Ive been seaching for problems with boost on the apexi and there is quite a few post's but my problem dosnt seam to have been covered.

basicly ive install the apexi but since doing it i having problems with my 2nd turbo. it dosent kick in untill about 5,500rpm then i get very very strong boost. im currently running version 2 of the controller set up diagram thing. im thinking about trying version 1 but wanted to know from people that have tried both. also im finding it very very hard to get a steady boost in any gear. it spikes and drop's all over the place.

the car has got a 3" downpipe and mid pipe with a blitz nurspec cat back, induction kit, and running a mine's ecu, which was mapped for a car running exactly the same mod's with 1bar of boost.

im not wanting to run 1 bar but i would like to be running a steady 0.85.

any help would be awsome

p.s check for vac leaks/boost leaks and rats nest etc redone.

 

bump

 

How have you programed the AVC-R? I found that I needed to tweak it a bit based on rpm to get a nice boost response.

 

ive played about with the duty cycle and the boost via the rpm. and i think this is my problem. to stop it spiking crazy amount's when the 2nd turbo kick's in i have had to reduce the duty cylce by quite a bit, this spike happens at about 5000rpm so for that 500rpm untill 5500 the duty cylce is low. but there isnt anything i can do about this coz of the spike.

what settings have you got on your avcr?

 

My duty cycles are pretty high from about 4500 on up. I did have to drop them down a bit at 3500 - 4000 because I was getting a boost spike in that range in 4th gear. I initially did all my tuning in 2nd gear pulls due to the road limitations I had. I found that with 4th gear, I was getting spikes of .92 bar even though I had it set for .85 bar max. I adjusted the duty cycle down a bit in that range and it smoothed out. If I get time, a nice open stretch of road, and a passenger, I'll see about tweaking it for each gear. I'm planning to put in a PFC and have it turned for 12 psi and I want the boost control rock solid before then.

Anyway, my settings are going to be completely different than yours since the twims seem to be so different depending on age, condition, etc... In general, I do better in primary so my duty cycles are lower below 4500 than they are above, but YMMV.