Zetonator

I have a AAM spacer, DC-sports headers and exhaust (with stock catalysts) in my non-revup Z. JWT popcharger is waiting for assembly and I have read the threads about running lean with those mods. Do you think there is a real threat to run hazardously lean (meaning engine failure) with the popcharger and mentioned mods? If so, is it a real threat under normal driving conditions or just under exessive track use? Or is it more about not getting the best out of the mods without a tune?

I know i need a tune but simplier said than done here in Finland (not that many (even lightly) modded Z´s running around). Planning to get it done at some point but wondering if it is safe to install the popcharger before.

I know the topic has been discussed at some extent before but could not find clear answer. Thanks (putting the flamesuit on just in case...)

clipso 01

iTrader: (1)

i have a pop charger, apexi exhuast, strupp test pipes and an aam plenium spacer, and everything is fine here. I know that if you get a tune or even a reflash you won't ahve to worry about running to lean and also really see what those mods can do for you. I know that AAM can reflash your ecu if you send it in and it doesn't take that long to do since you don't have anywhere to get a tune localy.
Goodluck

Wired 24/7

iTrader: (2)

No danger, if you have detonation your ECU compensates by pulling timing.

Of course getting tuned will unleash more power and make it run better.

PM-Performance

iTrader: (2)

from a tuning standpoint on other cars, unless this car doesnt hold to be the same, usually cars run mad rich from the factory. Mostly turbo cars, but even NA cars.
I wouldnt see why an Intake would make you run dangerously lean to be honest with you. The spacer might not help the situation, but honestly I dont think it will be a problem.

These people that claim this? Do they have wideband readings and actually have tuning experience to know what they are looking at?

Sharif@Forged

iTrader: (92)

Attach a wideband AF gauge on the car, and see if you are actually running leave. If you are in the lo 13's at WOT or less, thats perfectly safe. Of course, there is more power to be had with retuning.

Ziggyrama

iTrader: (15)

The answer is: it depends Running lean itself is not necessary bad. The problem is that as you lean out the mixture towards stoich AFR, the combustion temps will rise which can induce detonation or worse, preignition. The engine can usually handle mild to moderate detonation without issues for some time. Severe detonation can damage engine components. Preignition is usually very damaging.

As Wired already mentioned, the ECU is equipped with a knock sensor and will retard timing to compensate. That usually gets it out of trouble. However, the timing pull only happens as a reactionary measure. That means that the detonation must happen first before the ECU can pull timing. Depending how severe it is, it may be too late to pull timing before damage occurs. This is why a good tune is imporant. Relying on the knock sensor is not a bullet proof method of averting trouble. Detecting knock actually requires some sound frequency analysis by the ECU to determine if it's just noise or actual detonation so the ECU may not always recognize it. The sensor itself is just a microphone feeding the signal to the ECU for further processing. The ECU does a pretty good job of recognizing it. The hit ratio is very good but it isn't perfect. Another reason I would not bank on ECU's ability to fully compensate.
Realistically, since you're not FI, the ECU will probably manage. It's a question how comfortable you feel with it doing that adaptively. I am not sure if the Z's ECU keeps an adaptive history of detonation occurances though. I know my old Subaru did. Nissan probably does as well. I haven't had the time yet to study the Z's ECU so I can't be certain but it would make sense. That is a very imporant feature of the adaptive ignition system which helps you avert trouble before it happens. When you run lean to a point where detonation occurs, it's occurance is usually specific to certain conditions and is usually consistant. The ECU hopefully keeps track where the detonation happened and pulls timing briefly to compensate. If it keeps seeing the same detonation occurance in the same map area, it "learns" to pull extra timing in that map area next time you're there to prevent future detonation before it actually happens. Pretty clever. So, in your case, if you do see minor or moderate knock, chances are the ECU will see it a few times and learn to reduce timing to prevent it from happening again. These adaptive maps are stored in RAM so if you disconnect your battery, or just do an ECU reset, you'll be back to square one and the ECU will have to relearn to rebuild the adaptive map. Another reason why a good base tune is important. Some reset their ECUs often, so do not. May not be an isssue in your case.

The best way is to measure your AFR to see where you're at. I never liked to guess when it comes to engine health. You can also install a detonation detecting device to see if you're knocking while under load. Knock-lite is a decent one and pretty affordable. You can also build your own set of det-cans. It's a piece of metal tube attached to a hose that runs into a set of headphones. You'll hear the knock events with your own ears if they happen. Obviously, this method requires that you do it off road. Driving around with headphones on both easr is illegal.

Z1 Performance

iTrader: (564)

that's about the worst advise I've ever heard. As mentioned, pulling timing is reactionary - and by the time it happens, detonation also has happened. Depening how severe it is, that can literally cook a motor.

Yes it is VERY dangerous to run these cars, or ANY car lean. You may or may not be at a threshold - there really is no way to know without connecting a wideband 02 and monitering things

Sharif@Forged

iTrader: (92)

And the stock ECU knock detection is not active after 5500rpm....so if it doesnt catch the knock before that point, it's too late.

All the more reason for a UTEC and a custom tune, IMHO.

Ziggyrama

iTrader: (15)

This can happen if the diameter of the intake is significantly bigger from the stock one. MAF based metering will produce readings lower than actual and will result in insufficient fueling in open loop operations.

In closed loop, feedback from the O2 sensor will correct the problem until fuel trims max out to about +20%.

Wired 24/7

iTrader: (2)

Do you have any links to where N/A bolt-ons caused serious damage via detonation? I've never heard of a case where this occurred.

I've had plenty of knock on the dyno with no trouble.

I stand by what I said... there's no danger to running N/A bolt-ons (it will not lean you out dangerously), but tuning will improve the performance.

No, I'm not going to cover the cost of any damaged motors, but it would be a very rare occurrence.

Z1 Performance

iTrader: (564)

NA or FI makes no difference - the ring lands, pistons etc don't know if there is boost or not...all it knows is the AFR is wrong and if all you are relying on is the cheesy knock sensor to "save" things, it's a recipe for disaster.

If its not a bad thing, why does Nissan even bother tuning them to run so rich when stock? Why not just set it at a steady 14.7 under all conditions and let the knock sensor do its thing when needed? Again....bad bad bad idea.

If detonation is not such a bad thing, why not just toss in 87 octane and save some money? Because, just like adding too much air and not enough fuel, this causes things to run dangerously lean.

All the hardware in the world is utterly useless without the software to run it properly - its the same equation no matter what.

Wired 24/7

iTrader: (2)

Obviously running lean is not a good thing.

But have you heard of any instances with 350Z / G35 where running N/A bolt-ons without a tune caused engine damage?

I have not.



Chill out man, even the owner's manual says a light amount of spark knock is normal on these motors. No need to claim the sky is falling.


Adding headers, intake, plenum spacer, HFC, test pipes, exhaust, etc will not result in a >16:1 AFR on these cars, at least, not under load.

Stock ECU = safe for N/A bolt-ons... you challenge this statement?

Z1 Performance

iTrader: (564)

but what's so bad about it if the knock sensor is there?

I don't pay attention to the "I blew my motor threads", and I won't profess to know the conditions of every blown motor out there. But I would never recommend anyone to not get tuning, having seen countless times what even a plenum spacer and test pipes can do to a once-perfect AFR

Wired 24/7

iTrader: (2)

Point taken, and I'm sure everyone appreciates your input as you are clearly very experienced.

I have made it a point to poke my nose into a lot of people's threads here, and I basically agree with you. I wouldn't ever recommend getting bolt-ons without tuning either. But I also believe whole-heartedly from seeing MANY dynos with AFR etc, that the stock ECU is designed in a robust way, to be safe even if more air comes in than was designed by Nissan. Not to mention, almost every un-tuned stock ECU I've seen gets RICH in upper RPM range, and it rarely gets into AFR above stoich. even in low RPM range. Except when the car is under low-load (wheels slipping) it can get into the 15's...

Zetonator

Thank You all for Your answers and vivid conversation. Just in case it matters i run on 98 octane (RON) fuel or better (equals about 94 PON). I will definately get a tune and it seems that my best option is to send my ecu to the US for reflash. Only problem is that the Z is my daily driver... I guess i´ll go to a dyno to check my AFR´s just for caution.

Before the Z i had a tuned FI Saab. Saabs trionc ecu and direct ingnition system has advanced system to avoid knock. To my knowledge it can control the AFR in each cylinder individually (somehow measured from the ignition). If it senses that knock is about to occure it can change the AFR in each cylinder individually before it happens and if that doesent help then pulls boost before knock happens. The system has a microphone as a backup but the point is that it can work preventively not just make changes after knock happens. I am not an engineer and can not explain in details how it is done but it works.

PM-Performance

iTrader: (2)

Stupid people blow their motors. Bolt ons should not affect the motor enuff to cause it to run lean enuff at WOT to cause a problem. I have never seen this on ANY car I have built or modded. Now FI is a whole different game.

NA, i would say a mid 13AFR tune is somewhat agressive. I would stay in the mid 13 range on NA tunes, maybe lower if you want to stay really conservative. NA is less tempermental.

FI, I honestly try to stay at a 12.0 at WOT. Maybe I'll dip a tad leaner, but I try not to.

Get a wideband on it and see where its at. i am willing to bet you are prob running rich still as most cars do from the factory.

Z1 Performance

iTrader: (564)

mid 13's NA on these cars, most times, tend to cause odd knock counts and pulled timing in the midrange - and its those precise events that can lead to cracked ring lands, and then a Spy Hunter type smoke show.

Bolt ons do odd things to these cars - some behave better than others. I've seen cars that simply loved the extra breathing and I've seen others that went to over 14:1 with just test pipes and intake and a spacer.

PM-Performance

iTrader: (2)

WOW. Maybe due to placement the knock sensors are sensative?
I dunno. I never cared for MAF'd vehicles honestly. MAF's are too picky IMO. Speed density all the way.
Much less problems with my Supra when I went Speed Density. The AFM's were crap and wayyyy too much hassle. They just kind of have a mind of their own and dont follow normal theory. lol