Hi, I've found lots of threads touching on this but not giving a definitive answer.

My 20VT gives 0.5 bar in first and second gears, and 0.8 bar in others. I occasionally see overboosts to 1.0 bar.

Is this what I should expect?

This sounds a bit low. Your wastegate might be a bit weak or your EBV is a bit lethargic. Your boost gauge could be out of course.

You should get anything between 0.9 to 1.1bar sustained boost and 0.8bar ish in 1st and 2nd with a healthy standard car.

On my car I get a sustained 0.6 to 0.7 bar of boost, which can spike up too 1.1, when I'm giving it a bit of stick.
I think this is about right for a vertually standard car.

.8 to .6 bar holding depending on revs and gear, with upto 1.1 bar overboost is normal.

It varys from car to car depending on actuator pre-load and EBV condition as mentioned.

But anything lower then above and its worth getting it checked out.

edited to say; Sorry correct .6bar to .9bar holding... typo

You see, ask a question and get three different answers

I think there is some confusion over what is considered sustained boost, overboost etc,

The actuator itself can hold 0.5-0.7bar without any boost control at all so you should get much higher than this sustained.

My definition of sustained is 3Krpm in third gear accelerating to 4Krpm or so where a standard car should achieve 0.9b/ 1bar no problem. Once you get past 5Krpm the boost level will start to fall.

Thanks for the info. I've got a GrahamL chip to fit today, will be interesting what difference that makes. I suppose I can risk a quick test run before getting it RR'd.

My boost gauge is made in England and was recommended as accurate by the shop. It reads zero with engine off and doesn't flicker at all. Still could be a culprit though.

I suppose the next step would be to try a PRV to eliminate the EBV being a problem, or is it worth giving the EBV a clean up?

Hey cosmo, I've PM'd you.

PM'd back

You can try cleaning the EBV but Ive not had much success with this myself.

SkyHigh - you wanna come along to SRR this Saturday? I only ask because you were down to come on 30/12 before they started putting the dates back. (Cosmo will be there too)

Yeah I'd love to come but typically I've got Mon-Fri off and then have to work on Sat! I've got in touch with SRR to arrange my own test, billy-no-mates style!

Can't be bad. All of December off then you only have to work 1 day a week
Have a good 'un when you do go.

actually according to fiat the 16vt should overboost to 1.05bar and constant boost should be 0.8bar the 20vt should overboost to 1.2bar with 0.9bar constant boost.

Have a look on this one, in the general data section.

http://www.fiatcoupehistory.com/e_daten.htm

Regards,
Hani

A standard 20VT should hold 1 bar mid-range (say 2800-5000rpm).

hello,
I think of having the same concern. I do not have a overboost and in fact, my boost gauge always indicates 0,8 to 0,9 bar on all the reports/ratios.
It is one 20 VT; I checked the hose connections, cleaned my EBV (I even changed it) and anything better. Nevertheless, I noted that the overboost is active(on) when the engine is not yet too hot: I think I have troubles with one of the captors>that transmits bad information to the ECU and so the EBV doesn't work correctly.

chr77176, keep me posted if you find a fix.

I've now fitted a GTEC1 chip and there's a noticeable improvement. Boost level 3-4k revs is now 1.0 bar, overboosting to 1.1 bar. So this seems to be more like a standard car, but not the boost levels I hear most people get with GTEC1 chips (1.2 bar I think).

Now that I get a higher boost level with the GTEC1 (albeit less than it should), does this help at all in diagnosing possible causes?

okay,
today i went to fiat. we have test the car with the Fiat examiner and the results is: 0 fault....GRRRRRRRRRRRRR
the mechanic said to me, i should try to disconect the air t° sensor to pass my car in RECOVERY mod and see what happened.I ll try today!