Closed Loop???? Open Loop????

[P11GT]

After looking thru many of the boost controler on the market, ive noticed that most of them state that they are for closed loop applications. so as im gonna be using an HKS SSQV blow off valve, then will my open system still be compatible with these products? i just fancy something real tricky to go on the dash i suppose.

text:
SBC i-D (Sequential Boost Controller)

Blitz's latest boost controller keeps the same superb solenoid unit as their Dual SBC boost controller, but adds features found in no other electronic boost controller. For starters, the SBC i-D has four selectable boost settings, plus short-term "scramble" boost, overboost alarm, peak/hold boost gauge, and digital and bar graph boost displays. But then there's the infrared link to the Power Meter i-D. When installed side-by-side, the two devices can communicate to provide speed-dependent boost control, plus logging of boost during timed runs. The SBC i-D is the first electronic boost controller that we know of that can display boost in any units you want, including PSI. At long last, there's a boost controller that speaks your language! No more converting bars or kg/cm2 to PSI... The SBC i-D control unit is half-DIN size and only 0.6" thick, for easy mounting in a radio slot, or any other convenient location.

[ky_infiniti2000]

Doesn't closed vs. open loop have to deal with the O2 senor?

[qab5b]

Closed Loop is when the Engine Computer constantly adjusts air/fuel mixture based on the Oxygen Sensor. Open Loop is how the computer acts WITHOUT the O2 sensor (i.e. the computer uses what it thinks to be a good air/fuel mixture constantly.)

[P11GT]

so by fitting a blow off valve to a closed loop system, does it mean thats its now an open loop system? or am i just confusing myself now?

[qab5b]

No. In order to be running a open loop system you would have to remove the oxygen sensor. If you have an oxygen sensor plugged into your engine computer then your car will always run closed loop (except for the first minute or two after turning the car on and the oxygen sensor is warming up).

Some background info that might help:
The oxygen sensor is used by the computer to determine the amount of oxygen in the exhaust compared to the ambient air. It then uses this information (output of the sensor is voltage variations) to determine if the engine is running too lean or too rich. The computer will then constantly adjust the time the injectors stay open to attempt to get the best air/fuel mixture for power and emissions. If you hook an Air Fuel Ratio Meter to your O2 sensor, you should see the lights dither back and forth from rich to lean, and back (except under full throttle or coast, depends on the maps air/fuel maps in the ecu eprom): this is normal and the computer is doing its job. This is Closed Loop.

Open Loop is when the Engine Computer ignores the mixture output of the engine (like no Oxygen Sensor to tell it whats happening). Now it will use a set of predefined APPROXIMATE air/fuel ratios. This is NOT optimal for power or emissions. Your engine could be running very lean (or rich) and your engine computer wouldn't know it and thus wouldn't adjust the mixture.

Hope this helps

[P11GT]

yeah thanks man, i do have a air/fuel meter and it does go back and forth except on thottle, as it says.

[T4 Primera]

Firstly here's the definition of closed and open loop control systems:

Open loop.
The control system (ECU) takes the input (airflow and throttle position) and produces output signals (signal to the injectors and ignition timing) based on predetermined fuel/air and ignition timing maps.

Closed loop.
Same as above but there is a feedback loop to the ECU from the O2 sensor. The ECU takes this signal and modifies it's original fuel output signal to obtain the correct fuel/air ratio.

Not sure whether the Blitz you are looking at means this or if it means a closed air intake system. A phonecall to them should sort it out .

Sidenote:
Some people have a preference to recirculate the vented intake air (from blowoff valve) since it has already been metered by the MAF.

[P11GT]

the good thing is, with the HKS SSQV i do have the option of recirculating it if need be i.e. if the car runs rough when the air is dumped into the atmosphere, so i guess i will probably go for the AVC-R to control the boost.

[ric]

wait a sec, i dont think this guys talking about closed loop, open loop ecu functions. if your running a stock ecu then there should be no way of turning on and off the closed/open loop system. i know for honda's closed loop only happens when the primary oxygen sensor hits about 600 degrees, and even then closed loop is only functional during low and partial throttle positions. untill the warm up the car functions in open loop mode for all throttle percentages and makes calculation corrections based on MAP or MAF values and IAT sensor against pre determined fuel and ignition maps. once the o2 sensor is heated and functional open loop mode only occurs at heavy to WOT loads. now this may be slightly different for you boost readable boys but i cant see how you could engage or disengage open and closed loop mode?

are you sure that he isnt talking about open and closed loop mode when refering to the wastegate dump? closed loop when dealing with wastegate dump means the excess exhaust from the wastegate is routed back into the exhaust system (18 inches into the downpipe is considered universaly standard, any shorter and you can have power loss) and open loop when refering to wastegate dump is venting the exhaust from the wastegate directly into the atmosphere. open loop mode has more power potential but is enviromentaly unsound and loud as hell, ive heard it compared to a jet taking off, literally.

by the way just install the ssqv after the intercooler and dont worry about routing the pressure anywhere since its only pressurized air. remember its helping to prevent compressor surge during sharp off throttle movements. one thing you may want to experiment with is venting that blow off valve into the intake side of the intercooler, it may or may not help reduce pressure drops across the core..

and if i am off beat on anything please do tell, as you can see im a dumb honda guy but willing to learn :smoker2:

[b-b00gie]

Originally posted by i like naked girls

are you sure that he isnt talking about open and closed loop mode when refering to the wastegate dump?

Actually I think Kevin was under the impression that open and closed loop referred to the BOV recirculating or venting to atmosphere.

Originally posted by i like naked girls

by the way just install the ssqv after the intercooler and dont worry about routing the pressure anywhere since its only pressurized air.

This is not correct. On a car with a MAF you should route the air back into the system.

Originally posted by i like naked girls

one thing you may want to experiment with is venting that blow off valve into the intake side of the intercooler, it may or may not help reduce pressure drops across the core..

Almost... I wouldnt really be as concerned with pressure across the intercooler as I would be with letting metered air escape and having the air/fuel mix be out of wack.

The proper place to re-route to would be on the pipe in between your MAF and Turbo.

[ric]

Originally posted by b-b00gie


This is not correct. On a car with a MAF you should route the air back into the system.

sorry i live in the land of map sensors so yes i guess that would be right.

[P11GT]

Yep, thanks Brian, i was refering to the BOV, i just got a bit confussed about it all. I thought that open loop / closed loop was refering to how you vent / recirculate the air, but as ive found out, its nothing to do with that as such, but more to do with how the engine reads the airflow going in.

[T4 Primera]

Originally posted by P11GT
Yep, thanks Brian, i was refering to the BOV, i just got a bit confussed about it all. I thought that open loop / closed loop was refering to how you vent / recirculate the air, but as ive found out, its nothing to do with that as such, but more to do with how the engine reads the airflow going in.

I'd still call the supplier and find out from them for sure rather than rely on our internet musings

[P11GT]

Ive asked a guy before about it, explaining my setup and he seems to think its fine.

[v_knot]

So is there an answer to the original question? Will the Blitz SBC i-D boost controller be compatible with the HKS SSQV BOV setup?