Audi TT Quattro (225) 1.8 Turbo

[acidrainy]

Hi there,

We all know how this ones goes... I've graduated, been in a job for a few months and finally decided to get a new car that I liked.

As the title suggests, I've just got myself a TT. Through my limited research, I know about it's all-wheel-drive system, the ESP the fact it has two inter-coolers and some kind of turbo that does something fancy to "eliminate" turbo lag.

Wikipedia has explained a lot about most of these to me, but I still have no idea (yet an interest to find out) how the turbocharger diggers from your run-of-the-mill variants? I know roughly what it's doing, but I certainly wouldn't call myself an expert. Is there anyone out there that could explain this to me?


Thanks,

[jackvdbuk]

you really should be in bed rather than thinking about cars

[acidrainy]

you really should be in bed rather than thinking about cars

I get up early.

[acidrainy]

I think I found a perfect explanation.

How does Variable Turbine Geometry work?

[Neo_VR]

IIRC the K04 isnt a Variable Vane turbo...
Its still a relitively small turbo though so spool up will be quite quick.

The main components that help the spool up is the wastegate being electronically controlled rather than just a spring vs vacume like "oldskool" turbo cars have.

The engine control unit has the ability to control how much, and when the wastegate opens which means mainly it keeps it shut for a bit longer when in a "oldskool" setup the pressure would have started to push against the spring to open the wastegate.

The VW TDI engines use Variable Vane turbos, so theres no wastegate.

I can go into more detail if you want... i have the same engine as yours in my Octy vRS

[acidrainy]

Oh, you could be right; it was the [franchise] dealership salesman that told me about it. In either case I know there isn't and "lag" when driving it and I wanted to know how that worked.

[dangel]

Small turbos take less time to spin up is the short answer - and most accurate one for that engine. Plus side is they spin up quickly from low rpm (1500+) downside is they won't hold on as long at high revs (hence you'll find it's not worth redlining it during brisk acceleration). The KO4 unit is a repackaged KO3 for the 225 (versus 180) engine which allows for more power (it's internally a larger turbo but in the same KO3 casing as I remember). Chipped (and go somewhere reputable for god's sake) will see 270->290bhp typically whereas the K03 can only managed 240 max. Great engine the 1.8t
Oh and don't bother with whoosy dump valves - they don't work properly on the 1.8t as it's a recirculating system (as opposed to dumping to atmosphere). If you like noises look at induction kits (but again, do some reading). The best mod you can do is chipping (remapping) with suspension running a second best (for me the stock suspension is a bit wallowy - it's a golf underneath after all).

[acidrainy]

The dude has spoken.

I've been doing some digging and I'm trying to isolate something about the alloys/suspension on the model I have... It's an 03 plate and from what I can gather it got the 9spoke lightened alloys as standard and coupled with lowered suspension. Is any of this actually true? if so, what ramifications does this have with regards to the suspension upgrade suggested?

[dangel]

lol

Happy motoring!

[acidrainy]

I may of updated my post after you read it :/

[dangel]

I've been doing some digging and I'm trying to isolate something about the alloys/suspension on the model I have... It's an 03 plate and from what I can gather it got the 9spoke lightened alloys as standard and coupled with lowered suspension. Is any of this actually true? if so, what ramifications does this have with regards to the suspension upgrade suggested?

First question with any mod is - what will I get for it? Does the car roll too much now or handle THAT badly? Is the car holding you back or your own ability? If the former then i'd look at some koni adjustable shocks/eibach springs (they're a very good mix on that platform but there are others). Don't lower the car too much either - a small drop is ok but large ones will generally give you poor comfort levels and scraping sounds over speed ramps Clearance is a GOOD thing for everyday cars

I'll reiterate - the best mod i ever did was the chip. I did suspension and brakes later on (the former because my suspension was **** [i'm not a brilliant driver or anything] and the latter because i'm a sucker for brembos (i.e. in all honesty good pads and the stock brakes were good enough). Modding is a slippery slope..

[acidrainy]

In all honesty it is by far early days to start talking about mods to the car. The only driving that i've done so far in it was on a rather extensive (2 hour) test drive over about 20mins of motorway and the rest on lovely & challenging country b-roads. This was about enough time for me to settle into how the car worked (I was learning how to use a 6speed box and how AWD differs to FWD or RWD) but far from enough to actually get any real understanding of what it could do.

From looking around, I see a lot of people jump on the chip bandwagon, as it appears that the components under the bonnet are pretty capable. £4/500 sounds like a bargain for what is ~40bhp.

Places local to me appear to deal primarily with a GIAC model of chip, from what I gather this is quite popular with the 225's. What things do I need to know before adding something like this? Will my insurer tell me to run and jump off a cliff? Will my mpg (in todays ever turmoil market) drop through the floor? What does 40bhp actually mean in terms of noticeable gain? Are we talking drastic reductions in 0-60 or is it something else that I will most likely notice?

Sorry for throwing all these questions, but this forum appears to be the most knowledgeable resource that I've found so far!

[dangel]

The engine/drivertrain is tough (the six speed box is good for something like 330lb/ft) and you don't hear much in the way of post-chip failures as a result. To answer your questions re: chips.

If you can get a chip (like REVO) which is flashed via the diagnostic port then nothing on the car is opened - 15 minute job by a bloke with a laptop - and it's entirely invisible. Whether you then decide to tell your insurer is up to you - but it is therefore very difficult to find post-crash (part. when you consider that insurance inspections are far from in depth). I had my work all done by Jabbasport but i'm not up to date with current tuners etc and they're probably too far from you to be of use. Plenty of VAG forums with good advice on what to choose.
MPG - most report it gets better (and worse if you're heavy with the right foot) but that could be down to the trip getting confused. I can say mine got no worse and the car is still utterly smooth and easy to drive at a low pace when wanted. The powers there if you want it, and doesn't sap your MPG when you don't.
What do the gains mean? Well, yes, it'll be quicker but you'll probably find it improves the feel of the engine - it'll certainly hang on longer at higher revs for example. You'll suddenly think 'quick car' versus 'warm' IMHO. Lots of smiling is usually a consequence.
0-60 will probably improve for you but not by pub-bragging rights - think mid to upper shove improvements (which are much more important anyway) instead. Good for overtaking etc. Really it'll feel much, much better. Should you do it? Darn right!

[Zak33]

the big question is:

Do you understand 4wheel drive and are you gonna kill yourself thinking that it will make you invincible in cornering terms?

[acidrainy]

the big question is:

Do you understand 4wheel drive and are you gonna kill yourself thinking that it will make you invincible in cornering terms?

My answer to that is that whilst I understand the technology behind AWD, no I don't have any substantial experience with it yet. Anything I've owned myself has been FWD, anything that I've raced (track) has been RWD.

Do you have any advice?

[Zak33]

I do, yes

When a 2wd car tries to put down excess power,the axle that is doing it, loses grip in all directions and that axle slides towards the outside of the corner.

In a fwd, that means that it understeers.

In a 4wheel drive car the power is put down through all 4 wheels, giving the tyres slightly more grip, and potentially increasing exit cornering speeds.

It works....and you can feel it on any roundabout. The car is hard to dislodge.

This isn't where the problem arises.

The problem arises in the phenomenal grip in driving down country lanes. Why? Because you come out of the corner faster than ever before.......

and why is that a problem?

COs you enter the next one much quicker than you ever have before or ever expected too......

However, the Audi Quattro system is still, one of the finest systems ever devised and I wish you many many happy, rapid, high G cornering hours..... just remember this.....if you corner faster, you'll hit the horse rider faster half way round the long, blind, sunny warm corner