Daeron Posted June 30, 2008 Share Posted June 30, 2008 I have to stress that all of my "knowledge" is second hand and abstract before I continue; this is all theory to me yet, not having owned and maintained a turbocharged car myself yet... but the way I understand it, the wastegate is indexed to the vacuum signal in such a manner that when you have been on the throttle, and lift off, the wastegate is opened to allow the turbine to slow down, while simultaneously (actually, at a distinct point in this whole process) the recirc or BOV opens up to relieve excess positive intake pressure. And yes, a BOV and a BPV are the same thing, in terms of role played. The way I read the diagrams, the air being vented by the BPVs in that diagram is tapped off from just before the intake manifold; in other words, cooled charge, and it is then re-routed to a spot immediately downstream of the turbo outlet. In other words, cool air is interrupted just before it enters the plenum and is then routed to just after the intake charge exits the turbo. Please, if anyone can drop a +1 to confirm my statements it would be appreciated.. and if somehow I am misleading correct me, because I almost don't want to post any of this due to uncertainty on my part... That being said, I hope it helps. This is reality as I see it, at least Quote Link to comment Share on other sites More sharing options...
getoffmyinternet Posted June 30, 2008 Author Share Posted June 30, 2008 I am positive that the bov would route air actually just upstream of the turbo inlet, because you want to equalize the pressure on both sides of the turbo. If it routed downstream of the outlet, the bov would basically be feeding itself the same pressure i was under so nothing would happen. I guess in light of this information, I'll have to buy a bov and tap it into the elbow just before the collector. If I had known ahead of time, I might weld it right onto the collector itself as there is much more room. Nevertheless, there are two control lines on the original setup, and two valves, so it would seem that the pressure is bypassed on either of two conditions, but I'm not sure why. I can't figure out for sure where they are going but will post my hypothesis to see if it makes sense to anyone. Both valves according to the manual are set at the same vacuum control reading ~3psi. The lines at the arrow in the top picture are confusing. One goes right into or behind that T-pipe and to another hose towards the collector. The other is unknown. The arrow in the bottom picture is where I think one of the control lines ends up on the aac. I can't figure out where the other one goes or if it in fact goes right into the t-pipe, but even then I don't know why it would do that. The fact that there are two valves could mean there is just a redundancy or a fool proof type safety measure. On a side note, look at the bottom picture at [Point 7] The tube that the arrow is pointed to is described as the booster line, so that will go into my vacuum canister for the brakes. The tube directly in front of it is unlabeled and I have no idea what it does, so it's plugged for now. On the engine it sticks straight up just outside of the collector, while the other sticks up between a gap in the rear throttle bodies. Here's an alternate view of the aac with lines connected and the funny wording of the manual. I can't find anywhere in the manual that says what anything does, just how to remove and inspect it. Quote Link to comment Share on other sites More sharing options...
getoffmyinternet Posted July 1, 2008 Author Share Posted July 1, 2008 Sad to say this is becoming a yearlong project. Things still left to do that I can think of so far. fab/install intake box fab/install bpv flange and install bpv fab or buy exhaust system mount injector resistors, battery, boost controller, horn fab/buy/install throttle linkage buy/install odo linkage wiring... Months. It would take less time if I was set on doing everything myself or money wasn't as much of an issue, but on the plus side, going though my dad means that whatever we make ourselves or misc parts he can bring me home from work doesn't cost me anything. So far it's wait time v. spend money, and the former is winning. Still, I want my car back! I forgot what it's like to drive it! It's been non-op way longer than it ran. Probably the story of most of our lives though, right? When I finally took it off the jack stands I was like wow, I don't remember it being so low to the ground! The car looks so much smaller now. I was at Autozone today, looking for little parts even though I knew they never have anything I need, and I told the guy, who is an import lover, I was building a car to compete with the 2j and all he said was, "Good luck." Quote Link to comment Share on other sites More sharing options...
Careless Posted July 1, 2008 Share Posted July 1, 2008 pshhhh. stop complaining, you're making excellent progress. Quote Link to comment Share on other sites More sharing options...
Bishopsrock Posted July 1, 2008 Share Posted July 1, 2008 Hi Guys, Sorry for any confusion but I have no turbo experience/knowledge, no turbo technical language and pretty much no technical help other than HybribZ - so what the hell am I doing playing around with an Rb26 then??? Anyway, to clear up a misunderstanding that I caused, I am not feeding back into the airflow meters. I have no BOV or recirc valves so the pressure hammer ends up back at my R33 ceramic turbos - whoops! What I meant was that I am 'assuming' it ends up coming back out of the air flow meters. So where to next? Well I have decided to follow the advice of one of my ex girlfriends and "keep it simple stupid". The truth is we are not 100% certain why the recircs were used and why they were positioned as they are. It seems there is more to them than just emissions. Sooo, I have decided to install a set of recirc valves off an R33 pretty much as Nissan designed. I will fit the valves on the same side as the injectors and connect the two (vacume?) pipes up. I am lucky enough to have the same pipes dangling from my existing engine but I had blocked them up. I can simply connect them and make a bracket to mount the recircs close enough. On the intake side, I will fit the 'Y' shaped metal pipe into the two corresponding hoses on the intake side:- I will then get a piece of pipe fabricated to run throught the bottom hole in the radiator panel and cross the front of the car before returning back through the corresponding hole on the other side and meeting up with the recirc valves. I only want to make 450bhp so (I am told) the recircs should be fine. Plus, I can't stand loud gadget sounding motors. Our cars will be fast so we don't need to make them sound fast in order to try to compensate for something we don't have - do we? For example, today I booted my Z for pleasure. I didn't even know there was a AMG Merc close behind who thought I was trying to burn him off! I did burn him off and I stopped much quicker than he could too!!! He was clearly struggling to stop his heavy car in time at the traffic lights. Anyway, what do you guys think about doing it this way using the recircs? Cheers Quote Link to comment Share on other sites More sharing options...
getoffmyinternet Posted July 3, 2008 Author Share Posted July 3, 2008 It's pretty fortunate to have the original recirc valves and that y-pipe to boot. I'm going to have to fabricate some sort of y-pipe for my universal bpv and find a way to install the two of them in conjunction. Yes, the the two control lines are vacuum operated. Will you be able to turn up the boost with these valves though? They don't appear to be adjustable. Unless the control lines also control the blow off pressure setting and can be hooked up to an aftermarket boost controller should you go that route. I take the lines for being more of an on-off switch though. Do the valves themselves say what pressure they blow off at? I'm still trying to figure out the hurdles, if any, involved with replacing two small valves with one bigger valve. I don't think it will be much, since Greddy actually sells kits for just that: one large bpv that replaces these two and keeps the stock plumbing (probably for the purpose of adjusting blow off pressure as I mentioned above). But again, I'm just speculating. It would be great if your valves could reveal some hard facts on the matter. I wonder if there is an "RB26 For Dummies" out there. Quote Link to comment Share on other sites More sharing options...
Careless Posted July 4, 2008 Share Posted July 4, 2008 woops, nevermind what i posted. anyway. have you considered these, bishop? http://www.forgemotorsport.com/content.asp?inc=product&cat=0008&product=FMFK055 Quote Link to comment Share on other sites More sharing options...
getoffmyinternet Posted July 4, 2008 Author Share Posted July 4, 2008 What, you mean the part about me making excellent progress? :'( Quote Link to comment Share on other sites More sharing options...
Bishopsrock Posted July 4, 2008 Share Posted July 4, 2008 Hi Guys, Here is my thought process... I am told by RB Motorsport that with a apexi power controller (the one where I keep the AFMs) and 1 bar of boost, that I can easily make 450 - 500 hp. The problem if I turn up the boost is that my nice (lucky find) 34,000km engine could easily get wrecked. The only other person in the UK to have done this conversion ended up with a hole in a piston after only 2 weeks of driving!!! My car is now the only one on the road in the UK and its the start of summer here. You guys cannot have driven one of these cars yet. When you do you will find that they are flipping lethal with a standard GTR engine as it is. I took my biker mate for a quick spin yesterday and without any prompting he blurted out that it was quicker than any bike he had been on! The point i'm making is that I haven't fitted the power controller yet and it hasn't been setup or mapped. In fact, when RB Motorsport checked it out the boost was spiking at 1.2 bar so Rod (to save any risk to my engine until we get it sorted & mapped) pulled the pipe to the boost solenoid and blocked it up. Once the Power FC is in and mapped then I will have almost twice as much power as I do now!! Having said all that, my 3 questions for anyone considering more than 500 hp would be:- In a car that weighs almost nothing, do you honestly need over 500 hp? Can the extra be used i.e. What difference is the extra hp above 500 actually gonna make? & Is that difference really worth the extra cash/design risk? Not forgetting that from what i have read, as soon as you go over 500 hp you enter the realm of all sorts of drive train problems and failures.... So - thats why I arrived at the decision to stick with the stock recircs which save me varying the Nissan tried, tested & robust stock design - again anyone please verify this??? but I have been told that they are good for 500hp??? Cheers Quote Link to comment Share on other sites More sharing options...
Careless Posted July 6, 2008 Share Posted July 6, 2008 What, you mean the part about me making excellent progress? :'( ahahahahah. there there *pets your head* Quote Link to comment Share on other sites More sharing options...
Careless Posted July 6, 2008 Share Posted July 6, 2008 Bishop, you're going to need a touch more than 1.0 bar for 500. I'd say closer to 1.2ish. And I dont think I need more than even 400 hp in my Z. =) Quote Link to comment Share on other sites More sharing options...
Guest spider14368 Posted July 6, 2008 Share Posted July 6, 2008 What's up everyone out their, I'm new to this forum,and after looking all over the net i found that this site would be the most help to me,So here's the problem. I just came across a 72' 240z, It has 32,000 original miles on it, it's near mint and unmodified, I decided to upgrade and go with a RB26DETT engine w/an RB25 RWD trans, I found a complete swap,eng,wires,ecu,etc. I even found a complete custom engine and trans mounting kit,but my problem is that with all the seaching for this swap i'am very unsure as to what rear end set up I would need for this swap to be functional, my Z currently has the R180 rear end in it, what should I do about that? What should I upgrade to? I have everything already being shipped and I'm up in the air about this, can anyone help? Quote Link to comment Share on other sites More sharing options...
getoffmyinternet Posted July 6, 2008 Author Share Posted July 6, 2008 You guys cannot have driven one of these cars yet. When you do you will find that they are flipping lethal with a standard GTR engine as it is. Can you explain your setup? I'm curious. Are you talking about the 240? That's a pretty bold statement, but as for me I'm really looking forward to sharing the experience. But yeah, I don't think 1.0bar would cut it. Are you talking about crank hp? From almost all the personal accounts I have read, the ceramic spool won't last very long at much more than 0.8bar. Even if it were ball bearing, you'd need the n1 version (GT25) with a steel turbine to feel safe running it that hot. I imagine the others who have done it will say that aside from everything else, you tires won't last long with that much power P.S. Spider=hijacking. Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted July 6, 2008 Share Posted July 6, 2008 What's up everyone out their, I'm new to this forum,and after looking all over the net i found that this site would be the most help to me,So here's the problem. I just came across a 72' 240z, It has 32,000 original miles on it, it's near mint and unmodified, I decided to upgrade and go with a RB26DETT engine w/an RB25 RWD trans, I found a complete swap,eng,wires,ecu,etc. I even found a complete custom engine and trans mounting kit,but my problem is that with all the seaching for this swap i'am very unsure as to what rear end set up I would need for this swap to be functional, my Z currently has the R180 rear end in it, what should I do about that? What should I upgrade to? I have everything already being shipped and I'm up in the air about this, can anyone help? Yes, open up the RB section here and start reading.... everything you've mentioned is right here at your finger tips.... Quote Link to comment Share on other sites More sharing options...
Bishopsrock Posted July 8, 2008 Share Posted July 8, 2008 Hi Guys, I have just read some of my post back trying to explain my thought process and it sounds a bit rubbish. I have been reading other threads and posts where the mission is to uprate everything - pistons, injectors, turbos, cams, porting etc.. to get more hp. Having driven a 240 GTR in relatively detuned form, I suddenly appreciate that it is very difficult to apply this power to the tarmac and that for road use none of this makes sense. I do stand by my "lethal" statement though I am now a big fan of keeping the engineering pretty much near standard if possible. Any further opinions on recircs? Cheers Quote Link to comment Share on other sites More sharing options...
getoffmyinternet Posted July 9, 2008 Author Share Posted July 9, 2008 If you're planning on going the route of an aftermarket ems, consider the fact that if it is going to use map sensors instead of maf's, you could easily just use an atmospheric bov which could make the change-over easier/simpler. Quote Link to comment Share on other sites More sharing options...
mamba_888 Posted July 21, 2008 Share Posted July 21, 2008 Hey Spider... Do a search on R180 to R200 swap. Do it in the upper forums. This is really not the place for this question but I do understand you posting here because of your desire to put an RB into your Z. The R200 is built like a tank and have been used over and over with the high torque V8 swaps. If you're lucky, you might even find an LSD model that most of us want! So... of you go (Simon Cowell on American Idol) and let's get back to this wonderfully written journal of installing an RB thread!!!! PS... (a little humor) Hey "getoffmyinternet", my avatar looks like it wants to eat your avatar !!! What's up everyone out their, I'm new to this forum,and after looking all over the net i found that this site would be the most help to me,So here's the problem. I just came across a 72' 240z, It has 32,000 original miles on it, it's near mint and unmodified, I decided to upgrade and go with a RB26DETT engine w/an RB25 RWD trans, I found a complete swap,eng,wires,ecu,etc. I even found a complete custom engine and trans mounting kit,but my problem is that with all the seaching for this swap i'am very unsure as to what rear end set up I would need for this swap to be functional, my Z currently has the R180 rear end in it, what should I do about that? What should I upgrade to? I have everything already being shipped and I'm up in the air about this, can anyone help? Quote Link to comment Share on other sites More sharing options...
Careless Posted July 22, 2008 Share Posted July 22, 2008 What's up everyone out their, I'm new to this forum,and after looking all over the net i found that this site would be the most help to me,So here's the problem. I just came across a 72' 240z, It has 32,000 original miles on it, it's near mint and unmodified, I decided to upgrade and go with a RB26DETT engine w/an RB25 RWD trans, I found a complete swap,eng,wires,ecu,etc. I even found a complete custom engine and trans mounting kit,but my problem is that with all the seaching for this swap i'am very unsure as to what rear end set up I would need for this swap to be functional, my Z currently has the R180 rear end in it, what should I do about that? What should I upgrade to? I have everything already being shipped and I'm up in the air about this, can anyone help? dont take apart a near mint original 240z. you could probably sell it for more than you bought it for Quote Link to comment Share on other sites More sharing options...
Bishopsrock Posted July 28, 2008 Share Posted July 28, 2008 Hi Get off my internet (whats your name???) I have fitted my recircs and think, considering the prior discussion, that I should post it under your thread - but its your thread and I don't want to hijack it. Would you like me to post here or elsewhere? Cheers Quote Link to comment Share on other sites More sharing options...
wondersparrow Posted July 29, 2008 Share Posted July 29, 2008 First off, I know nothing. I have been frequenting this site because I am thinking of building an rb powered z. You guys confused the heck out of me with the recirc valves (I have never owned or worked on a turbo car), so I did some searching and found this. http://subiefreaks.com/rons-subaru-performance-information-corner/blow-off-valve-faq/ . I am not sure if anyone else was confused, so this might be for my benifit only. Now if i read that right, you should be recirculating back to the turbo inlet(s) after the maf. It allows the turbo to keep spinning and cool. piping it back after the maf, you avoid running rich. I am not sure if you are running dual intakes, but if you are, I would bet that it would be adviseable to run each bpv back to its own turbo. My uneducated 2 cents, carry on..... Quote Link to comment Share on other sites More sharing options...
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