chiefboon

I am considering removing my cheap Autometer boost gauge and relying on my Blitz Dual SBC for boost monitoring, the only question is whether the boost displayed on the Blitz is accurate? Does anyone have any advice / comments?

With the peak boost display and especially the Alarm / Warning feature that reduces power whenever the warning value amount of boost is reached, I believe I can just set the boost level where I'd like it and rely on the unit to make sure the boost does not exceed a certain amount (and log the highest amount of boost reached) -- eliminating the need for a more visible boost gauge for my purposes.

Any thoughts? General consensus on the net is that the SBC appears to be accurate, agreed?

I searched but did not find this discussion.

Thanks,

Stephen

Narfle

iTrader: (16)

Yes, it is accurate and should do a good job of managing your boost if installed and tuned properly.

arghx

iTrader: (3)

Accurate relative to what?

chiefboon

To the actual, true value of boost the unit is attempting to measure... Maybe not sure what you are asking, sorry.

R-R-Rx7

iTrader: (24)

while i have the SBC and im very happy with the results it provides, i still have the mechanical boost control. no harm in double checking.

You should expect a
~+/- .5 psi difference between the two (given that both work as they should)

at least if something goes wrong with your boost gauge u have something to confirm that something is wrong.. i blew an engine thanks to a stupid boost gauge

arghx

iTrader: (3)

Boost is relative to barometric pressure. If you put three devices that measure boost in your car, they are going to say three different things unless they are somehow calibrated to some "objective" measurement of pressure. Any boost gauge (mechanical), pressure sensor, etc is calibrated from the factory in a certain way. There are also production tolerances that make different gauges or sensors read differently.

The point I'm trying to make is that measuring "true value of boost" isn't really achievable in this scenario. You may go WOT and your boost controller would say 16psi, your MAP sensor (what's used to calculated fuel and timing) would say 15.25psi, and an external boost gauge may say 16.5psi . So which one is right? The only way to know is to compare to a known calibrated instrument. Even then there isn't much you can do about having three devices that read differently.

Narfle

iTrader: (16)

I think you're getting away from the scope of the question, arghx.

The dude just wants to know if the SBC is relatively accurate and good at controlling boost. Which I would say it is.

Let the MAP sensor worry about altitude and barometers.

7dust

iTrader: (14)

I use my Blitz boost controller as a boost gauge and its great!

Its HORRIBLE at maintaining stable boost (with my Synapese 50mm) Ive been ******* around for months and can't get it to work just right. Garbage.

arghx

iTrader: (3)

I see how my responses come across as making a simple question complicated. There are other threads where I take seemingly simple questions and give complicated answers. Just FYI, the reason why I do this is because I disagree with the premise of the question in the first place. I intend no disrespect and I'm not trying to be difficult or verbose in my responses.

To me there seems to be an element of "is the Blitz more 'correct' in its measurement of boost than an autometer/Sunpro mechanical gauge?" Or is it at least close? And the answer to that is, they're all 'wrong' to some degree. You can monitor boost with your engine management system (PFC Commander, whatever), an external gauge, or a boost controller display. They will all say something different. Typically a cheap mechanical boost gauge will be further away from the readings you get with other devices in the car. So by that metric, the Blitz will be a suitable substitute. I understand the desire to eliminate clutter inside the car.

Aftermarket boost controllers are basically all the same. There are a couple basic designs but they all pretty work the same way. The Blitz is functionally the same as an HKS EVC (stepper type, not the EVC-S). Compare the designs of the actuator units and the settings in their respective controllers. It's as good of a boost controller as you can make it. If you have a mechanical problem with your boost control, it won't do a good job. If you don't understand how it works, it won't do a good job.

I've never seen a bad boost controller (unless it was actually broken). Most of the time boost controller really are mechanical boost problems, or it is a case of the operator having trouble figuring out poorly-written instructions (Profec Spec II for example).

arghx

iTrader: (3)

Create a new thread in the single turbo section. I may be able to help you out with this. There are a lot of things you can try.

The Warning and Limiter functions of the Blitz will not save you in the event of wastegate failure. All it does is disable boost control at the solenoid unit. It doesn't pull timing, it doesn't cut fuel, it doesn't cut spark. If your wastegate sticks or the lines fail, you will still overboost. This is why I recommend some kind of overboost protection through your engine management system. For most people, the easiest way to do this is to set an overboost fuel cut in their Power FC as a last resort.

I discuss this in my big thread on the PFC Commander:

Narfle

iTrader: (16)

I'd love to see you delve into the physics of air density and relative pressure. I just thought we were shooting squirrels with a .30 '06.

7dust

iTrader: (14)

Nah. Again - great (and expensive) boost gauge. Garbage boost controller.

chiefboon

In short, this really hit the nail on the head for me: "Typically a cheap mechanical boost gauge will be further away from the readings you get with other devices in the car. So by that metric, the Blitz will be a suitable substitute. I understand the desire to eliminate clutter inside the car."

However, it was an open-ended question and I appreciate the lengthy responses and opinions. I believe the solution is that I will remove the poorly-functioning and eye-sore of a mechanical boost gauge, rely on Blitz for boost readings and will look into the fuel cut features of my PFC to protect the motor.

I'm glad to hear others find the Blitz to be an accurate reading. I will agree with 7dust that for whatever reason the controller itself is less than perfect. I don't have a problem overboosting -- my problem is that I will attempt to fine-tune a certain amount of boost, and when I mash the throttle in subsequent pulls (same day or later) it is not uncommon at all for the boost to reach a max of 1-2 psi less than intended. I could look more into it but am not fit to discuss at the moment, as the unit was installed by previous owner (actually a performance shop).

Thanks all.

arghx

iTrader: (3)

For the record, I use my Power FC for everything. A couple years ago I got tired of having so many boxes and gauges in my car. I don't have a boost gauge or separate boost controller. I like to do the same thing on Subarus, which have a good factory boost controller and a factory 2.5bar MAP sensor. With the Cobb programmer you can read boost and swap to low or high boost maps.

If you do want some input later, explain how the plumbing is hooked up and tell us your settings.

7dust

iTrader: (14)

^^^ What that guy said. Under or over boost target no matter how much you jack with it. Overpriced POS.

I have it because I think a shitload of gauges and gadgets in the cockpit is ricer-ific. The Blitz displays boost pressure in PSI and its a boost controller. Seemed like a great way to eliminate clutter. Too bad it sucks.

Of course, it might also be the Synapse wastegate. SO, I guess I'll settle for saying they BOTH SUCK!

7dust

iTrader: (14)

arghx, you think I can kick the blitz to the curb and run a synapse 50mm using the PFC commander for low and high boost with a stock or stock-ish boost control solenoid?

chiefboon

WHAT. I didn't realize it had this feature, downloaded the instruction manual and have played with it a lot -- didn't realize it could display PSI?

7dust

iTrader: (14)

^^^ Well yeah - thats why I got it.

Main menu - unit - psi

7dust

iTrader: (14)

^^^ Blitz SBC i-d.

arghx

iTrader: (3)

You would need a Datalogit