Engberg

Hey all
As a bit of history I've been having a boost problem, where if I dip into the throttle at a medium to slow pace I would over boost to about 14-16 psi. There are a few other people at around my alititude who have felt that their similar patterns were caused by altitude. So I bought an APex'i AVCR. I just installed it and the problem remains realatively the same. I followed the advice from www.scuderiaciriani.com on how to install. The rpm, boost, and speed function are all accurate on the avcr display. The solenoid clicks under boost. I removed the vac lines from the pre-control and wastegate control solenoids and plugs the ends on the hose and actuators. pre-control and wastegate lines T together to the COM port on the solenoid while the manifold lines T together to the NO port. I've tried lowering both my max boost and solenoid duty cycle and will still over boost upon medium throttle application. I have not kept my foot in it to see exactly what I run to, let go when I reach 11 psi as popping the motor is not on my list of TO DOs . (but at 11 psi it is still rapidly climbing) I've set the boost all the way down to 6 psi and still over boost!
If I over boost, quickly let off throttle and quickly get back on, i still over boost which makes me feel it is not the vac chamber. I think I may not have pluged the lines that I removed perfectly, but that should not cause a problem as the lines , regaurdless, are not connected to the actuators anymore. Any advice would be much appreciated.

Engberg

also...this is what 'seems' to be happening. The primary as stated over boosts. But does not do so until about 3K, then after transistion (4500) the secondary falls flat on it's face(about 4-6 psi). Obviously exhaust is not being diverted to prespool the secondary. I'll continue researching what that all means

Mahjik

iTrader: (1)

It sounds like you have a few problems.

First, have you verified that your Turbo Control Solenoid is working properly?

Engberg

Honestly, when I realized I had a problem, I checked the precontrol and wg actuator hoses because of the primary over boost. I'm also only running 10 inches of vac at ~750 idle. I've checked all vac hoses I could get to. So, I have not checked the turbo control solenoid and need too. (thanks for the relpy mahjik) While I'm in there, is there anything of related to check?

Mahjik

iTrader: (1)

Ok, just to make sure I understand what's happening (and anyone else who is reading this message) you were originally having uncontrollable boost. You installed the AVCR and the problem still remains.

BTW what are your mods?

You are not having a problem with the secondary boost, is that correct? If so, I misred your original message which is why I posted about the Turbo Control Solenoid.

SERIES7

Try adjusting your boost/Duty % on the AVC-R to .20 at 60%
Worked for me.

Engberg

Well, uncontrollable boost doesn't accurately describe the problem. When crusing at higher speeds and lower revs[primary turbo] (ie highway in 5th gear) and if I dip into the throttle I would over boost to about 14 psi. One a harder launch from a stop with the turbos prespooled a bit before launch I would get a near perfect pattern...most of the times. Sometimes my secondary would come on soft (about 6 psi) some times full bore. It all depended on how I handled the throttle at initial take off. That was all pre AVCR ... Now with the AVCR in, i have nearly the identical issues and no adjustments on the AVCR seem to make a differnece. I just took the car out and put boost down to .20 kg/cm^2 and duty at 60, 55, 50, and 40 all had no effect. I'm still not confident in my seal of the hoses from the factory solenoids or for the nipples they were attached to on the actuators. Even if I had something wrong with another part of the factory system, shouldn't the AVCR still cap off pressure?

Engberg

Ok, i have an idea of what is wrong. Please correct my thinking if I'm wrong. But basically, the actutor use the pressure signal sent from the solenoid to create a force that closes the wastegate to control boost. Thing is, I didn't think i sealed the old nipples on the actuators that used to go to the factory solenoid. If that is the case, I'm leaking that pressure and it is pushing out the nipple and not to actuate the wastegate. Driving around with the boost at .2 kg/cm^2 (set as max on my avcr with duty @40) when I hit about 5-6 psi I hear what sounds like someone sneezing into a tissure (boost leaking out my half *** closing of the nipple) When I hear this noice I'm assuming the apexi soleniod is sending a lot of pressure to the actuators to turn the damn boost down...but it is leaking. Soooo what I'm thinking is i installed wrong, otherwise i'd atleast see some effect from the avcr when changing settings. If I go back tomorrow and seal these nipples up right, this time, I should have control over boost with the AVCR. Am I making any sense?

BTW my car is completely stock except for the AVCR unit and an apexi BOV

Mahjik

iTrader: (1)

Yes, it sounds like your wastegate is not functioning. You might check through this thread:

https://www.rx7club.com/forum/showth...hreadid=225390

It's not the same boost controller, but a similar problem.

rxrotary2_7

you are trying to use the AVC-R as a bandaid to your problem.... thats whats wrong. fix the initial problem, then hook up your boost controler. the AVC-R is an excelent controler IMO, but if you are trying to fix a boost problem with it, you are just ..... nevermind

Engberg

I totally agree, this is why I've had the controller for a few months now. I've done misc. checking through the turbo system, and I admit it is never enough checking with turbo control system. And I've read all the indepth posts by LARacer about his similar problems. Honesly I got to the point where I assumed my problem was the same as his, and he has been through each and every aspect of the system. Live and learn I suppose

Here are the related treads:
http://www.nopistons.com/forums/inde...10&t=9291&st=0

http://www.geocities.com/laracers_vr..._problems.html

Thing is, no one at altitude has come forward and claimed a perfect stock pattern and claim problem like mine, some varying to different degrees but mostly the same. With everyone I've heard from at altitude claiming the same problems, and no one claiming other whys I choose to believe those that have lost years off their lives chasing down the problem.

SERIES7

So did it work? What have you been able to find out thus far? Also, I forget, are you running sequential or non-sequential?

Engberg

Totally stock, I believe the 'bottom right' wastegate actuator nipple (one that used to go to the stock solenoid) is bleeding pressure, gona go back the cap them right today and see if that helps.

SERIES7

Awesome! Let us know what you're able to find out.

LAracer

Guilty as charged .

rxrotary2_7: Actually, I had a very similar problem to Engberg (difficult to say its identical without driving his car) and I used two needle valves to lower the primary and raise the secondary boost. The boost pattern is almost perfect now...almost.

I now have a profecB, and I'll hopefully be installing it this weekend. I just want to correct the slight drop in boost I'm seeing before transition. Then maybe we can compare results.

Good luck

Engberg

I went back in and resealed the nipples on the actuators, went for a drive and maxed at 8psi with .20 kg/cm^2 and 40% duty in all driving condition. So it was the leaking connections that were keeping me from controlling the wastegate. The secondary came on a bit weak, but not bad...probably in the settings. Now to go play with the settings and get it running perfect. Thanks for the advice all.