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Discussion Starter · #1 ·
I know MBC's have this problem, and that it can cause high EGT's. I was wondering if anyone knows if the SBC-ID or a Unichip (Turbo XS chip) cause this problem too?
 

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they shouldn't. the SBC-Id and other EBCs allow you to customize boost based on throttle poistion or rpms. hence, you'll get whatever boost you tell it to at part throttle, eliminating fullboost at partial throttle, and the higher EGT's.

unichip's are the same story. they do what they're told.

dR
 

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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
 

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Yeah, I get a lot of the jerkiness with my ABC...it doesn't help being in a slushbox either. I was taking a turn in 2nd and gave it some gas coming out of the corner...the rpms went up and the boost kicked in with only part throttle, then promptly died down, all still staying in 2nd. It's definitely a weird feeling and I want to get myself an EBC very soon to alleviate this problem.
 

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Discussion Starter · #5 · (Edited)
I thought the Turbo XS unichip did not need a separate boost controller, unless you wanted to adjust boost because you were at a different altitude. Does the Unichip increase any boost by itself, and if so to how much? Their page also says this about the chip

Built in part throttle boost controller (<=30%) limited to 7psi -
Protection from high boost when factory ecu runs in closed loop @ 14.7:1 air fuel ratios. Factory boost level is 7psi and when using aftermarket electronic and manual boost controllers, full boost can be reached at partial throttle, resulting in high exhaust gas temperatures and lean run conditions.

I guess I don't understand exactly how the unichip, or for that matter the stock ECU differs from the EBC in the sense of how it controls boost at different throttle positions. Does the ECU control the boost at different throttle positions the same way as the Unichip would? And with a EBC it has 4 boost levels, so you could do 25% boost at 25% throttle, 50% at 50% and so on.
 

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Living in Seattle, where we're at sea level, I thought I didn't have to adjust it at all. However, when I installed mine, the highest I could boost was only 0.88 bar. Granted, it held the boost all the way from spool to redline, but that's only 12.76 psi. I can't explain it, but that's the highest I could boost. Thus, I installed the ABC. Now I'm boosting just about 16 psi and it makes a huge difference.

KanosWRX said:
I thought the Turbo XS unichip did not need a separate boost controller, unless you wanted to adjust boost because you were at a different altitude. Does the Unichip increase any boost by itself, and if so to how much? Their page also says this about the chip

Built in part throttle boost controller (<=30%) limited to 7psi -
Protection from high boost when factory ecu runs in closed loop @ 14.7:1 air fuel ratios. Factory boost level is 7psi and when using aftermarket electronic and manual boost controllers, full boost can be reached at partial throttle, resulting in high exhaust gas temperatures and lean run conditions.

I guess I don't understand exactly how the unichip, or for that matter the stock ECU differs from the EBC in the sense of how it controls boost at different throttle positions. Does the ECU control the boost at different throttle positions the same way as the Unichip would? And with a EBC it has 4 boost levels, so you could do 25% boost at 25% throttle, 50% at 50% and so on.
 

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KanosWRX said:
I thought the Turbo XS unichip did not need a separate boost controller, unless you wanted to adjust boost because you were at a different altitude. Does the Unichip increase any boost by itself, and if so to how much? Their page also says this about the chip

Built in part throttle boost controller (<=30%) limited to 7psi -
Protection from high boost when factory ecu runs in closed loop @ 14.7:1 air fuel ratios. Factory boost level is 7psi and when using aftermarket electronic and manual boost controllers, full boost can be reached at partial throttle, resulting in high exhaust gas temperatures and lean run conditions.

I guess I don't understand exactly how the unichip, or for that matter the stock ECU differs from the EBC in the sense of how it controls boost at different throttle positions. Does the ECU control the boost at different throttle positions the same way as the Unichip would? And with a EBC it has 4 boost levels, so you could do 25% boost at 25% throttle, 50% at 50% and so on.
Stock ECU does control boost based on throttle position. It will give you full boost after 58% TPS, when it goes open loop. Anywhere below that, it will run in closed loop mode, maintaining 14.7:1 A/F ratio and around 8 psi of boost (wastegate spring pressure).
 

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Verdugo said:
Living in Seattle, where we're at sea level, I thought I didn't have to adjust it at all. However, when I installed mine, the highest I could boost was only 0.88 bar. Granted, it held the boost all the way from spool to redline, but that's only 12.76 psi. I can't explain it, but that's the highest I could boost. Thus, I installed the ABC. Now I'm boosting just about 16 psi and it makes a huge difference.

The ABC shipped with TXS package needs to be installed in order to make proper boost. Even though it ships fully closed, its T-fitting has larger internal diameter than the stock restrictor it replaces, and it allows the boost control solenoid bleed more air (3/16 restrictor mod accomplishes the same thing). Without the ABC, you will always make less boost than stock.
 

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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
 

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pace said:
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.

-Pace
I agree with Pace. This type of thinking is just plain paranoia on the part of a few i-club members. I just use EBC's and no problems at all with EGT's or AF mixtures. As for the unichip it controls boost but not very well. A good EBC is recommended for more extreme setups. Even with stock turbo my friend has too much spiking and had to add an SBC-id. Now he has perfect boost control.
 

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Discussion Starter · #11 ·
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.
 

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Kanos, that's exactly what happens to me every day. I'll be in traffic and in part throttle, the boost will go up to almost full and my car sounds funny as I let off the gas and the rpms slowly go back down...it's like I just shifted to neutral for a second.
 

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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
 

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Discussion Starter · #14 ·
Cool, I think I will probably go with the SBC-ID to try and avoid those partial boost problems, after all the car is first a daily driver (work pays for the car), then a street racer/rally car (car gives me something to look forward to at work). Its a win win situation until one is not there anymore, gotta find the right balance.
 

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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.
 

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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
 

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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.
It can't. With the optional Power Meter you can make a speed map where you can adjust boost levels in 10 mph increments. I have both the SBC-ID and Power Meter and have been playing around to see what speed maps work best but I think just setting at a certain psi at all mph yields better results. I think it is mainly for 2wd cars so they can run less boost at lower mph and higher boost once they get traction at higher mph.

Does anyone have the Power Meter and had success with a speed map for our cars?
 

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Discussion Starter · #18 ·
Ok, so anyone who has a SBC-ID, have you had any problems with full boost at partial throttle, thats really all I am worried about.
 

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KanosWRX said:
Ok, so anyone who has a SBC-ID, have you had any problems with full boost at partial throttle, thats really all I am worried about.
Not me, but I have the PE1818 so I don't know if I am any help.
 

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I seem to get this jerkiness as well.....but my engine is completely stock.

It seemed to start happenning at about 5500 miles all of a sudden. Should I be concerned?
 
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