My 131 abarth (never ending) story - 2017 season updates

[miro-1980]

A nice shot for pure fun

[Guy Croft]

Pumping twice is - I should imagine - either lack of capacity in the master cylinder (insufficient volume) or too much static clearance betw the pad and the disc.

It can also be air in the line..

G

[TomLouwrier]

Both rear caliper have the same problem - the rear calipers backing the pads to a distance of ca 1,5 mm while it should stray say at .7 mm.

This sounds like a lot.
Is that the total distance for both pads or is it disc-pad clearance per pad?
What car were these calipers originally fitted to? What pad to disc clearance (if any) was specified for that application? (If the answer is 0.7mm you've already checked that).

I know of ATE front calipers on 911's that had a pin inside the piston with a mechanism to prevent knock back, but that system was deserted long ago. I don't know systems that retract the piston in a caliper, though in drums they exist. Are the piston seals new, and are the pistons sliding out the bore well? If they are sticking to the seals, that may be why they retract too much.
Air wouldn't cause this, but it would certainly give you excessive pedal travel and soft brakes (basics I trust you have under control).

regards
Tom

[miro-1980]

Just a small update ...

We have fitted new aluminum plate under the engine. It is made from 5 mm forged aluminum ( resistant to deformation - when hit it will spring back instead of deforming of tearing )

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We have also put a similar plate under the boot ( to protect the fuel tank)

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We have also put thin aluminum foot plates fr the driver and the co-pilot

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Installed the additional front loops for the seat belts ( to meet the FIA safety requirements)

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Welded in clutch pedal travel limiter (to prevent overstroking the clutch).

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The car will be tested on a test track near Opole next weekend. We ante to see how the car behaves on slippery surface , on sharp curves and how does it behaves on a jumping pod ... this will be done to verify suspension performance and setting ( and make final adjustments) as well as to verify brakes performance.

The car will be also dynoed on wheels and tested for the force it takes to throw it into a spin on curve ( using an accelerometer)

Will report the results ...

Miro

[Walezy]

Where is installed fuel tank? Do you use something else then OEM tank?

[Guy Croft]

Miro

you must get all that sound deadening mastic material scraped off. It is a terrifying fire hazard.

Do not put this job off.

If you get trapped upside down in the car in crash and the vehicle is on fire it will light up like a torch and drip on you like burning phosphorus.

G

[miro-1980]

Guy,

Thanks - extremely important !!!
This is the next step , before any serious starts.

Miro

[miro-1980]

Where is installed fuel tank? Do you use something else then OEM tank?

Tomek,

The tank is an ATL cell fitted int the spare wheel bay.

M

[Walezy]

Any photos?

[miro-1980]

Tomek,

Can't find anything better , bur will take some more pictures next weekend and post.

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M

[miro-1980]

Gents,

The first post of this thread was posted on Dec 4, 2007 - almost 5 years ago . Since than we have collected 519 entries (replies) on 35 CGRE pages and 46205 views. This makes this thread the second longest and the second most popular on GCRE "Readers cars" category and among top three member's threads of GCRE.

Taking into consideration that it is devoted to a car (131 Abarth) which is not the most popular (only 50 gr.4 cars ever built) I consider it great success and it looks like 50 000 views by exact anniversary is possible.

Thank you all for your interest and thank you Guy for the opportunity. It has been a privilege, a pleasure and a great assistance in the project.

Miro

PS : the longer we work on the car the more "never ending" story this becomes, so I foresee at least few more years of the project ( and fun, challenges, victories , disappointments, resolutions) and all those feelings that accompany building a 131abarth replica.

M

[Guy Croft]

Many congratulations Miro! Or should I say, 'many happy returns'..?!

Thanks very for the kind remarks about GC!


Now - about that spare engine.....?!


G

[miro-1980]

There is a new look to it now

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A real beast :

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I am not sure what happened with my front ...

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Any ideas or comments ?

Miro

[Guy Croft]

Golly, is this '20 questions' MM?

you have the car there - you tell us!!

G

[miro-1980]

I was hoping for some comments , bus since none were offered here is the answer:

This is our new geometry setting at work . This setting almost doubled the speed we can go on the curves.

Absolutely incredible driving.

The setting was done experimentally based on numerous inputs , lots of theory and and a lot of detailed analysis of gr 4 cars pictures on special stages.

Key elements were as one might predict camber an caster setting , and the trick was in selecting the best combination which would offer greatest traction on fast curves and no dangerous side affects. I. i.e slipping on sow curves)

The setting was initially done on "mechanic's nose" , but later fine tuned based on actual driving effects.

We are still to measure the setting properly ( and publish the results here) but the effects re as follows:

1/ great stability on straights
2/ great stability on curves
3/ incredible grip on fast curves allowing to go through the curves and amazing speeds with no tendency to oversteer or understeer . The car behaves neutrally.
4/ the on a wet and very slippery surface ( we had access to a large watered slip strip) the car obviously is very easy to loose control of with hard cornering and hard breaking , but when you take the off of the brake or off the gas peal the car straightens instantly following the telected driving track.

I have not detected any negative effects and ll positive effects . Actually the car drives incredibly fast (even with some sand and or dust present on the road surface). I was really amazed.

The only adverse effect is that you need to hold the steering wheel harder and use a bit more force to turn it. I expect this to be even more so when e go for a 2.8 steering rack.

Incidentally - here are some pictures of the new steering gear...

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There will be also a steering shock absorber .

All this will make driving actually a little harder ( requiring more force) but a little easier on sharp turns as it will turn a little quicker.

The lock to lock will be 2.78 instead of 3.4 ( about 20% ) quicker and hopefully not more than 20% harder.

It looks that with the new suspension steering and planned no brake booster ( two pumps with brake balance bar ) I will have to start visiting gym a bit more often ...

Miro