rob82

You should be scared I'm drunk and rambling!!!! HA HA Dont get me wrong I'm not tring to say one is better than the other as 95% of the time I would recomend a MAF based system over MAP as there is still merit to both with the right ECU!!! And I cant stress that last point enough THE RIGHT ECU!!!!!!!!!!!!!!!!!!!!!!!!!

Delco ECU's aka Autronic are based on speed density based calculations where be the mass of air within the the chamber is calculated via PV=nRT as stated previously. The pressure is derived from the MAP sensor, the temperature however is far more complicated as it applys a thermodynamic model to the acutal intake manifold whereby the absorbtion of termperature from the engine is approximated. Delco and Autronic do this by using a 3d table that has map on 1 axis and ECT on the other axis, the acutal values in the table are percentaged based and is applyed to the intake air temp. An example would be at idle as the air within the manifold is stagnent and therefore alot of heat energy is absorbed by the intake charge hence the volume is less, as manifold pressure rises or more air is consumed by the engine the manifold temp has less time to transfer heat to the charge so the actual chamber charge is more dense. They call this table a charge temp table and within the delco ECU's it changed with different manifolds that were used from factory ie standard 5L to twin throttle body GPA A. Once the acual mass of air is known then its as simple as comanding a desired AFR. You want 13.0:1 at 5psi of boost you get 13.0:1. The early map based fords used the same approach the later model fords however are alot more complicated as they acually apply a linear equation for each phase angle(cam angle). The more flow at the same cam angle the more fuel they inject. While you may think this sounds innaccurate I had a supercharged BA that was making about 350rwkw on about 10 psi of boost. At this level we knew the intake pipe feeding the supercharger was a restriction as soon as we took it off the car gained 30kw on the same boost pressure and you know what the the AFR were exactly the same as I was commanding beforehand on the lower power run. Expalin that!!

Dont compare a Wolf to an SM4 there is absolutely no comparison as the autronic has brains, end of discussion. Specs on a peice of paper saying they can do this and they can do that where in reality they are only trying to do it and failing miserably. Paul before you get all righteous on AFM based ECU's try to remeber that there are MAP based systems that are far more complicated and ACCURATE than a MAF based PFC.

Mate its got nothing to do with the amount of load points!! I've got to agree though and if you do go to a MAP based system go the SM4 without doubt the best MAP based ECU and in my experiences I would stay well away from wolf.

Can you explain how a longer dwell at TDC gives more tollerence to preignition???? The longer the time it spends at TDC the more heat combustion chamber consumes meaning more chance of pre ignition. You definately cant get the same timing numbers into rb30/26 compared to a rb26 both with similar dynamic compressions. fixed ur quote up rob (R31Nismoid)

Cant wait to see how you do the timing control. Do you move the 6-5-4-3-2-1 crank signal reference point or do you attempt to drive the coils like greedy and fail miserably - 8ms of dwell is tooo much aparently, did they not know this???

And what lean out your engine everywhere - thats dumb, thats why noobs shouldn't tune. To tell you the truth I have no idea how this guys sends his programs out every nissan we see at work either needs a fuel pump or the airflow meters are distrorting the real airflow value or the base timing is out 5 or 10 degrees or there is some dumbass idea typical of cheap nissan owners. The chances of getting the mixtures wrong is so much higher with boosted engines.

It does if your testing its oscillation as over 4000rpm your open loop.

Its not likely to cause to much issues apart from idle conditions as the PFC wont know when the throttle is closed. The actual TPS still works it just wont know when its at full throttle or closed throttle but it will still pick up transients so your acceleration enrichments will still work. The actual TPS value just floats usually and will never be set therefore the TPS can never calibrate itself to learn close throttle. Fixes - put the standard ECU back in. Use a separte TPS sensor. From memory the auto's have two TPS's but I think 1 is a closed/open throttle swith so thats probably no good to you anyway however I may be wrong. Also the condition is usually more easily picked up when cold as there is extra idle steps/dashpot and so forth it will still however happen when hot.

Its because your sharding the TPS signal - different internal impedances wtihin the PFC. I garuntee if you remove the wiring to the ABS/ALSD then it will go back to normal. Its a problem we sometimes encounter at work when you piggyback microtech or autronic ECU's. In these situations we sometimes cant use a TPS and we usually wire in extra ECT and IAT sensor separate to the factory ECU.

How the hell does your 02 sensor control idle settings? Its easy to test for a fouled IAC, all you have to do is crimp the hose that feeds it from the intake pipe with a soft pair of pliars, if the revs drop then thats your problem if it doesn't then there is air getting in somewhere else. Make sure your BOV is fully closed and all IC pipes are tight. If there it is still holding high the cold idle up valve under the manifold can sometimes f**k up too. You can check this by crimping the hose feeding it too. If the idle is sitll high then check your intake manifold gaskets. You guys have got to remeber that the AFM cannot make for a high idle especially not 2000 rpm. The only way this is possible is if the ECU thought it was pulling more load then what it was therefore addressing a higher airflow ignition number. Now a dirty AFM will casue a lumpy idle as the airflow signal usually reads less when it is dirty so the car runs lean. If anything the 02 sensor would attempt to cover this as it will trim more fuel in to get it back to stoich. The biggest sign that your AFM is carbonised is during a hot start condition as there is no cold enrichment and it will take about 10 -15 seconds for the 02 sensor to wake up and do its thing.

You should just be able to tell by looking at the wear the oil pump has created on the crank itself. If the wear mark is about 12mm long then you have a 33 crank. If its only about 4mm then its a pre 94 r32 crank.

You can tune the stock rb20 ECU what the hell are you talking about??

Yes and Yes!!

How the f**k does a cat give you better fuel economy??? Dude just take it to a mechanic that knows what he's doing. Get him to check the base timing is correct and that the 02 sensor is trimming, check fuel flow and pressure(just for safety), have the injectors cleaned and then get a chip if it is still shite. The problem with getting buildup on your MAF is that it desensitises the hot wire element therefore it reads that there is less air coming in and leans the engine out. Once you cleaned it it went back to being typically nissan programming rich.

Depends which year 02 onwards have an advance mutiplier that will continually add timing on top of there base ignition map until it reaches the "maximum learnt timing" numbers which can be up to 8 degrees at full load from memory. If you reset an 02 onward wrx or sti the advance multiplier will revert back to a factory setting of 8. If you ran the car with an advance mutiplier of 8 it would lose about 20% power. Once the engine is up to temp between 80 and 87deg it will start to learn ignition back in and you will see the advance multiplier go back up to 16(which is the maximum) and it will start to make power again. Even pre 02 had the ability to learn ignition advance in. I think before they changed over to OBD2 which was 98 the subi's could only retard igntion.

Apart from the fact that it has closed loop boost control that wont allow it to run any more than standard(unless edited) the standard IC is good 4 300rwkw thats about 100rwkw above standard!!!

What an absolute crock of shite where are they getting these figure from? An XR6T will gain nothing with an aftermarket intrecooler running standard boost. I know that for sure. If thats anything to go by then their figures are just BS!!!! The only car that would really benefit from an IC change would be the subi's as they have active ignition.

Are you refering to all stock ECU's in general or just the R33??

Ahh no it doesn't. If the second reg has more base pressure than the first reg it will force the diaphram up a little so that the total rail pressure is equal to the higher pressure regulator. So if you leave you standard FPR on which has a base pressure of about 38 psi with no vacumm and you put you shitty malpassi on after the standard FPR and raise the pressure to 50psi the total rail pressure is 50 psi. The trick is to leave the standard reg on as it has a metal diaphram and does a good job of controlling pressure unlike the malpassi. THe standard reg will also maintain rail pressure after the car has stopped whereas the malpassi will bleed off.

The bigger the injector the larger the lag time(time from when the electrical signal is sent to the time the injector opens). This means that under dynamic injection conditions (which in closed loop is all the time) the ECU or tuner has to take into consideration this problem. Alot of aftermarket ECU's out there dont recongnise this factor and mask this problem by using accelartion enrichments. I can tell you that just about every OEM ecu has provisions for calculating this delay. You've got to remember that steady state conditions usually only occur at idle. So practically all of your drive time from A to B is a dynamic condition. Fuel consumption has alot to do with closed loop control. The way it works is by taking an 02 sensor reading and sutracting fuel until its a little lean of stoichiometric and then adding fuel until its a little rich of stoichiometric and then subtracting fuel and so forth. If the injector has a delay in fueling the response will become alot slower and the injector will start to overshoot the bounds of a stoichiometric AFR. So while closed loop is fine on smaller injectors larger injectors may not prove to be more efficient fuel wise. The precision of the ECU is also a huge factor like sky30 has said the smallest increment in change of injector pulse width makes it either to lean or a little too rich. If you want better economy go to a better ECU.

Bigger injectors flow more fuel. There's no two ways about it.

Do you really believe that bigger injectors wont affect consumption??

We've found that the ATEN usb to serial to be the best runs everything we've tryed including autronic and datalogit.

As long as you can calculate the mass of the air charge ie manifold pressure and temp, both systems will be equally accurate in steady state systems. However the majority of cars life is spent accelerating and decellerating hence it is a very dynamic system. This is why MAF based ECU's can provide a more consitent tune as there is a delay in pressure drop with respect to throttle postion. This is mhy most map based system rely hevily on tps based enrichments. I'm neither for nor agianst either. But I can tell you for sure that it is alot easier to get a result drivability wise using a MAF based system then it is with a MAP.