I'm thinking about buying a Audi TT very soon. I have a few questions before I buy one though.
What is the deference between the Roadster and the Quattro? All I know is the Quattro has 4 wheel drive.
What model has 225hp?
What "ALL" do I need if I want a BOV (blow off valve) on the TT
I’m new to turbo’s, what gauges do I need? I.e. Boost, PSI so on..
What’s the deference between the stage 1-3 turbos? What's a good price on a 2001-2004 TT i.e. 40-80k miles
I have around $10k-$15K
Thanks for any help you guys, Hope to be a future TT owner!

 

since your knowledge of turbos is minimal, I'll say skip the blow off valve. VAG cars use a diverter valve, which is much like a blow off valve, except it recirculates the air into the intake again, instead of venting to atmosphere. Save yourself a headache, and stick with the diverter or a hybrid until you know whats going on, and then you can start screwing with that.

quattro is AWD.

Coupe is a hardtop car
Roadster is the convertable.

225 Hp cars are all 6 speed, they have a dual exhaust (the 180 has 1 tip). 225 also has 2 side mounted intercoolers (SMIC's) 180 has 1. Also, with the hood popped, you'll see a "L" shaped charge pipe on the 225, the 180 doesn't, and the intake manifold is on backwards on the 180 (intentional jab at the 180 guys) ; )


BTW, I'm being nice, all this crap is in the sticky at the top of the forum.

 

Sorry I didnt see the FAQ sticky, I didn't make it past *The OFFICAL pic ***** your TT thread*
Thanks again for the info, Ill look into the "DV" more before I make a decistion on the TT.

 

Simply upgrading/modifying the air intake will get you a decent amount of noise, if thats what you're going for. The hybrid splitter apparently does fairly well in the sound dept too. I'd take actual performance over sound though, but to each his (or her) own.

 

I thought BOV, HS, DV release boost adding performance?
Also i didnt read anything on how/where to install BOV, HS or DV

 

DV/BOV/Splitter only affects performance if what you have is no good (and you'd be upgrading, not straight installing, the cars come with a DV).

The air needs someplace to go when you take your foot off the gas and the turbo is spooled. Air is elastic, you compress it with the turbo. If you're boosting, and you lift your foot off the throttle, like when shifting gears, you close the escape route the air was using (thru your engine and out the exhaust). If you didn't have a DV/BOV, the air would come to a head, and then spring back in the other direction toward the turbo. All that air trying to go backward thru the turbo compressor would most likely stop the blades from spinning, imparting quite a bit of stress on the turbo, as well as stalling its rotation, which means even more lag before you make boost again.
With a DV/BOV, the air is given another route so the turbo can hold it's momentum.

The idea of upgrading a DV would be for more consistant operation, or potential to hold more pressure before it releases. This DOES NOT mean you can use it to make more boost. It means that if by other means you're making more boost, this 'door' is strong enough to hold the pressure until the proper time to release it.

I have a Forge 007 DV. It's a piston style DV that needs to be cleaned/regreased once in a while. I'll accept that bit of maintenance over the diaphram style (OEM), which has the potential to tear. (Kinda sounds like a duck) I should add APR makes a diaphram style called the R1 that is supposedly a fairly nice unit, 0 maintenance, and reacts quickly, but as Im happy with my 007, Ive had no reason to look into it much. I can tell you it's a bit more expensive, but such is the cost of never having to take it apart and clean/grease it.
My 007 has a couple different springs, as well as shims that can be used to set the tension on the piston near to what you're boosting too. Too light and the piston might open too soon, wasting good boost. Too hard and it may not open enough, or soon enough, and you risk the reverse flow I mentioned before.

While we're talking about reverse flow, I might as well add, although this doesnt apply to you at this point.. there's a thing called compressor surge, where the turbo (usually only after upgrading, but it CAN happen in some setups even stock) can move more air than what can fit thru the engine at that point in time. Same situation as I described above where the air having no other place to go, tries to go back thru the turbo.

 

Thank you for the run down on the DV, BOV!
My Last question is does the DV, BOV replace the recirculating valve?
If so to install a aftermarket BOV I would replace the DV, that takes place of a recirculating valve on a non turbo engine, and run a hose's from the BOV to the boost piping, intake and vacuum?
Also will I have to tweak the air flow meter in the TT to prevent a rich fuel mixture? Because the engine is venting air that has already been measured by the MAF right?