Wastegate advice

[4WheelDrifter]

What an excellent pre-S2 purchase question.

[prj]

By no means does it kill turbos extremely prematurely though.

No, not extremely prematurely, but the shockwave and the forces exerted on the turbo reduce it's lifetime. It's simply a physics calculation.
The k24-7000's often last 15 years without replacement.

[Dobby84]

I asked the same question to the guys at 034 Motorsport and this is what they said:

"Here is a very nice upgrade we offer which is a bolt-on replacement for the factory assembly:

http://www.034motorsport.com/engine-components-audi-i5-20vt-wastegate-tial-44mm-audi-20vt-drop-in-p-569.html

The Tial components are second to none, and you can find this same unit on many championship race engines all over the world."

Looks like this is more towards tuned engines but hey.

[prj]

The thing is, the stock wastegates pistons start leaking over time.
Boost wise it does not do a whole lot though, because the wastegate is connected to the N75 valve via a pretty tiny restrictor anyway.

[Dobby84]

Not really worth the money at this stage then!
Maybe just a forge or baileys blow off valve instead?

[prj]

Use search, blow off valves have been discussed to death.
If you use a BOV instead of a bypass, every time you shift, your engine will be overfuelled and slightly bog down. On stock engine management, you need to use a recirculating valve (bypass) to avoid losing performance.

If you are the kind of guy who prefers "cool sounds" over performance, then feel free to disregard my advice though.

[Dobby84]

You may have guessed that this will be my first Turbo car I will have owned (not my first Coupe) so everything is a bit new to me so will not be disregarding any advice. Bypass it is then!

[prj]

If your bypass valve actually will be shot on the car, then an inexpensive and reliable upgrade is to use the one that is fitted to Audi TT and Audi S3's.

Part code 06A 145 710N.

[Thuppu]

With stock mortonic it's recommended to use only bypass vents. No dumps and blowoffs, they mess up the mixture when thay dumps out all measured air. The mix would go way rich...

Edit. I'm way too slow...

[S2central.net]

Honesty is the best policy... don't feel bad about getting jumped for such an opening post - some of us on here get frustrated by peope getting conned into all sorts of silly 'performance' parts and 'upgrades' so we just want to educate and inform as best we can.

The vast majority of people here run with factory bypass valve - or an uprated (more reliable) version of when running big boost levels.

The factory wastegate is well enough capable for silly power levels.

Sometimes I forget that when I bought my S2 (way back in 2001) I had equally stupid questions... it is essentially why I started my quest for knowledge on the rare beast and created www.s2central.net along the way to spread what rare information I could find... then this place spawned out of that somehow and here we all are still going strong.

[prj]

Every time someone wants to get his car tuned and comes to me sporting a huge flashy and polished BOV, I just go:



Happened so many times it just stops being funny.
Then we go and buy the 710N...

[Dobby84]

This is exactly what I feel forums are there for, along will sharing your projects etc, its a great place, if not the best to gain knowledge on all kinds of things car related.

It is thanks to forums that I know the Pug 205GTi like the back of my hand! (owned 5 in total now)

Like I said Ive owned coupes before my current one being a 2.6E (for sale on pistonheads lol) and always wanted an S2 and may have silly questions to ask and appriciate everyones patients!

[S2central.net]

PMSL @ 'facepalm' - so perfectly fitting

[prj]

Just use the search function more.
If you search for "wastegate" or "BOV" you will find a ton of discussions and all that info is still relevant.

[s2_bo]

I would like to see a system that can measure how much air that is recirculated actually gets used.
The return feed from the DV may land right in front of the turbo but at that point most of the air is stalling in the intake system (especially if the TB is closed, then only the ISV is feeding the engine with air)
I think its unrealistic to asume that it all gets sucked back in. I would assume some would escape back past the MAF and in to the airbox.
I very much doubt the MAF can reverse calculate air and adapt the mixture to accommodate.

Say you lift of throttle at 1.5 bar boost. (thats 1.5 bar above atmospheric pressure) As soon as the TB closes the IM creates a vacuum which sucks open the DV and allows the 1.5 bar to equalize.
The DV stays open for about 1.5+ seconds during which time the air is forced out the pressure side if the system in to the MAF hose. At this point surely the air wont naturally want to go back in and the turbo has slowed down considerably.

I bet some of that air is going back out in to the airbox and is thus doing the same as a BOV but on a smaller scale..?