiring, that is changing. I assembled the main part of the loom and added a few "extra" bits. I was going to use an relay/fuse unit that puts the 16 fuses and 7 relays in a block on the centre consul. Now I have come to install it it looks too complex. If a wire ever came adrift, it would be a nightmare to find it. So I am now going to move the relays away from the fuses, so that the wiring in this area is easier to trace.

Currently putting in the main cable runs in the inside of the car. (fuel pipes, brake pies, extinguisher pies etc. etc.)

One question on fuel system. Twin facet pumps mounted in boot. Filter king- mount in the boot or in the engine compartment? Initially I was going to mount in the boot, ( or trunk for our American readers) but I have seen a few mounted in the engine compartment by some well known car pre guys. My thoughts about mounting in the engine compartment is that it may be easier to maintain. There is room as ther car is Right hand drive, so no brakes etc on the inner wing.
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