Re-circulation or Atmosphere dumping

[talon2gbuyer]

Hey all, ive currently got an open J-pipe which dumps to the atmosphere, I have seen folks that use the recirculating system on their turbo's, anyone know the pro's and con's of these types of systems, and also if its worth looking into? Thanks!

 

[1gAWD92]

The bov is located on the upper inter-cooler pipe, or the "charge pipe" cause the pressurized air is more... well i guess you can say accurate. thats the last pipe the air passes trough before the intake manifold. the BOV builds up air pressure intill you shift gears, at the time of shifting gears the valve inside the BOV opens to exhaust the air, ether back into the intake if you have a recirculating bov, or atmospheric if your running speed density.

i still haven't wrapped my head around the speed density mod. but im quiet interested on how that works if anyone can go into more detail about it.

 

[2GbTalonGuy]

How dont you like the sound of the o2 dump?! your crazy i think it sounds awesome if you dont like that sound dont even plan on running a bigger turbo with an external wastegate then!

Why not? There are plenty of External WG setups with recirculation available.

 

[1gAWDlaser]

Ok, ill look into the o2 housing units that recirculate, i couldn't care about a few hp for now, but i just cant stand being deafened when i hit the gas . Also, how much would something like this go for? I wouldnt hold onto it, better to let someone who wants that kinda noise have it

Im pretty happy with the BOV for the most part. Just not sure what manufacturer it is that made it. No markings on it at all that indicate maker.

Also, while ive got the experts here, the exhaust manifold, is that stock? I dont see why the previous owner would go with an aftermarket turbo, and stick with the stock exhaust mani. Ideas?

Black Widow is correct your exhaust mani is stock for the 2g yes. It may be a ported 2g mani. It's not a big deal at this point it will still flow very nice. I've made well over 400awhp with a slightly ported 2g exhaust mani.

 

[Aceman]

What kind of BOV is that? I'm guessing Greddy RS? You can buy a recirculation fitting to replace the horn looking thing coming off of it. I don't think the stock recirc tube would line up correctly on your setup. You can just get something like radiator tubing and some small clamps to recirculate it with the fitting.

Here is the fitting for a Greddy RS or RZ at extremepsi.com:
EXTREME PSI : Your #1 Source for In Stock Performance Parts

This is what it looks like with a Greddy Type S BOV and the stock recirc tube:

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[1gAWDlaser]

That explains the gas smell in between shifts...Ill look into doing that this week. Thanks for the help guys

You can still run that BOV and get a recirc nossle for it. The BOV looks to be a Greddy knock off.

 

[talon2gbuyer]

Yea, your guess is as good as mine at this point. it sounds nice, but I question its reliability since it has no markings on it. I was wondering what the other input hose on the intake after the maf was for, now I know Ill be looking to get that fitting and re-routing it to recirc into the intake charge again. It is unfortunately only one thing on a rather long list of things to do .

 

[AngelOfPassion]

Yea, your guess is as good as mine at this point. it sounds nice, but I question its reliability since it has no markings on it. I was wondering what the other input hose on the intake after the maf was for, now I know Ill be looking to get that fitting and re-routing it to recirc into the intake charge again. It is unfortunately only one thing on a rather long list of things to do .

For now just get a hose to connect it back to the intake. Then later, when you learn a little more and can tell if it is leaking or not, look into getting a diverter valve from a 1g eclipse or if you have money to blow: a Tial.

You will be in way better shape than you are now if you just connect the hose like the last post shows on page one.

 

[Dert]

This thread provides one more reason to stop calling it a "blow-off valve." It isn't a blow-off valve; it's a compressor bypass valve or diverter valve.

untill it is vented to atmosphere, bypass valves reciurculate

and to OP yours is a greddy type rs knockoff

 

[talon2gbuyer]

Ok, ill go grab a hose from the parts shop later on this weekend. Thanks for the heads up guys

 

[Bud92gsx]

Open J pipe..

 

[NathanCarlK]

I had troubles with my car from dumping. : /

 

[talon2gbuyer]

I wish there were people in tristate area that actually met up . There are people on the forum but no one ever meets up. What issue are you having with the dumping?

 

[Calan]

In the interest of clarity...

...the BOV builds up air pressure intill you shift gears, at the time of shifting gears the valve inside the BOV opens to exhaust the air, ether back into the intake if you have a recirculating bov, or atmospheric if your running speed density.

The BOV doesn't "build up" anything. Pressure in the UICP comes from the turbo.

When the UICP is pressurized (when you are in boost) air is flowing through the piping and into the engine. When you suddenly lift off the throttle, the throttle blade slams shut...so now you have vacuum on one side of it (in the intake), and are pressurizing the other side with no place for the air to go, since the turbo is still spinning. The BOV opens when that vacuum is applied to it, which provides a path for the excess pressure in the piping to escape. If that pressurized air stays trapped in the IC piping, the turbo will continue trying to compress the incoming air against the pressure pushing back against it. This causes unnecessary wear and tear on the turbo, and can get pretty ugly.

Where the excess air ends up has nothing to do with whether or not you are running speed density (commonly referred to as SD). If the BOV is recirculated, then the released air goes back into the turbo inlet; if the BOV isn't recirculated (or "vented" or "VTA"), it goes out into the engine bay. SD only comes into play because it is one method of metering air that allows the BOV to be vented without tuning issues.

i still haven't wrapped my head around the speed density mod.

Speed density isn't really a "mod". It is a method that some ECU's use for calculating fuel flow, based on an estimate of the amount of air entering the engine.