MrNizzles

iTrader: (5)

Just curious to know what others think about this setup:


- stock motor w/bnr3's (all reliability mods done, 13K on fresh rebuild)
- stock ecu, no boost controller or pills installed.
- boost controlled by wastegate spring only. without any pills in the turbo pre-control and wastegate lines, boost hits about 7-8 psi, without much creep. bnr's have ported wastegates.

- no smog pump (and use a pulley in place of it)
- full open exhaust, dp, resonated mid-pipe (hows the smell?), aftermarket catback.
- cold air intake (I like fighters garage)
- smic or medium size (M2 medium) IC

- upgraded 1300cc secondary injectors
- supra tt fuel pump, fresh filter and fpd (maybe even aftermarket fpr installed)
- 2nd oil cooler added

- Methanol Injection and Tuned!

reliable? how well would this control boost? I'm guessing pretty good, but maybe someone knows better can share?

good for the track?

wouldn't spool up time be pretty freggin fast too?

Right after my rebuild, I didn't have pills installed and I could hit 7psi pretty fast.

It was also comforting to know that I could sink my foot all the way and hold it and not have the slightest worry that I was gonna lean out and pop the motor.

Even on a cold night the boost would hold at about 8 psi and not creep. But I don't have an open intake and full exhaust, so I'm wondering if adding that would it be too much?

Banzai-Racing

iTrader: (11)

How are you suppose to tune the car for 1300 injectors and meth with a stock ECU?

Install a Power FC, then you can have your car properly tuned for the injectors and meth. Not to mention all the other benefits of having an engine management system, like runing stock boost of 10psi or even taking advantage of all the mods and running 15-16psi.

MrNizzles

iTrader: (5)

Several people I have talked to (who tracked their car) have had tunes on stock ecu with a wide band afr hooked up... maybe it's not worthwhile tho?

I realize the benefits of a PFC, but I also want to know the "dark side" as well

JStrib

iTrader: (6)

I think trying to stick to a stock computer would defeat the purpose of the BNRs. That's me though.

93rx74lyfe

iTrader: (1)

You need a Power FC, being stubborn about this will only result in that new motor becoming a brick.

silverfdturbo6port

iTrader: (26)

the dark side of a power fc? i guess not blowing your motor is the dark side in your world lol. this all should be interesting

MR_Rick

iTrader: (7)

The stock ECU can't be tune to run with 1300cc injectors. Second, 7psi on the stock twins is not the same as 7 psi on the BNR's III. You are going to need tuning regarless. Those are a lot of mods to run on the stock ECU with BNR's.

MrNizzles

iTrader: (5)

ok, so maybe no 1300 secondarys... and Ive heard all about bnrs are overkill ... and I've also heard all about stock twins vs bnrs psi numbers not being "exactly" the same, yada yada yada... but this has been in relation to running 10psi, not 7psi. I ran 7 psi on my bnrs for a long time albeit with stock intake.

so then how do you explain why people who track their car with stock ecus, open intake and open exhaust don't blow their motors?? they also have had tunes. not sure if they had upgraded injectors.

And what happened to all the sayings "as long as you control boost within your fuel supply" you're OK ! ?

I'm hearing allot of conflicting information.

RXtacy

iTrader: (7)

"Boost" aka air pressure is not the same thing as air flow. You can keep the pressure the same while exponentially increasing the amount of air flow. This is what will cause issues and lead to a blown motor. So while you may be seeing 10 psi of boost you could potentially be flowing a significantly larger volume of air then your fuel system can support.

silverfdturbo6port

iTrader: (26)

dude i have a plug and play AEM ems for your car for 650$ shipped it will solve all your problems

MrNizzles

iTrader: (5)

^ thanks, but I'd get the PFC first, and never a "used" computer ... it's not an issue about saving $$$. I just want to know more about different setups that people run.

MrNizzles

iTrader: (5)

I've heard allot about that too... I have no doubt a GT35r at 10psi would be "significantly" higher "air flow" than stocks twins or BNR's.

but how much "air flow" could BNR's really have over stock twins ? this is a question no one really has a "qualified" answer for. I have asked this on other rotary forums as well. It's all hearsay....

However, that ambiguity alone may be THE deciding factor for me.

Another curiosity I have, is with an open intake and exhaust, do the BNR's (or stock twins) have a higher "air flow" at the same psi level vs. stock intake and exhaust? Probably slightly higher? but how much?

I thought boost creep/spiking was the common indicator of this and if you don't experience allot or any, then whats the worry?

And... if air flow IS so important, then why not invent a mod that detects mass air flow? does the PFC do this?

(ahh.. the flamming is just beginning

Banzai-Racing

iTrader: (11)

Please explain how anyone is "tuning" the stock ECU?

It does not matter if there is a wideband in the car, it is not going to interface with the stock ECU.

MrNizzles

iTrader: (5)

just finished reading this thread, pretty insightful - https://www.rx7club.com/showthread.p...=mass+air+flow

anyone try to hook up a maf sensor just to measure the difference between different setups.

Banzai, I don't think the "tune" refers to adjusting the stock ecu since that isn't possible, obviously, but hooking up a wide band on a dyno can shed light on what mods are pushing the afr's lean. At least this is what I have been told. Sounds reasonable I think... no one has tried this?

I guess my whole point to this is that I want more concrete information that just "get a pfc" because thats what everyone says. I'm not discounting it, in fact I will .. at some point .. get one.

Monkman33

iTrader: (28)

1. YOU CANT TUNE THE STOCK ECU.

2. The airflow of bnrs is more than stock. Enough to merit upgraded injectors even at stock boost levels.

3. If you want to mod your car, and get your money's worth from your mods, you need an aftermarket ecu. Otherwise, you will never reach the potential of your car, and risk engine damage from running too lean.

It's just how it is.

Banzai-Racing

iTrader: (11)

The typical thought process is......Why bother spending thousands on go fast parts if the ECU can't be tuned? We consider the PFC a reliabilty mod, right there with the DP and AST.

It is your car and you can do what you want to it, but spending a bunch of money on performance parts and cutting corners on tuning always leads to a blown engine.

We build these cars for a living. Our rule of thumb is that if there is a full exhaust on the car, it needs fuel system upgrades and an EMS. You can listen to whoever it is that is giving you this horrible mis-information, just remember that there were a bunch of people telling you the exact opposite of these "people that track thier cars with the stock ecu" and full mods.

purerx7

iTrader: (61)

Maybe he is thinking that tuning the ecu would be the equivalent of getting the ecu "chipped" ie pettits computer upgrade modification which I believe PFS does too. Honestly, if money is not a concern it seems like you are cutting some of the most important corners. Really think you are going to need more than just a wastegate spring to control boost even though the bnrs have a ported wastegate. IMO, I would add PFC, Wideband, dont forget about gauges (your pfc commander can help with the readouts on those), and a boost controller. Do it right and more importantly, do it once.

-Someone who has seen 1000000s of these threads and has seen those same individuals post back months later asking why they blew their engine.

MrNizzles

iTrader: (5)

doh. I just stated that in my post above... I know u can read Ok, So lets put that miss-communication issue to rest. I am "only" referring to adding a wide band afr meter and recording the readings for a current setup. I'm not referring to "chipping" the ecu ala Petite or any other method of "tweaking" the stock ecu.

And I agree mods with no ecu is "skeptical" at best.

I'm still curious if anyone has hooked up a wide band on a dyno with a stock ecu and what mods you had.

I'm also curious to know if anyone has tried installed a maf sensor -- NOT to hook up to the stock ecu, just to get readings from different setups.

thanx fellas, appreciate the feedback.

RLaoFD

iTrader: (6)

To answer your question, I have hooked up a wideband O2 to my car w/ stock ECU because I was curious about if the stock computer could handle my mods. Relative to AFR, they are DP, CB, Intake and FMIC. Since the stock cat was in place, my boost was kept in check. @ WOT on a pull my car was still in the upper 10's.

You are right in that as long as you control your fuel supply, you are okay. I understand what you are trying t do with lowering the boost and all, and its up to you to decide if the stock ECU has enough fuel for it, but in the end... why?

Your build will be incomplete without a computer to bring out the full potential of your full exhaust and BNR 3's.

Double_J

iTrader: (28)

I'm not going to lie, this thread seems silly so I didn't read all of the responses. My thoughts are....
Get a pfc and be done with it. It will ensure you are safe once it has been tuned and perhaps make the drive ability better.

Use the bnr's for more power like they were intended for. 15+psi

It is only my opinion based on my car and the results I've got but bnr's do not flow or make more power than the stock twins given the same psi. That means in (my opinion) you spent $$ on turbos you didn't need because you could have just ran stock turbos at 7psi. And I have no idea why you want to do that.

Bnr @ 10 = stock at 10lbs
Bnr @ 15 = stock at 15lbs

The only difference is the bnrs can handle the higher boost.

In my case my stock twins with the same mods made the nearly the same hp as the bnr's. I dynod the car before and after and the HP was the same.

Bnrs are only better if you are turning up the boost becauuse they can last longer than stock twins. That's it.

My mods are in my signature if you want to see them.

MrNizzles

iTrader: (5)

^ thnx RLaoFD, this is kinda where I'm getting at... and in fact, I know that this setup would be incomplete and I would add a pfc to take advantage of these mods and my bnr's ... I'm just curious like you.

Right now, I have stock intake, stock ic .. but also a DP, and RB catback, with stock mid cat. What I would like to do, to be more accurately educated in this learning process, is to dyno the car just as you did, and change 1 thing at a time and run again on the dyno watching the afr's.

Maybe... just maybe.. that bnr's don't really run that much leaner afr's with some or even all of these mods?? .. then again, maybe they do, and just for ***** and giggles I want to know what the breaking point is. Maybe add a mid cat, ok... add intake (or cheap bastard intake mod) and still ok ... but then add a bigger smic, and wham... too lean.

Also, having a MAF hooked up (not sure how) and monitoring the recordings after each change and run, can show when too much air flow occurs correlated to a given afr reading.

Jason

iTrader: (5)

Whomever you are listening to regarding mods please stop. Putting the car on the dyno will show you the A/F but not going to show you which mods making it go lean. Like others have said you need a PFC or you are going to end up with a blown motor pretty fast.

silverfdturbo6port

iTrader: (26)

Ya know there are people on here that are more than qualified to answer your questions and us answering question for people like u is a gift. This forum is one of few forums for cars that actually have good source of information and its all free.

So now that thats out of the way i think common sense will help u answer your own questions instead of over thinking everything in a unlogical way.

Now when it comes to comparing flow of a turbo many factors come into play instead of me and everyone else telling u how i think u should just follow some of Howard Coleman's threads, he has taken id say 1/3 of his life so far testing, thinking, and providing proof as well as very good information for everyone on this site.

Now as far as the stock ecu goes.... You can mod a stock fd with stock ecu all you want the ecu WILL adjust itself using the O2 sensor input to the ecu but that will only let u do limited mods and even at that it cant do what it needs to do on its own.
Again your best bet is to get a power fc. I love the power fc and i am really good at it. I am selling the AEM that i used only for one day as i think it sucks for rotarys. YOU CAN PICK A POWER FC UP LIKE I JUST DID FOR 300$ OFF CRAIGSLIST AND USED ECUS ARE NOT THAT BAD.

MR_Rick

iTrader: (7)

^I don't think BNR's and stock turbos are the "same". They do have upgraded turbine/compressor wheels.

MrNizzles

iTrader: (5)

some people wouldn't agree with that... some argue that bnr's at the same boost level produce more air flow, which causes a lean condition because the stock ecu doesn't recognize that change in additional air flow.

Until a maf sensor is hooked up somehow (not to the ecu, just for recordings and calculated to have understandable numbers), and compared to stock twins, it's just hearsay... but the notion still carries risk, which is why anyone and everyone (except me so far anyway) who has spent the $$ on bnr's also upgrades ecu and intake, etc.