Discussion
They r e no worse than any other car with engine at back and not much weight over front wheels . What ur model has are potentially superb brakes if well maintained .............discs need to be blown or drilled out where holes fill up with dust and clog up and if all pressure hoses are still in good nick[ always used Goodrich myself] look at rebuilding the calipers ................they can be fine .
Mine did exactly that until I had a full geometry check done at Parr. The back was too low and the weight wasn't transferring forward under braking.
It's fine now, but was terrifying beforehand!
I also had new stiffer rear shocks and a 28mm torsion bar fitted which may have something to do with it.
Have you had your geometry checked recently?
Tim
It's fine now, but was terrifying beforehand!
I also had new stiffer rear shocks and a 28mm torsion bar fitted which may have something to do with it.
Have you had your geometry checked recently?
Tim
tim_930 said:
Mine did exactly that until I had a full geometry check done at Parr. The back was too low and the weight wasn't transferring forward under braking.
It's fine now, but was terrifying beforehand!
I also had new stiffer rear shocks and a 28mm torsion bar fitted which may have something to do with it.
Have you had your geometry checked recently?
Tim
Tim I,ve only had the car a couple of months and so far had the gearbox re-built engine out and re-tuned.
So having spent 3k in the first 2 months I,m frightened to tell my other half I need to spend any more money or she might throw me out.Out of interest if you dont mind me asking what did the geo set up cost, And did you change the rear shockers yourself.
Cheers
Steve
Kinda depends where you are coming from brakes wise as to what you feel of 930 brakes, in their day they were top banana supercar brakes, but nowadays even hot hatches sport fooking great 4 pot brembos & huge discs, while somat like a 996T's are retina detaching in comparison & really nowadays in brake tech terms they are nowt special & with many yrs of wear on 'em can be distictly un impressive.
As well as geo set braided lines & new fliud, a caliper refresh & new discs & pads if needed will make 'em feel 100% better.
As well as geo set braided lines & new fliud, a caliper refresh & new discs & pads if needed will make 'em feel 100% better.
[quote=s,one]
Tim I,ve only had the car a couple of months and so far had the gearbox re-built engine out and re-tuned.
So having spent 3k in the first 2 months I,m frightened to tell my other half I need to spend any more money or she might throw me out.Out of interest if you dont mind me asking what did the geo set up cost, And did you change the rear shockers yourself.
Cheers
Steve[/quote]
Steve,
I think the Geo was about £250, but I'm not sure as I had all the work done at the same time. The shocks and torsion bar were the biggest part of the cost, and the whole lot came to circa £1500.
As has been pointed out by Iguana, the brakes are wooden and with very little feeling when compared to modern brakes. They do work though, with a shove!
Tim
tim_930 said:
Mine did exactly that until I had a full geometry check done at Parr. The back was too low and the weight wasn't transferring forward under braking.
It's fine now, but was terrifying beforehand!
I also had new stiffer rear shocks and a 28mm torsion bar fitted which may have something to do with it.
Have you had your geometry checked recently?
Tim
Tim I,ve only had the car a couple of months and so far had the gearbox re-built engine out and re-tuned.
So having spent 3k in the first 2 months I,m frightened to tell my other half I need to spend any more money or she might throw me out.Out of interest if you dont mind me asking what did the geo set up cost, And did you change the rear shockers yourself.
Cheers
Steve[/quote]
Steve,
I think the Geo was about £250, but I'm not sure as I had all the work done at the same time. The shocks and torsion bar were the biggest part of the cost, and the whole lot came to circa £1500.
As has been pointed out by Iguana, the brakes are wooden and with very little feeling when compared to modern brakes. They do work though, with a shove!
Tim
Most folk in the game have forgotten that the 930 chassis was homologated with additional anti-dive built into the front suspension geometry. What this means to you and me is that the front A-frames are lower at the front mount and higher at the back than a standard 911, all of which reduces weight transfer under braking because it stops the front end from diving down due to tyre grip.
What you should really do is learn how to transfer weight onto the front by progressive braking, i.e. press the pedal to start braking, then progressively apply more as the grip level and weight transfer increases, until the front end is burried. It does work, I have tried it, but it is something that you will have to practise in order for it to become a habit, just like trail braking into a bend. Ultimately though even this may not be enough.
Upgrading the brakes does not help lock up, although do not forget that you may be running on 10 year old tyres, but do make sure that everything is perfect to start with, and if in dount replace the flexible brake pipes because they are prone to swelling with age. But what if you have done all that and you are still not happy?
One easy option is to reduce the level of A-D by lifting up the front A-frame mount. With the car safely up on stands, if you unbolt the front mount cover you will see that the outer sleeve of the mounting has lugs welded onto the top side. All you do is to turn the mounting through 180 degrees and remount it with the lugs pointing down, recheck the geometry and try it. One of my respected 930 customers who is also a Porsche Club track day instructor has had his G50 930 fitted with stiffer bilsteins & torsion bars, 993 calipers on the front & the fronts calipers fitted to the rear, but he swears that this mod did the business even when running on Pirelli P Zero C tyres.
(9m.....ex 930 Motorsport for a reason!)
What you should really do is learn how to transfer weight onto the front by progressive braking, i.e. press the pedal to start braking, then progressively apply more as the grip level and weight transfer increases, until the front end is burried. It does work, I have tried it, but it is something that you will have to practise in order for it to become a habit, just like trail braking into a bend. Ultimately though even this may not be enough.
Upgrading the brakes does not help lock up, although do not forget that you may be running on 10 year old tyres, but do make sure that everything is perfect to start with, and if in dount replace the flexible brake pipes because they are prone to swelling with age. But what if you have done all that and you are still not happy?
One easy option is to reduce the level of A-D by lifting up the front A-frame mount. With the car safely up on stands, if you unbolt the front mount cover you will see that the outer sleeve of the mounting has lugs welded onto the top side. All you do is to turn the mounting through 180 degrees and remount it with the lugs pointing down, recheck the geometry and try it. One of my respected 930 customers who is also a Porsche Club track day instructor has had his G50 930 fitted with stiffer bilsteins & torsion bars, 993 calipers on the front & the fronts calipers fitted to the rear, but he swears that this mod did the business even when running on Pirelli P Zero C tyres.
(9m.....ex 930 Motorsport for a reason!)
If you're able to lock the front wheels then the brakes are clearly powerful enough to overcome the available grip of the frony tyres.Pulling to one side isn't good - check if the calipers are seized.
As above, being light at the front reduces the force onthe front tyres, ie the available grip so " they all do that, sir".
Tyres with better grip can help - what are you running at present?
The reason for asking about modified suspension is that stiffer front will reduce dive under braking and the forward weight shift helps with front grip.
As above raising the rear slightly relative to the front also helps for the same reason.
It's worth remembering it's an old car and the brakes are stone age comparatively speaking.
As above, being light at the front reduces the force onthe front tyres, ie the available grip so " they all do that, sir".
Tyres with better grip can help - what are you running at present?
The reason for asking about modified suspension is that stiffer front will reduce dive under braking and the forward weight shift helps with front grip.
As above raising the rear slightly relative to the front also helps for the same reason.
It's worth remembering it's an old car and the brakes are stone age comparatively speaking.
Thanks ninemeister,certainly food for thought.Tyres are virtually new so that shouldn,t be part of the problem,car does feel a little uneasy at high speed (over 120) on the front end,although I am told this is a trait.I will adjust my driving initially and see what effect if any this has.
Thanks
Steve
Thanks
Steve
ninemeister,
Does fitting 993 calipers on the front and moving the original front calipers to the rear significantly improve braking feedback? I have been toying with doing this since seeing the brackets for sale on your website.
I am wary of my car's brakes at the moment, mostly due to lack of feel.
Tim
Does fitting 993 calipers on the front and moving the original front calipers to the rear significantly improve braking feedback? I have been toying with doing this since seeing the brackets for sale on your website.
I am wary of my car's brakes at the moment, mostly due to lack of feel.
Tim
ninemeister said:
What you should really do is learn how to transfer weight onto the front by progressive braking, i.e. press the pedal to start braking, then progressively apply more as the grip level and weight transfer increases, until the front end is burried.
Do this. Forget upgrading the brakes.
tim_930 said:
ninemeister,
Does fitting 993 calipers on the front and moving the original front calipers to the rear significantly improve braking feedback?
Tim
The 993 front conversion is definitely a brain out decision, improves feel and modulation as well as increasing braking effort (modulation is the ease of control of pad grip in response to foot pressure).
Fitting the front caliper piston blocks on the rear increases rear braking effort and hence pad bite, so again since no parts are required for the job, it makes sense to do it at the same time.
My only other recommendations are the usual braided hoses, Castrol SRF, o.e. Porsche discs & decent pads.
ninemeister said:
The 993 front conversion is definitely a brain out decision, improves feel and modulation as well as increasing braking effort (modulation is the ease of control of pad grip in response to foot pressure).
Fitting the front caliper piston blocks on the rear increases rear braking effort and hence pad bite, so again since no parts are required for the job, it makes sense to do it at the same time.
My only other recommendations are the usual braided hoses, Castrol SRF, o.e. Porsche discs & decent pads.
looks like I'll be ordering some brackets off you then! Does the front to back bias change at all? I know with some brake conversions the proportioning valve needs to be removed.
Anyone have a good source for good used 993 front calipers? Also what pads are recommended?
Tim
Leave the rear brake pressure limiting valve in the system.
For road and light track use use o.e. Porsche pads. For harder track use try Pagid Blue, but if you are mad and run with sticky tyres you need Porterfield or Pagid Yellow.
.....of course we also stock everything if you need it.
>> Edited by ninemeister on Friday 21st January 12:38
For road and light track use use o.e. Porsche pads. For harder track use try Pagid Blue, but if you are mad and run with sticky tyres you need Porterfield or Pagid Yellow.
.....of course we also stock everything if you need it.
>> Edited by ninemeister on Friday 21st January 12:38
Right had the Geo checked, car is spot on no need for any adjustment.Gotta say a full report (4-5 pages)telling me everything I could possibly need to know about the setup for no charge, very unusal when drving a performance car.Anyway conclusion is steady up my braking and dont drive it in the wet.
cheers
Steve
cheers
Steve
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