3l GTV6 PRC project

[Thmpar]

I have not heard of the peugot brakes on them,But i have mazda b2000 rotors going on the back the same set up we use on the sud,and wrx turbo rotors and calipers going on the front.Of course there are no easy way to do it,it took nearly a month to get it set up on the sud,but it stop's on a stamp even with the rear brakes locked off.

[redalfaracing]

For what benefit?

Sheldon, i'm thinking i've got 190 kw, and a 1100 kg car, if i'm going down a mountain full noise i still want rear brakes when i get there. Rally cars run a lot of rear bias, i subscibe to the theory that if the rear is loose the front is biting. Yes i could put some sz ventilated discs on, but i believe they are pricey and some times hard to get. if 306 discs can be made to fit easily, why not? What the guy also did was relocted the calipers to behind the diff ( 90 degrees rearward) which i think is a good idea. This gets them down in the wind and aids cooling and also away from the red hot exhaust. I am going to give it some serios thought. Keep you posted.

And whist the GTV6 is away getting caged... i'm going fishing. talk to you in a couple of weeks. 

[Sheldon McIntosh]

Yeah, fair enough

I wasn't aware that rally cars run a lot or rear bias.

I think the rear brakes are fairly good, but the main issue, as you say, is keeping them cool.  I think drilling holes in the floor for ducting would be easier than relocating them though.  If you're allowed to relocate them, can you go outboard?  Probably easier.  There's at least one car in the club with outboard rear brakes, may be worth investigating too?

[Jekyll and Hyde]

Sheldon, i'm thinking i've got 190 kw, and a 1100 kg car, if i'm going down a mountain full noise i still want rear brakes when i get there. Rally cars run a lot of rear bias, i subscibe to the theory that if the rear is loose the front is biting. Yes i could put some sz ventilated discs on, but i believe they are pricey and some times hard to get. if 306 discs can be made to fit easily, why not? What the guy also did was relocted the calipers to behind the diff ( 90 degrees rearward) which i think is a good idea. This gets them down in the wind and aids cooling and also away from the red hot exhaust. I am going to give it some serios thought. Keep you posted.

Don't suppose you could point us towards the link for this 306 disc conversion, could you?  Just stuck my head under significant others frogbox, and it's definitely conceivable - the 306 front discs have a very shallow hat height, are vented and pretty small in diameter.  Caliper may require a little spacing out from the gearbox as well as the widening spacers if you want to retain standard location, but otherwise looks very possible....

[redalfaracing]

hi all, back from some r & r.

here is the link to the forum on braking, some of the guys waffle on ,( we would never do that!) but if you wade though all the BS you actually find some gems.
http://alfagtv6.com/phpBB3/viewtopic.php?f=3&t=18&st=0&sk=t&sd=a&start=330 The thread is some 27 pages, the relevant bit is on page 23
as to going outboard, i think its more work and the increase in unsprung weight on a rally car would be detrimental. It's ok for you guys on mirror smooth black top, think about a rutted and corrugated bush track for a second, what would you rather, light or heavy axles??
here are the comparisons of the 2 discs. look at the dimensions. Very do-able.
I'm planning on ditching the boat anchor weight rear calipers and using the alloy brembos of the front on the rear. a hole in the floor for cooling isn't such a good idea on a dirt road. sooner or later i'm going to fill the car up with dust! i figure if i rotate them 90 degrees rearward and incorerate a gearbox bash plte ( allowable on prc) with a turn up at the rear to direct some air onto the calipers it is my best option. I suppose that is ok? Maybe Peter Aird ( a rally scrutineer and a member of this forum may wish to comment) They should be a good match for my Willwood Superlites on the front. I'll get some knackered PUG discs from a wrecker and have a play with them. Keep you posted.
Picked up a Haltech E11V2 and loom for the new engine last week. Can't wait to bring my car home and start putting her together. Might pick it up Monday Arvo work permitting. You better tell me where i find you Phil for that coffee

[Sheldon McIntosh]

Ah, okay.  I should have elaborated.  The holes in the floor would be sealed and connected to a pipe running from the outside of the car.  This is a pretty standard mod for a track 116.  Also, where would you route an exhaust on a rally car?

Tis funny, the WRC guys seem to cope with outboard brakes? (Don't bother to respond to that comment, I know where you're coming from).

[alfagtv152]

Hi Greg,
On my GTV I upgraded the front to 164 discs and Volvo 4 spots only to find they would lock much to easy with not much affect coming from the rear so I bought a Kit from Vin Sharp which provided slotted vented rotors(Ford Courier I think) modified to mount on a custom center and a spacer kit for the rear callipers to space them out wider to go over the disc.The only change I made was to mill a little on each side of the pad recess and redo the pin holes to use Alfetta front pads and with an adjustable pressure control valve in the rear line I can balance the braking effort just the way I like,I generally take one notch less for the wet than the dry.
Cheers
Andrew

[redalfaracing]

On my sedan PRC i still run standard brakes straight from an alfa 90 donor, with no booster and an adjustable bias valve and RB74 pads all round. For that car ( 1000 kg and 85 RW KW) i find it more than adequate. How ever with this car , which i expect to be 160 RW KW and 1100 + KG i don't ever want to find myself short on stopping power. I want to get this right before i find i have a problem. I did some investigating today and the PUG discs and brembo calipers will fit so easily, take only a few hrs to knock up the brackets and re drill the discs. i have to turn up some spacing rings as the center hole in the pug disc is a few millimeters larger than the alfa disc. i will have to get extra lugs on the rear pads so i can have an operational hand brake ( road worthy requirement) but that shouldn't be a drama.
Looking good 

[meizhak]

just my two bobs worth,

greg i used to rally a alfetta a long time ago without any protection of rear brakes. on one occassion i must have hit the disc on a rock or something similar. the  disc cracked around the centre where it bolts to axle.still turned through caliper till it eventually went off centre locked in the caliper and pretty much ripped the side of the diff off {very nasty}. I think this woul be a good reason to go outboard, bit of protedtion inside the wheel.

meizhak

[redalfaracing]

meizhak, and i have had a rock jammed between a dics caliper and the rim, punching a hole in the rim well and letting all the air out. where ever they are they can cause grief, you takes your chances either way, thats rallying! I'm still inclined to go the lower unsprung weight route with a bash plate / air scoop under the gearbox, but i appreciate your 2 bob

[redalfaracing]

meizhak, i wonder if you would be able to post a couple of pics of your old rally car if you have any, really be interested to see it, Thanks

[redalfaracing]

thought i would give you an update from Alfa Mountain, Car is back with a great cage. Spent some of my Easter break stripping more unwanted parts of it. Have the Peugeot discs mounted up on the gearbox. Such an easy conversion. Going to get the new braket to mount the brembo calipers laser cut and cad plated. Going to have some awsome rear brakes. New brake balance bar and cylinders on their way from the UK. Cheapest place to get them. I bought a girling 5/8 master cylinder locally last week and paid $113 more than exactly the same item i am getting from the UK. I give local people a go... but $113 is a bit rich.  put som pics up this week end. Cheers

[redalfaracing]

work is slowly progressing on my GTV6, doing a lot of stareing and thinking. big hurdle.. spare wheel wont fit any where. I will be using 195/65/15 or 205/65/15 rally tyres, and they dont fit flat on the rear hatch floor , let alone in the spare wheel well. A rally car without a spare is pretty useless, so what to do? The solution that i have come up with is to cut out the panel between the shocker towers, reform the tank with a 3 inch water pipe and a heavy hammer, extend the straps and the tank is now 40 mm further forward and the wheel will lie flat on the floor. I have had to extend the filler neck but it all works. I was going to remove the battery box, but instead i am going to mount a surge tank, 2 fuel pumps and filters in there. Where the pump is now, would get wiped off in no time. I have given up on using the front calipers on the rear, just don't lend themselves to living there because of the fluid inlet. Looking out for some radial mount Brembo or Wilwood 4 piston calipers. The ones of the rear of a Porsche 987 Boxster look promising. ( any one have any lying around?) I have some 147 gta 305 mm discs now which i am in the middle of modifying to suit and mounting the 4 pot Wilwood calipers to the stubs. They are impressive looking stoppers!! Unfortunately work has been getting in the way, this week is looking quieter so i may get some real progress .

[Evan Bottcher]

Great stuff Greg.  Did you weigh the car before/after the cage??

[redalfaracing]

Evan, i weighed the car b4 stripping, 1220 kg. i had every intention of weighing after stripping but ran out of time. I will have to settle with a weigh-in on the way to log booking. Rai estimates the cage to weigh 55 kg. Rest assured every thing i touch will go back on at minimum weight, with the exception of brakes. I dont want to skimp on that item!