My FD came with a single turbo (Apexi RX6), but oddly enough, it retained the pressure chamber you'd find that came with the stock twins. One side came loose during alternator removal and I never bothered to reinstall it - everything seemed to run the same. Today, I decided to remove the unit altogether, and capped off the other end (see picture). When I did this, the exhaust would be billowing out white smoke. Reinstalled it, and it's fine again. Any idea what caused all the smoke?

 

you dont need either of the pressure chambers when you go single. from my understanding. the chambers are like bridges in the vacuum system to help maintain pressure over the 4.95 miles worth of vacuum lines. when you go single and get rid of all the craziness then they serve no purpose.

 

That's my understanding also....

Anyone else weigh in on this? I have a full vacuum diagram in front of me but I doubt it will help as this system is no longer stock.......

Will be very interested to learn what's causing the white smoke.....isn't that usually caused by condensation in the exhaust or coolant being burnt?

Hope someone can help soon!

 

the vacuum diagram is just as useful on a modified system as it is on a stock one. since youre set up is modified, you use the diagram as a reference to route what you need to route. the diagram tells you what gets air from where and by what means. with that information you can sort of reverse engineer it and do what you need to do.

i cant comment on the white smoke... theres a lot of variables

 

Yeah, I had a look at the vacuum diagram, and where the hoses on the stock unit hooks up to the twin turbo components, which no longer exist on this car. Very odd.. But now I know the builder didn't just have it to cover the old rats nest. I'll leave it be as the builder intended it.

 

The pressure chamber is only used for the pressure side of the turbo control valve on the stock twins. That's all it does. Are you sure it's the pressure chamber and not the vacuum chamber? Is it connected to pressure only or does it see manifold vacuum? Is there a check valve on it, and what direction is it going?

you should investigate what's going on. Draw out a diagram of all the vacuum lines on the car as it currently sits. There should not be any smoke associated with it. Did he somehow hook it to crankcase ventilation?

 

Looks to be connected up as a cheap catch can? .

I'd be removing that and the hard lines with it.

 

Yes, I believe it is the pressure chamber.
I've attached a photo of it from the top. There does seem to be oil associated with it.. a tiny bit of oil came out when it was removed. Even looking at the photo, the hose on that end appears oily. The other end (the clean, top hose) I have open because I have no idea where it was hooked up to before and it runs without any issue.

I don't have the car at my house to confirm, but from this photo I took, it appears the oily end goes to the oil filler neck, like a catch can as suggested?

 

That's what I would figure, it's hooked up as a catch can from the looks of that picture. The pcv is deleted and blocked off then the bottom nipple runs one side of the chamber and the other may just be an open vent.

 

I assume the ACV and airpump are still in use?

Even so that is a real untidy way to go about it. I'd split the black box down and just keep the solenoids you need.

 

I'm not sure, to be honest. Just had a look and it's definitely hooked up to the oil filler neck like a catch can, and capping it will cause the exhaust to smoke a lot. Appreciate all the help!

 

You've got to vent that filler neck to something. Either to the UIM with a check valve, like stock, or to the turbo inlet, or to a vented catch can.

P

 

The hose you are depicting in the first pic is the vent from the oil neck to the stock primary turbo inlet. If you ran that to the pressure chamber, most likely you are blowing boost into the oil neck and pressurizing the crank case. That is the cause of your smoke. The pipe the hose is on really needs to be run to a vented catch can. Looks like someone was just lazy installing the single turbo and didn't remove all the sequential equipment.

 

I'll drop in a proper vented catch can to replace the chamber. Thanks everyone!