Is this overboosted?

[benvw]

Please see attached file.

[tangcla]

Yes it is, the middle-range line shows that the primary turbo is slightly overboosted but the secondary... that doesn't look right, looks like heaps more boost when the secondary is on too.

[benvw]

I guess the question I should have asked is "is it dangerously over boosted to the point of BANG"?

[chadza]

Thanks for putting that up Ben, That is a COMPLETELY different way of tuning the B4 than has been done to mine. I will take a photo of my manifold pressure graph and put it up tomorrow as the contrast is pretty stark!!

I still dunno if I would call it 'overboosting', but 15psi is pretty high on the primary. I dunno if it would go bang, but it may reduce the life of the turbo significantly. Note this is just my OPINION, and not backed up with any experience with the VF series turbo's.

[benvw]

Thanks for your opinion. Would be very interested to see yours.

I must say the car certainly goes a lot harder now so am happy with that. Just concerned with for how long.

[chadza]

So thats my "technicals" side of my Dyno sheet. Blue is BEFORE TUNE and Green is AFTER TUNE.

On the primary turbo its actually providing less boost (and on the power graph slightly less power) and it peaks at 11psi before the changeover.

The other interesting point is that your power graph actually declines when the secondary is brought online, whereas mine just flatlines for a few hundred revs. In real life, the flatspot is hardly noticeable and it 'almost' feels like its just one constant acceleration.

[benvw]

Thanks for the upload of the graph. I dont have the AFR but next time I will get that. I think I will print out yours and take it with me. I am also having a little bit of a detonation problem now at about 3500 rpm which needs to be fixed. Have you got any knocking in your car or is your tune perfect?

Cheers

[chadza]

detonation is BAD!! Get it looked at and retuned ASAP as you will have a spun bearing in no time.

Zero knocking in my car, although we haven't had any temps above 30 degrees here since I had the tune done. However Im not expecting there to be any issues, I am very happy with the tune. I wouldn't call it perfect, but the guy who did the tune knows his shit, so its pretty good!

Once again no offense, but the graph of yours just doesn't look right. I would be getting either a second opinion at a different shop, or take it back and demand that they "clean" it up. It could be an expensive mistake otherwise.