I’ve been playing about with my apexi settings recently since I had it unplugged for about 3 months and decided to start again.

I’ve never really gotten on particularly well with the self-learn function and just set up the duty on my own. (‘O’ means self learn is on, yes?) I believe this might have been due to the fact that I had a stretched accelerator cable which meant I wouldn’t be getting full throttle which you need for it to work properly.

Anyway, the way I have it set now is giving me the boost levels I want. But, on part throttle and when building boost I’m sometimes getting a fluttering type situation. I’m slightly concerned that it’s compressor surge but seems far too high frequency to be that. So I think it’s the dump valve misbehaving a little bit. It doesn’t happen so much when I put my foot right down, and isn’t happening when I reach full boost.

Does that sound feasible? I’d expect if I had the duty set too high I might get compressor surge (it’s set higher now than it was previously), but any time I’ve had what I would call compressor surge before, it’s been more of a see-saw effect at full boost and not that high frequency.

Any suggestions/comments?

Cheers
mattB

I have found the best thing to do is let the Apexi learn and then tweak from there i.e. rpm duty, in-gear duty etc. You would be hard pushed to get compressor surge on a 28R as it is so well matched to the 20vt

I would find it nigh on impossible to get compressor surge from a 28R.

But that's cos I'm running a GTi-R hybrid.

Suppose I could stick my new dv on and see what the story is.

Doh! Well then it's defo not surge, sounds more like the boost solenoid or as you say the dump valve.

I'm also having the same problem especially if i set my 1st/2nd gear to 90%-duty, i'm suspecting of my diverted valve is NOT acting fast or big enough to release the pressure.

~what dump valve are u using???

I get this at the mo as well in 4th and 5th gear on half throttle, the boost is stuttering and dumping like the dv is opening and shutting all the time, this was on my bailey which alot of my friend have had probs with, it to do with not a hard enough spring either side of the piston, but i have also tried a mates Blitz one and it still does it. I have heard the dump valve stong enough is the HKS ssqv which im waiting to arrive and try, if this doesnt work then i havent got a clue. Apparently alot of the punto gt boys get the same problem when they are using baileys.

Hi guys,

I am having the exact problem, Matt. It shouldn't be compressor surge as this usually only happens at full boost.

I am using Apexi AVCR too. Could that be the problem? any thoughts guys?

Jamie, I am alreading using a HKS ssqv. The boost still flutters especially at 4th gear onwards.

for reference:

http://www.fiatcoupeclub.org/forum/...amp;Number=261765&page=5&fpart=1

SOund familiar, guys?