Electronic Boost Controller

[Tizer.B]

Just a quick question!

My mates got an Impreza STi Type R with an electronic boost controller and i was wondering if it was possible to fit one on to an S2? And if so how much would it be?


Tyrone.

[Greg_S]

not sure its worth your while, youd be better off having a word with mihnea and getting it chipped instead.

[Floddy]

IMO a electronic boost valve is just a bling-bling version of a bleed valve. No loopback to the ECU if something goes wrong is no good at all.

[Lee]

IMO a electronic boost valve is just a bling-bling version of a bleed valve. No loopback to the ECU if something goes wrong is no good at all.

Agreed, it will prevent your car going into safety modes if it needs to (boost leaks etc). Get a proper remap to get the fuelling tweaked to suit your car too. It is far better. Bleed valves are BS tuning too . Some of the Car Tooners only touch the boost chip when they 'remap' the car. I have heard some don't touch the fuelling/ignition at all. You should also get your boost profile done by someone that understands the specific turbo in your application. Trust me, you do not want a turbo to let go at full chat because you got greedy and dialled in too much pressure.

Lee

[S2central.net]

Totally agree with Lee and Greg on this. Such controllers override the ECU targetted boost pressure and do nothing for fuel and timing. Send me a PM if you want a generic chip upgrade for your S2 - 3B or ABY. Send mihnea a PM if you have custom requirements.

Cheers,

Paul

[dan_b]

Agree with all that's been said here - a quick re-map on the stock S2 brings big benefits without serious risk to the car's health - contact Paul as mentioned above for that, or if you're planning to get serious with custom turbos/cams/injectors etc then contact Mihnea for an on-the-fly re-map specific to your car.

[91_S2]

I will voice a contrary opinion. Atleast I'd like to see more discussion to understand this better.

I fully believe remapping ECU chips is the principal way to gain power. So Tyrone, understand that a boost controler is NOT by itself an alternative to a good remapping. On the other hand, I think it could augment the WG/ECU/WGFV system.

The WG is just a spring loaded pressure release valve. It has been around for a while. The next step in the evolution was to allow the ECU to modulate the pressure to the lower WG chamber using the WGFV. Now, most of us wouldn't want to be without it. I think the BC is a further refinement of the WG.

What I think Apexi and HKS do is regulate the pressure to the upper wastegate chamber. Pressurizing the upper chamber can prevent WG creep, which is the gradual cracking of the waste gate even at low pressures. The WG spring being linear will open slightly even at low pressures. Boost controlers (I think) work like non-linear springs. The result, I am told is coming on boost sooner.

I don't think the problem is that BC's are bad in themselves. The problem is, as Floddy points out, getting the BC into the regulation loop with the WGFV.

[Greg_S]

The ECU on the S2 already compensates for WG creep i believe and opens in about3 stages which is regulated thru the use of the WGFV. If it was allowed to crack open suddenly to the full extent it could stall the turbo slightly so it opens in stages instead.

Greg

[91_S2]

The ECU on the S2 already compensates for WG creep i believe and opens in about3 stages which is regulated thru the use of the WGFV. If it was allowed to crack open suddenly to the full extent it could stall the turbo slightly so it opens in stages instead.

Greg

Interesting about the 3 stages. I would have guessed something more like a signal with 8 bits resolution to the WGFV. But I follow your reasoning about partly solving the creep prob.

About stalling the turbo, isn't the whole reason for opening the WG to stall the turbo slightly?

[Greg_S]

I dont claim to be an expert on this im afraid, I will have to have a read thru one of the books before go put my foot in it.

Depends what you mean by stall? the way i understood it is that the wastegate opens to bleed off some of the exhaust gas to stop the turbo over spinning and giving too much boost and when the throttle is closed (like if your doing a gear change)

Greg

[91_S2]

I dont claim to be an expert on this im afraid, I will have to have a read thru one of the books before go put my foot in it.

Depends what you mean by stall? the way i understood it is that the wastegate opens to bleed off some of the exhaust gas to stop the turbo over spinning and giving too much boost and when the throttle is closed (like if your doing a gear change)

Greg

I'm certainly no expert either. I learn something every time I have an exchange on a topic. Which what most of us are here for anyway

In the case of going off throttle, I think it is the "dump valve", or whatever the proper Audi term is, that opens and prevents the the compressor wheel from stalling.

[Greg_S]

yeah, i thought that was just the other part that goes towards it. Since you have both hot and cold side both need 'disconnecting' from the loop to keep the turbo spinning when the exhaust flow drops alot and so isnt able to keep the turbo spinning to produce a given pressure.

Greg