what is a good brake mod. on my 1985 GTV
is it to use gtv6 callipers or something else??
keeping in mind i dont want to change to five stud.
thanks brad.. ;)
What do you want to do with the car? Medium road, fast road, track? What is the limiting factor with your current brakes?
fast road.
umm really just for better performance.
to stop quicker and better
thanks brad
i was thinking about slotted rotors allround on my giulietta with alfa 75 Calipers but still are single pot.
i have seen volvo 4 pot Calipers been modified to fit the alfas but alot of work involved.
A 75 (t-spark or v6) has the same brakes as a gtv6 - two pot brembo's. 4 Cylinders also have twin pistons but i believe they are slightly smaller and only come with solid discs - not ventilated like the v6's.
We have a 4 cyl at home with the upgraded v6 brakes and they are great on the race track compared to the standard ones...but on the road there isn't really a difference. Stopping quicker will probably come down to driver skill... as if you have brakes the bite very hard you are most likely to lock the wheels if you suddenly jump on the brakes.
The Volvo calipers fit straight onto a 75/90/GTV6. Is the GTV4 different?
Slotted rotors will make two tenths of f all difference on the road. It will wear your pads wallet out quicker though.
i know the 4cyl /4stud are solid disc`s. i thought the 75 brembro`s where still single pot? i must have been wrong.
I'm confused. 75/90/GTV6 is Brembo two pot. Volvo is four-pot. What does GTV4 have? What does Guilietta have?
Giulietta's & 4 cyl GTV's have ATE single piston (one each side) cast iron calipers as standard. They are non ventilated type disks. Many people retro fit the GTV6 (style) aluminum four piston calipers to the giulietta and GTV 4's along with its ventilated disk as an 'initial brake upgrade, its easy as it fits on the hub and the 'offset' is no problem. The GTV6 caliper is lighter, but MUCH more flexible, however it does provide significantly better stopping, especially on the track where repeated stopping can be 'useful'. Its basically a 'bolt-on' upgrade hence its popularity..
jimn~
Jim, I think you'll find the GTV6 'style' calipers are two piston.
yes.. two per side...
Jim, I gather you have not seen a pair of Brembo GTV6 or 75 Front Calipers.
They are Alloy 2 Spot (one piston per side) as Sheldon said.
They are an improvement on the 4 Cyl brakes because of larger Pad area and the Ventilated Rotors.
They are not that good for serious Track use as they flex causing the Pads to taper and therefore losing braking efficientcy and feel.
Thats why my 75 now has 4 Spot (cast iron) Volvo Calipers which give far greater feel and better pad wear due to their stiffness and far greater pad area.
The only draw back is the weight.
If anyone wants a decent front brake setup for a GTV/GTV6/75 call Bruno at Marranello Pursang.
Rob D
+1
I have the same set-up on the front and it is almost too much for my standard sprung 90, it just about face-plants itself. Nice to have the confidence going into turn one at Sandown or Phillip Island though. Nice to not have to worry about fade either.
Thanks Rob, I thought I was going crazy for a minute there. I was thinking, 'hang on, maybe they are 4 spot, it's been a while since I saw them....)
A friend came round today in his racing Sud. I went out for a fang in it around the block and had a great time, apart from the brakes. He then went out in my car, and said 'Gee your car is shit, but ohmigod those brakes are almost too good!" That is actually a true story.
rob/sheldon, you are right, of course. It was late, I was wearing sunglasses etc.
Hey Brad,
The choice depends on what you are after.
If you're after repeatability, upgrading to a ventilated rotor you should be able to stop more often without encountering brake fade. The rotor acts as a heat sink to dissipate all the heat generated from braking and a ventilated rotor has better performance.
For stopping distance, the pad is what determines the vehicles performance. With the original pads I could just lock the brakes up under heavy foot pressure. I since swapped the pads over for 'RB74's' on the front and 'Comp 2's' on the rear. This halved the braking distance at Winton and the car could lock all 4 wheels.
Thus if your just after better baking performance I'd try a set of pads. I got mine from "Race Brakes" and I've been happy with them. A number of the more serious guys use different types for different applications. Ask around and someone will suggest something that suits what you are after.
If you want to keep the 4 stud hubs and upgrade the callipers to GTV6/Alfa 75 for street performance, get a 5 stud rotor machined to 4 stud. John at "Alloy Race Components" are able to do this. I would also swap over the upright as the brake mounts on my 82 GTV's uprights were significantly less gusseted than on the 75's uprights.
If you want serious performance then you're looking at serious cash for larger brakes, rotors, bias bars, bias valves, pedal boxes etc.
This said I would also check/change the fluid as well as check that each brake is working evenly and the brake bias proportioning valve is working correctly. To do this I used a technique that Carrol Smith recommends in "Drive to Win" and it works well on our project car at uni. Place the car on 4 jack stands and get someone to sit in the driver's seat. Straddle the front wheel (a bit trickier on a sedan) and turn it while the driver slowing increased the brake pressure. When you can no longer turn the wheel get the driver to hold that pressure and check the other side, the resistance should be the same. Then check the rear wheels. You should be just able to turn them (this checks the bias.) Then again increase pressure until you can't turn the rear wheel and check the other side. Although this method isn't perfect it should tell you if something is wrong and it gets the bias to within a turn on the bar every time.
That also said technique also plays a big part when you don't have a computer to figure everything out for you so get a copy of "Drive to Win" and have a read on stabbing then squeezing the brakes.
Tristan
Jim rather then admitting you were wrong. maybe the others had another interpretation that was more right.
Brad,
Changing to 5 stud does have its benefits.....you have a much larger choice of wheels as anything off a gtv6/75/90 or 147/156 will fit straight on, plus there is no need to fabricate anything to make the V6 brakes fit... they should simply bolt on.
The last owner has fitted what appears to be alloy Camira brakes over the solid front rotors on my GTV4. I'm yet to try them myself but he seemed to feel there was some improvement and that the brakes worked well.
(http://i238.photobucket.com/albums/ff41/OzMidnight/100_0812.jpg)
Hi Brad,
As a fairly simple improvement just for road use you can bolt straight on a set of callipers from a late (85?) Alfa 33 which takes a DB 349 pad.It is only a single piston sliding calliper but it gives you 1.7xthe standard Alfetta pad area and will even accomodate a 13 inch wheel if you want.As many have said it just depends on how far you want to go,the next easiest is the GTV6 brakes which bolt straight on,all you have to do is redrill the brake rotor to 4 stud instead of 5.I run Volvo 4 spots with 164 rotors,redrilled and using a spacer between the rotor and the hub,on my track car with the rear calliper modified to take Alfetta front pads and slotted rotorsfrom Vin Sharp.
Pics 1 rear 2 front 3 Suggested mod 4 suggested mod
Also a BIG part of braking performance is dictated by the pads used,I personally swear by Hawk,HP Plus black(Ferro Carbon),pads which for me have excellent performance without any fade and still have good cold bite in a power boosted road car,lots of black dust and not much rotor wear.
There are all sorts of pads to choose from depending on your requirements.
Cheers
Andrew
Interesting about the 33 calipers as I run a 13" wheel! Anyone got any ideas on vented setups to suit a 13" wheel?
Quote from: alfagtv152 on May 11, 2009, 06:36:08 PM
Hi Brad,
As a fairly simple improvement just for road use you can bolt straight on a set of callipers from a late (85?) Alfa 33 which takes a DB 349 pad.It is only a single piston sliding calliper but it gives you 1.7xthe standard Alfetta pad area and will even accomodate a 13 inch wheel if you want.As many have said it just depends on how far you want to go,the next easiest is the GTV6 brakes which bolt straight on,all you have to do is redrill the brake rotor to 4 stud instead of 5.I run Volvo 4 spots with 164 rotors,redrilled and using a spacer between the rotor and the hub,on my track car with the rear calliper modified to take Alfetta front pads and slotted rotorsfrom Vin Sharp.
Pics 1 rear 2 front 3 Suggested mod 4 suggested mod
i like the vented disks on the back
Hi OzMidnight,
I have seen vented discs for 33's advertised on Ebay which could probably be fitted.The GTV6 rotor is not out of the question for you,I had a look at those calipers Today and if you get some GTV6 rotors at or above minimum machined thickness and take a couple of millimeters off the pad thickness,(You will need to do some sums to determine the caliper maximum opening and the thickness of pad to go with your rotor thickness),then you could use the 33 caliper and have vented discs.
Quote from: Storm_X on May 11, 2009, 09:17:53 PM
i like the vented disks on the back
You forgot to ask how much they cost ??
A few questions for OzMidnight if you don't mind.
Could you post a decent pic of the Camira caliper if possible. Have you tried it yet, any good?
Why are you running 13's on a GTV, I've never heard of such a thing?
What's up with the coilover?
Hi OzMidnight,
Is that the yellow one with the F3 wheels that was on My105.com some time ago?.There are plenty of 13" F3 slicks(second hand) available from the Adelaide Kumho Motorsport Dealer.
Cheers
Andrew
Hi Andrew...thanks for the tip about the brakes and the tyres, I've funnily enough just received four near-new F3 rear slicks from SA thanks to a friend down there! It was that car from my105, I planned to have it running again before now but had to store it for a year whilst building another house, so things got delayed.
Sheldon, I've answered you in PM so I can help not taking the thread further off-topic. I'm wondering if the Camira calipers are bigger in pad area than the Alfa 33 ones - might have to do some homework.
a technique that Carrol Smith recommends in "Drive to Win" and it works well on our project car at uni.
so get a copy of "Drive to Win" and have a read on stabbing then squeezing the brakes.
This sounds like a great reference, are there any other recommendations for race driving reference books before I go to chase this one up?
Hi Craig C,
Carroll Smith is considered a legend at out university and his racing books are our bible. He has written a whole range of different books. Check here for details: http://www.carrollsmith.com/books/
Personally I've read 'Drive to Win' and I've looked stuff up for reference in both 'Tune to Win' and 'Engineer to Win.' I will say the books do tend to focus on high end, open wheel, racing cars but everything is first explained simply in first principles usually using sedans. There is also a number of tips and advise throughout the book, stuff that could normally only be obtained through years of experience. Best of all, 'Drive to Win' comes with Carrolls list of other books to read so its not a bad place to start.
Hi all,
I got a quick look at Victor's brakes at Mallala but not enough time to get the story,can you give me the story on your new brakes please Victor?.
Brakes 101
Brake pad area has nothing to do with stopping power. Braking force = friction co-efficient times applied force.
Increased braking force needs a bigger lever arm (ie bigger diamter discs), higher friction co-refficient pads, and / or higher clamping pressure (bigger caliper pistons, smaller master cylinder or push harder). I am using rear pads from a Nissan GTR on the front, which are the same as the Alfa pads, but not as deep which theoretically gives greater braking force and some cost to pad life.
Nearly all the enegry from a stop goes into the brake discs as heat. The bigger the mass of the brake disc the more capacity the system has for braking. Getting heat out of the discs prepares them for the next stop, so heavier, vented rotors are better. Open spokey wheels help and so does ducting.
Alan is correct about caliper flex, but my pads wear evenly, so I don't care. I'm one of the few who stick to road tyres and my experience has been that when I ran Ferodo DS3000 pads I could lock a front wheel at any time at any speed. So I reckon there is enough stopping power available in the standard GTV6 system unless you are in Allan, or Robin or Victor & Mary's league.
I have proper ducting for the front, vented rotors at the rear, use Motul DOT3 fluid (I think DOT3 gives better feel and less caliper drag than DOT4 or DOT5), Endless type R pads on the front and Pagid on the rear. The car has more braking than I have willpower, but my next project is better coling for the rear. I get through a club sprint with as good a pedal at the end as the start, but the pedal started to get low in my stint at the Malalla 6 hour, so cooling the rears is going to get more attention.
Doug
Hi Andrew,
They are AP Racing 4 pot calipers on 330mm vented rotors. You may recall that I had the Group A double caliper set-up. At the time it was going to cost about $700 each for new rotors (old ones worn out...ran them for 8 years!) because they were some unique size. Also the roll center mod had been done but not the extended stub axle mod done (Hugh would not let me modify the existing ones..got some Group A historical value). So bit the bullet and changed the entire front end.
Result? Bloody fantastic! Still need a bit of fine tuning with the brake bias...the back brakes just seem to be locking up. The brakes felt as good on Sunday afternoon (minus engine power obviously) as they did Saturday morning. They've got lot more "feel" than the old set up, not forgeting I'm using a pedal box and therefore no power-assistance.
This should keep us out of trouble for next few years! ;D
Hi Guys,
thanks for all your replys!
this is all very helpful information,
what model or year volvo does the 4 pot brakes come from?
and what mods are required to fit them?
cheers brad
Hi Brad,
I believe mine came from something like a 1986 Volvo 264,just be sure they come from vented discs and are Girlock not ATE.The only mod for the calliper is to turn it from 2 input lines to 1,you can do this by drilling the calliper internally to common the inputs and plugging one threaded hole,you will need to change the nut on the end of the alfa pipe to suit the Volvo calliper.Alternatively you can use a little brass block to put the 2 Volvo lines into and the one Alfa pipe as I did(see earlier pictures).The calliper bolts straight on to the standard upright.
For the the disc you have 3 choices I know of,#1 is use the gtv6 disc and redrill it 4 stud but you will waste the top 10mm or so of the pad.#2 is use the Volvo disc and machine a little off the outside of your hub until it fits inside the Volvo disc then redrill 4x98mm pcd and use the wheel to hold the disc on.
#3 requires a bit more machineing,use a 164 disc,redrill it 4x98 and bore the center out to suit the hub,then machine a spacer 9mm thick(i think) off the front of some old 4 stud discs,Put the studs through the 164 disc then the spacer and then the hub to give the correct offset.
You will probably have to run 15 inch wheels after.
Cheers
Andrew
thanks andrew,
i will go down to u-pull-it and see what volvos thay have,
im intrested in the volvo calliper with the volvo disc,
my mate has a small engineering shop so machining shouldnt be a problem.
also was the brass brake line adaptor fabricated or off another car?
i already run 15 inch v4 simmons so they should fit?
cheers, brad,
Hi Brad,
I bought the brass T and all the necessary fittings from Auto Brake services and they made up my pipes for the calliper and changed the nut on the Alfa brake pipe.
Cheers
Andrew
hi guys,
finally my brakes have been drilled, machined and are ready to go,
i was lucky that the volvo i got the brakes off was sitting next to a bmw at u pull it,
bmws have a t-piece at the rear that takes volvo pipe and alfa pipe,
so do not need to get them made or adapted to the alfa pipes ect.
cheers for ur help andrew :)
brad
some more,
this is of the t-piece - alfa pipe and volvo pipes.
and all the fittings and pipes for the the volvo 4 pot brakes,
i tried fitting them on my parts donor car and just like andrew said they fit straight up!
this is a great mod and is highly recomended,
in background you can see my v4 simmons, they have just been pulled apart and restored (new zinc plated SHS with new nylock nuts and dad painted them in 2-pac metalic grey) and should look sweet 8)
cheers, brad
Hi Brad,
Dont you love it when it all comes together,good work.
Cheers
Andrew
Brad,
If that's a Volvo rotor you are using, what diameter is it please?
hi MD,
the diameter of the volvo disk is 260mm,
cheers, brad
Thank you.