hi folks, not sure if this has been covered, i know there is an equalizing thing to measure the boost from, my question is, if both turbos are putting out say 7psi, what does this show up on a boost gauge?? does it just show 7psi?? and also, would it not be better to have 2 seperate gauges to monitor both turbos?? is this possible?? another quick one(sorry)... i hear of people upping the boost and stuff like that, so if somebody wanted to raise the boost to 14psi, does that mean both turbos are pushing out 14psi each???(basically 2 bar over 6 cylinders) i've been thinking about it, and the more i've thought about it, the more confused i've become :)

 

please help, haha, thanks in advance :blush::blush:

The boost pressure your reading is the equalised pressure at the Engine Inlet, this is where the pressure matters.

 

Each turbo feeds a seperate bank of the V6 seperatly, which is equalised by the Plenum balance bar.

 

Think of it as 2x 1.5 litre 3 cylinder turbocharged engines bolted together.

Edited July 29, 201114 yr by Yowser

that's exactly how i think of it!!! i always say 2 engines running on 1 crank :):) so, with that in mind, there would be 2 bar of pressure from the turbos, (14psi each) so what would the boost gauge show?

that's exactly how i think of it!!! i always say 2 engines running on 1 crank :):) so, with that in mind, there would be 2 bar of pressure from the turbos, (14psi each) so what would the boost gauge show?

 

its not actually as simple as that, there is pressure loss between the turbo, intercoolers and inlet...but for the purpose of your question, you would see 14psi

and also, how would you know both turbos are running the same psi with only 1 gauge??

and also, how would you know both turbos are running the same psi with only 1 gauge??

 

it does'nt really matter. What matters is the Boost pressure entering the engine, which is equalised.

ah, so the equaliser eaqualizes it between the plenum?? sorry, i had in my head that it was for the boost gauge, now i understand :) is there a way to measure both turbos seperatley?? quite like the idea of 2 boost gauges :D

ah, so the equaliser eaqualizes it between the plenum?? sorry, i had in my head that it was for the boost gauge, now i understand :) is there a way to measure both turbos seperatley?? quite like the idea of 2 boost gauges :D

 

Yep, pressure is equalised by the balance bar to each bank of the engine.

 

Boost pressure, in automotive terms, refers to the intake manifold pressure above atmospheric pressure.

 

If you wanted seperate guages for taking a measurement from each turbo, then you would actually need 3 gauges. 1 at each of the turbos that are not accurate for the actual purpose of measuring boost and would only show positive pressure and not vacumn, and a 3rd, the important one, at the Intake manifold, that shows actual boost pressure.

Edited July 29, 201114 yr by Yowser

Yep, pressure is equalised by the balance bar to each bank of the engine.

 

Boost pressure, in automotive terms, refers to the intake manifold pressure above atmospheric pressure.

 

If you wanted seperate guages for taking a measurement from each turbo, then you would actually need 3 gauges. 1 at each of the turbos that are not accurate for the actual purpose of measuring boost and would only show positive pressure and not vacumn, and a 3rd, the important one, at the Intake manifold, that shows actual boost pressure.

 

 

yeah, they would measure the actual psi the turbos were producing, rather than the psi at the plenum, i understand this, that's not what i mean lol, ok, so there's no way to measure pressure at the plenums seperately due to the balance bar :(

yeah, they would measure the actual psi the turbos were producing, rather than the psi at the plenum, i understand this, that's not what i mean lol, ok, so there's no way to measure pressure at the plenums seperately due to the balance bar :(

 

nope, and you wouldn't want to remove that balance bar either, if one side is out of balance on pressure being given to the cylinders on each bank, your engine isnt going to last very long, or preform very well either.

the long of the short is... theres no need for the other two that show your 14psi reading they are an irrelivant measurement. and the balance bar on the plenum is a very important piece of kit :D

so if one turbo is putting out 7psi, and the other 14psi, there's no way to tell?? i understand that the balance bar equalizes it at the plenum anyway, thanks for the replies, i'm just being curios as i'm new to the zeds, i like to learn :)

yes, you can tell because you would only produce like 5-6 psi.

ah i see, so if one is down, you would know because overall boost is decreased, i guess that makes sense, cheers :)

As explained to me: The boost guage measures the pressure in the intake manifold. On tickover it shows a negative presure, because the engine is sucking air and in effect, trying to cause a vacuum in the intake. When you run on boost, the turbos are forceing air into the intake, creating a positive pressure, like blowing up a balloon. I think thats about right, hope it of some help.

haha, yeah i know how it works man, i was wondering if the pressure at the intake could be measured seperatley, but it can't :(

oops, sorry, I misunderstood.