bushuteF6

I would think cost is the reason, dunno why when you consider how much extra is spent on other bits. Just remember (in theory) that a single piston sliding caliper has the same braking force per pedal pressure as a dual piston of the same size I.e. the brake fluid pressure at the single piston is double that at a twin piston caliper. The force is transferred to the sliding side and therefore halved, making it equiv to 2 pistons of the same size. Saying that though, there must be some loss in efficiency with a single pot setup simply due to friction in the sliding mech. Any thoughts anyone? Whenever I change pads on a "slider" the pistion side pad is ALWAYS more worn than the other - not by much though. I still reckon you just simply measure your front and rear piston areas to get the ratio. Just remember your single piston caliper is X 2. This will give you some confidence with what you're about to embark on when increasing piston area. Mind you, many multi-piston (6+) calipers have smaller pistons so the new piston area may only be "marginally" bigger than standard, its just the barking area is increased via BIG pads - a GOOD thing!

Yep spot on! Pity more people don't follow the same philosophy. Get the handling "sorted" first then do the "go faster" bits later.

Turbo6man is spot on. Deisgned tolerances in an engine only become so when at the designed temp. 1 or 2 minutes warming up is optimal in normal ambient temps. Colder temps, like down south in winter, maybe a a little longer (but not much and only when fully run in). Key is to just run soft and smooth for the first 10K or so as this is when most wear occurs on engine parts.

Forgot to mention - check out Competition Friction in the ACT (AP Racing stockist for Australia). They do big brake upgrades for lots of HP cars, esp HSV etc. I get all my race gear though them and I'd be happy to help out with pickup etc as I know the guys and live in the area. If there are a few people interested I might be able to work out some sort of "package deal". I could probably talk to them about a "kit" (if they don't have one already). Thoughts?

It is a painful process. On my track car I changed from twin piston fronts to 4 pot AP Racing and moved the original 2 pots to the rear (lost my handbrake in the process Doh!). I ensured the piston area ratio between front and rear was maintained but forgot about the extra pistion area I created. As a result I have to push the peadal further. I still stop the same no doubt but the pedal travels further. This would not cause an issue on the street but when doing "heel toe" on the track it sucks as I'm used to a certain "style" and foot position. I now have to put in a bigger master cylinder to compensate and get the "hard feel" back in the pedal - means more force is reqd though - good for "heel toe". My track car has no power assist so it is realtively straight forward. An educated guess tells me a power assist setup with ABS would a different story completely. Maybe someone out there has a better idea than me re setup on XRs?? Also - a larger rotor diameter will have an effect on brake force too and must be taken into account. Bottom line - do an all corner job if you do it.

Yep I've seen many of your previous posts and a LOT of very good info you've provided too. I guess that's why I was a little suprised at your rather short comment, that's all. Although I'm new to the Forum I'm certainly not one of those who just spend big bucks on their cars without a specific reason for a "fit for purpose" plan. So I'm sure that comment was not directed at me To me one of the most important things is good rubber on your paws and I certainly don't skimp. I was probably somewhat inaccurate in my previous statement as the new AVS is now called the Advan Sport V103. Which I've found to be a ripper tyre and still my pick. The previous version, the V102 was good too (50,000 Ks on 2 sets) but I admit they were not quite as good as the factory dunlops. Worth noting that the V103 is OEM on HSV, 911 Carrera 4 and Elfin. Too many Ks? I can't do much about that other than ensure I feel I've got the best rubber on the road. I live 80kms from the city and have no option. Besides, 160kms a day in a brilliant Ford torque monster is just the ducks guts btw - the Advans don't cost me any different than the Dunlops. I agree with your comment re big wheels and crap rubber. Often bigger wheels, esp the sh*tto ones from most retailers, only add to the unsprung weight, causing poorer handling and decreased braking efficiency. I cringe when I see what some people have done to their rolling rubber and the globs of poor casting with 5Kg of lead balancing weights they call wheels!! I feel your pain. I too have often preached about good rubber, handling and braking to many, unfortunately it is lost on those who only seek "the look". I try and practice what I preach. Therefore I have to actually import tyres form the US to ensure I get the "right" compound tyre for a given purpose I.e. track work. Although I can get "close" here in Oz they are not quite the right compound and I'm not willing to comprimise. Costs me more but it satisifies the objective. I think we may have got off on the wrong foot somehow with the original posts. Again, although I'm new to this forum I feel I also have a lot to offer given my background and experience. I look forward to learning as much as I can from this forum as there is sooo much good stuff and would like to share my knowledge too. I hope to always provide an unbiased and informative approach to advice and only expect to receive the same. Cheers

I probably should have qualified my statement a little better I admit. Of the tyres I've used to date I've found the AVS to be the best. I travel a LOT of Ks every year and go through more tyres than most - without doing burnouts/wheelspins and the like. As a result I've also had the opp to try many different brands. The top AVS, the Sport, (there are 3 types of AVS), although a bit harsh on the front shoulders in the old Boss 290, are just great. I don't pussy foot around either and every days sees many Ks of tight twisty driving from -5 winter mornings to 38+ summer arvos. Basically, this was my opinion based solely on my experience. Don't get me wrong the Dunlops are magic and I use their semi-slicks on my track car - they are just awesome. I am somewhat dissapointed that you made a comment like that without substatiating it with a little more info. Although I'm very new to this forum I didn't think it was about slagging off at other posts if they differed from another member's opinion. I thought it was about sharing information with others regardless of ones own personal views. It appears you are a regular contributor to the forum, are well regarded by other members and have a lot of experience to share, so how about sharing that experience and other information in a friendly and professional manner?

Yep the Phillips or the Osram Silverstar. I've used both and the Silverstar are just superb. that's with LOTS of country night driving under my belt! Other than that you'd have to go for a HID kit which is prob around 4K.

Tyres - a classic example of you get what you pay for! Tread pattern and compound is the most important thing to go for with your expected driving conditions. Most "name" brands develop new tread patterns and compounds each year and then sell the "old" moulds to cheapo tyre mobs like Nangbangers (or whatever). Trouble is the other "non name" brands use sh*tty compounds. Bottom line - the "name"brands do the R&D and set the standard, the others just follow with cheap immos. I'm not slagging the cheaper brands, well I spose I am, but after travelling 50,000 Ks a year for the last 6 years in everything from a Pursuit to Subaru to a F6 I can only give this advice: 1. Grip in dry and wet is paramount. 2. Wear is secondary. 3. Yoko AVS Sport are simply the best - factory dunlops come a close second.

As BAturb said - you'll need to balance front and rear. Your master cylinder will also have been designed to provide a certain amount of pressure by volume for the current setup. Coming from a full rebuild on a Lotus race car I can provide the following tips: 1. Master cyl valving/bore will provide a set volume "push" for a given pedal travel. 2. Braking force is directly depenedent cylinder bore/pistion diameter. Bigger pistons will need more brake fluid volume to push them the same distance. 3. More pistons does not necessarily equate to more brake force. 4. Calculate your combined pistion area. If its more than standard your brake pedal will travel further. This is NOT a bad thing it just means you have to push further (but less effort) to compress the brake fluid. Unless of course your master cyl is way below the volume reqd for the new pistion area. 5. Calculate your current front to rear ratio I.e. pistion area front / pistion area rear. Do the same for the new setup and if they are WAY different you'll need a bias valve. E.g. std = 70% / 30% and new = 55% / 45% then you'll need a bias. As an aside, always be careful with doing this on ABS systems. Changing front rear bias could have a dramatic effect. Cheers all - this is my first post so apols for the rambling.