Pfc Tuning For Hot Weather

[Don Dada]

Well I went for a quick lap today and have altered the settings for air temp vs INJ on injector 2 as JonnoHR31 has suggested. As Paul had confirmed, these settings 2 air temp corrections have no effect at idle, yet the corrections are applied when driving. So thanks for your assistance guys.

Thanks for your assistance to Trent. Especially offering to look at a map for me in the middle of the xmas break period.

I changed the 70 degree air temp value from 1.147 to 1.050 ish(I think.. that was 6 hrs ago and im in holiday mode!). This seems to have done the trick as the AFR's are no longer diving well into the 11's when on boost. It actually went to 12.0:1 (so it seemed I guessed close).

Hey man its been awhile so maybe you can share the latest info reguarding to this....if any?

I live in a similar climate to yours and have already done my inj map but it varies from as much as 11.3 afr at arounfd 47*c ,down to 10.8 afr at around 55*c .......my aim is for 11.0 afr

I see you mentioned you changed the 70* setting to a lower value which will lower the entire curve a little, but it still remains that at any temp above 40* fuel is still being added

I was thinking of shifting the first point up to maybe about 50* and also decrease the 70* value a little, so in essence fuel will only be added after 50* and will not be as much either due to the lowerd 70* value

I think those temp on the table were originally meant for Jap cooler climate and is not suitale for our tropical climate....my car reaches 50* after about 8-10 mins driving on a cool 24*c morning with just a couple of short stops at the lights

The only thing i am concerned about is the 3rd row(boost) on the table....if i change the 40* value it would affect this too and i have no idea what that setting is for??

[GTRNUR]

Hey man its been awhile so maybe you can share the latest info reguarding to this....if any?

I live in a similar climate to yours and have already done my inj map but it varies from as much as 11.3 afr at arounfd 47*c ,down to 10.8 afr at around 55*c .......my aim is for 11.0 afr

I see you mentioned you changed the 70* setting to a lower value which will lower the entire curve a little, but it still remains that at any temp above 40* fuel is still being added

I was thinking of shifting the first point up to maybe about 50* and also decrease the 70* value a little, so in essence fuel will only be added after 50* and will not be as much either due to the lowerd 70* value

I think those temp on the table were originally meant for Jap cooler climate and is not suitale for our tropical climate....my car reaches 50* after about 8-10 mins driving on a cool 24*c morning with just a couple of short stops at the lights

The only thing i am concerned about is the 3rd row(boost) on the table....if i change the 40* value it would affect this too and i have no idea what that setting is for??

Summer has nearly come to an end where I live so tuning for me has gotten a whole lot easier. The ambient air temp outside today is 27 degrees, which is a lot better than the 38 I was seeing a month ago.

I still see high air temps after only short running time. Typically above 50 degrees the moment the engine is up to temperature. Sometimes over 60 when stuck in traffic, and never less than about 52 (on hot days) when cruising on the open road. But what is being read here is the plenum temp, not the air temp. As the climate has cooled down a little im not as concerned with air temp corrections as I was, and am more so focusing on getting better transitions into different load bands by moving my load and rpm scales around. I will definatly be relocating the air temps sensor to 1/2 way up the return pipe from the intercooler next time I pull the hoses off the car. I might try sourcing the Mazda air temp sensor as well, and give that a try too.

As for the 3rd row with air temp vs setting vs boost, thats something ive yet to play with as well. If I had to guess I'd think it was boost control related, and not many of us are using the FC's boost control feature so it will probably do nothing at all. That it mentions boost for an L-jetro map does back up that guess. Maybe Trent could confirm?

Edited May 5, 2011 by GTRNUR

[paulr33]

i believe the air temp vs boost is set to cap max boost based on airtemp and correct it down for excessive intake temp

i have gtr boost kit working but i do not have air temp sensor (gtst) so i cant test and advise sorry

the powerfc maps are as-is maps and the airtemp correction is used to retard timing as airtemp goes up

that is, it only retards timing with higher airtemp, not add timing when its cooler

so basically you should tune the car in the coolest possible conditions as a base line and when summer comes along the PFC will self correct down (IGN) when intake temps are higher

but as you said, thats using the factory sensor in the factory spot which nissan setup for that reason

so im not sure if moving it helps or makes it worse, if the intake temp is hot, its basically hot, so therefore run less timing

[Don Dada]

Even on a 24*c morning before my engine is even up to temp, the air temp is close to or sometimes passing 50* depending on traffic

The ait sensor suffers from heatsoak badly in my book because surley with an ambient temp of around 24*c the intake temp should not get past 50*c driving like a granny

Ive thought about using a teflon washer or similar between the sensor and plenum but i havnt been able to source one...maybe you can as a first option instead of moving it totally

I think i'll shift up the 40* temp up a little since the ecu has no reference to boost that last column should have no effect, so it will start to add fuel a little later, wouldnt add as much, and i would rely on ign table to do the rest

I always welcome Trents input....havnt seen him around in a while tho?

[paulr33]

i guess if you think about it and close the bonnet

then add in the intake temp of the engine bay + compressor wheel + all the pipework etc it doesnt sound too unreasonable (50deg intake temp)

[DVS JEZ]

Get a infrared thermometer and check the temp of the outlet of the intercooler. The intake charge temp shouldnt increase much from there to the engine. I know this isnt air temp exactly but should help

[Don Dada]

Another thing...I noticed when i tune my idle cell to 14.7 at around 48*c as the air temp increases it gradually leans it out to around 15.2 at 54*c ...O2 feedback off obviously

Now this is totally opposite to the table we are referring to now as this table is designed to richen up with an increase in temp

Anyone have any idea as to why its doing this ?...it seems like it only leans it on idle tho cause the higher parts on the map it definitely getting richer with increased temps

[GTRNUR]

Thats the opposite of what I see. My cold start AFR is 13.4:1 as that is where most heat is generated and also where peak torque is. This richens out to around 12.8 once its warm. The injector pulse value stays more or less the same, but the air temp change directly affects air density, so it goes rich.

I could lean it out but the side effect is the injector pulse width gets too small and then the bad spray patern of the injector causes a random lean miss (at idle). I prefer the smoother running as opposed to being enviromentally friendly. Given the opportunity I would switch to a set of ID1000's so the pulse width's can be pulled back a lot further.

[DVS JEZ]

This lean pop happens with stock skylines too.

[Don Dada]

Yea..my cold start is around 13.5 too but leans as it comes up to temp as it goes down to the idle cell.

The strange thing is tho it continues to get lean with an increase in air temp even tho it stays in the same cell....i dont think there is any setting for this right???

I've heard that lean pop in all rbs so i dont bother with it really and it seems quite happy idling even down to 15.2 @920rpm....on the rb31 it will be a different storry tho....