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Hella_GTR

Do I Need Programmable Fuel Management with Basic Bolt-ons?

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Hi Guys,

Been doing a lot of research on here and can't find a clear threshold in mod's when a programmable fuel management system will be necessary for my bcnr33.  I just picked up a RSR Equal Length Front Pipe and HKS high-flow cat and haven't installed them yet as I don't want to install them then get boost creep or anything risky.  I'm also wanting to install a suction kit and possibly turbo outlets.  The car only has an HKS Hi-Power exhaust on it.  Thought'd I'd ask the question...Do I need a fuel management system for:

1)  Front pipe, high-flow cat, exhaust - Yes/No?

2) Suction kit, Front pipe, high-flow cat, exhaust - Yes/No?

3) Turbo outlets, Suction kit, Front pipe, high-flow cat, exhaust - Yes/No?

Car BCNR33 with 87k kms on it with HKS Hi-Power cat-back.  Everything else is stock.

Trying to feel-out where the safe line is not to cross before needing a tunable ecu.  Also debating about the turbo outlets as I've read mixed reviews weather they're worth it or not.  Probably best time would be when upgrading the turbos. I don't plan to go beyond the above as I need to put the car back to stock for future California compliance.  Just want to know if spending $2,000 (USD) on a PFM system like Haltech or Link G4 is worth it with such limited mods.  Apexi Power FC is cheap here in Japan but I know they're quite outdated.  Perhaps just a boost controller would keep things in check and safe rather than a PFM system. 

Thank you all for the guidance.

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You can go either way, depending on what your goal is. 

Basic mods like a free flowing exhaust will sound good, maybe offer a small improvement in power, but overall if you want to take advantage of the power increase you will need fuel/timing management of course.

You will be 'safe' to drive around with an aftermarket exhaust and probably intake as that's what maybe 75% of young guys do here in Aus with no tune. Do some of them run into trouble and cause damage? Yeah. Can it be blamed entirely on lack of engine management? I would argue probably not. A lot of those same people also thrash their cars, probably lack maintenance etc.  The smart ones realise that if they want to push their cars they should be using management of some kind.

In my mind, for an RB the same line has always been exhaust and intake/pod filter/s. Add a boost controller to sit at 12/14 psi or so (maybe different for the RB26 stock twins, I'm not personally sure) but in that low-ish range and you shouldn't have many problems.

I had this setup on my old R33 about 9-10 years ago and had that for about 2 years with no issues at all, but I used my car mainly for a fun daily and some spirited cruising on the streets. No track work, no limiter bashing or drifting etc. 

Having said all that, while the Power FC is older tech, it is still fine in cars of that era and as you said costs a fair bit less, and I would guess there are still a good quantity of tuners in Japan who tune them? That's the other point you need to consider.

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6 hours ago, Hella_GTR said:

Hi Guys,

Been doing a lot of research on here and can't find a clear threshold in mod's when a programmable fuel management system will be necessary for my bcnr33.  I just picked up a RSR Equal Length Front Pipe and HKS high-flow cat and haven't installed them yet as I don't want to install them then get boost creep or anything risky.  I'm also wanting to install a suction kit and possibly turbo outlets.  The car only has an HKS Hi-Power exhaust on it.  Thought'd I'd ask the question...Do I need a fuel management system for:

1)  Front pipe, high-flow cat, exhaust - Yes/No?

2) Suction kit, Front pipe, high-flow cat, exhaust - Yes/No?

3) Turbo outlets, Suction kit, Front pipe, high-flow cat, exhaust - Yes/No?

Car BCNR33 with 87k kms on it with HKS Hi-Power cat-back.  Everything else is stock.

Trying to feel-out where the safe line is not to cross before needing a tunable ecu.  Also debating about the turbo outlets as I've read mixed reviews weather they're worth it or not.  Probably best time would be when upgrading the turbos. I don't plan to go beyond the above as I need to put the car back to stock for future California compliance.  Just want to know if spending $2,000 (USD) on a PFM system like Haltech or Link G4 is worth it with such limited mods.  Apexi Power FC is cheap here in Japan but I know they're quite outdated.  Perhaps just a boost controller would keep things in check and safe rather than a PFM system. 

Thank you all for the guidance.

I would pass on pods, those don't do much of anything and have been known to damage engines because they aren't very good at filtering out dust/silt.

You really just don't want to run more than ~1 bar boost on the stock ECU. So if you're already there you shouldn't try to de-restrict the exhaust more.

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I am of the opinion that you should be able to retune both the fuel and ignition from even before you do any physical mods. The factory tune is just too rich, and there is heaps of stupidity in the high load high rpm corners of both maps in old Nissan tunes.

You will gain power, driveability and reduced fuel consumption from a tuneable ECU all on it's own.

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Your intention is to turn the car back to stock when it goes back to the US, so adding tunable engine management is definitely not required to support basically any setup you have revolving around the factory turbos. Full exhaust, intercooler, 14psi of boost, stock turbos - the stock tune in a 33 GTR is arguably more "correct" tune wise in this state of modification than the restricted state of the stock car. Pulls about 200rwkw like this.

Also no boost controller required either, as the restrictor olive in the vacuum line once removed sets the boost to 14psi, which the standard ECU is fine with.

A tunable computer will always result in improvements in fuel economy, better a/f ratios and more power, but I really don't see the point if you need to to keep the car completely stock later on. A Power FC is probably your best bet if you want to have it tuned in Japan, and then just remove it and put the stock ECU back in later. If you can get away with tuning it in the US on a different ECU, then absolutely go to a tunable ECU now, but for what your talking about the factory tune can handle all of it safely.

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No need for an aftermarket ecu with basic things like that. One of the nicest r33 gtrs I've driven had dump pipes, exhaust, hard pipe kit & removed restrictor. Was fine until the owner added a boost tee and turbos exploded.
If you do want some extra features like flex fuel, closed loop boost control & better fuel economy look at a Link ecu plugin, goes in factory case so nice & discreet when you go home. I have found them very easy to use over the last 10 years, wire in a wideband , do some logging and have a go tuning yourself and hire a dyno when you want to do WOT tuning.

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To be fair, Aussies are really good at making these things make way more power and pass far more stringent "I'll look and see if thats stock" than the USA has to deal with.

The real answer here is

Are you affecting Airflow?
If so, you need to adjust fuel to suit.

In the real world you're not affecting airflow 'much', but with a R33 GTR, the wick can be turned up quite a lot on stock equipment, and a 270awkw GTR is a very different thing to a ... whatever they actually make on a dyno truly stock and untuned. Making the most of the base equipment on a GTR is well worth a tunable ECU imo. 

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5 hours ago, joshuaho96 said:

You really just don't want to run more than ~1 bar boost on the stock ECU. So if you're already there you shouldn't try to de-restrict the exhaust more.

A good exhaust will lower back pressure, making your turbos not work as hard for whatever your target boost is. 14psi is what you get with the boost restrictor olive removed with at least a 3" system, different front pipe and better cat. Stock actuators are 1 bar, so he's not going to get more than that no matter how derestricted the exhaust system is, unless you were using a boost controller, so it's a non issue really.

4 minutes ago, GTSBoy said:

Plus, Nistune is almost undetectable.

Absolutely the go if he could still use it in the US / California and get it passed for emissions. I think we are all in agreement that better everything can be achieved with tunable engine management over stock, it just is it worth going down that path just to remove it later.

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It's not really worth going down the path just to remove later because whatever exhaust the car has when it gets to the emissions testing lab is going to get massacred. The front pipe gets chopped up to put in some booger-welded cats, a new main cat is installed too with comparable quality in welding. The ECU is inspected as a part of the smog referee visit so you don't want to mess with that. I don't think they open it up but if it's clearly the wrong ECU for the car or there's a random USB port in the casing that's going to be a red flag. There's no way you're going to pass the lab emissions test with the hybrid speed density/alpha-N load sensing that the Link uses.

My advice is keep it stock and focus on things like making sure your fuel injectors are cleaned up so they have the right spray pattern and even flow, replace stuff like OEM paper throttle body gaskets with metal gaskets, make sure your turbos aren't leaking oil and your engine doesn't have excessive blowby as well. The less you mess with the car, the less pain there will be for CA registration. You can throw a standalone in there and get it tuned as soon as it's CA registered, as long as you don't end up at the smog referee again nobody is going to be checking to make sure you're running the stock ECU, especially if you're passing the tailpipe test by a large margin.

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Wow you guys are awesome and great info here.  Josh, if I recall right, you went through or will be going through the California compliance work.  I got my car completely full normal so I have all the original parts and my intent was to have some fun with it while here in Japan for another 2 years or so and then swap it all back to OEM before shipping it back.  It's depressing to hear how they hack away at the front pipe like that...knowing that I may want to pick up an extra OEM front pipe and exhaust.  Or i just say screw it and move to Oregon or Washington (I would love to go to Australia as well but would need a visa lol).  The good news is I can register my car where my parents live in California which is still currently a no-smog County so I would not need the 2-year SMOG check after I get it through the initial Bureau of Automotive Repair.  So crazy what we have to deal with in California. 

Regarding the parts, it's still not crystal clear to me but it looks like I can at least install the RSR isometric front pipe and high flow cat with my HKS Hi-Power exhaust and be ok. I'll skip the pods and if anything just get a filter element.  I may go for dumps but hear that's a bit of labor so may save that for the future turbo swap in California (Josh, do you know if switching to n1 turbos or switching turbos in general would make it through CA compliance?).  Hmmm seeing that the Power FC is pretty cheap here, like $500 or less used on Yahoo auctions, I will still consider that.  I don't plan to increase boost and have not touched the restrictor olive.  I just don't want to have the boost increase on me and run lean by adding anything that would trigger that without a tune. 

Again I appreciate the guidance as it's hard to find clear information living here due to my language barrier (which is my fault).  My car is a one-owner car before me and in great shape and I want to keep it that way and healthy which is why I'm asking for some guidance.  Happy Friday!

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34 minutes ago, joshuaho96 said:

but if it's clearly the wrong ECU for the car or there's a random USB port in the casing that's going to be a red flag

And this is why Nistune is the win. It looks stock. It behaves exactly as if it was stock, unless the tune is modified. You can put the stock tune in it for emissions testing and then you can put a good tune back in it afterwards.

What is not to like?

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1 hour ago, GTSBoy said:

And this is why Nistune is the win. It looks stock. It behaves exactly as if it was stock, unless the tune is modified. You can put the stock tune in it for emissions testing and then you can put a good tune back in it afterwards.

What is not to like?

As long as the ECU looks completely stock and runs the car completely stock, then that would be great.  My thinking was to just swap back in the OEM ECU for the California Compliance, which is why a stand-alone was what I was thinking.  I do think Nistune is a good value though.  I'd just need to find a tuner here who knows how to use it.  I've found a couple Haltech ones but most common is HKS F-con or Apexi PFC from my initial research. 


Thank you

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3 hours ago, GTSBoy said:

And this is why Nistune is the win. It looks stock. It behaves exactly as if it was stock, unless the tune is modified. You can put the stock tune in it for emissions testing and then you can put a good tune back in it afterwards.

What is not to like?

I don't know if they're going to check the part numbers, last I checked the guy working on the Nistune type 6 board got most of the way there and then disappeared off the face of the earth.

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1 minute ago, joshuaho96 said:

I don't know if they're going to check the part numbers, last I checked the guy working on the Nistune type 6 board got most of the way there and then disappeared off the face of the earth.

What are you talking about? The part number remains the same. On an RB26 ECU, you pull the lid off, rip out the original EEPROM/processor (depending on ECU model) and install the Nistune board (which does involve a little more fiddling than I make it sound). Then you put the lid back on. From the outside, you cannot tell. Anyone who does not know what a daughterboard is for would not even recognise what had happened to the ECU if you showed them the inside.

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Also having actually passed the IM240 test, a Nistuned otherwise OEM car is not going to fail. You would be lucky to actually see boost, and I would wager a 900kw GTR is also not going to fail the IM240. I passed it with a pretty large cammed LS in my Skyline 😛

If they use the 5 gas system, you'll pass that even easier.

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1 hour ago, GTSBoy said:

What are you talking about? The part number remains the same. On an RB26 ECU, you pull the lid off, rip out the original EEPROM/processor (depending on ECU model) and install the Nistune board (which does involve a little more fiddling than I make it sound). Then you put the lid back on. From the outside, you cannot tell. Anyone who does not know what a daughterboard is for would not even recognise what had happened to the ECU if you showed them the inside.

For the BCNR33 and BNR34 they use a different ECU that doesn't have a Nistune daughterboard available, so you have to use a BNR32 ECU. So it's possible for smog refs to see that you've installed a BNR32 ECU in a BCNR33 and fail you for that alone. This is not a purely hypothetical issue, smog refs have been known to check ECUs, some will overlook it and some will make your life a nightmare: https://honda-tech.com/forums/honda-civic-del-sol-1992-2000-1/yet-another-state-referee-question-1650879/#post22175832

The really "fun" part is that you can fail for silly reasons like this even after getting your certificate of conformance from the emissions lab, which is the actual hard part. So you could put in a Nistune, remap to improve emissions + fuel consumption, pass the FTP-75 drive cycle test, then fail at the referee for a "defeat device".

5 minutes ago, Kinkstaah said:

Also having actually passed the IM240 test, a Nistuned otherwise OEM car is not going to fail. You would be lucky to actually see boost, and I would wager a 900kw GTR is also not going to fail the IM240. I passed it with a pretty large cammed LS in my Skyline 😛

If they use the 5 gas system, you'll pass that even easier.

The actual hard part isn't smog referee's emissions test, the hard part is the referee's visual inspection and the emissions lab test which is actually the FTP-75/ADR 37 drive cycle: https://dieselnet.com/standards/cycles/ftp75.php

If you call CARB's helpline they will tell you to your face that they don't want you to be importing these cars, which is why it's so painful and expensive to do it.

Edited by joshuaho96

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So the drive cycle is similar to the IM240 (just a different drive cycle)

That drive cycle would have no effect from stock ECU in regards to that level of stress (i.e, none).

The question is what do they compare it to/what targets do they have to hit? If they have to hit the targets for a 1998 vehicle then yeah you should be fine and having an aftermarket ECU (or a R32 GTR ecu for a RB26, it's the same engine after all) shouldn't be any major issue here at all.

I mean if you were really worried, you could just get 2 stock ECU's and unplug one before the test. It would take about 4 minutes total, but I doubt heavily it'd be an issue.

If the FTP75 is what is being tested against, I found this:

"The FTP-75 cycle is known in Australia as the ADR 37 (Australian Design Rules) cycle and in Brazil as test standard NBR6601."

This is this:

image.png.d704858df15b31e98b07458dcf9d5dde.png

The ADR37/01 (for cars after 97), is what I passed easily with my cammed LS. The only risk involved was literal unburned fuel due to the overlap on the cam. A stock cam would have passed this easily.

I can't fathom a Nistune/base tune being so far out not to pass this, that said - So will a stock ECU. Especially given the Nistune can be programmed with a factory map, this really shouldn't be an issue.


Worth testing and seeing if it even gets picked up.

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4 minutes ago, Kinkstaah said:

So the drive cycle is similar to the IM240 (just a different drive cycle)

That drive cycle would have no effect from stock ECU in regards to that level of stress (i.e, none).

The question is what do they compare it to/what targets do they have to hit? If they have to hit the targets for a 1998 vehicle then yeah you should be fine and having an aftermarket ECU (or a R32 GTR ecu for a RB26, it's the same engine after all) shouldn't be any major issue here at all.

I mean if you were really worried, you could just get 2 stock ECU's and unplug one before the test. It would take about 4 minutes total, but I doubt heavily it'd be an issue.

It's much harder than IM240 because you have to do both a temperature controlled cold start portion of the test, then kill the engine for 10 minutes after the stabilized phase then restart and redo the first 505 seconds of the drive cycle again. A stock RB26 fails the test pretty badly. There's also a shed evap test that the car has to pass.

The performance standard is whatever the CARB minimum standard was for the year of production, in this case it's tier 1 which means 0.31 g/mi HC, 4.2 g/mi CO, 0.6 g/mi NOx in the FTP-75 test. It takes a set of two catalytic converters in the front pipe as well as a double catalytic converter where the main cat goes, on top of various little adjustments to things like base timing and weirdness like an fuel filler restrictor to keep people from trying to put leaded gasoline in the tank.

I was looking into things like VCAM step 1, secondary air injection on cold start, more modern injectors at higher base pressure, stepper motor controlled wastegates, stuff like that to try and get emissions down but I realized even if I could prove that everything I was doing was to reduce emissions I would never get past the smog referee because you're not going to pass with a standalone.

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44 minutes ago, joshuaho96 said:

For the BCNR33 and BNR34 they use a different ECU

I thought R33 GTR was same as 32. My bad.

Just put R33 lid on 32 ECU?

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