SKS

Greddy, Apexi, HKS, etc. Likes, dislikes, difficulty of install...I need to learn. Thanks

Mike O.

Lucas - Apexi ACVR (I think)

CP

and am not too sure about their performance. <b>Assuming</b> they can cause the MAF to adjust the fuel accordingly based on air flow, they could be somewhat safe. But I just don't see how they can properly monitor the engine like the Audi chips can. Apexi and Greddy have a few costly ones w/ fuzzy logic for around $500 that are supposedly pretty good. But I'm still learning like you are ;^)

2SLO

Although I did not do the install myself, a friend of mine did it for me and there did not seem to be any issues. As you probably know, there is no harness to plug it in directly.

As for performance gains, I can only speak from how it benefitted my setup (previously K24, HKS standard wastegate and currently TO4E/K26 and 92-96 S4/S6 wastegate). The boost controller brought the whole setup to life. Without using the SBC, I wouldn't get full boost (e.g. 1bar) until 4500rpm.. with the boost controller, i had full boost by a little past 3000rpm and also much quicker boost response.

Hope this helps..

jon

WClark

...no (or very few) Audi turbo owners are using these, optioning instead for performance ECU chips.

Boost controllers from years ago got the not-so-fond name of Dial-A-Death because of their relative lack of sophistication resulting in lean burn, overboosts, etc. I know the tuners of more mainstream turbo cars like the Eclipse have had success with new controller designs in addition to or in place of ECU internal mods. What I am not sure of is how much experience these tuners have had with the 1.8T and 2.7T. With VW using the 1.8T now, I am willing to bet the experience is growing since the volume of engines is now interesting from a business potential perspective. I would also bet that many of these products will (or are presently) not trying to get to the level of performance offered by the ECU chip tuners at this point - better safe than sorry.

RangeR BoB

They are mapped to handle a certain air flow at a certain rpm equals this much fuel and a spark... Now! They use a myriad of other control inputs (air temp, boost pressure, coolant temp etc) to ensiure that the mapping of fuel and spark (the only thwo things an ecu normaly controls on a normally aspirated engine, discounting gegaws like traction control)

In a turbo w/o a ecu controlled wastegate, pressure from the intake goes thru a hose to the wastegate diaphragm and presses open the wastegate at around the boost pressure neeeded, which is set with a spring. It is a decent analog system, but is not perfect at handling spikes of boost.

With a turbo with a ECU controlled wastegate, a signal line goes from the manifold to the ecu, where a frequency valve (think a valve pulled open and closed rapidly. The frequency it is pulled open sets the flow based on the DURATION of the opening rather than a solenoid valve that opens to a certain SIZE opening). This freqw valve bleeds off a certain amount of pressure from the wastegate, so it opens later. The higher the duration of the freq valve, the more venting and the less pressure on the diaphragm.

With this level of control, boost spikes can be handled by "anticipating" the coming boost and opening the wastegate a bit before boost hits max, that way you don't go over. The penalty is that boost doesn't fully develop as quickly because as long as the wastegate is open, some energy is going out the tail pipe.

A well designed booost controller can run the bleed more to let you develop more boost, but also the "logic" can anticipate the spike and try and mitigate it. How successfully is a matter of conjecture. I routinely get spikes of 18-20 lbs on my APR ecu before the wastegate is brought in fully to chop it down to 1 bar.

If your ECU can supply enough fuel (based on its map) to meet the increased flow thru the MAF, and the injectors can supply it without maxing out (90% duty cycle, they are freq valves as well) then higher boost should be fine, as long as detonation etc don't cause you trouble. If you fall off the map, or run out of fueling, you are so screwed.

"Dial a death" was a decnt nickname for a **** bleed on a wastegate on cars like the old 930 Turbos. Their injection could not tolerate running very far off the factory tune, so folks who bled their wastegate hoses with a **** or shimmed the wastegate spring really took their motor's life in their own hands. The purely mechanical wastegate on what was a really large turbo for its application meant controlling it without boost spiking, leaning out, or overspeeding the turbo was a very dodgy subject.

BANG! was the frequent outcome, wit hthe resultant reputation turbos enjoy today.

Hope that was informative, and not a waste of yuour time.

SKS

trying to do. I have a 3+ 1.8T, 330hp+ going in the back of a 1800lb, 914 track car. This turbo would pull 2+ bar the whole length of the Glens front straight if I let it, without any "noticable" detonation in an A4. I don't want this much boost and don't need it anyways. I want to tone it down...I have looked around at Greddy, Apexi, HKS, etc. and I don't think I need the fuzzy logic stuff. Greddy and Apexi both offer a simpler version that would give me a number of predetermined boost settings at 500 rpm intervals proabably aimed at the drag racing group. Basically I'm looking for traction control as this is welded up rear wheel drive. Even with 315's in the rear, wheel spin will be an issue, it would be nice to have the capability to dial this out... especially on a wet apex. Thanks for all the input so far.