Digit@lex

I've been doing some reading on boost controllers and I'd like to experiment with one.

First thing. I'm a non-DBW T-28 and these are the boost characteristics I have experienced with my 1.5 bar street program.

1st gear spikes to 12psi (haven't seen it settle since I wind up shifting).

2nd gear spikes to ~20psi and settles to ~15psi

3rd gear spikes to ~21-22psi and settles to ~17-19psi.

4th gear spikes to 21~22psi and holds around ~20psi.

Same with 5th gear.

From the reading I've done, I've read that boost controllers are bad for non-DBWs (mainly in response to K03s though). I've also read that it's because we don't have a MAP and we'll lean out the car. This leads me to a few questions...

1) Does the ECU go into open loop mode at WOT (given that it's GIAC non-DBW programming)?

2) If yes to 1), is that the reason I could run lean in the lower gears? I know that the BC would allow me to keep the boost consistent in every gear. However, if the fuel map at WOT does not inject enough fuel at the set pressure (20psi in my case) I'll run lean. Is this a correct assumption? How do the DBW cars deal with this?

3) I'm going to get an MBC (ball/spring) to play with. I've read that EBCs are faster to respond though. Does anyone know how much faster?

My ultimate goal is to smooth out the boost characteristics. Also, can anyone suggest Vag blocks to log (nonDBW) so that I can characterize what I am seeing on my boost gauge?

Thanks.

Yippers®

with nDBW and a BC is partial throttle modulation. The BC in effect tries to build to and hold whatever setting you've dialed in . . let's say 21 psi. So the wastegate is held shut until the pressure reaches 21 psi. With the N75 in the system the ECU uses the N75 to cycle the wastegate to modulate the boost, ramping it up to full boost as warranted but more slowly. The effect is a slight throttle input yields a fairly substantial boost build. This has the effect of making boost build a bit earlier and more rapidly at the expense of herky jerky throttle modulation. That's sorta great for a quick street race or 1/4 mile but a bit of a pita on a daily driver and can get scary on a track.
The DBW exibits this but not nearly as abrupt. Maybe it's the built in delay of getting the full throttle plate opening ...
Running a BC in parallel with the N75 seems to help smooth any boost spikes and helps keep timing lost to those spikes.
RS has a fair amount of experience running a BC on his nDBW APR car .. maybe post a query to him on teh A$/S$/TT forum in that 'other' place?

Digit@lex

Thanks for the great feedback.

paulroad

every which way. Very adjustable. We also do not us the n75, although it is connected electrically.

Bost doesn't really happen with our turbo untill about 2800.. but it is a steady build..no spikes..unless Alex (son) sets it that way.

Digit@lex

You just keep it connected so no DTCs pop up correct?

AntiSocial

That's what the gain is for.

paulroad

is an occasional missfire code.. but that is another matter and not related to the n75. Its just electrically hooked and secured out of the way.

Alex (son) is bringing it home NEXT weekend to do the final Dyno tune with Mike (www.tyrolsport.com ) he was the mod-shop/guru who made the original package and did the work.

CP

My Galant has a MBC set to 14psi, stock 14b turbo. And it hits full boost (albeit around 3200 rpm) at just the slightest throttle pressure. It sucks when trying to modulate the clutch. And 25%-100% throttle is pretty much the same for me. A direct result of the manual boost **** for sure. But it's a cheap mod that won't do any damage if you're getting enough fuel into the engine.

1.8tScreemer

of weeks but I havent thrown a code, I left the n75 installed though so the ecu thinks its doing something(what it doesnt know wont hurt me)ha I like it alot so far car feels faster which is nice.

paulroad

While cruising Vortex, I cam accros the BC (Greedy that we have) for sale. New in box. He only want $300.. he may bargain.<ul><li><a href="http://forums.vwvortex.com/zerothread?id=1628209">Click Here</a></li></ul>