Z U L8R Posted June 22, 2007 Share Posted June 22, 2007 basically every turbo nissan motor i've ever had running an atmospheric bov, i've had to set the base idle to 1000-1100 so it'd stay running after letting off. on my rb25 now my maf is about a foot in front of my throttle body and my bov is about 8 inches before my maf right next to the intercooler. i have absolutely no more idle problems, i can hit full boost and go straight in neutral and my idle drops right to 850rpm everytime. plus if you've got 6 feet of pipe with the maf on one end and the motor on the other, then throw in 2 variables that mess with the flow aka turbo and bov, as opposed to sensing the air coming into the manifold a couple inches from the manifold...i'd assume the latter would be more precise, wouldn't you? the only cons i've heard is that, "nissan maf's are plastic and were designed to have air sucked through them (implode), not have 22 pounds of boost forced into em, you'll pop the frickin top off that thing soon" .....so far no probs with the z32 maf... the only other thing i can think of is joe shmoe with a stock rb, nothing to tune with at all, no safc, deciding to go blow through instead of where it is stock because inbetween 1st and 2nd getting on it there's a slight hesitation, and after he blows off the car wants to die and he's tired of feathering the gas pedal. i think joe'll run into problems with how the maf actually reads because sucked air going passed the elements would be colder than compressed air being forced through the maf's elements, thus cause it to run weird, or not as good with the stock map that's in the stock ecu. therefore he should get at least an safc2 so he can make the maf corrections. just my 2 cents, it makes a lot more sense to me to go blow through, any other opinions? will i blow the top on mine in the near future? Quote Link to comment Share on other sites More sharing options...
Z U L8R Posted June 22, 2007 Author Share Posted June 22, 2007 ps. my sig pic,that was before converting it to blow through obviously Quote Link to comment Share on other sites More sharing options...
Evan Purple240zt Posted June 23, 2007 Share Posted June 23, 2007 My car is blow through. I haven't made it to 22 psi yet. THE biggest problem I see with the blow through is turbulence. My car runs well and idles well. HOWEVER, I had to tune for the blow through. Stock ECU and blow through is not good. You will run way rich (I did). I have my Maf map in my power FC almost maxed out at 20psi. I did my blow through over a year ago FYI. I am happy I did it that way, but wish I had more straight pipe before/after to smooth flow. My cover has not threatened to blow off yet. I popped the stock cover off my old MAF and siliconed it on for security purposes! Take it easy man, nice numbers BTW. Evan Quote Link to comment Share on other sites More sharing options...
Z U L8R Posted June 24, 2007 Author Share Posted June 24, 2007 cool. yeah when we first did it it was running rich as hell too. i have a power fc, after he fixed the air fuels, no problems whatsoever. thx for the reply Dave Quote Link to comment Share on other sites More sharing options...
jerryb Posted June 29, 2007 Share Posted June 29, 2007 Im gonna try Blow throu... My RB20 stalls when the electric fan turns on and/or off. After alot of silly electrical troubleshooting efforts I noticed a significant MAF milivolt reading with the engine off and the fan on!!!! I went back to logical thinking 101 class and asked myself what does the MAF do....measure air! And when dose the car stall.... when the rad fan goes on or off. Its quite funny as I can prevent the stalling by placing a face cloth over the air cleaner.....but its hard to keep there when driving the car:icon10:! I know understand its because of my current set up....short pipe straight off the turbo inlet....into the MAF into the air cleaner....into a big ass electrical fan. I guess it creates a big spike that the PFC cant handle so off it goes. So its either build a shield or move the MAF....I may eventualy do both but first the MAF! By moving the MAF there will also be more room so I can replace the smallish foam air cleaner with a larger K&N air cleaner. Ill let you know how it goes but my search on all the NISSAN forums indicates a better running setup. On another funny note...my car would stop dead every time I shut the passanger door???? The ground to the PFC was hooked up to a random but solid ground wire. It turned out this wire was part of the interior light switch so when I closed the door I lost the ground!!!!:biggrin: haha..doh! The quest continues! Quote Link to comment Share on other sites More sharing options...
Z U L8R Posted June 29, 2007 Author Share Posted June 29, 2007 lol. yeah, on all my rb20's inbetween first and second getting on it, there'd always be a slight hesitation, blow through rocks! Quote Link to comment Share on other sites More sharing options...
streeteg Posted June 29, 2007 Share Posted June 29, 2007 Would you be willing to take a pic of the setup you have? About to do my front mount and interested in doing blow through Quote Link to comment Share on other sites More sharing options...
jerryb Posted June 29, 2007 Share Posted June 29, 2007 Me?? check it out here http://www.photoshow.com/view/Tj2vW3ws Quote Link to comment Share on other sites More sharing options...
Z U L8R Posted June 30, 2007 Author Share Posted June 30, 2007 i don't know if i'm being to analytical (sp?) but relatively speaking (that means if we lived in a vacuum LOL) that maf would restrict a little flow to the turbo's ingestion if it were in front of the turbo, where as after the turbo it's no problem for that sucker to blow air passed it. as far as turbulence i can't see it being anymore turbulent than all the fins/passages in your intercooler before the boost actually gets to your throttle body. just my .02 =P i can't see your pics jerryb, my flash player is ole school. streeteg if you still need pics let me know or whatever. i want to reiterate that 1. if you're going to go blow through, you should have some form of engine management, safc, power fc, aem ems, etc. because compressed air is hotter so the maf's element will be getting a different reading, which will change your a/f ratios. for my car after moving the maf my a/f map got richer, someone elses car may get leaner, so to be on the safe side, get eng mngmnt. 2. cut the flange off the maf so there's still a little bit of a lip, that way your intercooler coupler won't slide off as easily & don't make the clamp too too uber friggin tight cause it's only plastic, you don't wanna crack it. 3. to be safe i'd give the maf some space from your throttle body & bov, couple inches or so, i'll just say at least 6 from the tb and 8 or more from the bov dave Quote Link to comment Share on other sites More sharing options...
jerryb Posted June 30, 2007 Share Posted June 30, 2007 Im ok on all accounts....PFC with FC-edit, with plenty of space before TB .....good straight spot....and wide band. Thanx!! Quote Link to comment Share on other sites More sharing options...
jerryb Posted July 4, 2007 Share Posted July 4, 2007 Well...I did it and was very pleased with the results. After days of tring to idle learn my PFC/fc-edit on an pull through MAF I was about ready to throw the whole thing away. So I moved the MAF to a push through location, reset the PFC and started the car. It started instantly, idle learned the first time and so I went for a drive!!! MY first! YAAHOO. Its far from a perfect tune but now I have a starting point. It never stalled once and I run an atmospheric bov. The spring was a bit light and it would start to blow at around 3500rpm but the car still ran well....! It did run very rich, idled at an A/F ratio of 11.3 with little increase at higher RPM but a few quick adjustments brought that somewhat in line Anyway I guess its too early to make a final call but I am optimistic that all will go well. Thanx Dave! Jerry Quote Link to comment Share on other sites More sharing options...
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