What should I do with this hose?

[GTRSOAR]

Ok, I found a place to tie in that vacuum hose to a large nipple on the new pipe between the turbos and the MAFs. Ill put together a barbed fitting set up so the tie the stock hose to this new nipple. (Its about .5 dia so ill need the barbedd coupler to shrink it down). Ive read what youve said carefully but one thing keeps buggin me. The stock nipple was AFTER the MAFS, so I dont see how bleeding to atmosphere would change anything compared to bloeeding to the intake. The ecu wouldnt be able to account for a change in air because its after the MAFs so it couldn't compensate with more fuel. I can only see it making things more lean then anything else. I have new AEM Widebnds with guages so ill keep track of the A?F ratios carefully :P

[cortexx]

If you have a electronic boost controller you can plug that line at both ends and not use it.

[DarkCaporaL]

Ive read what youve said carefully but one thing keeps buggin me. The stock nipple was AFTER the MAFS, so I dont see how bleeding to atmosphere would change anything compared to bloeeding to the intake. The ecu wouldnt be able to account for a change in air because its after the MAFs so it couldn't compensate with more fuel. I can only see it making things more lean then anything else.

The air has already been measured by the MAF, that's why it's being recirced after the MAF in the intake piping. By dumping it to atmosphere, you are removing mesured air from the system = rich since the ECU is expecting Y amount of air but only receiving X.

It's a closed system. As soon as air makes it into the IC piping, it has been mesured by the MAF, which means the ECU is expecting it to be used for combustion at some point. Removing any amount of air from the IC piping to atmosphere is removing mesured air.

[GTRSOAR]

Oh ok, im sorry I thought this air has not been measured yet. Ill feed the line into the intake piping like I said earlier and reset the ECU. I have been running about 3 points lower on my A/F gauges since the piping kit so that makes sense with what your saying. The 'nipple' on the intake piping is quite large, about .5"-.75" diameter, so ill run a large hose of that a couple inches long, then get some barbed fittings to shrink that down to the same size as that stock hose and link it together. Ill be do this around 5:00pm and update on whats happened :P PS Your amazing for your help and knowledge. I really appreciate it

[GTRSOAR]

It just occurred to me, even on the stock piping, this boost hose is going to only the back turbo, so that turbo is always flowing a bit more air the front turbo?

[cortexx]

the line the OP is talking about is used by the stock boost controller to bleed air to allow the waste gates to remain shut longer and thus increase overall boost. Because this air has been metered it is fed back into the intake side of the turbo .

Because an electronic boost control solenoid does not use the air bleed principle to control the wastegate actuators , there is no air to return to the intake and therefore the pipe can be capped off .

[DarkCaporaL]

Does he have an EBC? I don't recall reading it, but yet again I skimmed through the thread pretty quickly.

[cortexx]

If you look at the piping , the recirculation from the blowoff valves AND the bleed return pipe both feed into what is effectively a black y-pipe that intersects between the turbo compression side and the maf on BOTH turbos . The return of pressure essentially gets fed to both turbo inlets.

It just occurred to me, even on the stock piping, this boost hose is going to only the back turbo, so that turbo is always flowing a bit more air the front turbo?

[GTRSOAR]

Sorry forgot to mention, I do not have a EBC, stock manual one. I do have an external BOV so the recirculate tube has been capped

[cschepp]

Isnt that line that he is talking about go to a waste gate actuator? Of this was the case couldn't he put a y joint and have it split between the two to get what he needs out of it? I'm pretty sure that would work

[GTRSOAR]

No not this hose, both the actuators have their original hoses connected again, they were never touched

[GTRSOAR]

OK hopefully this solves it, i reset the ECU and am taking it out for a drive now. Heres the set up I did. Simple enough, the nipple on the new intake between the MAF and the turbo is 5/8 so I have a 5/8 hose down to a 1/4 hose and tied it in to the original with a barbed fitting. Thoughts?

[cortexx]

So you are dumping to atmosphere ?

Personally , unless you run a blow through MAF setup i would run the recirculation. Your system is designed to operate that way and the ECU will expect recirculation . Dumping to atmosphere will make the engine run rich each time you change gear or backoff the throttle.

I'd also invest in a basic EBC at least . Look at a greddy profec II for ease of hookup and simple setup , or if you want get a DSBC blitz unit or an Apexi AVCR . If you do this you can dispense with the line you have reconnected.

[GTRSOAR]

All that happens is it'll back fire a little if I don't engage and clutch soon enough. Theresno other difference. A BOVto atmosphere is fine and very common for GTRs. But I wasn't even referring to that hose in my last post

[GTRSOAR]

Car ran well, back to full boost, the only thing is that the revs still fall to 0 when the clutch is held in. This never happened when I had the BOV done, that was months ago but started when the piping kit went in. When the clutch is held in it falls to 0, stutters and juuusttt gets going again. About one in every ten times it'll stall completely. Very dangerous because I lost power steering in a sharp corner :S