Knock Map Question ?

[r32dan]

I was reading another thread about different management set ups and read something interesting about knock maps. It was suggested that while nistune retains the standard knock maps, other systems like power fc do not, even though they display a knock reading.

I would like to know if this is correct. Would this mean those running power fc have essentially done away with the rich and retartd function as result?

Also do other systems like microtec use any kind of knock detection, R+R, or just a waring sytem?

cheers..........

[Adriano]

Rich and retard can be incorporated into a map on any ecu, but a knock map is a second map when detaonation is detected. microtech and pfc only have one fuel/ignition map, so no knock map.

[89CAL]

If your power FC is tuned right it shouldnt need to have extra settings for increased knock really

But having said that im pretty sure the VIPECS can do it and they are starting to become pretty popular

[r32dan]

my understanding is that R&R is the knock maps activating....Pretty sure R&R only applies itself when knock is detected....

[JonnoHR31]

no, R+R is simply the higher airflow end of the map. from factory both the normal and knock maps are hugely rich and retarded towards the end of the map wit the knock map obviously being more retarded than the normal map.

power fc's have no form of knock control whatsoever, they run whatever timing is on the map and simply flash a number if one of the knock sensors picks up something.

nistune uses the factory system, with a normal map and a knock map. will run off the normal map until knock is deteced, then it'll switch over to knock maps. if the knock map is too advanced then it'll keep knocking, it wont pull out any more timing. so you have to set it up rather conservatively.

pretty sure vipecs have true knock control, retarding timing until theres no more knock, this is the safest way

[STATUS]

AEM version 2 has the best knock map-style functionality ive seen so far, VIPEC and LINK have an ok system it as do the new Haltech's and most MOTEC (once enabled) so its not really an issue if you want it as most decent ecu's support it.

The NISTUNE setup is pretty cool and very easy to setup on your basic std engine but like all knock systems becomes harder once the engine and car become more modified, clutch choice, engine clearances and lash type can all play havoc with the knock sensors which require recalibrating to the "new noise" introduced with such modifications.

[r32dan]

Thanks guys that explains r&r a lot better for me.

I need to understand it better as i am trying to figure out the most inexpensive way to get more mid range out of my r33, as it seems to be a bit doughy before 5000rpm. I thought it might have been running knock maps in that region and i was considering padding out the sensors with resistors as a tuner told me the car is not knocking but was being retarded by my overly sensitive sensors? But now it seems that i may also have an issue simply with the r&r end of the normal map.

I have the usual basic mods including a high flow turbo (hypergear) and a safcs2 as my only form of tuning. I have checked my vvt solinoid is ok and it seems to be. I know high flow turbos are slightly bigger, but i would not have thought that they would sacrafice so much mid range over standard.

The car has only had one breif tune and made 275hp at 6000rpm (11psi) which is all well and good but it has nothing prior to 5000rpm. Funnily enough if i only use half throttle it seems to be far more responsive in the midrange and goes about as hard as full throttle? Any suggestions? Cheers......

Ps. i have not yet put in adjustable fuel reg. Perhaps this would help tune out R&R with safcs ?

[STATUS]

Thanks guys that explains r&r a lot better for me.

I need to understand it better as i am trying to figure out the most inexpensive way to get more mid range out of my r33, as it seems to be a bit doughy before 5000rpm. I thought it might have been running knock maps in that region and i was considering padding out the sensors with resistors as a tuner told me the car is not knocking but was being retarded by my overly sensitive sensors? But now it seems that i may also have an issue simply with the r&r end of the normal map.

I have the usual basic mods including a high flow turbo (hypergear) and a safcs2 as my only form of tuning. I have checked my vvt solinoid is ok and it seems to be. I know high flow turbos are slightly bigger, but i would not have thought that they would sacrafice so much mid range over standard.

The car has only had one breif tune and made 275hp at 6000rpm (11psi) which is all well and good but it has nothing prior to 5000rpm. Funnily enough if i only use half throttle it seems to be far more responsive in the midrange and goes about as hard as full throttle? Any suggestions? Cheers......

Ps. i have not yet put in adjustable fuel reg. Perhaps this would help tune out R&R with safcs ?

Issue is the big drop in timing in the factory tune, you will need either a remap or a new tunable ecu.

Have a look at the timing numbers in this R33 map from 4800rpm onwards load areas 72-on (timing drops from 20 to 16 which is around 20kw in one fatal swoop. Thats why part throttle (lower load) will actually make more power as it will run along load point 56 which has 26 degrees Nissan aint stupid they know exactly what goes on once the car leaves the showroom.... call it built in safety..

http://www.skylinesaustralia.com/forums/post-a284940-

[r32dan]

Thanks heaps for all the advise guys, i just learnt a lot. Looks like i should start by making my car more tuneable. Thanks again.....

[JonnoHR31]

http://www.skylinesaustralia.com/forums/post-a284940-

is that a 100% stock map? nice little jump from 16 to 53 degrees up the top

also interesting how much timing they drop right around where the stock turbo hits full boost

[Rolls]

This is why nistune is such a brilliant way to get a completely tuneable ECU, cheap and it has more features than most aftermarket ECUs.

is that a 100% stock map? nice little jump from 16 to 53 degrees up the top

The reason I imagine the map does that is because when 100% standard the car most likely runs only along 75% of the map, then when it gets modified you run up to the rest of the cells, because nissan assumed that this was because someone had slapped a dirty big turbo on it they retard the ignition immensely to prevent damage, however during normal driving with a stock setup the ECU would never reach those cells.

Edited July 6, 2010 by Rolls

[r32dan]

i would have thought that standard or not, the entire map would be used because the load points appear to be throttle position reference points. so if you are foot flat and towards the end of the rpm range you will find your self in the least desirable end of the map regardless of modifications or not.

[rob82]

i would have thought that standard or not, the entire map would be used because the load points appear to be throttle position reference points. so if you are foot flat and towards the end of the rpm range you will find your self in the least desirable end of the map regardless of modifications or not.

The load axis is theoretical pulsewidth (based on maf voltage and injector constant) not throttle position.

Don't let the knock feature of the factory system sway your judgement when selecting an ecu as it's quiet poor and will usually only revert to the lower octane map if you see lots of knock at low rpm high load. That being said I'm a big fan of the factory system compared to most other aftermarket ecus.

[JonnoHR31]

The reason I imagine the map does that is because when 100% standard the car most likely runs only along 75% of the map, then when it gets modified you run up to the rest of the cells, because nissan assumed that this was because someone had slapped a dirty big turbo on it they retard the ignition immensely to prevent damage, however during normal driving with a stock setup the ECU would never reach those cells.

the part i'm talking about is very light load, off boost. turbo size would be irrelevant. you could reach those sells parked in your driveway if you wanted

[STATUS]

The load axis is theoretical pulsewidth (based on maf voltage and injector constant) not throttle position.

Don't let the knock feature of the factory system sway your judgement when selecting an ecu as it's quiet poor and will usually only revert to the lower octane map if you see lots of knock at low rpm high load. That being said I'm a big fan of the factory system compared to most other aftermarket ecus.

Correct (i agree wholly) and to add to that the factory system only has closed loop knock control to around 4000rpm (model specific) so if you find it is reliable you can raise it via nistune.

[STATUS]

the part i'm talking about is very light load, off boost. turbo size would be irrelevant. you could reach those sells parked in your driveway if you wanted

The only way to reach the cells you talk of are to rev your car to redline and quickly let off the accel and coast ie above 5200 rpm with no load and it will only pass through there on the way back to idle, soon as you add any throttle it will be out of there in an instant.

[JonnoHR31]

fair enough then, wasnt sure just how little load it was

[r32dan]

So in theory if you could some how cap the voltage signal from the afm so that you eliminated a few of the high end load reference points, and use a fuel reg to replace the lost fuel, although crude, you would at least have improved timming without the expence of an after market computer? I relise it would not be as good, but would it work? Obviously it would be subject to a safe tune!

[JonnoHR31]

very crude. safc would be a little better

[James_03]

Sell the SAFC and put the money towards a Nistune.

Don't muck around with hack jobs, it's just money down the toilet.