Hi,

I'm driving a 2009 Grande Punto 1.4 T-Jet which drives really really great i must say.

Only thing that it has, and with me a few other members on the dutch facebook group, is that when pulling from 3th, 4th and sometimes even 5th gear you feel little hesitations. Like turbopressure is gone sometimes a bit or the wastgate is opening (too early).

I've made a few logs with multiecuscan with the desired and actual boost pressure (and a lot more ) and i'm noticing that low in rpm my actual boost presure is way too low and in midrange between 0,1(4th gear) and 0,2 (3th gear) bar (100-200mbar). I think this actually a lot.

Do you have any clue what could cause this hesitations and/or this difference in boost pressure?

Otherwise the car drives absolutely fine with a fuel consumption of 14,5 km/l (measured with fuelio over the past 20k km).

Hi

What filtration system are you using??

(How stock is the motor.?)

Hi,

Filtration is completely original, only changed it with a new oem one this summer, but that didn't change anything.

I've bought a k&n 57S-3300 but haven't installed that yet

onnaj said:

Hi,

... I've bought a k&n 57S-3300 but haven't installed that yet

Click to expand...

Clever decision, fix your issue(s) before bringing modification(s), otherwise You'll never know where it comes from ...
Beside the initial lag, I can't see big discrepancies in your logs, have converted them to an excel sheet if you like it ...

BRs, Bernie

If someone here helped You fix -or better, understand- your issue, hit the thanks icon @ bottom right corner, it's free and makes us feel helpy ;-)

Thanks Bernie, would really like to receive the file

But isn't 0,2 bar in mid-range a big difference? And is there initial lag normal?
Any idea about possible cause?

Not sure if the forum allows .xlsx file to be uploaded; if not send me your mail address in PM and I'd sent it to you.

The initial lag is normal since the turbo needs some delay to spin-up when requested, about the "missing" 0,2 bar, it's hard to tell if it's significant; for sure it would be nice if the actual pressure curve would perfectly fit the desired pressure one, but I think it's a bit of utopia ...

BRs, Bernie

ps: had to zip the file ...

If someone here helped You fix -or better, understand- your issue, hit the thanks icon @ bottom right corner, it's free and makes us feel helpy ;-)

Hi,

Thanks for uploading!

I've made 2 new runs today and added them to a new excel file (zip). I've marked where the desired is lower then actual green and the others red.

I think it's strange that my first run is off a lot and the second run is much more 'spot' on with very little difference. Imo this tells me there's a (little)problem sowehere?

Hi,

I have modified a bit your spreadsheet, like this it shows clearly that there is an overboost after about 2 seconds turbo lag, then the regulation over-compensate; quite a lot @ first run and more precisely @ the second as you noticed.
If it was about a variable geometry turbo, I'd say the vanes actuator is partly seized ...

BRs, Bernie

If someone here helped You fix -or better, understand- your issue, hit the thanks icon @ bottom right corner, it's free and makes us feel helpy ;-)

Hi,

Great customised Excel!! Thanks

I don't think the VL37 is a turbo with variable geometry. Could it simply be the wastegate actuator?

I went to someone who's very known with remapping Fiat/Alfa/etc.

He remapped the car but the turbo didn't respond well to the remap. Very little turbopressure at all. We've changed the N75 (Pierburg) valve and then it responded well to the tuning.

But a few days later with (very) hot weather the power losses occured over and over again.
Diagnose: most probably a crack in the manifold and/or turbine housing.

So i've bought a (bigger) VL38 turbo from a Abarth 595 with only 55k km on it. Even that one already had some little cracks in the turbine housing around the wastgate. I've decided to buy a new (Armec) turbine housing for it. The turbo itself has very little play.

With that i've decided to buy a second hand (originally factory) modified exhaust header.

About 3 weeks ago we've decided to change the turbo and manifold by ourselfs. It was around a day job for us, but I literally was right on time. Look at the pictures and see all the cracks in the turbine housing and (long but not very big) cracks in the exhaust manifold. The housing almost touched the turbine wheel

And the result is super. In my opinio a much better driveability with a less peaky engine but a smooth torque line from around 2200-5000 rpm i guess.
I've remapped the car after that to adjust to this bigger turbo and i should have around or above 165hp and about 270-280nm. Not that the exact numbers matter to me but the driveability is just superb!
Tested it once in Germany and now it touched 211 op GPS and i think there's abit more in it, but this was against the wind. But overall improved torque is wat i like

So a great upgrade if your turbo fails or starts to fail. The VL36 or 38 are exactly priced the same as the VL37. Only thing you need is a remap afterwards which would cost around EUR 400,-. Mine was remapped at Savali Tuning in Holland, which a remapper that even covers OEM guarantee

SO if you're having the same problems be aware of a crack in the manifold or worse a crack in the turbo!

Looks like you go to that just in time much longer and it have ended with the blades shredded