Jump to content
SAU Community

Recommended Posts

Rowdy.

Generally, I've been advised, to get good braking across front and rear, to run a higher temp set of pads in the front, then in the rear.

And also, if you really want to, run solid rotors in the rear, and run slotted and ventilated rotors in the front.

Generally brings the rear pads efficiency up a little bit more compared to the fronts.

But, the true way to adjust brake balance, is by adjusting either caliper sizes, or getting a brake bias adjuster.

The brake balance front to rear won't change how much the front of the car dives, that is caused by the total braking force not the front/rear split, and the front alignment and suspension.

All you need for brake balance is both front and rear tyres getting to lock up at exactly the same time. its that easy lol

If you want an effect where the tail is looser under brakes you should start with toe out in the rear. Softer front springs, rear brake bias and 2 way diffs are all just ways to bastardise your rear end handling to make it lock up....just does not make sense for that purpose.

Certainly in some cars like light fwd you might want the tail to swing mid corner but not in a big rwd, you are better of keeping it tidy, late brake and apex and then on the gas hard.

Yes the semis are worth 3-5 seconds depending on the track, and also they will last much better than road tyres on the track too - with roadies you always want to push them to hard so you end up chewing them to peices, especially on the outside edges.

If you want cheap semis look outside the bridgestone and dunlops, maybe try falkens, toyos etc, they are about half the price. Also stick to smaller rims 16 or 17 they get much more expensive in larger sizes

I believe I don't have enough rear brake bias. After a whole day at the track there was hardly any rear pad dust and I'm only running el cheapo pads. I think it is time for a big bleed first. I put the abs back in and bled it but maybe in needs some more bleeding.

What you are saying makes sense. It could help stop a little of the weight transfer to the front and there for take some weight of the front tyres. Good idea. I have never had a problem with the rears locking.

One of the really quick Vic guys drives his car fast by braking a little later into the apex to unsettle the rear of the car so he can drive out fast without power understeer. And he is fast!

There is no way of putting more rear bias into a gtr though unless you change the master cylinder right? Anyway I won't be doing this. Hopefully some good pads will sort this area out.

Keep your suggestion and opinions coming in. All of your tried knowledge is better than my theory's atm.

What is the general time increase with running semi's over average street tyres? Am I right in guessing 2-3 secinds a lap on a 1.30ish circuit?

You need to differentiate the cars handling characteristics during the three (four if you want to be pedantic) sections of a corner.

1. Braking prior to the corner.

2. Turn in.

3. Mid corner.

4. Power down/corner exit.

If you trail brake during turn in you will reduce your understeer markedly. This is not a function of brake distribution (front/rear) as the pedal effort used is quite small. In an understeering biased car (read GT-R) it may have the effect of reducing your speed during part 3 (ie mid corner) of the turn. Done properly it will reduce the time spent at low TPS & hence allow the important bit, ie power down to happen earlier. You can then carry more speed down the following straight which is important as it has more of an effect on your lap time than apex speed.

You use trail braking to transfer weight onto the front tyres & hence allow them to develop more grip. You shouldn't be trying to unsettle the rear as this will simply lose you time.

In any case mucking about with brakes, toe settings & small adjustments in camber will not solve a fundamental issue with the ride height & rake angle. You need to sort this first as some settings can markedly change the behaviour of the car in the different parts of the corner.

Snowy I forgot we have one at work. One of the guys dragged it out today when we were in testcell. I'll bring it along to the next track day. It would be really interesting to see the difference between all the cars and the speeds they're doing.

You need to be carefull when using laser pyrometers, they measure the skin temperature (ie; the tread surface). This is affected by stuff like the run down pit lane. For example, if you have lots of negative camber, the skin on the inside of the tyre will stay hot while the skin on the outside will cool down rather rapidly. That's why race teams use probe style pyrometers which enable us to read the temperature just below the skin, which doesn't cool down as quickly.

Regardless of which type of pyrometer you use, make sure that you don't slow down on the in lap if you want representative temperatures. Come it hot, then measure and then go out for a cool down lap.

:D Cheers :D

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • just an update to this, poor man pays twice  Tried sanding down the pulleys but it didnt do the trick. Chucked another second hand alternator in the na car which I got for free off my mate and its fixed the squelling. Must have been unlucky with the bearings.    As for my turbo car, I managed to pick up a cwc rb alternator conversion bracket + LS alternator for 250 off marketplace, looked to be in really good nick. Installed it , started the car and its not charging the battery.... ( Im not good with auto elec stuff so im not sure if this was all I needed to do but I verified such by using a multimeter on the battery when the engine was running and I was only getting 12.2v )   I had to modify the earth strap for the new LS alternator , factory earth strap was a 10mm bolt which did not fit the bolt on the LS alternator which was double the size so I cut it off , went to repco bought some ring terminals that fit, crimped it onto the old earth strap and bolted it up to the alternator , started the car and same issue. Ran like shit and was reading 12.2 at the battery.  For a "plug and play" advertised kit thats not very plug and play but alas.  My question is , am I missing something ? Ive been reading that some people recommend upgrading the stock 80 amp alternator fuse to a 140 amp but I dont see how that would stop the alternator charging especially at idle not under load.  Regardless ive pulled it out and am going to get it bench tested by an auto elec tomorrow but it would be handy to know if ive missed something silly or have done something wrong.   
    • My wild guess is that you have popped off an intake pipe....check all of the hoses between the turbo and the throttle for splits or loose clamps.
    • Awesome, thanks for sharing!
    • To provide more specific help, more information is needed. What Android screen? What is its wiring diagram? Does the car's wiring have power at any required BAT and ACC wires, and is the loom's earth good?
    • So, now all you need to do is connect the 2 or 3x 12v feeds into the unit to permanent 12v, ACC 12V and IGN 12V that you can find in the spot behind the stereo, and the earth, and then it will switch on with the car.
×
×
  • Create New...