rob82

Yep wasn't sure on the spelling. The bores are already accepting the largest standard oversize piston. The average bore diameter measuring thrust side is between 86.7 and 86.8 with little to no runout however there is some rather large scores on cylinders 4 and 5. I was looking at using 87mm CP pistons that I think run a 3.5 though clearence. I think by the time I bore the cyclinders to remove scour and allow for honing I will be just out side the 3.5 thou clearences. So I was wondering what thickness and if it was possible to nickasil the bores to allow me to run the 87mm pistons. However I wasn't aware that aluminium alloy cylinders was a needed. I could re sleeve but dont want to go to those lengths.

Any one tryed nicosealing the cylinder walls in a RB motor, more specifically RB26? Its just that I want to try and use 87mm pistons as probably going to be a little over 87mm + clearences, so I need to build up the walls. I know they use it in some porche motors and a shitload of bikes but never really heard of it anywhere else. Also does anybody know where I could get it done?

Do you know if he emulates or does he burn chips ervery time he makes a change?

Check the over boost isn't set at like 8psi.

The values you put in are a little miss leading as they are not in boost pressure. It may be Duty Cycle but I'm not really sure. So if you set SP1 to 10 it wont necessaryily give you 10psi. Try setting it 20 then 30 etc etc until you get the desired boost level and then you will proably find that you will have to increase the sensitivity to stop it bleeding off in the top end. Does anybody know if there is any kind of feedback control as in closed loop operation PI or PID loops, or is dumb as shit? Has anybody check the duty cycle on the solenoid to determine if it changes up and down or only up or does it change at all from the set DC.

Make sure you have the solenoid hooked up correctly. Port 3 of the solenoid is manifold pressure, port 2 is actuator reference and port3 is vent. There are three setting boost setting - SP1, gate pressure and sensitivity. Set SP1 to you desired boost level then adjust the gate pressure until it just starts to overshoot your desired boost level and set the sensitivity so that boost dosn't drop off higer in the rev range. That said I have had alot of trouble setting these boost controllers and dont really have much respect for them.

Are you sure your base timing is correct? Thats alot of timing. You realise that there is no point advancing the timing past MBT as all you do is increase your HC. My general rule is to pull the timing out until you start to loose power. While this is easy to do on a DYNO at WOT its alot harder under cruise and low load conditions. You really need to watch your HC levels to do low load timing.

If you know the the frequency and the duty cycle then you could probably work out some formula based on the bleed orifice size to determine how much boost needs to be bleed for the desired boost level. The maths would be extreme though as the flow through the device is pulsed not constant. I know as the frequency is increased the flow through the device is decreased however the ability of the solenoid to control the boost is diminished, if thats any help. This is why you just have to trail and error until you get a result.

I bet they lost power, drivability and economy over the standard PCM.

The choice of ecu will determine if its MAP or MAF based. I personally would stay with a MAF based computer if it is not a race car. As for idle speed we often use a XF idle control solenoid however I not sure it will work with a PFC. You could always just adapt the standard one I suppose.

If you go decent size cams and de chamfer the head you should be fine for 20psi.

The ability of a coil to fire across a 0.8mm gap is essentially dependant on potential voltage difference across the gap and the conditions within the camber. When the density of the mass within the chamber is sufficiently high that ionisation cannot occur only an increase in plug current will propogate the spark. Thats why a good CDI ignition system has a high secondary voltage along with a high current capacity.

Just wondering if anybody can post me the spec sheet for an 87mm GTR CP pistons. Nominal bore diameter, clearences, pin dia etc etc.

VF22, FMIC, 3inch exhaust 3" high flow 200 cell cat and an XEDE good for 160-170ish awkw maybe a bit more.

Who is he? What is his background? Can he only chiptune nissans? Does he emulate or just guess?

Get a chip. Much cheaper and if you go to a good tuner they should be able to do the same amount of things as a PFC.

Whats your plug gap? Is your base timing correct? There should be some variation in ignition timing depending upon desired idle variences. Positive numbers for below desired idle and the oppisite for above desired idle.

Pin 29 is the front O2 sensor and pin 55 is the rear O2 sensor. For what its worth I would place it on the rear O2 sensor.

Its only used for displaying boost pressure within the dash.

You shouldn't share any sensors when wiring an aftermarket computer over the top of the original ecu as the internal biasing will most likely be different. Whenever we wiring in like this we always install new CLT and IAT and sometimes TPS sensors.

Yes, a heap of people have tryed wiring over the top of the original harness. The problem is that in order for a proper change the ignition must be cut back a certain degree as a sort of torque reduction operation. Now if you could use the output of any one of the torque solenoids as input into a computer that was able to retard timing a certain amont then it would be able to be done. How well it would work is unknown and I only now of one computer that could do it.

Yes, a heap of people have tryed wiring over the top of the original harness. The problem is that in order for a proper change the ignition must be cut back a certain degree as a sort of torque reduction operation. Now if you could use the output of any one of the torque solenoids as input into a computer that was able to retard timing a certain amont then it would be able to be done. How well it would work is unknown and I only now of one computer that could do it.

No - Simply putting an O2 sensor on a car wont make fuel consumption better. Your ECU must have closed loop function to trim fuel up or down. And as for microtech and Auto tune function - wouldn't rely on it. Have not seen any of the cheap ECU do auto tune very well at all.

By the sounds of things its not sensor related because if it where a loose wire to a sensor or one of the sensor/s itself the ECU would go into a backup mode wether it be limp home or just change to another set of parameters and the car usually still runs. How I interpreted your post is like it was a straight cut of the ignition as in no cough and splutter then cut. So check your connection to the ecu. Also while the car is idling shake the ecu and the loom and see if anything happens.

Not sure about other peoples experiences but I havn't seen enough gain to warrant retarding the exhaust cam to bring boost on eariler. The problem then becomes you start to heat the exhaust valves higher up in the rev range which introduces the chances of detotnation (and it will ping).