Subaru WRX Forum banner
1 - 4 of 4 Posts

· Registered User
Joined
·
5,786 Posts
This is a somewhat controversial subject. Many of us that run/ran MBCs experienced no indicated raise in EGTs whatsoever at part throttle situations. I feel this was one of those I-club-induced mass hysteria scenarios with little if any factual data to back it up. In reality the 'problem' with part-throttle full-boost is more of a drivability issue: You may experience some 'jerkiness' and with an MBC the boost comes on very hard indeed.

An electronic boost controller may certainly alleviate some of the real issues, but I do not believe that the SBC-id can map boost using the TPS as an input, so any supposed problem with EGTs would also afflict electronic boost controllers not just MBCs. The Unichip employs the oe solenoid using an auxilliary boost controller (similar to an MBC) to raise the peak boost. It has similar boost characterics and shortcomings of an MBC, although it comes on smoother and is still infinitely better than stock.

The main motivation for an electronic boost controller (versus MBC or oe solenoid) is going to be the improved boost response, and the more consistent boost characteristics (no spikes, less fade, etc.)

-Pace
 

· Registered User
Joined
·
5,786 Posts
1. The unichip has a single TPS threshold - at 40%. The supplied TurboXS ABC is used to raise the boost map, which is necessary with the stage-4 map or when running the stage-2 map at altitude.
2. Don't confuse boost mapping from rpms, with boost mapping from TPS.
3. AFAIK, most aftermarket boost controllers do not have the ability to map boost based off TPS. In a previous investigation of available EBCs I found one that could, and it was priced over $1k.
4. Most EBCs have the ability to map boost from rpm, duty cycle, gear selection, etc.

Hope that clears up some confusion.

-Pace
 

· Registered User
Joined
·
5,786 Posts
KanosWRX said:
So would the best thing to do would be to get a SBC-ID and set different boost levels at different TPS/RPMs whichever one it does it at. So you get a nice curve, but when you WOT, you get full boost. Then it would be pretty close to stock in how it will only give partial boost at partial throttle.

I just don't want to see my boost guage shoot up when I am accellerating normally. My commute to work has lots of stop and go tracffic and I don't want it accidently go full boost on me.
Most people are very happy with the SBC-id. It maps boost from the vehicle rpms I believe. With the optional Power Meter i-D unit, it can also map from vehicle speed. The Apexi AVC-R also appears to be a solid choice. Both will give you vastly improved boost characteristics.

The last issue of SCC had a boost-controller shootout with those two units being rated the best. The SBC-id has dual solenoids and in theory should give better response. The AVC-R has more bells-and-whistles, and some users report it is difficult to program.

It looks like Godspeed currently have the best price on the SBC-id. German Autowerks have a great price on the AVC-R.

-Pace
 

· Registered User
Joined
·
5,786 Posts
Si2WRX said:
I'm kind of lost... the SBC-id will control boost based on rpm? How?

I have one and don't think it can do that.

I have used Unichip with ABC, MBC, EBC and had no problems with any of them with regard to EGTs or A/F.
Yikes, my bad. I was reading the SCC review of the AVC-R when I posted that. It is the AVC-R that has that capability, although the SBC-id will do mph mapping using the optional Power Meter i-d. My sincere apologies for the confusion.

As is probably obvious, I own neither unit but am currently investigating both for purchase within the next couple of weeks. Rocky is running the SBC-id with success on his car, but I'm still undecided. In the SCC test, the SBC-id built boost quicker than any of the other units, but the AVC-R has considerably more functionality.

-Pace
 
1 - 4 of 4 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top