Author Topic: Preparing a 75ts for some club sprints.  (Read 5919 times)

Sheldon McIntosh

  • Hero Member
  • *****
  • Posts: 1954
    • View Profile
Re: Preparing a 75ts for some club sprints.
« Reply #45 on: December 20, 2012, 01:17:21 PM »
I did Winton in my standard 90, so it was interesting to get reacquainted with stock Alfa brakes.  I have two year old slotted and cross-drilled discs all-round, braided lines, and put in some QFM track-day pads.  I didn't do a complete flush of the fluid (lazy), but did a thorough bleed. 

With two drivers the car did around 10 sessions, and the brakes were definitely starting to feel a little tired in the last session.  I was pleasantly surprised by how well they stood up to the punishment though, and I think I'm fairly brutal on brakes; they definitely would have been okay throughout the day with only one driver.

I'm not surprised that you had issues with unknown pads and fluid.  The stock set-up seems to be fairly good, but not that good!!  You're on the right track though; get good rotors, pads and fluid, do a flush and bleed a few days before, and the brakes will be fine for a track-day.

Don't neglect the rear brakes either, they do more work on these cars than a lot of other cars, due to the weight of the transaxle, and they also get pretty hot sitting right next to the exhaust and gearbox.  If you can, try and rig-up some kind of ducting to both front and rear brakes.  Probably does bugger all, but can't hurt.
(\_/)   Please donate to a great cause if you can - http://fundraise.shitboxrally.com.au/fatboyracing
(='.')    < Look, it's a cute bunny!!
(")-(")

alanm

  • Full Member
  • ***
  • Posts: 166
    • View Profile
  • AROCA Member #: 3444
Re: Preparing a 75ts for some club sprints.
« Reply #46 on: December 20, 2012, 01:34:56 PM »
Hi all,

Just discovered this thread (clearly I am a bit slow on the uptake).

Paul, my apologies for not responding to your words of encouragement about having a go at sprinting.

Darren, great to hear that you resolved your braking issue. I came away with an issue as well, not evident while I was at Winton. Mine involved the master cylinder seals. I am very happy with the brakes now, they are 30% better now than when I bought the car. I have Ferodo Race 2500 pads and high temperature brake fluid, the pedal feel is excellent. I look forward to some further testing...

Re. the suspension, I am tempted to explore the Handling Kits offered by Alfaholics and EB Spares for the 75. Essentially thicker sway bar, and stiffer rear springs and Koni yellow dampers. From memory the EB Harvey Bailey springs lower the rear a little. I always think that the 75 sits too high at the rear. Doesn’t seem to slow Joe Falcone down though!!

Cheers
Alan
1987 75 TS
1986 GTV6 Grand Prix
2001 156 V6 Monza

Sheldon McIntosh

  • Hero Member
  • *****
  • Posts: 1954
    • View Profile
Re: Preparing a 75ts for some club sprints.
« Reply #47 on: December 20, 2012, 11:28:33 PM »
Re. the suspension, I am tempted to explore the Handling Kits offered by Alfaholics and EB Spares for the 75. Essentially thicker sway bar, and stiffer rear springs and Koni yellow dampers. From memory the EB Harvey Bailey springs lower the rear a little. I always think that the 75 sits too high at the rear. Doesn’t seem to slow Joe Falcone down though!!

Only my opinion of course, but I really don't think that is the way to go, in fact I'm very surprised that such a well-known outfit would recommend that as a first-stage upgrade.  If you want to do one thing to make your transaxle handle better at the track (and it will be far nicer on the road too), install bigger torsion bars, as well as Konis.  27 or 28mm will be more than adequate, and after that you can fine-tune things with rear springs and front and rear sway-bars.  The rear-end of a transaxle Alfa is the best thing about the car, it's the front that needs sorting out.  Concentrate on that area first.

Like I say, only my opinion, but also based on a few years of experience. 
(\_/)   Please donate to a great cause if you can - http://fundraise.shitboxrally.com.au/fatboyracing
(='.')    < Look, it's a cute bunny!!
(")-(")

Alpine Chapter Inc.

  • Hero Member
  • *****
  • Posts: 723
    • View Profile
Re: Preparing a 75ts for some club sprints.
« Reply #48 on: December 20, 2012, 11:46:34 PM »
G'day Alan,

l have taken, from memory a half a coil from the rear springs on the 75 without any probs.  l did however clamp the base of the springs down to the mounting plate on the De Dion tube, as it didn't feel like it was going to stay there when l had the car up on the hoist with the wheels off the ground.
 
The standard Koni yellows on the 75 work nicely, l have mine on full soft.

However on my Alfetta GTV which has the larger 28mm torsion bars with the matching rear springs, l sent the Koni yellows off to be tested and re-valved to Pace Engineering spec.  l had raced it at Winton before and then after with about a month between the two meetings.

Words can't describe the difference, waaaaay waaaay better, three seconds better.  Same tyres with a little less psi from the time before. One thing l did adjust, other than the dampers was lowering the rear end of the car by 6mm.  The car rode the bumps better, l could brake latter, it felt spot on, front tyre wear was perfect from the inside edge to the outside edge.  l could feel the difference even when driving to the track that morning, the ride quality over some very average back roads was nothing short of brilliant.  When l get a chance l will do the same to the konis on the 75, l think it's worth the extra dollars.
 
lt's worth noting that l feel, ride quality and general road manner of the Alfetta is considerably better than the 75 even though the Alfetta has firmer spring rates and a 100mm shorter wheel base.  At the end of the day the dampers play a very very big part in just about everything we do with our cars but are often over looked.

l will never forget when being shown through the new and almost finished home of Triple Eight Engineering building.  l was allowed to go anywhere l needed to when installing the new signage on the entire building inside and out,(3 days work) but when it came to the shock/damper room l was to contact Trevor the general manager of Triple Eight engineering because the damper room is absolute top security, no one, but no one goes in there other than the two full time guys that do all the building and testing of the dampers.  As Trevor said it's one of the most important rooms in the complex.
 
That rather privileged experience was pretty damn good.  To see the build quality of the cars from inside the fabrication room, talking to the guys that actually do the fabrication from scratch, to the graphics bays where the cars get all the race livery.  Is it any wonder the Americans are looking very very closely at our Supercar formula with the view to replacing the old Nascar formula, yes they want and admit they need to change. They want four opening doors, working lights, cars that look like the family car only with numbers and stickers.  So you blokes that go around Knocking the Supercars, think again, it could be that the Aussie Supercars lead the way in the world of fast sedan racing, and l'm serious. ;) ;)
Sorry to get distracted at the end of this post, thought it worth telling.  I’m proud of Aussie motorsport  and damn proud of the quality of race cars we build and formulate in this country, not to mention the thousands it employs every day.

Cheers Paul
« Last Edit: December 21, 2012, 08:25:16 AM by Alpine Chapter »

alanm

  • Full Member
  • ***
  • Posts: 166
    • View Profile
  • AROCA Member #: 3444
Re: Preparing a 75ts for some club sprints.
« Reply #49 on: December 21, 2012, 07:45:15 AM »
Thanks for you input guys,

Okay, so I know where to get Koni yellows (though reds on the car may not be on their firmest setting  ::))
Where do you get torsion bars though??
Was interested in all of the comments a picture of Joe’s car attracted after Sandown sprint showing compression of the suspension at the front of the car.
People always seem to say things like... oh, a mate offered me a set, or, I found them in the back of so and so’s garage.
I have never seen them offered for sale new by a parts supplier.

Cheers,
Alan

1987 75 TS
1986 GTV6 Grand Prix
2001 156 V6 Monza

Alpine Chapter Inc.

  • Hero Member
  • *****
  • Posts: 723
    • View Profile
Re: Preparing a 75ts for some club sprints.
« Reply #50 on: December 21, 2012, 08:12:55 AM »
G'day Alan,

Give the Alfa God of speed a bell, 03 9844 0147,  he makes the 28mm torsion bars plus a few other little things that will have your 75 sitting and riding like a gem, both on the track and on the road.

Cheers Paul

Paul Bayly

  • Sr. Member
  • ****
  • Posts: 394
    • View Profile
Re: Preparing a 75ts for some club sprints.
« Reply #51 on: December 21, 2012, 05:32:08 PM »
Has anyone come up with a reliable method of reducing the uptake in the 'slack' in the brake pedal before the brakes begin to be applied?  Most of the recommended mods are to give you less pedal travel between initial and maximum brake pressure (firewall flex, braided hoses, different fluid) but I'm yet to hear ideas on getting the functional portion of brake pedal travel further toward the top of the stroke.

All my transaxle Alfas have suffered the same fault to varying degrees. 
Paul 'Beatle' Bayly
'85 90
Port Stephens NSW
Past:
'79 GTV
'76 GT
'89 75TS
'76 Alfetta (sacrificed for the greater good!)
'83 GTV6
'67 Duetto
'66 Super
'92 164

MD

  • Hero Member
  • *****
  • Posts: 1414
    • View Profile
Re: Preparing a 75ts for some club sprints.
« Reply #52 on: December 21, 2012, 09:20:34 PM »
This fixes it.
It's an Alfetta world.
MD

Paul Bayly

  • Sr. Member
  • ****
  • Posts: 394
    • View Profile
Re: Preparing a 75ts for some club sprints.
« Reply #53 on: December 21, 2012, 10:51:22 PM »
That's not fixing it, that's replacing it  ::)   Great idea but wouldn't that render it non-registerable (without a booster?).

So you are saying all the slack is in the cross tube?  Therefore a LHD car wouldn't suffer the same problem?  Or is it also down to the m/c design?
Paul 'Beatle' Bayly
'85 90
Port Stephens NSW
Past:
'79 GTV
'76 GT
'89 75TS
'76 Alfetta (sacrificed for the greater good!)
'83 GTV6
'67 Duetto
'66 Super
'92 164

MD

  • Hero Member
  • *****
  • Posts: 1414
    • View Profile
Re: Preparing a 75ts for some club sprints.
« Reply #54 on: December 22, 2012, 09:26:06 AM »
Paul,
All the extra "movement" is a cummulative thing which includes the booster. If you remove all the RHD brake conversion parts, it reduces the weight of the car by around 14.5kg as well.

What you lose in the pedal pressure assistance from the booster, you need to make up with an improved pedal leverage ratio to make the pressure acceptable. You also need to replace the pedal lever arm with one that's at least 8mm thick (or more) as the arm itself flexes. Bracing the pedal box also braces the firewall.

The remote reservoirs are not a requirement, they are installed here for other reasons not related to this issue.

The fact is, a careful choice of street pads (ones that work  best on cold brakes) will have the factory components working adequately for the job. However if one expects these same brakes to do the job on the track, well, they haven't experienced seriuously good brakes.

The question regarding the legal compliance is simply answered by a Blue Plate certification from a qualified mechanical engineer that the system is up to the job. (Goes for any modification within reason actually.)
It's an Alfetta world.
MD