My regular driver - Autocross - Roadrace Monza

Moderator: Moderators

Re: My regular driver - Autocross - Roadrace Monza

Postby tinsfci » Mon Oct 05, 2009 5:04 pm

A closer look at the braking system after trackday!

First the wheel with heat bubbles and grease transformed to more like "fluid" leaking out:
IMGP1176.jpg
IMGP1176.jpg (168.31 KiB) Viewed 1091 times


Plenty of brake dust:
IMGP1179.jpg
IMGP1179.jpg (164.01 KiB) Viewed 1091 times


Plastic sleeves meltdown:
IMGP1180.jpg
IMGP1180.jpg (68.32 KiB) Viewed 1090 times


Used brake pads :shock: (To be honest they were not new, but surely 2/3 left before the race (which was approx. 2 x 10minutes!)
IMGP1186.jpg
IMGP1186.jpg (249.52 KiB) Viewed 1093 times
User avatar
tinsfci
 
Posts: 206
Joined: Mon Mar 10, 2008 3:14 pm
Location: Stockholm, Sweden

1975 Chevrolet Monza 2+2


Re: My regular driver - Autocross - Roadrace Monza

Postby 72 SS PNL » Mon Oct 05, 2009 6:32 pm

dam that is some hard brake usage

think you need some air ducts to bring air to the brakes , plus larger brakes
first and best car owned 72 GT(changed to SS) panel wagon

pictures of the car from 86 - http://www.myrideisme.com/Garage/06_IBM_GOAT/955
User avatar
72 SS PNL
 
Posts: 2716
Joined: Sat Mar 14, 2009 1:18 am
Location: phx az

1973 Chevrolet Vega Kammback GT

Re: My regular driver - Autocross - Roadrace Monza

Postby Kenova » Mon Oct 05, 2009 9:23 pm

It is definetly time for a brake up-grade!
As for the camber issue, don't put too much focus on the inside tire. Most of the cornering load is taken by the outside tire. Having said that, after looking at your photos you could use a little more negative camber gain on the outside wheel. You don't have very many options for improving it and all options will require a fully adjustable upper control arm.

Ken
My other car is a Nova.
User avatar
Kenova
 
Posts: 1529
Joined: Sun Jul 02, 2006 9:46 pm
Location: Ontario, Canada

Re: My regular driver - Autocross - Roadrace Monza

Postby rpoz-29 » Tue Oct 06, 2009 6:49 pm

You could have a set of the sleeves machined out of metal. I've gotten them mushy before, but nothing like what you have there. I would also upgrade to better pads. Are the rotors still okay? It looks like you got into the rivets a bit. Finally, I think a better set of tires would keep you from having to work the brakes so hard.
rpoz-29
 
Posts: 1199
Joined: Sat Nov 04, 2006 11:39 am

Re: My regular driver - Autocross - Roadrace Monza

Postby tinsfci » Wed Oct 07, 2009 3:28 pm

Hey thanks for your replies and suggestions!
For those of you that havent seen the pics from the track, and my thoughts about strange camber angles, go one page back or click on viewtopic.php?f=12&t=24282&start=15
User avatar
tinsfci
 
Posts: 206
Joined: Mon Mar 10, 2008 3:14 pm
Location: Stockholm, Sweden

1975 Chevrolet Monza 2+2

Re: My regular driver - Autocross - Roadrace Monza

Postby tinsfci » Wed Oct 07, 2009 4:01 pm

Better brakes are on my wish-list, so are new tires as well :)

If I should put the list in some order, I beleive it would be like:

1. Fix cooling to brakes, something like this:
brake_cooling1.jpg
brake_cooling1.jpg (109.58 KiB) Viewed 1018 times

brake_cooling2.jpeg
brake_cooling2.jpeg (112.66 KiB) Viewed 1017 times


It would be fun to see the difference. I think it means a LOT.

2. Buy better brake pads with friction material designed for rough use. I though it would be impossible to find such pads for our cars, but Carbotech has (at least for the ´76 and up Monza):

http://www.ctbrakes.com/pads/chevy.html

3. I must buy new tires, those BF Goodrich´s are.... OLD :) But I am in some kind of Catch-22 here... it´s hard to find good tires for 13" wheels, so I better buy new 14" or 15" wheels...but wheels with 4-bolt patterns are rare, therefore I better upgrade to 5-bolt, and if I do that, I better replace the whole brake system (rotors,brake cylinder etc) :rolleyes:
User avatar
tinsfci
 
Posts: 206
Joined: Mon Mar 10, 2008 3:14 pm
Location: Stockholm, Sweden

1975 Chevrolet Monza 2+2

Re: My regular driver - Autocross - Roadrace Monza

Postby tinsfci » Wed Oct 07, 2009 4:08 pm

Btw, I (and some other guys) took some pics of the other cars at Track Day, after my brakes not willing to race anymore :lol:

(In Swedish I´m afraid)
http://rejsa.nu/forum/viewtopic.php?t=59449
User avatar
tinsfci
 
Posts: 206
Joined: Mon Mar 10, 2008 3:14 pm
Location: Stockholm, Sweden

1975 Chevrolet Monza 2+2

Re: My regular driver - Autocross - Roadrace Monza

Postby rpoz-29 » Wed Oct 07, 2009 5:09 pm

I would look at those wheel bearings while you're working on it. You can get "R" compound tires in 13", and some decent street tires. 14" and 15" 4 lug wheels are available, but I imagine shipping would be expensive to Sweden.
rpoz-29
 
Posts: 1199
Joined: Sat Nov 04, 2006 11:39 am

Re: My regular driver - Autocross - Roadrace Monza

Postby 73astregt » Wed Oct 07, 2009 6:54 pm

have you road race guys ever had problems with snapping the rotor hats off the hubs from cornering? we used to run the pure stock roundy round races here years ago and used to snap the hats and sometimes the center of the wheel broke too! our problem was always with the right front corner. we cured it with larger wheel studs and used the monte carlo, corvette style wheels(rallys) and leaned the top of the tire in as much as we could get away with and still stay legal.
73 astre gt 355 small block 435 hp 435 torque edelbrock performer rpm power package
User avatar
73astregt
 
Posts: 2215
Joined: Sun Aug 12, 2007 4:50 pm
Location: Bridgewater Nova Scotia Canada

1973 Pontiac Astre GT

Re: My regular driver - Autocross - Roadrace Monza

Postby rpoz-29 » Wed Oct 07, 2009 7:43 pm

Back in the late 80's when I started running "R" compound tires, I cracked the centers on several GT wheels. The crack usually went from bolt hole to bolt hole. When I went to Cosworth wheels, I didn't have any more issues. Much less flex.
rpoz-29
 
Posts: 1199
Joined: Sat Nov 04, 2006 11:39 am

Re: My regular driver - Autocross - Roadrace Monza

Postby ck_carnut » Tue Oct 20, 2009 12:54 pm

tinsfci wrote:
Used brake pads :shock: (To be honest they were not new, but surely 2/3 left before the race (which was approx. 2 x 10minutes!)
IMGP1186.jpg


Looks a lot like the brakes on my Cosworth after my runs at Pocono back in May. 3x 20 minute runs. Pads were almost new when I started. The Vega rotors are not veted, and the pad area is smaller!

I'm in the process of putting on the later Monza vented rotors and larger pads, but it looks like it may not be enough!
My fleet:
'75 Cosworth Vega #1103
'77 MG Midget
'91 BMW 318is (the next project)
'00 Ranger (Parts hauler and occasional tow rig)
'09 WRX (her DD)
User avatar
ck_carnut
 
Posts: 91
Joined: Fri Sep 28, 2007 11:21 pm
Location: New Jersey

1975 Chevrolet Vega Cosworth

Re: My regular driver - Autocross - Roadrace Monza

Postby NixVegaGT » Tue Nov 03, 2009 11:21 am

tinsfci wrote:I went to a track day about 3 weeks ago, that was fun! :D
Hmmm...take a look at the front wheel angles:
Image
I have about 2-3 degrees "static" negative camber for auto-x:ing, but that looks a lot more...due to my worn out control arm bushings?


And GM's weak justification for moving the center of rotation outside the front wheels:

The stability factor is even MORE pronounced as the car rounds a curve. The centrifugal force throws more weight on the outer wheel so that this wheel moves up.… because the bottom of the tire shifts inward as it moves up the center of gravity of the car shifts also. It shifts into the curve to help counteract the centrifugal force pushing the car outward.


WHAT??!!! Even crazier to me is that they kept this setup for YEARS!.
- Nic '73 Vega GT "DogBoxx" Batwing LS1
http://www.cardomain.com/ride/2357894
User avatar
NixVegaGT
 
Posts: 2196
Joined: Sat Nov 11, 2006 2:24 am
Location: Minnesota

1973 Chevrolet Vega GT

Re: My regular driver - Autocross - Roadrace Monza

Postby NixVegaGT » Tue Nov 03, 2009 11:36 am

OH I also wanted to post about the brakes.

2. Buy better brake pads with friction material designed for rough use. I though it would be impossible to find such pads for our cars, but Carbotech has (at least for the ´76 and up Monza):


This will make a HUGE difference. I have been fighting this issue with my SRT4. The brake pad compound changes everything. The heat will still be an issue but will be mitigated a bit by a more effective compound that works at higher temps. You will encounter a lot lower temps overall and way less pad breakdown.

One thought on the vent idea. I would want to move the outlet to the vent more toward the center of the spindle so it ducts the air as close to the hub as possible. That way the air can flow better through the vents of the disc. I know we are limited by the bulk of the spindle itself but it's probably worth trying to get the air as close as possible. Cool idea using the lower marker light as a vent.

It may be worthwhile to do the S10 spindle upgrade. There are also a bunch of relatively inexpensive "Big brake" kits.

Just a thought. Keep up the good work.
- Nic '73 Vega GT "DogBoxx" Batwing LS1
http://www.cardomain.com/ride/2357894
User avatar
NixVegaGT
 
Posts: 2196
Joined: Sat Nov 11, 2006 2:24 am
Location: Minnesota

1973 Chevrolet Vega GT

Re: My regular driver - Autocross - Roadrace Monza

Postby tinsfci » Tue Nov 10, 2009 1:10 pm

NixVegaGT wrote:
The stability factor is even MORE pronounced as the car rounds a curve. The centrifugal force throws more weight on the outer wheel so that this wheel moves up.… because the bottom of the tire shifts inward as it moves up the center of gravity of the car shifts also. It shifts into the curve to help counteract the centrifugal force pushing the car outward.

WHAT??!!! Even crazier to me is that they kept this setup for YEARS!.

Thanks Nic for that quote. I had missed that topic http://forums.h-body.org/viewtopic.php?f=10&t=28432#p150648
Quite interesting. I can agree to the first reason when going over a bump with one wheel, but the one on cornering doesn´t make sense to me either.
User avatar
tinsfci
 
Posts: 206
Joined: Mon Mar 10, 2008 3:14 pm
Location: Stockholm, Sweden

1975 Chevrolet Monza 2+2

Re: My regular driver - Autocross - Roadrace Monza

Postby tinsfci » Tue Nov 10, 2009 1:30 pm

NixVegaGT wrote:One thought on the vent idea. I would want to move the outlet to the vent more toward the center of the spindle so it ducts the air as close to the hub as possible. That way the air can flow better through the vents of the disc. I know we are limited by the bulk of the spindle itself but it's probably worth trying to get the air as close as possible. Cool idea using the lower marker light as a vent.

Absolutely Nic! The outlet should end in the center of the rotor, NOT on the rotor braking surface. I think many has missed this important thing on vented rotors, that the air is being sucked in at the center of the rotor on the back, and goes out thru the fins on the rotor. I´ve made a note about that in some other thread, that when upgrading to ´76 and later brakes on a ´75, dont forget to replace the dustshields too, because they have air-holes for the vented brakes!

The brakes on the pics I borrowed for the air-vent has much bigger rotors, so the outlet is actually quite OK.

NixVegaGT wrote:It may be worthwhile to do the S10 spindle upgrade. There are also a bunch of relatively inexpensive "Big brake" kits.

Yes. I might do the S-10 swap. Have you seen my fellow swede grandam75:s observation that the S-10 spindle mounted is actually longer, and not shorter than the original spindle? viewtopic.php?t=26198
grandam75 wrote:I dont know if anyone considered the difference in spindle height when using S10 ball joints. Yes the stock spindle is about 1/4" taller than the S10 but if you measure the height with the ball joints attached you find that the S10 spindle with S10 ball joints is about 15mm, 1/2" taller. This should help camber gain.


Interesting!
User avatar
tinsfci
 
Posts: 206
Joined: Mon Mar 10, 2008 3:14 pm
Location: Stockholm, Sweden

1975 Chevrolet Monza 2+2

PreviousNext

Return to Road Racing and AutoX

Who is online

Users browsing this forum: No registered users and 1 guest