Apexi AVCR tuning question (transition)
 

Mods: Intake, I/C, dp, mp

I installed an Apexi AVC-R boost controller awhile back, in the manner described in the manual. This has the one solenoid controlling both the wastegate and prespool actuators.

Issue:

The car is primarily set up for autoxing. The issue I'm having is that shortly after I'm coming off of low speed corners (slow enough to be only on the primary turbo) I can hear an excessive blowoff noise. My guess is that it is boost being released by the Charge Relief valve, since the noise goes away as soon as the second turbo kicks in.

This is an issue since it seems like second turbo is building plenty of boost (guessing that because of the noise) early and when the transition comes it is very abrupt with a large power spike.

I've tried decreasing the duty cycle on the solenoid prior to 4500 rpm (by about 5%), but it hasn't helped appreciably. I'd like to get the transition smoother if possible. So, here are some questions....

1. Any suggestions on what settings to use for the AVC-R? I'm targetting about 1.0 kg/cm^2.

2. If I wanted to switch the 2nd turbo on earlier (500 or 1000rpm earlier), what would be the best way to do it? I was thinking you'd need to control the 4 solenoids that normally switch at 4500rpm (2 for turbo control, 1 for charge relief, 1 for charge control). If you switched them at a lower rpm, any problems that might come up?

Any advice appreciated.

Thanks,

Andy

I got tired of trying to get the AVC-R to control boost and prespool. I ended up using the AVC-R to control just the wastegate and a needle valve for the prespool. I have found that to be the easiest way.

I figured I might have to do that and will probably try that next time I;m on the dyno. I wanted to use the prespool control to run higher boost on the first turbo. Using a fixed valve to do that might lead to worse spiking problems since it is similar to using the AVCR at one setting.

even better, go with a ball and spring type of valve. Damian made a post about finding some nice ones.

Bump, anyone have input on question #2?

TIA.