Front Brakes ?

[paulj]

Does anyone know what the front discs are from on my 1994 chimaera ?

I took it around Donnington park on thursday - my first track day, it was an awesome experience!

The only thing the car suffered from was a bit of brake fade after a few laps. I was thinking of getting some cross drilled discs, has anyone done this ? Does it make any difference ?

Cheers
Paul.

[shpub]

Search the archive or look in the bible but be careful as the discs have varied so you will need to measure to make sure they are the same.

Steve
www.tvrbooks.co.uk

[dannyboyo]

Manek (previous owner) had the same when he took my car on a track day. He had the big brake upgrade done and made a difference apparently. The front discs are now (after upgrade) 285mm i think. Not sure what they were to start off with though (maybe 235 or 245?)

[paulj]

Is there a cheap(ish) upgrade, i.e. just fit a bigger set of ford discs, or do you have to go the full AP racing £1000 route ?

[dannyboyo]

Just dug out the old receipt and in Oct '99 it was 572 quid for the big brake upgrade.

Quote "Supply and fit big brake upgrade kit consisting of: 2x285mm cross drilled front brake discs, adapter kit, Tarox pads. Aeroquip front flexi brake pipes"

Done at tower view, give them a bell.

[philr]

I already have some nice Tarox discs on the front of my 5 ltr, but at Donnington recently I experienced strong vibrations through the steering wheel on hard braking. It got worse as the day progressed - scorcher of a day though.
Now the obvious call is that the discs are warped, but I just can't reproduce the effect on the road to test out the theory. I've had the car up to pretty high speeds and braked hard (nice safe part of road etc), but no vibration. I even swapped to my track day wheels in case that was the problem, but still couldn't reproduce.

Either this is only something that happens from serious speed (120+ down to say 50/60 at the craner curves) or it is heat related.

Any body got any ideas ?

I have looked about on the web for possible solutions and the idea of adding additional ventilation direct onto the discs came up. This might reduce the heat issue (if that is the problem).
Any idea how best to achieve this on a Chimaera ?

I know that there is the loverly £1400 brake upgrade kit that TVR will be doing, and it does sound like value for money etc, but I wasn't looking at spending that sort of money really.

Cheers

Phil

[shpub]

What pads are you using?

[philr]

Cheers for the reply Steve.
Presumably I have the standard pads fitted by TVR at a service on the front.
I have fitted Green Stuff pads to the rears -OK I now know people's views on these, but it hasn't been a problem on the rears.

I did have a touch of this same juddering at the end of a track day last year and just put it down to the state the tyres were in after the days fun, also the brakes were not a problem on the road after that.

David Batty completed a service on the car a few days before the track day, but I haven't had a chance to ask him if he changed the pads on the front or not (I think he's on holiday this week). I assume that the pads were not changed and are as fitted by Fernhurst previously.

The discs look to be in good shape (though I haven't used a micrometer etc to test them) with only very minor wear lines showing.

[lateconvert]

I had a front brake upgrade done on my 500 by Castlesport - although a fairly basic upgrade the results are staggering for £320 fitted. I was advised against larger rotors so swapped for Tarox grooved and drilled ones, with Mintex 1144 pads and Goodrich braided hoses. I since done three track days and can thoroughly recommend the upgrade.

[rat]

My car has standard brakes. While these suffered with the heat at Castle Combe last Friday, they were nicely balanced (front/rear). How does changing just the fronts affect this? Presumably stronger at the front - so doesn't this cause the fronts to lock if you're still on the brakes while turning in?

[philr]

I have read (probably in Steve's Bible) that upgrading the front only can cause an inbalance. Not sure if this meant upgrading the complete front set up or just upgrading the discs to something that suffers less from heat problems and fading.
However, I have not noticed an inbalance in the brakes at all. Having said that, I bought the car with the Tarox discs on it, so can't compare to how it was before.
Brake fade hasn't really been a problem even on hot track days. Admittedly I do clear any brake dust from the groves on the discs at least once during a track day. probably overkill

[mojorider]

I have just upgraded to 340mm AP's on the front and left the back as standard, Steve Howard did the work.

The amount of braking power is now mind blowing. I have locked the fronts a few times under very hard braking but they released very easy and the car felt very well balanced and under control.

Steve H feels I should leave the back brakes alone, he feels the balance should be to the front and that I do not want to lock the rear brakes since this will cause major control problems.

I have gone for the most extreem upgrade on brakes but must say it is one area I wanted perfect. I also have Nitrons which help the brakes since there is little or no nose dive under hard braking.

>> Edited by mojorider on Wednesday 25th June 09:57

[GreenV8S]

mojorider said:

I have just upgraded to 340mm AP's on the front and left the back as standard

This is a big enough change to throw the static brake balance way out and can make the car very dangerous. If you're feeling brave, you can try this simple test: set the car up in a corner just short of a four-wheel drift and dab the brakes. Front and rear should get to the point of locking at about the same time, and the car should remain neutral until a wheel locks. Similarly, break very hard in a straight line and confirm the front and rear brakes lock at about the same time. Obviously not something you'd do on public roads, but these tests will show up any major problems in the static and dynamic brake balance. If the balance is out, the fronts locking too soon will mean you lose steering and have reduced braking in an emergency, the rear locking too soon will mean the car tries to spin and you have reduced braking in an emergency.

TVR are in the habbit of putting too much braking on the back for my liking, and increasing the front braking effect by 10-15% will compensate for this and is likely to be improvement. But you've made a much, much bigger change and I very much doubt the balance is right now.

[mojorider]

I will pose the question to Steve Howard one more time just to be sure the balance is correct.

I have not had them long but my feeling is that have improved the braking in a huge way. I will check the size since they are still fitting in the standard 500 style wheels.

[shpub]

If they are the standard size wheels then either:

1. There is a slot in the wheel to accomodate the extra 40mm of brake disc.
2. You don't have standard wheels.
3. The discs are not 340mm and more like 285 or 300 in which case the balance issue is not one.

Steve

[mojorider]

Steve,

I do have the standard wheels and the AP kit is the max you can get for the wheels so it must be the 300's.

So with that in mind you think the balance is ok?