SR20DET - Tuning for vented BOV

A place to discuss the systems and methods of tuning Nissan engines.
maxpsistop
Posts: 87
Joined: Tue Apr 08, 2008 2:41 pm
Car: 1990 Nissan 240sx

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HEy guys, I have decided to go with a vented blow off valve. I was wondering if anyone had any tips on tuning your ecu to help with the stalling problem some people are having, I am currently running with nistune but I have not done any major modifications yet to really start messing with it. Anybody with tips please let me know, thanks

Mike


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Neil
Posts: 745
Joined: Tue Apr 20, 2004 10:27 pm
Car: shooting laser guns

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If you understood the reason why a vented BOV causes problems, then you'd know those problems aren't something that can be remedied with ecu tuning.

To do it right you'd have to run standalone with a MAP sensor instead of MAF, and that seems kind of excessive for a little bit of vanity (which, by the way, gets old real quick, trust me.)

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david200095367
Posts: 1632
Joined: Mon Mar 29, 2004 7:57 am
Car: 91 fastback 93 coupe w/s14 sr20det 98 s14 kouki

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yup go with a pfc and convert to map thats what i did, but not for the venting bov reason. no stalling or anything.

or

you can run a blow thru setup where you put the maf on the cold side.

BEST1TUNING.COM
Posts: 141
Joined: Wed Apr 04, 2007 6:23 pm
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Actually there is a specific section in the ecu that controls the maximum pulsewidth allowed when at zero throttle. This is great beacause even though the ecu reads the airflow, which is reduced when it escapes through the BOV, you can tell it not to go above a set point. This is not something that alot of people understand. I use this section to fix the problem 100%

I was trying to get nico to give me a section where I can answer questions like this...its so hard to dig through and find them, but Ive had no luck.

After tuning for 7 years you gather alot of info and find some great things about ECU tuning. I would love to share them...
Modified by BEST1TUNING.COM at 5:31 PM 2/18/2009

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Neil
Posts: 745
Joined: Tue Apr 20, 2004 10:27 pm
Car: shooting laser guns

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Being able to adjust a maf 'limit' when the tps reads closed makes perfect sense, actually. You can tell I had no idea that was possible. If you do get that section you mentioned I'd definitely like to read about some more of the things you know.

back OT though, a vented bov opens a bit while cruising in vacuum, letting in unmetered air. What's your experience with the impact that has on the mixture?

BEST1TUNING.COM
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That is very common also! Luckily it is during cruising where if afr fluctuates from 14-15 under high vacuum, I havnt seen it alter egt enough for it to be a big concern, but just like a max pulse width there is also a min pulse width setting for tps. Good stuff.

There are allot of ways to get creative with the ecu tuning and finding ways to fix certain problems...the hard part is, unlike a standalone, there is no instruction manual


smelly240
Posts: 135
Joined: Sun Oct 15, 2006 11:26 am
Car: 240

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I can vouch that this works - you should all listen to the hadawar.

you'll probably have to tighten the bov a little to keep it from doing too much opening bs @ cruise/part throttles. i know i always run my bov stupid tight anyway... its really only there to plug the hole in the IC pipe.

dtowndrifter
Posts: 176
Joined: Wed Oct 19, 2005 8:14 pm
Car: s-14 kouki

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hks ssqv

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s13-t
Posts: 419
Joined: Wed Jun 18, 2008 6:07 pm
Car: s13 pig nose w/blacktop sr20det

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Im looking into this as well simpy to clean up my engine bay- bypass hose stretches across infront of rad- I found that if you get an enthalpy tune, or any ecu reflash- that you simply tell them to tune for atmospheric bov and they adjust it like best1tuning says. ecu flashing is pretty cheap and fairly common. most common to do when you upgrade maf, injectors, turbo, etc... but alot of people include the atmospheric bov too.

smelly240
Posts: 135
Joined: Sun Oct 15, 2006 11:26 am
Car: 240

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blow through isnt terribly effective.

If you actually test it with over 10psi - the plastic maf's (n60/62) leak around the square part. there are people that offer metal housings that are sealed up and work better, or people have sealed em with jbweld and hose clamps.

I run 25psi with meth so blowthrough isnt an option for me - unless i go with one of those housings.food for thought for anyone wanting to do blowthrough.

I ran blowthrough for a while with hose clamps around the maf - worked good on a t28.


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