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Discussion Starter #1 (Edited)
I just got home from the shop (1am) with Fabrizio's (super-racer) Giulia Super race car behind my truck. I am taking it to California Speedway in a couple hours for a 2.5 Challenge race.

We dynoed the car today...
[email protected] RPM (hp measured at the rear wheels)
[email protected] 6000 RPM

Here are some pics, I'll post more after the weekend.

3/4 front

PS: Happy Birthday Fabrizio! I bet this will be a birthday you won't forget.
 

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170 hp!

What size engine is in the Super? 170 hp at the rear wheels is amazing. I would guess the gross hp would be about 200! Even from a 2L that's 100hp/liter.

Fabulous car! Thanks for sharing.

Garrett
 

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That is a very neat car. I love to see Supers on the track!!

I have been meaning to ask: What are you folks doing to lower cars these days? Any good off shelf setups around? Looking for a hot street setup on a Giulia Super
Thanks
MrC
 

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Discussion Starter #8
Yeah it's a 2 liter. The dyno guy said 170 at the wheels comes out to about 205 at the flywheel.

When we lower cars, we usually get some aftermarket springs that are a little stiffer and cut them down a little. Shankle springs seem to work fine, it's the first thing i do to any street Alfa I get.

Motor has everything done... JE 12:1 pistons, Carillo rods, oversized valves, race cams my dad had made up, weber 45's, GTA headers...the usual stuff. Actually, i think it is a class C car since it has such a low base point. I gotta double check, I did a classification when we started building it and can't seem to find it.
 

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Super Car

wow. another wounderful car from you guys!!!!
Great job!!!!
Again I wished I lived closer
Enjoy
Peter
 

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thanks everyone for the kind coments on my car. it ran awesome this weekend at California speedway and the power was amazing. once we dial in the suspension some more and i acquire some more talents behind the wheel, the car should really scream.
 

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... and I acquire some more talents behind the wheel, the car should really scream.
Does that mean you are looking for a driver? :D, I'm always keen ... but expensive as I live in Sydney and would need travel expenses, etc. paid for too.

My resume includes a club level championship win, and no written-off Alfas ...:D

Pete
ps: only joking, BTW: would love to see that photo of the rear suspension ... especially interested to see how you have located the axle ... standard?, or what?
 

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The shocks would replace the 'suspension max extension position stop' that the straps do.

I think the straps have another function to do with body roll, etc. but not exactly sure ... maybe somebody else knows more.

Moving on to the rear suspension setup of the GTA and GTAm's, I have seen the sliding block arrangement a very long time ago. BUT what do they do to replace the A arm on top.

Sniady has replaced the A arm with a rose jointed trailing arm ... does this allow full suspension movement without blinding?. I assume it does because it looks like you still have rubber bushes in the lower trailing arms ... and thus flex is still possible. The panhard rod would lower the rear roll centre to the centre of the diff according to all the books, but that is an improvement from the top of the diff.

I am real interested to know if the GTA/GTAm's used a 4 link trailing arm system or what?

Many years ago I built a club car that had to use a beam axle for the rear. I have always admired the Alfa rear location but the disadvantage is the very high roll centre. Thus I flipped this concept upside down and had a lower A-arm (and thus very low rear roll centre) and upper trailing arms. Colin Chapman tried this with the original Mk1 Lotus Cortinas too.

The problem with this is that the bottom of the axle has enormous forces (from your engine) trying to move it forward on acceleration. The top of the axle is in tension, thus with the standard Alfas setup the A-arm is in tension, while the lower trailing arms are in compression.

Thus my rear axle (not an Alfas) bent forward. Oops, but handling and grip was fantastic. Chapman also had this trouble and also rear axle leaks because of axle housing flexing, etc.

To solve this I added lower trailing arms, but to ensure full axle movement (for a single wheel bump, etc. and to keep the wheels on the road all the time ... ) I installed very soft rubber bushes in these lower trailing arms. Thus the rubber would flex and allow the axle to go where it wanted to a limit. This limit would stop the axle bending.

The traction and handling of this setup was the best beam axle setup I have ever driven.

The tradition problem with beam axles is that the roll centre is in the middle of the axle, and with most setups they are hopeless over a single wheel bump, ie. the whole car chassis moves with the bump not just the wheel/axle. This is because the axle movement is really just up and down, no angled to the chassis movement is possible (except for rubber flexing).

Alfa solved this BUT compromised on a very high roll centre that is no good for traction through corners ... thus they have to run the front of the car very stiff.

Note though that photos of GTA/GTAm's show the front wheels in the air but the rear wheels on the ground ... thus whatever they have done with the sliding block and axle location allows very good one wheel bump axle movement, and thus traction. Thus again who knows what other location they did on top of the sliding block???

Pete
 

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Pete,
A few years ago, Racecar Engineering did a whole series on Asymmetrical Racecars, one article was only on Beam Axle suspensions.

Really interesting, but did not really give solid examples of the results of the calculations. (V9N6)

One of the other benefits of lowering the rear pick up point (rear roll center) is that it changes the geometry from wanting to lift the inside tire (stock location) to wanting to pull it down (lowered location). Which reduces the need of welding the axle solid. While not quite as important on high speed tracks, some of the ones we have in the mid-west can, and do, break welded rear ends.

In the copy of the CRH I have, the sliding block does lower the roll center to very close to the rear diff fill plug. The upper trailing arm is almost identical to what Anthony has on his Super. So it's a 3 trailing arm, sliding block design. A Watts link would do the identical geometry, if you can picture that...

Eric
 

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In the copy of the CRH I have, the sliding block does lower the roll center to very close to the rear diff fill plug. The upper trailing arm is almost identical to what Anthony has on his Super. So it's a 3 trailing arm, sliding block design. A Watts link would do the identical geometry, if you can picture that...
Thanks Eric, very interesting and now I can see why Anthony has copied that.

Pete
 
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