lower than expected boost

[chardo]

Ok, so I have just fitted a boost gauge, and seem to be getting less than expected boost levels.

The gauge is reading about 20 mmhg when decelerating, which seems to be about expected. However the boost is only reaching 5 psi and spiking to 6 on one pull in 3rd gear.

I have a HKS ssqv which does not seem to be venting as loud as it used to, however I have also replaced a custom cold air box and pod filter with a standard air box, so that may have contributed? Or it may be a figure of my imagination...

Any input its welcome.

cheers, Richard

 

[veegeeta]

check boost solinoid sounds like your running waste gate pressure.

 

[chardo]

How do you check that?

 

[Nitephyre]

3-port and SteveTune stat!

 

[Guest]

Try using a boost gauge with Psi or Bar as well,as mmhg Is terrible, My Skyline had a mmHg boost gauge and they are a pain in the ass to work out what it is actually saying in Psi.

 

[tails]

Try using a boost gauge with Psi or Bar as well,as mmhg Is terrible, My Skyline had a mmHg boost gauge and they are a pain in the ass to work out what it is actually saying in Psi.

Don't they only use mmhg (or inhg) for vacuum though? Every PSI gauge I have ever seen has used inhg (inches of mercury) to measure vacuum.

 

[chardo]

The gauge is PSI I just thought the vacuum side was mmhg I may be wrong though.

 

[Badger]

Don't they only use mmhg (or inhg) for vacuum though? Every PSI gauge I have ever seen has used inhg (inches of mercury) to measure vacuum.

Yeah Im pretty sure that its like that, under 0 is measured in mmgh/ingh, over 0 is psi

 

[chardo]

so, tesing this solenoid?

 

[TME_Steve]

Gauge sounds fine, you're running wastegate pressure....

 

[chardo]

ok, so after a quick search, all I need to do is directly connect each of the two vacuum tubes that run into the solenoid?

And Steve how often if ever do you, come through Canberra to tune? (or am I better coming to you)

 

[Black_Ice]

Definitely better going to Steve since you arent too far away...dont think Steve has ever gone to Canberra for a tune...

 

[noony]

I'd be interested in getting a tune as well. Road trip weekend maybe?

 

[veegeeta]

to test solinoid take small pipe of intake that leads back to boost solinoid start car rev it past 2000 rpm and blow in pipe. If you cant blow into it ( like its blocked) then it doesnt work. if you feel pulsating and its taking your air then its working . Make sense? easy to test

 

[Lasiorhinus]

Id be interested in a boost gauge that reads entirely in inches of mercury. It takes far too much effort for me to convert PSI to inHg.

 

[Guest]

Standard R34 GTT boost gauge does it. Pain in the ass to work out, stupid set up hey. Sorry to get off topic.

 

[tails]

Its the only time where the metric system sucks as were so used to them using pounds and inches of mercury.

I'm pretty sure you can't use INHg to measure pressure as its just a measure of vacuum. Vice versa for psi.

 

[Guest]

Worst boost gauge ever mate, I hated mine so much. -700mmHg to +1KG/CM2 doesn't even seem like a real thing haha. It's like one of those made up car things from the fast and the furious movie's haha.

 

[TME_Steve]

Definitely better going to Steve since you arent too far away...dont think Steve has ever gone to Canberra for a tune...

Better to come to me for dyno use a I'll be cheaper than most and unless you want to wait till march/April, I'm not planning in coming to Canberra. Happy to do a trip then though

The solenoids are fussy heaps of crap, they rely on not having a flood of air to them with restrictors and stuff that can easily go wrong, resulting in virtually no effect. And they're old and they fail.

Best thing to do, get a tune and 3 port failing that, just by a cheap mbc and use that for now....

 

[TME_Steve]

Metric is awesome, it should all be in kpa in my opinion but everyone knows pounds....