My Audi TT front suspension.

[Golf_GTDI]

Well, here are the first pics. Jon was kind enough to not even open the boxes that Petr (VW4motion) sent me from Prague so it was like Xmas come early yesterday. In the boxes were the Audi LCAs, Spindles with front binders as well as an 11mm pump. Can you say yummy boys and girls? Knew ya could!

Here are the parts...

Here are the front spindles with brakes. I asked for VR6 brakes but these things are just monsters. 312mm if I had to guess which means I may (may) be able to get away with 16" wheels but 17s may be a better idea due to better choice of wheels and tires in that size at fiar price points. Then again I may just ditch them and stay with the VR6 setup. Stay tuned to find out.

Here are my Audi TT/R32 LCAs. As you can see they are very different than what comes stock. We did not weight them to this point but I do think they weigh a bit more. They are however adjustable and can give a bit more negative camber in addition to what the TT spindles do by design.

This is some detail of the LCAs. Right now I am unsure if these are the same as what we get here in the states but I am somewhat hopeful that these are the now outlawed old school Euro LCAs that are now highly sought after by the TT guys. I need to do a bit of digging on this subject.

I was also happy to see that my LCAs have the area that can be easily drilled for a front sway bar. I am however pondering going with the TT front PSS9 kit with an Audi TT front sway. This mounts on the inside of the shock body and not on the LCA itself. Once again stay tuned and or feel free to kick in your thoughts on this.

This is the 11mm pump that will be feeding my TDI with all of its other newer go faster goodies. Its due to all of this that makes me feel the need to turn better and stop faster. My aim is to build a very quick and well balanced car that does most things rahter well with as few as possible shortcomings.

Its my plan to update this thread with updates in regard to the install and choices in setup. Feel free to ask questions or leave feedback in hopes of making this a bit of a resource for this sort of upgrade.

 

[gern_blanston]

Probably won't stop any faster. Might be able to stop fast a couple more times in a row, though, and they do look kinda' cool.
2 words for ya': Unsprung Weight.

 

[oldpoopie]

You'll need TT ball joints too.

 

[jnecr]

Probably won't stop any faster. Might be able to stop fast a couple more times in a row, though, and they do look kinda' cool.
2 words for ya': Unsprung Weight.

they'll help him stop faster from high speeds. The stock 280mm brakes are good for three or four hard braking instances then fade after that.

 

[jnecr]

Let us speak theoretically here:

Let's suppose we have two seperate turning masses with a good bit of rotational inertia but they aren't rotating very quickly. Let's suppose we have identical braking systems on these turning masses except one has a larger rotor than the other. These systems will be of typical automotive type, both have the same calipers and same pedal setup (remind you of anything? 288mm and 312mm setups use the same caliper is what I'm getting at, TDIs use an even inferior caliper).

Now let's apply the same amount of force to the pedal of each system. Which one will stop first? Well, the one with the larger rotor of course. It won't be a great difference, but it will be there.

Now let's speed up the rotating masses, apply the brakes, the difference will become greater the faster we go. This is because we are applying a force further from the center and can apply more torque to the larger rotor. This is despite the fact that we are applying the same amount of force to the pedal.

I know, I know... you're going to say that the reason we can't stop faster is because of our tires. Yes, this is true at speeds where you can apply enough force to lock up the wheels. So it's probably true up until around 70-80MPH. At speeds above that I doubt that our cars are completely traction limited. At that point our braking systems are the reason we can't stop in a shorter distance. Is it really needed? Not a chance in hell.

So why do race teams use larger rotors? It's a combination of trying to brake a 2500# vehicle from 190MPH and fade resistance. Could they make a 10" rotor last an entire race? I'm completely sure of it, F1 teams use a smaller rotor than that because they are forced to (and also don't have a 2500# vehicle). Do they wish they could run a larger rotor? Hell yes!!


One final thing, which one looks cooler, I mean really!!!

or

 

[MileageDude]

Let us speak theoretically here:

Read the Thread

F1 teams use a smaller rotor than that because they are forced to (and also don't have a 2500# vehicle). Do they wish they could run a larger rotor? Hell yes!!

F1 Technology on Brakes
Formula 1 brakes require air at the cost of upsetting the airflow around the car and creating drag. Inside and slightly ahead of each hub/wheel assembly, are the brakes cooling ducts. These ducts are necessary to force cool air over the brake discs. The brake duct actually contains a large fan, that rotates around the wheel's axis (upright) and at its same speed. This causes the fan to rotate very quickly at high speeds, and thus sucking air onto the brakes, where without a brake duct, the air is pushed onto it, just guiding the air to the brake. This brake duct allows the air inlet to be way smaller than it used to be, which generated a considerable aerodynamic advantage.
The most important elements of a brake system are the brake pads and disc, rotating at the same speed of the wheel. Today, these are made from carbon but this is not the same carbon used in the chassis, but a pure carbon that's very expensive to produce. It's done by a process called chemical vapour deposition. A matrix is made and put it into an oven rich in a hydrocarbon gas. Gradually pure carbon is deposited onto the matrix to make brake discs and pads - but the process takes 150 days. The resulting components weigh very little and can withstand very high temperatures. Indeed, they only work above 200-300C, which is why they'll never replace steel brake discs in roadcars.

 

[gern_blanston]

I know, I know... you're going to say that the reason we can't stop faster is because of our tires. Yes, this is true at speeds where you can apply enough force to lock up the wheels. So it's probably true up until around 70-80MPH. At speeds above that I doubt that our cars are completely traction limited. At that point our braking systems are the reason we can't stop in a shorter distance.

To oversimplify, if the brake system'll run up against the anti-skid threshold or lock the wheels, the tires are the limit. Our cars will hit the anti-skid at just about any speed if you jam on the brakes. Just finished a class today on carbon brakes, brake-energy limits, etc. Our cars are sorta' like airplanes in that they use the smallest, lightest brakes that'll do the job.
For our cars, larger brakes hurt acceleration, since there's more rotating mass to spin up. They hurt handling, as well. They typically WILL allow more stopping in a given time period, but there's no really good reason why they would, in a well-balanced system (which our anti-skid provides), shorten stopping distance until they got hot, which, granted, they probably would after one or two stops from 165 km/h. If you're gonna' go out and race on a road course, our TDI brakes are a joke. For daily driving, the small size and light weight save cost and fuel.
Go to an autocross or dragstrip day sometime and see what the winning cars are wearing for wheels and brakes. You won't see many 18" wheels or monster brakes.

 

[jnecr]

Indeed, they only work above 200-300C, which is why they'll never replace steel brake discs in roadcars.

Ha! what a joke, try 1200-1300 C!

Let's not steal Golf_GTDI's post here... this has been discussed at length many times on other threads.

 

[gern_blanston]

[/size][/i]
Ha! what a joke, try 1200-1300 C!

No joke. They do get very very hot under continuous use, but they start getting grippy at 200-300C.

 

[Golf_GTDI]

These are some of the reasons why I was in part only going to go with the VR6 brakes. They weigh less and let me run 15"s in the winter. The cool factor is nice but its not at all what I'm all about.

 

[SilverD]

Supposedly those big brakes will work with some 16" wheels but not others. One nice thing about big brakes other than stopping distances is that the rotors might last longer without warping. I'm still using the stock system at 67,000 miles, but I'm on the third set of rotors on my '02. The OEM rotors warped at about 30K, then the Ate Powerslots I installed went another 30K. Now I've got Brembos and unless they last longer I'll be looking into big brakes just to get some rotors that will last as long as the pads. IMO VW really cheaped out on the OEM TDI rotors, which is why I read all these big brake threads!

 

[MileageDude]

These are some of the reasons..

Funny part about this story ...your choice of upgrades were in line with the car. If you have issues over the size of the front brakes ...the rotors and calipers can be sold in a blink over on Tex.

Don't sweat it.

Make sure you paint up those parts. Here's a thread on those TT-Parts... but I figured you were already reading this by now.

How are your rear brakes? Have you upgraded them yet?

Good Luck to you,
You're heading down the right track.

 

[MileageDude]

..last longer without warping. ... which is why I read all these big brake threads!

Good Article on wraped rotors if you're interested. Made a great deal of sense.

M.D.

 

[hsus2k]

GOLF_GTDI,

Just curious how much you had paid for those TT LCAs? Impex have them on sale at $75ea. brand new. That's cheaper than the stock TDI LCAs they are selling.
I didn't know they are adjustable (camber adjustment). Great! Now, I'll have to decied if I'm going with the 1.8T/VR6 set-up (from H2Sports, with lowered spindels, corrected camber). May be just look for a 1.8T/VR6 or TT spindels to cut the cost? Also think that the H2Sport Spindels are a bit heavier than OEMs?
But still want to upgrade my brakes. Looking at the Wilwood's (had them before on my Hondas, really like them; super light weight!) But most brake upgrade kit are for the 1.8T/VR6 spindels, can't find anything fit the regular TDI or 2.0 spindels???

MileageDude,
Why do we need to upgrade the rears? Most braking are done to the front.
Specially our cars are front end heavy; when braking, the weight shifts forward on most cars. I don't think you want to lock up the rear brakes? Have you tried to lock up the rear brake on a motorcycle? But then, I wouldn't want to lock up just the front either. he, he...done that too, also in a front wheel Honda; almost flipped the car! Well, at least felt that way, I knew my rear tires were off the ground! And my butt was off the seat, the seat belt held me back (may be I was going a tad too fast?)
May be just increase the Dia. of rotor a bit and slotted for cooling (add bracket for the caliper), and use a better pads shouldn't that be enough? I saw some large (12") rotors with Alum. hub (to cut weight) on the net somewhere?

 

[MileageDude]

MileageDude,
Why do we need to upgrade the rears?

If I'm not mistaken it's probably not necessary to upgrade the rears. I just thought if Golf_GTDI wanted to start searching for 10.1" x .79" vented rears from the 337/20th Anniversary/R32 ...he could find a few being sold over at TEX. The rear solid rotors sized 232mm x 9mm (9.1" x .35") are OEM throughout 4 models TDi/1.8T/2.0/VR6.

M.D.

 

[hsus2k]

Yeah, vented rotor are always nice (to cool)
Wow, didn't know they were all only 9.1".

So, if we are changing 9.1" to the 10.1". Are the Wheel hub different? The location of the caliper mount is got to be different because of the Dia.
And the Caliper must be differnt too? Since the thickness of the rotor is much thicker with vented rotor.
What about the handbrake cable? Are they interchangable as well?

Thanks for the info. 9.1" will LOOK too small inded, unless you're running with 12"-14" wheels. he, he................

 

[KROUT]

So whats the advantage to tt front end other than larger brakes.

 

[MileageDude]

So whats the advantage to tt front end other than larger brakes.

"read" -Huge advantages, especially in lowered suspensions. Some other info too.

M.D.

 

[oldpoopie]

The tt suspension, Specifically the lower controll arms and bearing housings, set the car up to have a lower roll center than the vw ones. Basically the a-arms wind up being closer to paralell to the ground.

 

[oldpoopie]

Of course if you really want to make the upgrade, you can do the kit from h2sport. They are even better than the TT units.
http://www.h2sport.com/products.php?productid=296

 

[KROUT]

See this is why I love this web site.

 

[peter pyce]

The H2Sport are not better if you decide to stay OE ride height. They are designed for lowered cars and will give bump steer on lifted cars. For OE ride height the TT spindle is better option. Also, careful with these things as the stock 15" and some 16" wheels will not fit anymore (specifically on the H2Sport spindle).

 

[david_594]

Peter... What is it that doesnt fit with the stock 15" rims? I know with the Audi setup that the brakes wont clear, but would it be possible to use the TT spindles and LCA with the VW vr6/18t brakes? In that case the brakes will clear and its only a matter of the lower control arm sitting to low?

 

[peter pyce]

I do not follow much those things but once in a while there is someone who complains about spindles and small wheels..... just got this link for you:

http://forums.vwvortex.com/zerothread?id=2280200

You can do some more search in there and see if you can find some more info, but on top of my head remember that these things did not work with 15" OE wheels.

 

[nicklockard]

One final thing, which one looks cooler, I mean really!!!

or

My stock alloy's look better. Really. I don't like the 'wagon wheel' look at all.

YMMV.

 

[Golf_GTDI]

Peter has been a WONDERFUL resource for me on so many issues. I knew that I wanted to upgrade my ability to not kiss a tree at a high rate of speed here on the back roads of SE Ohio and have honestly been rather unsure as to how to best do it. I knew I wanted something that was more about performance than looks but was not sure how to get there... to be honest I'm still far from fully understanding.

I knew that I wanted to stay close to stock height. Going lower would risk my pan and also hurt the geometry of the A4 suspension. This meant Shine, stock or a more exotic style coil over system seeing as most of them were all about the drop. I went with stock and grabbed a set of VR6 springs and dampers over at Vortex for a song. The Dampers only had about 12k miles on them and Peters testing show them to be far better than many of the aftermarket "performance" dampers. It was a deal that I could not pass up.

I also knew that I wanted to go with VR6 brakes. I wanted better options with pads and did not care to have some of the fade problems I was getting with spirited driving. To do this I knew I was going to have to upgrade to a full VR6 front end so why not go with the Audi TT/R32 system that gives the better geometry at the same time? I did think about going with the H2Sports but as Peter pointed out this was great for a lower car but seeing as I wanted to stay taller the OEM set up was the way to go. I'm sure he could do about 20 full motion animations on this but I thought I would just take the guys word for it.

Now I must confess that I don't know how much I paid for them. I got a great deal from VW4motion for all the parts with LCAs and an 11mm pump at the same time. There is however a guy over at Vortex out of Fla who offers the same for 650$ shipped.

One thing that is pointed out above is that I got the bigger binders and it looks as if I'll be keeping them. Jon and Oliver seem to want to live vicariously through my big brakes and how can I make them sad? I also may not be able to run 15"s anyway so why not just make the move? I have a line on some 16"s that I'm putting snow tires on for winter and will be running dedicated seasonal rubber from now on as a result. Later I may well move up to the 30th AE rear brakes but for now stock will do. I hate to admit that I'm doing it mostly for looks but I fear that it may just look damn odd to have those tiny little things inside some big meats on the back. Time will tell.

Now the last part of the saga for now seems to be what will come of my springs and dampers. I will be running a rear sway which should help even the performance of the car and cut down on the push. With that said I have a strong fear that I'm going to want to get better rotation that I will with this set up. I do not want to go with the short Shine rears but this is an option to help stiffen the rear to keep it in line with the stiffer VR6 fronts. Then again I want the option to rally cross and the short Shine rear springs have been known to jump out. I hate to admit it but I have actually tested my car in rather low g situations and fear a catastrophic circumstance should something odd happen while cresting some of the very abrupt drops on some of the local roads.

This brings me to some of those coil over sets. I am pondering trying to find a proper set that will allow me to keep up with the above goals and let me adjust and fine tune without having to reinvent the wheel. Right now the object of my affection is the Ground Control system with some Konis. Get a base system dialed in and then fine tune... a spring here, a sway bar there, a little damping adjustment, wash, rinse and repete.

At least thats what I'm feeling today. Its due to change any moment now.

 

[MileageDude]

Peter has been a WONDERFUL resource for me on so many issues..

And for many of us as well!

Look, have you read anything about the Koni Reds? I'll explain why. I've ordered a set with some springs. Of all the most important factors involved in grip it would be tires and shocks. If we shopped tires like clothes for the changing seasons ...we'd have a better understanding that what works sometimes won't work always. On everything you've posted so far in this thread the one remaining compromise is around the choice for rubber. Do not under estimate what a great tire can do for a stock suspension. An example was a kid who works at Sam's Club in Connecticut, he's Canadian and is on Vortex [alot]. He had a huge FMIC on a 1.8T Golf GTI and beefed up the engine professionally. Speaking with him one afternoon he said that his suspension was 100% stock.

Odd.

But then I looked at his tires and it came to my mind. Following him that earlier afternoon in a ramp S-curve on Route 2E to Route 3 Weathersfield, CT ...even with all his controllable stock body lean ...he still had heads over heals in grip safety at 75mph. He later said, "I can never flip stock, believe me I've tried..."

 

[peter pyce]

That is so true, MD! The OE setup with the best rubber you can afford is always "The Best". Many would argue to death about how stiffer springs and stiffer dampers made their car much better - but that was great improve in feel, not much in actual performance. What really happens is that the "soft" setup does not inspire confidence, so people drive it slower, but that does not mean it is slow. What the OE springs offer is grip, a lot of grip! There is something very important to realize, race teams spend big money in testing to get this data - the stiffer the spring, the higher its natural frequency. One would say - so what? Tires are very sensitive to that aspect. Or shall we say - grip is very frequency dependent. You go too high (too stiff) and the tire "suffers" and provides less grip. The softer the spring, the more planted to the road the tires is. And I hope that no one would argue that after all, what really matters is how long and how much tire you keep on the ground - the rest is secondary. Yeah, camber curves, tire width and yada-yada are important, but if you can not keep the tire well connected to the ground at all time, the best camber will do little for you.

Example that comes to mind - there was this team doing some testing on a track. Race car stuff, can't remember but I think was an Acura TSX, so similar car to ours, not some formula voodoo. The spent the day testing different spring rates in an attempt to catch at what frequency (spring rates) the tires they are using develop the best grip. At the end of the day, they found out the best lap times came with frequencies in the range of 128 CPM (cycle per minute), which would translate into 2.13 Hz. If we translate this into spring rates, we have to do lots of guesses for the weight of the car, but it really is not that stiff. For example, our little VW TDI cars come from the factory with springs that are in the range of 1.66 Hz (100 CPM), so we can see from there that the spring rates they got were not so much stiffer than what we have. To get their 2.13 HZ on a Jetta, for the rear for example, all you need is about 280 lb/in spring. Someone will now say that there are many kits that offer even stiffer springs for our cars for the street. And in fact, that is perhaps one of the reason why such kits do not really make your car much faster - but in some cases, like when raining for example, the car is much slower and tricky to drive. And anyway, the team I was talking about was doing these tests on R compound tires, on a very smooth, designated track, not on street tires, not on the street. I am sure our cheapo tires (no matter how good they are) need a lot less frequency to perform at their best. And of course, I did not believe all that, but after many trials and errors, it really is true. A stock car, with a little bit more controlled (but still soft and nice) dampers and with max performance summer tires is an incredible performer, very very hard to beat. I had one, in the middle of our long term never ending experiments that was what the car ended to be (some may remember from the long threads) - revalved Yellows to much softer values and Potenza S-03 rear, GoodYear F1 front. The car was so fast, it became actually boring, because just nothing never happens and there is no attention needed to blast at speeds above the law - and that was becoming stupid.

But to bring it back on topic - what the topic starter is doing is perhaps one of the very few things that could be done on our cars and that makes sense and there is net improvement. It is basically converting the car to an Audi. Reducing roll in the best way it should be reduced - correcting geometry, not using stiffer springs that make other things worse. So, you can have a better camber curve, less roll AND at the same time keep the awesome grip the low rate OE springs will give you. This right here was one of the essential parts in the big McPherson thread - but very few believed that just some spindles would reduce roll. However, everyone can go and check ETKA and see that early models Audi, those with the twist beam in the rear just like our cars, had in the front the same exact spring as an ordinary Golf GTI. Same color codes at least, so I do believe they are the same exact spring, but the two cars feel so, so different in roll. Of course, the TT has little bit lower CG, but still it is a heavy pig and no one would believe it has some 150 lb front springs - but indeed it does as the main work is done by the geometry, not the spring....... Ok, this got too long now. You all have a good Friday

 

[Golf_GTDI]

Now were getting somewhere!

I do in fact plan to devote some very serious consideration to rubber. As I pointed out above I intend to go to dedicated summer/winter sets. At this point I am not sure what those tires will be but I will either be running Bliz or Firestone winter tires. I can get the Winterforce tires at a very good price so I may accept a bit less performance than the bliz's and spend the extra coin on good brake pads.

Now as for springs and rates. I may well be happy to stay with stock but I don't know if I could do rallycross with them at stock height. I think I may need to be a bit taller and somehow I need to stop beating the heck out of the underside of my car. I risk damage to my pan and other soft parts on our awful back roads as it is... driving with real gusto would seem to make it a given to start blowing up parts.

Now why could one not make use of a system such as GC and use springs in the 180-200lb area? You could tie them to the Koni reds with some synth oil in them and make some adjustments to height and set up depending on what you were doing at a given time... or am I missing something else?

 

[SCCAONE]

15" wheels and Audi TT LCA.

It's not the rotor diameter, it's the distance from the hub center line to the lower control / ball joint that's the killer.