My A3 Quattro

Prawn said:
Great stuff Alex, I was gutted to miss another Curby day!

From the clips I've seen the engine sounds great! Are you pleased with your choice of 3076?
Click to expand...
It would have been great to see you again, but I know what it's like when children arrive. Hopefully see you soon.
Very happy with the turbo so far. Once I've sorted out the tyres and brakes, I'll see if I need to adjust the torque profile.

antwan64og said:
is that lift off oversteer or did you add the quattro rear end and not mention it?

I'm dozey, I just realised you are Mr DTA
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Lift off oversteer/pushing it in hard to see what would happen. It had been really well behaved all day, and is really progressive on the edge, so I wanted to see what would happen if I pushed it a bit too hard.
It's still FWD for now.

I am indeed. :)
 
ABS unit is now out, and temporary pipework made up to test the brakes with no bias valve. If it's required, I can easily add it in, and then make the final pipes up.

However, I can't bleed the front calipers. Fluid won't come out the bleed nipples.
If I remove the brake hose on the caliper, fluid pours out as expected.
All 4 bleed nipples are the same, so I must be missing something. These are the Seat Sport AP Racing 4 pot calipers.
Are there any tricks to bleeding these?
 
Technically the same caliper as I use (AP CP6600) but lug mounted rather than radial mounted...

Not had an issue with bleeding mine... you bleed inboard first then outboard... fluid should come out of the nipples so maybe they are blocked or something

<tuffty/>
 
Thanks Paul. I'll pull the nipples off (sounds painful....) and see.
It's just odd that all 4 are behaving the same.
 
sparrow said:
ABS unit is now out, and temporary pipework made up to test the brakes with no bias valve. If it's required, I can easily add it in, and then make the final pipes up.

However, I can't bleed the front calipers. Fluid won't come out the bleed nipples.
If I remove the brake hose on the caliper, fluid pours out as expected.
All 4 bleed nipples are the same, so I must be missing something. These are the Seat Sport AP Racing 4 pot calipers.
Are there any tricks to bleeding these?
Click to expand...

blocked/corroded holes?
(or actually not drilled at all, had that on new audi rear caliper on my s8 years ago.. took me a while to figure it out..)
 
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Not sure. I took all of them out, blasted through with brake cleaner, and refitted.
One now bleeds fine, the other three are better, but not great. I've bled them by removing them totally, and refitting while the Easibleed is still on.
Will test at some point.
 
Brakes bled, left overnight to check for leaks, none found. Hooray.
One of the plates on the driveshaft took a knock, so I've order a couple of spares from the Skoda place opposite. £1.03 inc. VAT.
They'll be here on Monday, then I can test the brakes.
 
Brakes are working, although only tested across the workshop. :)
I now need to book on to something for a proper test.
 
Time for an MOT surely? Even if only for testing purposes.

I can't see how developing a non road legal car can ever be satisfying or financially viable when it costs a fortune each time to find out IF the latest round of changes have worked at all.
 
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I'd have to fit a horn, then tax and insure it, assuming it even passed. Not sure that would be much of a saving.
That's at least three cheapish track days a year, which will be enough.
 
I went to Donington on Sunday. I had a mixed day, but I'm please I went.

The front brakes still don't work properly, so I was having to leave loads of braking room.
The rear of the car was very loose, but it got better during the day with suspension changes.

I got black flagged for noise (103.2dB), broke 3 of yoofs small drill bits trying to drill holes to lock wire the extra silencer on, got a puncture (no spare wheel, so had to take the spare tyre to the nearest KwikFit), spun on the sighting laps (although that was because I wanted to find out how bad the brakes were - turns out very bad), spun trying to move over to let someone past (due to the tyre already deflating) and spun again when I tried to push the brakes too hard, and ended in the gravel trap.

However, I figured out how to adjust the damping on the suspension, so went full hard on the front, and full soft on the rear which helped, and then disconnected the rear ARB when changing the wheel with the puncture. Each change made the car better.

I'll now pull the calipers off and get them refurbed, and also get a big centre silencer fitted.
I also need some new tyres, as these are all starting to resemble 50p pieces after all the spinning.

Some pictures:
XSP_8183.JPG

XSP_8214.JPG
 
Alex, am I allowed to be abrupt in a way that'll help you in the long run?
 
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Don't spend a penny more on those front brakes you have.

Sell them on, they'll fetch good money, and they will do someone very well on a lesser car, but they're not for you.

If there's one thing I know well on this platform it's brakes. I've owned most setups you'll ever see used, and those I havnt personally owned, I've fitted, used, and problem solved for others.

The seat sport lug mount calipers on a 312x25mm disc just are not up to the job on a car of your spec.

On a 300bhp road car with some decent pads and road tyres they'd be plenty adequate. But on a car like yours, which will be driven the way I know you will, you will only ever be disappointed with them.

Pads with a huge CoF can generate the stopping force, but with a small rotor and high CoF modulation becomes very difficult. You're either not slowing enough, or you're locking up. Then after a short stint you'll find the discs reach their full capacity for heat, and power will soon start to fade.

Also, even when you are able to generate enough stopping power through a small disc, the elevated temperatures they run at give hugely accelerated pad wear. Ive still experienced this on my 330s running a lightweight rotor which didn't have enough to heat capacity due to its lightweight construction.

In the last I've used a set of brand new pads in a single day on track, without having until a single fade issue, just a setup that runs SUPER hot and breaks down the resins in the pads.

Ultimately, for race use, given the weight of the car, and the tyres you'll likely be running, it's a case of the bigger the better in terms of disc and pad size, so long as you keep the hydraulic balance correct, which requires a caliper with around 2500mm^2 piston area as a start point.
 
Thanks for the feedback.
I will still refurb the calipers, I can't sell them if they're not working properly.

One thing to remember, is this is a sprint/hillclimb car. Track days/circuit racing are not the main aim.
Runs will be short, either a single lap of a circuit, or up hills like Shelsley Walsh/Prescott. Going too big on the brakes will add weight, and also may take too long to get up to operating temperature.

With that in mind, any recommendations?
 
Even with the short duration use, high CoF pads and small rotors are still so prone to being grabby, especially now you've lost your ABS.

Given you're not looking for massive heat capacity I think a 323 or 330 x 28mm 4 pot setup would give ample power.

On the cheapest end of the spectrum is the LCR brembo caliper. 36 and 40mm pistons. A 323mm disc, and some decent pad options and 330mm 2 piece disc options from Bill if weight saving is a concern.

Going slightly better on the calipers would be 996 c2/c4 calipers on a 330 disc. Either alfa brera discs refried, or the same 2 piece 330s mentioned above from Bill. Both run the same disc offset.

Pad wise, whatever you run your want to be looking at a pad with a very flat line on the CoF graph. Ds1.11 happen to be incredible from cold and hold their CoF across a very wide temperature range, although igh there are several other pads that would also be suitable.
 
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Thanks Nick. I'll measure up what I have, and go from there.

I'm a fan of Carbon Lorraine pads, I've used them on the Golf before.
 
LCR Brembos 323mm fit under most 17's, do 330's?

I can see some brake kits advertise the 330mm brake kits as 17" friendly but they use different calipers.
It might be a consideration if you have stockpiled 17" tyres
 
sparrow said:
Good point. I don't know if 330mm Brembos fit under 17s, which I do have some of.
Click to expand...
Yep... I have used my 17" Avus with my AP CP6600 (essentially the same caliper as your Seat Sport ones but radial mount) on 330mm 2-piece rotors...

<tuffty/>
 
Thanks Paul, but it looks like I need to move these on and get bigger discs and calipers. I do need to check whatever I get is going to fit under 17s.
 
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Is that a 330 or 335 @<tuffty/>?

I've run 335s on my AP calipers under all my 17s with no issues at all.

Alex, depending on your time frame, my AP setup may well be available this winter. AP cp5200s, performance friction discs, B5 floating bells. Just a thought...
 
Prawn said:
Is that a 330 or 335 @<tuffty/>?

I've run 335s on my AP calipers under all my 17s with no issues at all.

Alex, depending on your time frame, my AP setup may well be available this winter. AP cp5200s, performance friction discs, B5 floating bells. Just a thought...
Click to expand...
330mm at the time... the 335's I am running atm might be a tad closer but not tried them yet

<tuffty/>
 
Prawn said:
Is that a 330 or 335 @<tuffty/>?

I've run 335s on my AP calipers under all my 17s with no issues at all.

Alex, depending on your time frame, my AP setup may well be available this winter. AP cp5200s, performance friction discs, B5 floating bells. Just a thought...
Click to expand...
I'd almost certainly have them, so let me know what you want for them.
 
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Brackets came from Stuart Mutch at FreakyParts Alex. I had the brackets designed around LCR /Alfa Beers disc offset, this means in you can drop on a solid alfa disc if needed, or even machine 3.5mm off the bracket and use an LCR 323mm disc.

It also means the floating bells are made from a flat machined 8mm piece of Ali, so cost less than bells which have a change of offset.

Cp5200 has recently been superceded by Cp9200:

https://www.apracing.com/product_de.../cp9200-forged_front-152mm_mounting_ctrs.aspx

It's hydraulically and geometrically identical to the Cp5200, using the same mounting bracket and pad shape, they've just added a few more radii to the design to modernise it ever so slightly :)

https://www.apracing.com/product_de...-152mm_mounting_centres-16.8mm_thick_pad.aspx

I'd like to say mine will be available soon. If I could find a spare set of 18" wheels to get me rolling they'd be available even sooner! If anyone reading wants to see some decent brakes on alexs car and has some spare 18s kicking around, let me know!
 
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Thanks Nick

I have 2 sets of 18" wheels, so we can make a plan if you'd like? One brand new still in the box set of Team Dynamics 1.2, and a used set of OZ Super Ts.
 
This arrived today:
Brakes2.jpg


Which contained these:
Brakes1.jpg


Thanks @Prawn

These will be going on instead of the Seat Leaon APs. Bigger and better, and known to be working.

I'll get them on the car this week, and see if that fixes the brake problems.
 
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I'm loving the Lambrini, I remember when 2 litres of strongbow was 99pence
 
sparrow said:
This arrived today:
Brakes2.jpg


Which contained these:
Brakes1.jpg


Thanks @Prawn

These will be going on instead of the Seat Leaon APs. Bigger and better, and known to be working.

I'll get them on the car this week, and see if that fixes the brake problems.
Click to expand...

Excellent news Alex! I hope you'e
very happy with them. They've been absolutely fantastic for me. I think they will suit you down to the ground :racer:


Stuart B said:
I'm loving the Lambrini, I remember when 2 litres of strongbow was 99pence
Click to expand...

Only the finest goods available at my local UPS drop off point :laugh:
 
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Oh Hell, I remember beer at 10p a pint, fags 5p for ten and petrol at 2s 6p a gallon. Can anyone beat that. ???:sign omg: AND only two tv channels.
 
audi upgrades
bigal 1 said:
Oh Hell, I remember beer at 10p a pint, fags 5p for ten and petrol at 2s 6p a gallon. Can anyone beat that. ???:sign omg: AND only two tv channels.
Click to expand...


Can we try and keep thread derailment to our own thread please Dad :laugh:
 
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I fitted these just before Christmas, but was still unable to get a pedal. This could only mean the master cylinder had failed.
I ordered a new one, and it lay there for 4 weeks.
I gave up trying to make time and took it down to Stealth Racing, along with the brake bias valve. They fitted that, then found the brake servo had been changed at some point in the car's past, so the MC didn't fit. They tracked down the correct one, so I now have working brakes. Yay.

Next up, the car is going to have the alignment and corner weighting done, and then I need to fit a new silencer as the car was 108dB on drive by at Donington. I'm going to try to fit in a test day in the next couple of weeks.
 
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I wasn't happy with how the car had handled on any of the outings so far, it just felt horrible. Turning in was an exercise in "guess how much oversteer will happen this time", I just couldn't get any confidence in the car.

I decided to take it to a local company called Spires Tuning, which is run by ex-JLR suspension designers, so they know a thing or two.
I arranged to drop the car of with Matt yesterday after work. He put it on the ramp, and looked at a few things, and made some comments.
Matt: "Front rebound is way too high, that will be source of the understeer".
Me "Er, it oversteers. A LOT"
Matt: "That's not possible, it should be understeering massively."
Me: "It feels like it's on ice. I'm sure the springs are too hard."
Matt: "What are they"
Me: "Can't remember, what KW specced. Hard though, around 800lb front, and something less on the rear"
Matt: "That sounds too hard, let's check"

So we checked the springs.
The fronts are 140/140 (so 140Nmm (800lbs)/140mm long).
The rears are 80/180 (so 80Nmm (500lbs)/180mm long).

Or not. I have the values the wrong way around. The rears are actually 80mm long, and 180Nmm, so over 1000lb rear springs!! What on earth KW used to calculate that I have no idea. I can only assume they missed the bit about removing the Haldex, but even then they are too hard.
That would explain why the rear of the car just skated everywhere.

Matt's working out all the ratios and weights, and I'll get some new springs. He'll then also set the camber, caster and toe (front and rear) to something where the car should be neutral.
No rear ARB for now either.

He will also be sorting out a new rear silencer, and is confident we can get under any track day limit with just a bigger silencer.

He's hoping to get it back to me by the end of the week, but it depends on lead times for springs and the back box.
 
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