People with GReddy Profec-B Spec II... help with

Im still struggling to get the settings perfect on my greddy BC.

When the SET is around 30% I get 1.2 bar exactly when the second tubby kicks in at 4k but rapidly drops to 1 bar or less.

So the logical step... turn up the GAIN from 5-35, but nothing happens

Just wondering if the boost peaking at 4k revs then dropping is normal? I was under the impression that the Greddy BC would hold 1.2 bar untill redline??

Any ideas of what im doing wrong??

I used this link as a rough guide...

http://www.sr20forum.com/turbo-guides/86098-how-how-tune-your-greddy-profec-b-spec-ii.html

Thanks in advance;)

are you sure it's the boost controller that's at fault? Does it hold the boost it reaches with it turned off?

Yes mate, its got a 1bar RR in, it holds that no problem.

iv replaced the intercooler and checked all the IC piping and replaced all the fittings.

I have my SET to 30% GAIN to 7% and SET GAIN set to 1.20, maybe the SET GAIN is to high causing boost spike at 4k?

I see you have this unit to

yeah I have. Took me a while to get my head round the thing but I'd definitely try turning set gain down (by a fair bit too to start with). I'd post up my settings, but mine and Daman's car were miles apart on the setting to get the same results, so it wouldn't really help! Make sure you've got the peak setting at a reasonable level while you're setting it up too - don't want to push those turbo's too far

Thanks mate, iv now got my set @ 48%, gain at 35% and set gain @ 0.98 bar.

Im now hitting 1.22 bar at 4k, then drops to 1.14, so im getting there!

Im going to turn the set gain up tonight and see if i can get it to level out.

I'll let you know how i get on

Rob i wish i could help you out a little more on top of what Adi has said.

Post your results when you level the spike out, i have exact same problem!

No problem mate