Defi and Syvecs 4bar disagreement!

[dr_jones]

Now I understand that the DEFI gauges someof us know and love can be somewhat 'optimistic' in terms od boost pressures.

That aside I seem to have a 'larger than expected' disagreement between Defi and Syvecs 4bar sensor:

Defi - 1.3 bav
Syvecs - 2100 mbar

...Giving an apparent mismatch of very around 0.2 bar.

Just checked my 4 bar linearisation and it looks correct (right from the Db) and at atmospheric pressure at around 10m (ish) above sea level I see 1022 mbar (1.227v).

Anyone else seen this large an error between the two?

[RICE RACING]

http://www.fluke.com/fluke/auen/process ... ?pid=73941

I have and use a Fluke 700G06 (0-100psi gauge pressure) certified instrument to check any pressure sensors I fit up.
Personally have seen variations but not of that magnitude you report. Either way myself I don't trust anyone's database entries and always check them, but that is just me

[stevieturbo]

As above.

Whilst not a super accurate gauge either....get a Mityvac or other means of testing such sensors and test them. This one can do both vacuum and pressure.

You could choose to add another mechanical gauge to this that may be more accurate for any tests ( or an electrical gauge of some sort...but mechanical is nice and simple ). But do avoid really cheap gauges, I've had loads in the past and 2 the same type, make etc can read very different ( talking £5 industrial gauges here so I guess probably shouldnt have any expectation for them to be good )

http://www.ebay.co.uk/itm/MITYVAC-MV855 ... Swt7pXMsTO

[TimH]

I've heard many reports of Defi's being 0.2 bar out so I wouldn't worry. The Syvecs 4 bar is very unlikely to be wrong - the KA sensors we sell each come with their own individual calibration sheet, but not sure about the Syvecs ones?

[stevieturbo]

Where possible or any doubt whatsoever, always test

[dr_jones]

Thanks All - If the syvecs sensor is indeed OK (unfortunately I don't recall ever seeing a separate calibration sheet) then then the linearisation from the db must be out I guess - which I'm somewhat surprised by - I do note that there are two (or three) hint points that load up with the curve (straight line of course) - which also seemed a little odd.

I'll have to figure out a 'cost effective' method of calibrating manually - did have a look at the Fluke 700G - nice bit of kit no doubt - little out of my price range!!!

[TimH]

Is your 4 bar a KA or a Syvecs one?

[dr_jones]

Just going to double check...

Edit - definitely syvecs - the 4 bar version - no markings at all - but this is it:

http://webdev.syvecs.co.uk/wp-content/u ... yvec-5.jpg

[TimH]

Syvecs 4 bar linearisation looks more like 3.5bar data to me!

[dr_jones]

As default high (4.5v) is 3.5bar?