It has an internal wastegate, the ECU controlls the boost, through monitoring it from the boost control selinoid. Located right in front of the passenger side strut tower,it's the little box located right beside the turbo where some of the lines should be running too. It through ECU signals controlls the wastegate. That's the nutshell answear.

The02-03 ECU works differently and actually better if you want to boost controll, since the new cars are throttle by wire. The old cars go into open loop mode easier from what I've heard as compared to the newer WRX's. It's something like that, other people could probably explain this better.

 

between the different years I have not found that much of a difference. There is a huge difference when choosing a manual or electronic bc.

 

In my 2004 I am running an Apexi AVC-R and seem to like it better then all of them. I got mine for $300 about a year and a half ago. I think out of all the companies, Apexi has the best. It gives constant boost all the way up to 7k with no hesitation and pulls strong in every gear.

my .02

 

I put mine in front of the ashtray and cig lighter. I dont use a car charger for my phone (they are bad for your battery) and I dont smoke so I dont have much use for it. You can look at pics on my aol profile (screen name Cyrus923) of the avc-r there. I have also seen it mounted above the rearview mirror in place of the small flip down visor there which looks really cool. You just have to hide the wires right through the A pillar.

As far as ease of use I think it is. You just have to plug in a few things like the cylinders of the car and what not. Then you are able to adjust the boost in bar and the duty. You can change the duty in each gear then to stay in the right power curve. I run mine @16.5 psi in every gear right below cut-off. If you happen to get an AVC-R I can give you my bar and duty but it tends to be slightly different for each car, and weather conditions.

Justin

 

The02-03 ECU works differently and actually better if you want to boost controll, since the new cars are throttle by wire..................sorry but that is wrong , I have an 05 wrx and it is not an throttle by wire, throttle body it is cable controlled , the STI is .

 

Air flows from your exuast to the hot side of the turbo and out the muffler. This spins the cold side of the turbo to pull air in so much that it creates more pressure than just the intake cycle on the engine can on its own. That's "boost". The wastegate allows the exhaust gases that turn the turbo to escape the exhaust system or circumvent the part of the exhaust that turns the turbo. The wastegate is set to react to some given pressure on the intake side. When boost gets to a certain point, it causes the wastegate to open and since the exhaust gases now can avoid turning the turbo, the boost decreases on the intake side. If this sounds circular, it is.

The factory boost controller is logically stuck inbetween the boost pressures on the intake side and the wastegates input for reading boost. The factory EBC is a combo of the ECU and the BCS (boost control solenoid). The ECU uses the BCS to essentially lie to the wastegate. You might have a certain level of boost on the intake side, but the BCS doesn't let the wastegate see all the intake pressure, "information". So the wastegate responds as though there was actually less boost. So, the waste gate doesnt open (as much or at all), the exhaust doesn't bypass the hot side of the turbo as much and boost keeps rising.


A solenoid is a coil of wire. if you run current through it you get an electromagnetic field in the coil. This can push or pull a solid core placed inside the coil. So, essentially, its an electronic valve. Turn it on and push the core forward through the coil to block a hole. Turn it off and the coil plops back in place and the hole is open. The BCS does this hundreds of times a second as directed by the ECU to let through only a certain amount of "information" (read "boost") to the wastegate. The reason why its connected to the wastegate should be obvious by now. It is connected back to the intake so that the "information" that it hides from the wastegate has a place to go. Many of these "bleeder" type boost controllers bleed the unwanted boost "information" to the atmosphere. Our stock system bleeds it back into the intake. I suspect this is a way to keep the fuel system (MAF) happy. Otherwise you might end up with a rich condition similar to what happens when people run blow off valves that vent to the atmosphere.

Also read: http://auto.howstuffworks.com/turbo2.htm

study all the images carefully.

jason

[edit]
p.s. I would recommend getting a Blitz Spec-R. If you are going to spend twice that $ to get an AVC-R or a Blitz SBD-iD, you might as well get a UTEC or ECUTek reflash
[/edit]

 

UTEC.....$ 1000.00 + options

AVC_R...$ 290.00

 

where can I buy one for $290?

 

you are absolutely 100% correct there. i was running a bleed valve mbc for a while, and at first vented it to atmosphere. it ran ok but i could feel that something was just not as smooth as stock. i picked up a few more fittings and plumbed it into the intake like stock and it was much smoother.

 

Keep watching Ebay. They have lots. Also look in SCC ads. You are bound to find one for around that price.

 

UTEC = timing map control,open and closed boost map control, open and closed fuel map control all with 40x11 map granuality, plus launch control, 13 paramater logging, fuel cut-off control, knock sensitivity control, timing cut-off, upgradable firmware, plug-in ability with various WB kits, etc., etc...

AVC-R = map (RPM-only) based boost control with only 17x1 granularity and open loop boost control. Analog boost display with peak hold. No timing or fuel control.

Comparing them just by price is pretty silly.

jason

 

Yeah we all know the Utec is better, but the reply about comparing the price was because it was stated that if you were going to spend the money on an avc-r you might as well buy a UTEC. Look in the above posts. I was simply stating that a UTEC is far more expensive and not even close to the price of the AVC-R. Not which one has more features. So when saying that the AVC-R is twice the price an a manual and you might as well spend the money for a UTEC is stupid because the UTEC is 700 bucks more.