gmazzu

iTrader: (1)

My question is what is the difference in how MBC, EBC and the vishnu method of conrolling boost work when the temperature changes over a period of time. In the Northeast in the winter it can be 0 degress in the summer it can be 100 degress. This will definetly change the way air can the effect a boost controller.

stevEVO8

iTrader: (4)

I dont know that I have ever heard of a boost controller adjusting for temp and densityof the air.

MBC will definitley not adjust for temp/density

Im sure that the EBCs could do it; but why tune your car onthe edge and not allow room for temp adjustment? just keep the boost adjusted accordingly and fuel cut etc wont be too big of an issue.

MalibuJack

iTrader: (5)

an MBC will always bleed a set amount of "Air" out of your "boost circuit" (the loop between a vacuum/boost source and your wastegate actuator) since its fixed, it will always bleed the same amount, unfortunately when the weather changes, so does air density, so on a very cold day, your packing "More air" into the compressor. When it heats up when being compressed, it tries to expand a bit more, therefore your boost is slightly higher.

there are two types of Electronic boost controllers. One will function similar to your MBC, that is, it will also bleed a set amount of air from the wastegate actuator vacuum circuit, it will have gain settings to allow you to improve spiking by varying the amount of air bled off, but basically the stable boost reading would still be slightly higher in extremely cold days, therefore it can potentially need to be readjusted.

The other type of Electronic Boost Controller (which If I recall, many are, but you have to verify that) is Called CLOSED LOOP, it has a pressure sensor (not just for a gauge) and it will allow you to set a target boost, and target spoolup ramp, and other parameters, even gear based targets (to reduce spiking when downshifting, etc) these will generally not vary much in boost when the weather changes because it reads its pressure after the compressor (turbo) does its work and will adjust accordingly to maintain that same pressure regardless.

Hope this info helps a bit.. Took me awhile to grasp this concept at first, its also an issue with altitude where weather and air density will make a bigger difference.. (especially if you go from low altitude, to high altitude on a regular basis where it will need to be readjusted accordingly)

gmazzu

iTrader: (1)

Thanks for the Info, the reason I ask is I'm trying to understang how the tuners are controlling boost. They all seem to do it in very different manners. The closed loop system sounds better because atmospheric conditions don't effect boot as much. I really don't want to be adjusting this thing all the time. Also the turbo isn't very efficient at higher rpms I believe so holding max boost all the way to redline would "over run" the turbo (I believe). Anyone know how the stock computer and selenoid controll boost? If a couple of tuners could chime in here, on their boost controll methods that would be great.

MalibuJack

iTrader: (5)

In the stock ECU, the solenoid is basically on or off.. when its on, it lets a bit more air out, hence raising boost (to its preset level).. (Logically it makes sense so if the solenoid fails, or is disconnected, the boost will be at a safer level.

There two piggybacks out there that will control boost with the stock solenoid by giving it a "Duty cycle" (I'm only aware of one that will do it in closed loop with some addon hardware) Those products are the Vishnu XEDE, and the TurboXS UTEC. Additionally I am fairly certain the standalone products can control boost with the stock solenoid, but the standalones recommend replacing it with a solenoid designed for the application.

And your right about the boost through redline.. Most recommend letting the boost taper a bit at redline (21psi tapering to 19 or so) Mainly because of fuel cut and the fuel system's capacity when its stock. Though even upgraded it makes sense to not overwork the stock turbo.

I'm currently using the UTEC, and will be adding the map sensor to utilize its closed loop features in a few days. I've also used the Profec (had some trouble with it) and the APEXi S-AVCR (which worked great) for standalone boost control.

gmazzu

iTrader: (1)

Can the stand alone boost controllers pull back on the boost as the rpms rise? I assume the hks ebc can do this? I'm trying to decide what tuner to go with. Dynoflash is in CT and is local to me but I need an additional boost controller. I can order the vishnu stuff and install it myself. The Vishnu stuff is expensive and is closed becuase there is only maps for their equipmentand they are across the country. If I go with dynoflash or another tuner I can mix and match parts and have them custom maped at Pruven.

4G63>OOOO

iTrader: (1)

You can also tune the Vishnu stuff yourself...and there are maps out there for at least one non-Vishnu hardware car that laid down some pretty good numbers on pump gas.

The thing to remember with any ECU reflash is that you have to keep forking over money whenever you change something, but with an XEDE or UTEC, you can change the parameters yourself.

catdaddy

JFYI, I have noticed that I can peak at 22psi and drop to 20 on a day 55 degree's or less. When the temp gets up into the 60 dgree and warmer I peak at 20 and drop to17-18. This without adjusting the mbc. Also takes a bit longer to spool up on a warm day.

SinCityEvo

iTrader: (3)

Should we turn down the boost in the warmer/hot summer months? I know I was boosting lower with the warm weather when I was ECU controlled. Now with a MBC, I'm free to set it where I want. Do you think we can do damage by boosting high in warm/hot weather?

yesevo

iTrader: (13)

dont we need to turn more boost up in summer? confusing

stevEVO8

iTrader: (4)

I would tune for less boost in the winter if you are worried. The denser air in the winter if anything would be what you want to look out for.