Whats The most accurate way to set boost?

[grdsm]

What is the most accurate way to set a manual boost controller? I have a aftermarket boost gauge, bigger turbo, egr block off, external wastegate aftermarket bov..... I would like to know what is the most accurate way to set my mbc. I seems that my wastegate opens roughly around 15 and 18 psi. and it boost up fatser at time then others.

 

[1992awdlaser]

Big differences in temperature can cause noticeable changes in spool.

 

[thatblondechik]

Yea I'm not too sure I understand this question. Turn the dial, do a pull and watch your gauge. Not too much to it.

 

[mitsu-luver]

yeah like 1992awdlaser said different temps will effect the way your turbo spools, it mostly depends on where u get your signal from for your wastgate, the closer to the compressor outlet the less heat your inter cooler will soak up , but if you take your signal from the intake manifold it will spool up faster but this burst of boost will cause the efficiency to drop from all the heat that came out of the compressor outlet. if your wastegate signal is not already hooked up to your compressor or close to it try doing that

 

[1992awdlaser]

Actually, having it at the intake manifold is the best spot.

"Reason : You want the pressure source after the intercooler because there is a pressure drop across the core. If you take the boost source from the J-pipe, then you will be taking the reading from a source that will drop in pressure after it travels through the intercooler.

Example:

MBC is set at 25 PSI
25 PSI at the J-Pipe (Pressure source is taken from here)
Boost Travels through intercooler
Exit pressure out the intercooler is only 22 PSI

In this case above, the boost will only be 22 PSI in the motor, even though the MBC is set to 25 PSI. This is because the boost source is taken pre-intercooler. This causes very inconsistant peak boost pressure because changes in the weather will alter how much of a pressure drop there is through the intercooler core.

The larger the turbo, the larger the pressure drop through the core. This is why it is always best to take the pressure source as close to the motor as possible so that you get consistent boost peaks."

 

[MrBoxx]

I'll speak up for oldman here. I'm sure he would respond by saying that taking the MBC pressure signal from the intake manifold is "okay", as long as the signal is not taken from the BOV line.

 

[mitsu-luver]

haha sure the signal taken from the intake manifold will cause better boost peaks that's because the turbo is free to make all the boost it wants until the wastgate cracks, that's just a way to get better boost response (it seems like everyone's afraid of lag ). just get ## signal from the compressor outlet and hook ## boost gauge up to ## intake to get an accurate boost number at all times. the only time u should hook it up to the intake manifold is when boost response is the MOST important to u! and a blast of HEAT to your inter cooler is fine with you

 

[1992awdlaser]

Did you even read my post? It wasn't about response, it was about stable boost.

 

[kris_stewart10]

well 1992awdlaser i think that was an awesome post i wish i knew that when i had my gst i ####ed it all ways to sunday

 

[mitsu-luver]

ok well if were talking about stability (which i was in the first place) if you hook it up to the intake manifold it will take longer (and maybe go over the desired boost pressure) to make the wastegate crack open thus giving a false boost pressure. if you put it close or on the compressor housing the wastegate will open sooner and the chance of boosting over and or falling of is small, but its really up to you.

 

[knochgoon24]

ok well if were talking about stability (which i was in the first place) if you hook it up to the intake manifold it will take longer (and maybe go over the desired boost pressure) to make the wastegate crack open thus giving a false boost pressure. if you put it close or on the compressor housing the wastegate will open sooner and the chance of boosting over and or falling of is small, but its really up to you.

So for clarification (if I understand correctly), you have 2 options.
1. Take it from the intake manifold.

Pros:

• You get the actual boost reading at the motor.
• More stable peak boost pressure.
• Better boost response.

Cons:

• You may "over-boost". Aka, the pressure will be higher on the hotside of your IC, but not the motor.
• Blast of hot air to the IC.

Am I even understanding this correctly?
2. Take it from the compressor housing or pre-IC.

Pros:

• The reading will be the max pressure in the system
• No extra blast of hot air

Cons:

• Peak boost pressure will change with the weather

 

[mitsu-luver]

yeah you pretty much got it down

source from intake manifold:
- slightly faster boost response
-induces intercooler heat soaking

source from before ic:
-slower boost response
-best control over wastegate

the source in which you hook your wastegate from is not a way you should try to get
around upgrading to an external system or choosing a better manifold design (not saying you are)
if you really want to put you boost on a leash upgrade components from the hot side of the system. especially you wastgate setup
and make sure there is not leaks.
and adjust boost from what the motor is actually reciving after the intercooler and whatever else is in the way before the air gets to the motor.
other wise adjust boost from your gauge hooked up to the manifold so you know what you motor is actually receiving, if that made sense its hard to explain

 

[grdsm]

calm down ladies


Its okay I have an larger ic on it.

currently the line is coming off of the intake port to a T fitting one line off that to my bov and the other to my mbc to my wastegate. I was just asking Didn't mean to get everyone panties in a bunch, Damn wear thong ladies, leave the granny panties for grannies.

 

[1992awdlaser]

ok well if were talking about stability (which i was in the first place) if you hook it up to the intake manifold it will take longer (and maybe go over the desired boost pressure) to make the wastegate crack open thus giving a false boost pressure. if you put it close or on the compressor housing the wastegate will open sooner and the chance of boosting over and or falling of is small, but its really up to you.

I understand why you think it will take longer but it won't, not where you could notice anyway. The only con to having it at the intake manifold is, you have a longer line so there i more room for a boot leak. I guarantee it, I wouldn't have mine hooked up there if it would cause any problems.

Why do you think it will induce heat soak, because it won't?

 

[jrohner]

The boost is definitely more consistent when the boost controller is going from the IM. I didn't reall notice that it spikes any worse either.

 

[toofast82]

I think either way is effective as long as you dont tee off the bov

 

[mitsu-luver]

i wasn't saying its gonna make a huge difference but it does make a small difference it pretty much has to do with the heat from the quick spooling instead of slowly. not a big deal i was just breaking it down
i was just trying to give him some advice.

 

[rEclipserGST]

^OWNED

UmMmm... heat soaked? Im STILL a noob, but i would really doubt that your "upgraded" IC would get heat soaked just from teeing off a bov OR the manifold. Actual Boost would be affected... but isnt it better to be safer than sorry? Im sure the pros would just use a... idk... EBC. That tells EXACT boost and such. Just put the damn thang where its SUPPOSE to be. Stop being ridiculous. Arguing silly points and such. MBC and digital boost gauge or Electronic Boost Controller. BOOSTIN.

 

[grdsm]

If your are not supposed to tee off the bov then how?

 

[dsmfa9nutter]

Drill a hole in your piping within a foot after the outlet of your IC, tap it, run a hose barb off of it. There's your perfect wastegate signal.

 

[Imback]

Interesting . Does anyone have any pics of there set up like this ?

 

[turbosax2]

I agree with 1992awdlaser. This is how we have my brothers car set up now and his boost has been more consistent between runs. His boost spikes maybe 1 to 2 psi before settling in, but this also happened when we got the boost source from the j-pipe. Spool-up time did not change between the two ways. We have his boost controller tapped into the fpr vacuum line, which also feeds his boost gauge. The mbc is kept close to the turbo so the line from the mbc to the wastegate can be kept short as possible for fast reaction time.

 

[dsmfa9nutter]

If you follow the vacuum line, that's where my hose barb is coming from.

 

[1992awdlaser]

Drill a hole in your piping within a foot after the outlet of your IC, tap it, run a hose barb off of it. There's your perfect wastegate signal.

It's easy for people like me. The only vacuum lines on my car are the ones I need(fpr, boos gauge, wastegate, bov). All of them are routed to the intake manifold via factory fittings. You can also hook it up to the P port on the throttle body or T into the fuel pressure solenoid.

 

[slowgsr]

well.. on like a tial wastegate for example, always supposed to get the boost source FROM THE COMPRESSOR HOUSING, or else its hard on the diaphram. This is a fact. Call Tial and ask them, they will explain it to you. I have done it from the manifold in the past, but i don't anymore. I get 0 creep, 0 spike, no nothing. Everything works the way it should.

As far as controlling it.. a good ebc or ems that can control duty cycle, keep vac lines short from/to the solenoid, and dont try to go 1.5x more than your WG spring.. You can start running into issues.

Goodluck.