PowerFC: Some DIY tuning comments please

[paulr33]

320 on light throttle is attrocious.  Did they just tune your car for full throttle and not light throttle??  A/F ratios are much different at light throttle.  We tuned at very light throttle then zero vacuum and then full throttle.  The factory PC maps is quite rich at light throttle.

<{POST_SNAPBACK}>

well as far as i know my tune was done on full throttle and tuned for max power. which is what i've asked for so its ok and no dramas. yeah the economy is pretty bad but i will be fixing it soon. im just not sure how much i should adjust the highlighted cells. like the values are 1.02, 1.05, 1.10, 1.12 etc just not sure how much correction to throw in

[Sydneykid]

well as far as i know my tune was done on full throttle and tuned for max power. which is what i've asked for so its ok and no dramas. yeah the economy is pretty bad but i will be fixing it soon. im just not sure how much i should adjust the highlighted cells. like the values are 1.02, 1.05, 1.10, 1.12 etc just not sure how much correction to throw in

<{POST_SNAPBACK}>

Without lambda readings that is not a good idea. If it has partial throttle leaness that will mean burnt exhaust valves over a short time frame. The machine shop guys have had a GTR cylinder head back twice for new exhaust valves because the tuner didn't tune for partial throttle running. And that's all the engine was getting while it was being run in.

Tuning for full throttle only is very naive, it just makes the engine feel doughy and lacking in response. It is amazing how much nicer a car is to drive when all of it load points are properly tuned.

cheers

[paulr33]

Without lambda readings that is not a good idea.  If it has partial throttle leaness that will mean burnt exhaust valves over a short time frame.  The machine shop guys have had a GTR cylinder head back twice for new exhaust valves because the tuner didn't tune for partial throttle running.  And that's all the engine was getting while it was being run in.

Tuning for full throttle only is very naive, it just makes the engine feel doughy and lacking in response.  It is amazing how much nicer a car is to drive when all of it load points are properly tuned.

cheers

<{POST_SNAPBACK}>

Thanks for the feedback and comments I'll chat to my tuner and sort out some onroad wideband tuning as I really want to lean out the highlighted cells to get some more economy, and hey if its going run better and go better then bring it on. My "conception" of it was tune for max power and that's it, it was only when I noticed my economy and then did a map trace driving around my streets I realised that maps it was hitting.

Will update once my tune is done again

Thanks

[paulr33]

okay time for an update, we did some wideband road tuning last week and the light load, medium load a/f's were pretty spot on, 0.8 lambda if i can recall correctly. we made some minor adjustments in the low and light load areas (around %2 change) but im still getting crap economy. another thing we also noticed when i was filling up, fuel was spewing out the tank, this was because the black o ring to tighten the fuel cell was loose and not on correctly. this has been fixed however my economy is still crap. this time 320ks to a full tank and not much sign of imrpovement.

any other ideas what could be wrong? where does the stock fuel gauge gets its signal from?

im basing the "full tank" off filling up until the bowser clicks a few times and stops filling up and i can just see fuel at the top and the needle is sitting on E, i dont run it until the light comes on

[siksII]

okay time for an update, we did some wideband road tuning last week and the light load, medium load a/f's were pretty spot on, 0.8 lambda if i can recall correctly. we made some minor adjustments in the low and light load areas (around %2 change) but im still getting crap economy. another thing we also noticed when i was filling up, fuel was spewing out the tank, this was because the black o ring to tighten the fuel cell was loose and not on correctly. this has been fixed however my economy is still crap. this time 320ks to a full tank and not much sign of imrpovement.

any other ideas what could be wrong? where does the stock fuel gauge gets its signal from?

im basing the "full tank" off filling up until the bowser clicks a few times and stops filling up and i can just see fuel at the top and the needle is sitting on E, i dont run it until the light comes on

<{POST_SNAPBACK}>

hey paul, from what you have explained, it sounds like your economy is on ball with most others, including me.

i measure my economy every single tank, by working out kms over how much has gone into the tank (fill every time)

i have found if u fill when the needle is on empty you will have approx 20L left in the tank, assuming u get 320km/45L (65L tank) your economy is 14L/100km which is not THAT bad for stop start driving.

when the petrol light flashes there is about 15L left, when is is on all the time 10L left.

as a comparison,

on the freeway my car drinks approx 9-10L/100kms

open road with hills/corners etc approx 14L/100km

very light city driving about 14L/100kms

hard city driving about 18-20L/100km

i have powerfc with pretty much base maps, runs very rich and lacks power but never pings, i need to get it tuned.

[paulr33]

ok update again, leaned out the airflow correction again a bit more and also did some tests with +2 deg corrections. ran fine with a tiny bit of knock, nothing over 30 odd. tried +3 deg also and ran really well and again very minimal amount of knock. a few of 50odd ish. got 380km's to a full tank so its getting better. more testing to follow

[Butters]

The only way changing fuel pumps makes a difference to A/F raios is when the previous pump was not holding pressure

SK,

Is it not also possible with a new fuel pump if its running a "LOT" more pressure and flow, for it to actually push more then the fuel regulator can handle ?

Then creating greater rail pressure and a richer tune ?

extreme case probably but curious.

[paulr33]

hey gang,

after request from my tuner to try some ign correct as mentioned above i got great economy, see above and below. he said once its ok and doesnt knock too much bring it in and he can adjust it. thats cool im happy with that but i thought hang on i know how to edit the ign map and i can quickly get realtime feedback on the value changes and it would give me a chance to have a fiddle and learn it a bit more so i gave it a shot and here's what i found:

after a run of 2deg timing correction each day i found i had some better fuel economy. went from 320 odd to 380km's ish so much better but i reckon there is still more in it. i did some light load cruising tonight and did 4deg correction and light load was fine no knock at all but medium/heavy load and a fair bit of knock as i expected. so i then put correction to 0deg and for the first 10x10 cells i increased each ign value up 2 deg and then did some more light load cruising. again simiilar results hardly any knock.

wathced knock sensor for a while gave it some varying throttle and load and all appeared ok, one tiny spot just after 4200rpm on medium load that knocked a bit. tried +2deg more correction on the entire map and jack all knock on low load but some on medium/heavy. set ign correction back to 0deg and added 2 more deg in the first 10x10 cells. so ive shifted the first 10x10 up by 4deg in total. the remaing cells are back to what they normally are as i was not happy with some of the knock levels but really wanted the economy the +2 and +2more shift gave.

my questions are is this safe to do under light/low load. i am backing off thorttle as soon as i see knock over 40ish odd and i am doing tuning from passenger seat with girlfriend driving to keep it safe. once i run a full tank again and see my fuel economy should i keep upping the ign timing in the low/ligh load areas, say the 3x7zone to get "tune" the 1200rpm to 3000rpm low/light load areas until i see a decent amount of knock such as 40odd? or should i just leave it at a correction of 4deg in the 10x10 and leave it at that.

thanks

[Sydneykid]

SK,

Is it not also possible with a new fuel pump if its running a "LOT" more pressure and flow, for it to actually push more then the fuel regulator can handle ?

Then creating greater rail pressure and a richer tune ?

extreme case probably but curious.

<{POST_SNAPBACK}>

Yes, VERY EXTREME case, I have personally never seen it. You certainly wouldn't get it with any of the usual fuel pump upgrades and a standard fuel pressure regulator.

cheers

Edited September 29, 2005 by Sydneykid

[BookyVL]

What vlaue of knock is bad, or extremely bad and what is acceptable..

Also, what is your maximum about of ign timing what you get up your car PaulR33??

Mine is 46odish ign timing with 15knock..? This is under full load to 7 grandish..

Edited September 29, 2005 by BookyVL

[Sydneykid]

From a recent post..............

Firstly, knock sensors are simply microphones, they are calibrated to hear upper cylinder pre-ignition frequencies and pretty much ignore all other noises. Unfortunately there are quite few noises in cars that have similar frequencies to pre-ignition and the knock sensor can't tell the difference. Being a microphone, they simply transfer the noise into electrical signals that the ECU receives and interprets. The displayed knock is simply a number, it's not knocks per minute/second/hour.....it's just a number. In the case of a Power FC (my terminology) 100 is really bad (stop right now and fix it), 80 is bad (stop soon and fix it), 60 is almost OK (get the tune checked as soon as you can), 40 is OK (maybe get the tune checked if you are worried), 20 is perfectly safe (press on) and 10 is too low (the engine is not tuned close enough).

cheers

[BookyVL]

Ok cool, thanks for that...

Is 46* a high amount of ign timing? Under fill load

Edited September 30, 2005 by BookyVL

[paulr33]

thanks sk, love your work

so i should be seeing knock pretty much all the time

if not then its not tuned hard enough, or aggressively enough

woohooo more tuning to follow

is this safe to do in little increments without widebad 02 watching in real time?

[The Mafia]

this is a great thread..

SK has given me so many ideas, and great effort paul. You're a champ. Good luck with the tune

Edited September 30, 2005 by The Mafia

[Col-GTSX]

I also enjoyed reading this thread....

As a player of pfc myself i noticed many question i wish i knew the answers too 3 years ago....

However i ish for some people to post up their settings and their mods...

I was talking to paul earlier and in trying something i lost my original setup... (very upset)...

So now im back to base maps.... (not so good)

I believe if people could share their settings and car type and mods done. We can all have a better starting point. Therefore using less time on the dyno and more money in our pockets for bigger turbo's... LOL

So post em up fellers....

[paulr33]

hi guys,

just some more on powefc tuning i had a look at another r33 powerfc tune and under airflow setting it has the usual voltage range and percentages next to each of the values. does this correction % apply to ignition or fuel or both? the other tune i saw had in the vacinity of 105% as first value then %103 and then onwards from there getting lower and lower. looking at mine my first value is 98% instead of the other which was %105. just trying to understand what 105% actually means?

[paulr33]

after looking through fc edit and fctune it appears to be ignition correction. so 105% woud mean more ingition timing across the whole map for that voltage range ie 0.0volts to 0.64 volts and then 103% for 0.64 volts to 1.28 volts.

anyone confirm?

[benl1981]

Hi Paul - I too would like to know if that method of advancign the light load areas is valid. I find I can advance about +6 deg on the base map at low load before I get knock over 15...at low load of course..

[paulr33]

ive moved my ign map up currently 8 degress total and still gettingl not much knock. i tried another 3 deg in light load areas and still minimal knocking present so it can take more timing thats for sure

[Robo's]

The stock map reads max 43 degrees of timing at light throttle. Did you raise this to 50???