Topic: Project Undertow *2RZ Turbo Crawler*

[twistedtoy92]

You will need to recirculate the blowoff valve back in front of the MAF sensor. I had to do that on my Audi when I ditched the K03 and swapped in a Borgwarner GM3 snail.

[Nation]

Correct. The MAF has already determined how much air is going to be sucked through the motor.. so to waste to the atmosphere will make a rich condition because the air the motor thought it was going to get has just vanished...but the fuel is still injected for that amount of air and may even cause the engine to stall after hi-revving and completely letting off the throttle... so says the internet.. 

[Crunchy Taco]

Yea my bov is causing the same stumble. I changed where my fpr hooks up so it can sense boost and add fuel it help a lot. I used the nipple right past the tp that ties into my evap stuff. It fixed my acceleration prob. Before I had it hooked up in front of the tp where the egr stuff used to be. Sounds like you have your fuel pr hooked up fine if your accelerating good. I knew I had an issue somewhere cause I didn't think 5 psi was too much. We'll see if she stays running well. I literally just changed where my fpr hooks up and so far no stumble when the throttle closes. We'll see. The weather is also changed today too that might be a factor. 

[Tungsten Slayer [OP]]

You will need to recirculate the blowoff valve back in front of the MAF sensor. I had to do that on my Audi when I ditched the K03 and swapped in a Borgwarner GM3 snail.

I have the recirc valve dumping back into the intake pre turbo, post MAF.  Are you saying to dump the recirc pre turbo and pre MAF?  The problem seems that it runs too lean after the throtte body shuts which causes the stumble...

Correct. The MAF has already determined how much air is going to be sucked through the motor.. so to waste to the atmosphere will make a rich condition because the air the motor thought it was going to get has just vanished...but the fuel is still injected for that amount of air and may even cause the engine to stall after hi-revving and completely letting off the throttle... so says the internet.. 

It is already recirculated pre turbo and post MAF.  It seems to lean out, not richen.  I might put the MAF in the charge pipe and see if it helps.

[twistedtoy92]

Yes try the charge pipe. Seems it will richen up when it sees the airflow continuing to take place rather than an abrupt stop causing it to pull fuel it thinks it doesn't need.

[Tungsten Slayer [OP]]

Update for everyone following the 2RZ turbo setup!  I still need to test this out, but it looks good 

I was having issues with the 01 2RZ stalling when I let off the throttle after being in boost (4.3 psi).  I am using a tial 38mm wastegate off the manifold to control boost which was vented to the atmosphere.  The Tial wastegate was the most expensive single piece in the whole setup for me, but I believe it to be worth the money as it does a great job of controlling boost by bypassing the exhaust away from the turbo.

When the wastegate vented to the atmosphere, it was extremely loud and kept me from having a passenger on the trail.  Yesterday I had some time to work on the crawler and decided to vent the wastegate back into the down pipe pre AFR sensor.  After plumbing the wastegate back into the exhaust (pre upstream AFR) the motor quit stalling after being in boost.  The motor just rips now and everything feels good in the driveway.  Like I said, more testing on the trail is needed, but I'm pretty hopeful that I found the solution to the problem I was having.  Cheers

[twistedtoy92]

Good to hear! Now we need some more videos

[Tungsten Slayer [OP]]

I'll get something on the camera next time I go out.. 

[Crunchy Taco]

Good work. I've been meanin to tell you that my stalling issue was similar to yours and it was my BOV. It wasn't sealing all the way and caused an air leak. Two different Bosch recirc valves leaked and my crappy eBay BOV. I was able to fix the seal on the eBay one by putting a longer adjust screw and putting a bit more tension on the plug or whatev u wana call it and prob solved.

[Crunchy Taco]

Oh one more thing. You can't tell us about awsome stuff and not have pics to go with it.

[Tungsten Slayer [OP]]

Good work. So your runnin that same turbo from a merc. ? No leaks everything's good so far?

Same turbo I started with off the Mercedes.   No intercooler @ 4.3 psi on factory ecu and I am using a Tial external wastegate to control boost instead of the internal wastegate on the kkk and a Supra recirculation valve off the charge pipe to top it all off. 

 Turbo is in good shape and there are no leaks, funny smells, smoke or anything that seems odd.  If you want to know any specifics ask here on my thread.  I'd like this to be a good resource for others who want to put boost to these RZ's.  And yes it was worth it for the power gains!

[Crunchy Taco]

That's nice for an used turbo. Hope it holds up for you.

[Crunchy Taco]

Kinda funny how you inspired me now my truck is turboed and I'm learning and doing things I never thought I would. Thanks man!

[Crunchy Taco]

Can't forget about twisted toy. He's been a huge help to me as well. And everyone else on the forum !

[twistedtoy92]

Glad to give some inspiration and information for those of you with motivation!  You all have inspired me to boost my runner as well, be runnin a holset hx35 hopefully around 15-20 psi  Wish it was obd2 but I think I'm going with a megasquirt p2p ecu... we will see what happens. 

[Crunchy Taco]

Guna be sweet. Once everybody's junk is tuned in we'll have to pass some videos around!

[Tungsten Slayer [OP]]

Yes!  Video's of these little motors screaming is what I want to see!!!!  I am dedicated to do some filming next time out   

[Crunchy Taco]

Me too. Gotta go wheelin as soon as I get completely dialed in.

[Crunchy Taco]

I don't know how your turbo is but if I close my wastegate all the way I start spoolin from idle on up wich is pretty cool. So right off the bat I'm pushin anywhere from 0-4 psi then like 5-7 if I punch it. I lucked out with this particular internal wastegate setup it's working really well. The only downside to being in boost all the time is tuning has to be perfect or it will fall on its face especially at wot

[Tungsten Slayer [OP]]

Cool!  I noticed mine spooled a lot sooner after I put on the Tial Wastegate.  The internal was intentionally disabled and didn't work well at controlling boost.  Are you running a recirculation valve?  Or BOV?  Or neither?

[Crunchy Taco]

BOV. And don't really have any problems since I've worked out some kinns with the tuner I'm runnin as far as it runnin rough once it's get rid of the air.

[Crunchy Taco]

I wonder if it's even harmful to run without a BOV or recirc only runnin 5 or so psi. Another question I've been thinkin bout is what is a safe range of afr? And am I lookin for 12.0 all the time? Or is there some room between say 14 and 10. 10 being lean and 14 being rich. Any light on this?

[Nation]

BOV is optional . Some people refuse to use them. Some people swear by them. I won't be running one.

[Crunchy Taco]

I've never tried without, I think I might..I've had mine adjusted so tight that it didn't really blow off and my gauge still dropped every time I let off the skinny pedal so it should be fine without the bov

[Tungsten Slayer [OP]]

I think with small amounts of boost no BOV or recirc. valve might be ok.. I am going to try and delete mine while running 4 psi, so I guess time will tell.  You are looking for around 12:1 - 12.5:1  for the AFR's at WOT. 

Crunchy Taco.. Just to make sure we are on the same page 14:1 would be leaner than 10:1 since this is an air to fuel ratio.  I'm sure you know this and just had one of those moments

[Nation]

From what I have been told and read, the only down side, which is debatable im told, is that the pressure goes back to the turbo and MAY cause premature failure.  "MAY"  The Benefits of no BOV is that you would create your PSI much more rapidly between throttle (letting off for a shift and then back in it.. youll spool quicker and maintain more boost..

[Tungsten Slayer [OP]]

Yeah, that is the debate... I don't think the diesel I got my turbo off of had a recirc or blow off...interesting eh? 

If it is ok for the turbo my next question is what works best in conjunction with a MAF meter?   

I think that the recirc. valve might cause a slight no flow time when the recirc. is pumping back into the intake post MAF. 

Wouldn't that create a moment of no air flow past the MAF as it is getting the air from the charge pipe?

Has the MAF already decided how much fuel based on the air which has already passed by?

Does the air going back through the turbo have the same effect on the MAF as the recirc. valve?

Lots of things to ponder here

[Nation]

My old 7.3 did not have a bov either. I believe most diesels don't actually! As far as the air forcing its way back through the turbo and causing weird readings.. I don't think that will be an issue. You are simplifying everything by not running a BOV.  As long as you are not taking air away from the system that the MAF has ALREADY used to determine how much fuel to spray there shouldn't be any running issues.  I am pretty sure that there are a few companies out there that do not add a BOV for our 2RZ/3RZ motors so that nobody has to deal with this sort of thing and it also performs better because of the no delay before coming into boost after shifts. (sorry for my newb terminology)

If you had ever ridden in a diesel and preloaded the turbo so it was about to boost hard and then let of the throttle and heard that woof woof woof woof or whatever... That's the air not being blown off.  If it makes your life easier to not run a BOV id do it. Maybe rebuild your turbo a tad bit sooner... more performance... whatever..

[Tungsten Slayer [OP]]

I'm right with you.

I am chasing down this little issue of the motor kinda stumbling after being in boost or just revving in neutral.  It could be something entirely different than the MAF, but it ran great before adding the turbo setup..so I dunno 

[twistedtoy92]

The only reason you need a bov is to relieve the pressure when the throttle plate closes. Diesels have no throttle plate to close so no bov is needed. Petrol engines have a throttle plate and when that closes the pressure needs to go somewhere, if it is not recirculated or blown off it will cause turbo shutter/surge which is hell on the bearings and can possibley snap the shaft due to the pressure backfeeding into the wheel. It also heats the out of the air in the compressor more than it already is. Run a bov, whether you vent to atmosphere of return it post maf it is the way to go, trust me. Returning it into the turbo keeps spool up as well, of course this is all magnefied with higher boost so low boost isnt as bad. Make sense?