Tricky-Ricky

All this talk of using Up-rev with a FI engine has got me thinking.....I remember Mark mentioning that the VQ ECU has not knock monitoring at over 5,000RPM now this would worry me greatly, (unless there is some way of reinstating it during up-rev tune? but I somehow doubt it) Now I know from experience that you can map for safety and keep fueling on the rich side and the timing on the safe side of advanced when mapping, however it would worry me that there is no knock control should you get a bad batch of fuel or something else go wrong, I think I would always go for a decent stand alone ECU that has all the safety features.

Pointless IMO apart from needing a redesigned plenum (as tis is one of the primary limits on making power on the VQ motor) size isn't always the answer to making power on an N/A motor, and its already rather a convoluted path with this engine, Not essential on FI either as the airflow is under pressure anyway.

You don't HAVE to remap once you've added the mods... But does the ecu stop any changes to performance from taking place? As in override them? Have a look here for Marks explanation of the ECUs response,http://www.350z-uk.com/topic/92887-before-before-after-dynos-abbey/page__st__40#entry1399098 Personally after looking at the target AFR map I am inclined to think that breathing mods added to the VQ and probably the HR are not really enough to make that big a difference anyway, Mark said that most of the gains come from tweaking the ignition timing, and what looks to me like a quite small AFR adjustment, so I am inclined to think that its purely down to minor tweaks to the ECU that make the difference, like I have said before I would really like to see what remapping a completely std car would achieve? I am also curious just what the difference is between the UK ECU and its lambda feedback is as opposed to the JDM model? as I have been told that the UK has wide-band lambdas so must use a slightly different and more precise target AFR map?

I think its very subjective, some people will notice a big difference, others wont, I would suspect it also down to how you drive your Z, I am sure some people expect more than others.

I was under the impression BHP,WHP, FWHP, where all calculated from torque, IE torque x engine RPM = BHP, But depending on the measuring point IE wheels, hubs or crankshaft there are losses to be factored in, which are also calculated/educated guesses unless there is an accurately measured value, so anything that is not measured on a dedicated engine dyno is an approximate value.

The link works OK for me, http://www.350z-tech.com/wiki/index.php?title=Oil_Catch_Can_Installation_%28Cusco%29

I presume the top scale is the load scale v RPM? so I can see that the load scale is extended in the Abbey one, and it looks like the original table is a bit richer, so going by that surly adding breathing mods would lean these AFRs out slightly, and in theory making slightly better power? at leas in the lower side of the scale? Anyway glad Prichard is happy with his gains and improvements regardless of the figures, perhaps he will get a chance to have a drive today by the look of the weather.

Ahh! I see we are doing the old BHP,FWHP and wheel or hub HP thing, regardless of which you choose to use you gained 23 of whatever you choose to call it over std figures, which is the point I was making. Once we see some graph's all in one form of measurement we can see the gains.

i would completely ignore BHP. 248@hubs, 272@hubs correct and accurate figures. if your going to try and be accurate with BHP its not going to work. (23@ hubs isnt the same as 23@fly) If the figures are not BHP then what are they measured in????

I was going on the premise that as the ECU will dial out any mods before an up-rev remap, then the engine would be putting out the maximum std 276BHP + the 23BHP gained from the mods and remap so 276 + 23 = 299

A 23bhp gain over the std 276BHP would put it at 299BHP which is about average for mods and up rev....unless your car had over std to start with?

Happy Birthday fellas, have a good one.

So your going to put up dyno sheets for before any mods are fitted for a base level (presumably several runs to get the ECU up to speed?) Then a run or two after mods are fitted, and another couple after a remap? That should prove interesting, try and get Mark to print them with torque re calculated as otherwise its difficult to work out if you don't know the gear v loading.

Don't get me wrong I'm all for tidying up the engine bay and making things look and sound better, but at the same time I would strive to make sure the engine had a decent supply of nice cold air to breath, it doesn't take much to modify induction kits to draw cold air from outside the car rather than inside.

Quite why people fit an intake that can suck its air from within the engine bay, instead of outside the car I don't know.

Vacuum leaks will effect both cylinder banks,unless its from plenum to intake interface, and so would result in both lambdas reading lean and needing to compensate, you will also notice that the fuel trim will actually vary a fair bit between banks 1 and 2, IE you would quite often see + and - on each bank at the same time, not by much but still not exactly as you would expect. I had mine on live monitor and data log via ECU Data-scan, and I also had a couple of wide bands fitted to mine and was surprised at the differences. Exhaust leaks will make the lambda read a rich mixture for that bank, and so the ECU will chuck in extra fuel, it could be a dirty injector, but as I said before its just as likely to be the main or secondary lambda issue. Swapping the primary lambdas is a good idea, but they are a pain to get at and usually difficult to remove, but just monitoring their behavior should tell you if they are OK, as they usually fail by sticking at voltage so will read lean to force the ECU to run rich for safety.

The ECU would have reached adjustment trim limits way before 80 mls if the main lambda is out of adjustment the ECU starts to try and read the cat sensor to determine if its a sensor problem or something else.

Yes bulb faults are tied into the CANbus system, so worth getting a reader on it to check the code.

Cam position sensor is a known problem with this engine, so worth taking it somewhere that will listen to and act on the info rather than just quote you a new chain and then you would likely be back again with the same problem.

It could be that there is a fault with the primary O2 sensor and because of this the ECU is trying to read the cat sensor, but because this is in a high flow cat its throwing the fault code. The default for a faulty O2 sensor is to run the fueling slightly rich, but not by much with an N/A engine so its unlikely that you would notice a big difference, is yours a UK or JDM car?

Depends which bank, only the front O2 sensors are used for closed loop fueling adjustments, the rears are just for cat condition monitoring unless the is a problem with the front bank and or other conditions, but generally you can actually run without the rear set with no problems. Thanks for the informative answer Tricky. With regard to closed loop feeling adjustments, does these adjustments operate in the same way pre and post uprev? Yes but the fueling tables base figures are altered, to give better power.

Depends which bank, only the front O2 sensors are used for closed loop fueling adjustments, the rears are just for cat condition monitoring unless the is a problem with the front bank and or other conditions, but generally you can actually run without the rear set with no problems.

Exhaust leak before the lambda will result in the lambda reporting a rich mix due to more un burned oxygen being read, but the CEL code will be because the ECU has gone over compensation limits. and cannot compensate fueling.

Not possible as both the AFM and IAT are in the main air stream, so as long as there is moving air past the sensors it cant suffer heat soak, I often read people talking about heat soak, but in reality unless the intake air is already very hot IE taken from engine bay directly, then the moving air will always result in a cooling effect, I have proved this on FI engines again and again using top quality temp sensors, and like I said before apart from the boundary layer effect, N/A engines don't suffer such large intake temp variations.