Double The Boost Reading Wtf?!

[YCOPY]

Ok, so I have a strange issue...

I have a HDi SBC-D-EVOLUTION bought it brand new from HDi earlier this year, when I had this installed I took the car to the dyno just to set it up and do some runs.

I found that the controller / gauge is reading 18.5 psi...and the dyno printout is reading 9psi. so the HDi is reading what seems to be double!

So I have installed a autometre mechanical gauge in and yep, I only get 9psi.

Now ive spoken to HDi and tried everything they have asked, ive had it re wired several times,moved the vac lines used "specific" VAC lines also. so after ive done all this still no good...

last week i sent it away to HDi and they have tested it and told me that the gauge and the controller are working 100% perfect and to check my wiring as it must be that...I had it reinstalled again on the weekend and its still reading double the boost!!

Has anyone had this sort of issue?? how the hell can it read double the boost!

[YCOPY]

so i tried another mechanical gauge today just to check...its in the same vac source as the HDi controller and same this happens...the HDi is 18...the mech is 9.

any ideas??

[Moodles2]

This may sound like a silly question, but is the HDi gauge actually in PSI? 9 psi converts to 18.3 inHg (inches of mercury)

[YCOPY]

It is definitly PSI, the digital is PSI and the analogue is BAR

its reading around the 1.2BAR.

[Silo_Wagon]

It is definitly PSI, the digital is PSI and the analogue is BAR

its reading around the 1.2BAR.

Im only new to turbos and shit, my gauge was reading 20psi on dyno and the dyno said 12 psi

[YCOPY]

see thats what i dont get..dyno was9,my mechanical gauges all read 9 but the HDi reads 18.5...the vac part of the gauges all read the same @near on 20Hg but the moment you boost they are different.

Im half tempted to take it out and stick it in my daily thats not turbo and see if it produces some strange reading...its just such a pain in the arse!! all this time on it and HDi are telling me its perfect and its clearly not..

[Munkyb0y]

have you checked the installation/wiring yourself? you said you 'had it installed' twice. maybe the installer fkd it up twice.

[YCOPY]

I have redone the wiring myself, i didnt see anything wrong with the first installs but i changed it anyways...I have tried 2 different areas, one was off the headunit and now its sitting off the back of the ign,same as the turbo timer.

[Moodles2]

What are you using as the pressure source for the HDI unit?

[YCOPY]

Ive had it @ the nipple off the cooler pipe,off the FPR,off the back off the plenum where the stock gauge feed is from. its on the FPR @ the moment as thats how HDi asked it be installed..

Ive even had it in the same line as the mech gauge but was told by HDi to take that out as that could cause the issue..

What are you using as the pressure source for the HDI unit?

[Moodles2]

Sounds like HDi only checked the gauge was working, not that it was calibrated. Really need an aircompressor set to 9psi supplying air through a hose to the HDi gauge to prove its calibration is way off.

[count_rye]

A proper calibration is needed for 'zero' and 'span' for both the gauge pressure and absolute pressure. A pressure transducer also needs a stable power supply, a good multimeter may come in handy at these kind of situations. Calibration also includes a reference gauge or more often called a Master Gauge to tell whether the supplied(simulated) pressure and current(mA) are calibrated with each value.

Cheers.

[YCOPY]

So is there somwhere i can get this tested?? or am i best to chuck it in the bin now and be done with it...

A proper calibration is needed for 'zero' and 'span' for both the gauge pressure and absolute pressure. A pressure transducer also needs a stable power supply, a good multimeter may come in handy at these kind of situations. Calibration also includes a reference gauge or more often called a Master Gauge to tell whether the supplied(simulated) pressure and current(mA) are calibrated with each value.

Cheers.

[count_rye]

Basically, it's best to have the manufacturer calibrate it for they know the zero and span adjustment of the component but if you know someone(preferrably a friend) with an electrical/electronic/control engineering background, with a master gauge, compressed air source, a multimeter, and possibly a current simulator, he could easily calibrate that at a cost of a burger,hehe If it still works but out of range, it can be fixed.

Im here in Dubai, dont know where in Australia you could find that someone aside from the maker, sorry.

Goodluck though, mate.

[YCOPY]

Ah ok cool, i work in an engineering company (im in IT)... i will ask the guys tomorrow.

Thanks for you help

Basically, it's best to have the manufacturer calibrate it for they know the zero and span adjustment of the component but if you know someone(preferrably a friend) with an electrical/electronic/control engineering background, with a master gauge, compressed air source, a multimeter, and possibly a current simulator, he could easily calibrate that at a cost of a burger,hehe If it still works but out of range, it can be fixed.

Im here in Dubai, dont know where in Australia you could find that someone aside from the maker, sorry.

Goodluck though, mate.

[count_rye]

Okay then, hope it'll save you from buying a new boost gauge.