I asked the same question in the UK based sxoc.com forum but they are not very active atm for some reason and I need an answer asap, so I can get the things rolling and be able to drive the car, thats why I will ask you guys too

I decided to replace my atmo bov with recirc valve and I need some basic guidance if I am wrong. At first I checked the net to see a similar setup and I've found this vid

[youtube]http://www.youtube.com/watch?v=fdn0YjyGgLw[/youtube]

so from what I understand I have to do the following -



Is that right? Or I missed something. Thanks in advance!

There is no benefit in recirculating cooled air. It's just going to get heated right back up again and makes the intercooler work harder. I would place the recirculation valve on the hot pipe (the one coming out of the turbo, right above the inlet for the turbo). You will still need to add a way to return the air to the inlet of the turbo. make sure you keep the return air as far away from the MAFS as possible (ie, as close to the turbo as you can get it).

I don't know if I didn't understand what you said or you are mistaking the my "perfect" drawing lol. The new pipe will be connected not to the intercooler pipe but the one bellow it. The one thats going out of the turbo.

He saying you need to put the valve before the intercooler because it's inefficient to recirculate air that's already been cooled. Put the valve after the turbo, but before the intercooler. Then plumb it back into the turbo inlet as close to the turbo and as far away from the MAF as possible. This will also make the recirculatory plumbing much shorter and simpler.

Basically I have to put the valve on pipe 1 and then to connect the recirculating outlet to number 2? This will reduce the required work nicely. I'll just extend the airfilter pipe (2) as much as possible so the recirculated air is not near the MAF sensor

Bingo

Badass. Thanks for the explanation guys!

EDIT: no, wait. After thinking about it I totally forgot that there's no pressure on that side. It came out of my head. The valve won't work if I put it the way you are saying. Look -

There's more pressure on the "pipe 1" that you illustrated, than the way you initially talked about, and the last two pictures you posted.

Let me give you a quick rundown on what's going on here.

Turbo spins because of heat and pressure in the exhaust. Spinning turbo SUCKS air in THROUGH the AIR FILTER, into the MAFS, and then into the inlet of the TURBO. Then the air is PRESSURIZED. During the pressurization it's also HEATED. The HOT, PRESSURIZED AIR LEAVES the turbo and goes INTO the INTERCOOLER. There it is COOLED. There is also a slight DROP in pressure (varies, but usually 2-5psi in an air-to-air intercooler) The COLD air is then fed INTO the THROTTLE BODY.

There are two trains of thought behind the BOV/Recirc Valve placement.

The first is to place the valve as close to the throttle body so that the pressure wave that occurs when the throttle is shut (which also originates at the throttle body) is relieved near the source. This is supposed to be easier on the turbo. If you're venting then this is fine and there is no real drawback, other than the fact that you vented nicely cooled air into the engine bay, which increases thermal load on the intercooler system. The load isn't great, but it's there.

The second is to place it on the hot pipe. The reason for this is that it's much easier from a plumbing standpoint, and you're not venting/recirculating cooled air. Supposedly there is a greater risk for throttle closed compressor surge, which is hard on the turbo, but to be honest, I have yet to see that demonstrated/proved.

So all of that being said, When I had a MAFS and was recirculating, I had it on the hot pipe. The piping was simple and short and I ran 15psi on an SR T25 and never had any issues. I've also ran recirculated on the cold side with an S15 SR T28 at 18psi and I didn't see any difference. My last setup was vented on the cold pipe. I did this for simplicities sake. My hot pipe was REALLY short and I didn't have much room for a BOV. When I re-do my intercooler piping again, I'm going to put the valve on the hot pipe and have it vented. I have a standalone with a MAP, so I don't have to worry about off-throttle stumble.

Put it on the hot pipe. It will work fine, and you won't have any issues. Trust me. I've done it both ways and there is no noticeable gain from the effort of putting it on the cold pipe.

I got it this time Meanwhile the new valve came up But I don't know which spring to use. Usually they are colored but this valve is some cheap one and they are unpainted. Can you guess just by the look of it which one I should use? The left one is the one that was inside. The car is running on 14psi (1 bar) so I think this spring may be too loose

LOL, thats my video, and here is a newer one.

Could someone teach me how to make the youtube BB code work ?

[youtube]http://www.youtube.com/watch?v=kcSGIH8e9JY[/youtube]

Youtube is stupid. By default, they make the links httpS. You have to remove the "s" from the link for it to work. Annoying, but that's all there is to it. Click edit on this post to see what I did to make it work (I deleted all the other link stuff you posted).

louiswun wrote:LOL, thats my video, and here is a newer one.

Whats this for? Where it goes?

30K wrote:

louiswun wrote:LOL, thats my video, and here is a newer one.

Whats this for? Where it goes?

Air regulator , FICD and AAC

float_6969 wrote:Youtube is stupid. By default, they make the links httpS. You have to remove the "s" from the link for it to work. Annoying, but that's all there is to it. Click edit on this post to see what I did to make it work (I deleted all the other link stuff you posted).

Thanks for your help !

Here is the final (for now) setup



I still don't know how it runs though. I am going to drive to a lift stand in monday to fix the oil leak so I will start the car for the first time then, because there's no point to put oil atm just to see it on the floor tomorrow But anyway, the recirc loop doesn't look bad at all, imo.

30K wrote:

Funny to find a picture of my car in the 1st thread I read in a while, specially after almost 2 years without being able to use. Hopefully the rebuild process will be completed in the next months.

@louiswun, sweet looking car you have there!

I tried the car today. It feels more responsive, its not running rich and "alive" overall but the engine still stalls when I am shifting. Any ideas why this could happen? I've cleaned the AAC valve a few weeks ago btw.

check or maybe just replace EVERY vacuum / boost carrying hose for leaks (including break booster hoses etc). The smallest leak can be a pain...

Its not that. When I was doing the recirc setup I checked the whole "route" and its fine. I am starting to think its some sensor.

Btw is it possible to be caused by the alternator or by "almost" worthless battery? I noticed that when I am turning the headlights and the radio down (in my country you have to drive with your lights on through the whole year) and the idle rpm go up.

Actually I think I FINALLY fixed it. Some retard screwed the idle screw so much that I had to unscrew it for like 5 sec for the engine to go normal when I unplugged the AAC So when I did that I unscrewed the bolt until the engine was running on 800rpm with the AAC unplugged, then I plugged it and everything is OK, for now at least. It drives awesome, but we'll see.. nothing is that simple with the S13.