danieloneil01

The only thing I hate is C* even though it's probably the easiest of the metric system.

James@ShorTuning

Normally after you adjust the Bias you will need to brush up your VE table as well. So it is a lengthy process to get right.

I-H8-RICE

microsquirt sounds even better after reading through all this! lol

soundengineer

iTrader: (16)

microsquirt does not sound better in any way shape or form.....that system is junk

the problem doesnt go away just because you change ECU's...
its a problem that takes tuning to fix...
and most people do not understand how to properly tune, they think you just change the MAF/VE and spark tables and call it a day...that is not how it works

I-H8-RICE

I guess what I meant, that me being a beginner, the features of Hptuners and stock ECU is a bit overwhelming.

soundengineer

iTrader: (16)

thats because tuning,as I just stated, is not simple .....


as I would say to any person.....
you cant be lazy and tune....
you have to be willing to look up information and learn new things.

if you are too lazy to learn how to tune... then you shouldnt be tuning in the first place

danieloneil01

Tuning sucks if you're stupid like me. So lets say you got the bias and your tune is finally good. Do you still use STFTs or LTFTs? Do you stay in OL or do you still go into CL at a certain ECT? I only ask because when I had STFTs on my AFR would swing -/+ 0.5 but with it off it would stay within -/+ .1 from stoich while cruising at a constant speed.

soundengineer

iTrader: (16)

you want to use the Fuel trims for daily corrections...it will still swing a little bit day to day..
air density changes daily.

the point of the narrowband is to swing from rich to lean around stoic....
how much it overshoots in a given time determines fuel trims.


these values can also be adjusted...
stock they are quite far...and they need to be narrowed to a smaller window and update time to be more accurate in a small slice of time


Closed loop is designed to come on after a certain temperature...

I like to see closed loop come on quite early.....using STFT only at colder ECT values...
then when you get to about 20*-30* from yoru normal full operating temps, turn on LTFT as it will be pretty much stable at that point.

Checkmate

iTrader: (2)

Is there any reason why you couldn't run narrowbands on a turbo setup?

soundengineer

iTrader: (16)

you absolutely SHOULD BE running narrowbands.....
only problems you have are that a narrow band does you no good at anything other than at stoic
so you cant use them for WOT....
so you will still want a wideband with a gauge in the car so you can monitor your air fuel at WOT...

but the narrowbands will take care of part throttle fueling as they were designed to from the factory.

denmah

iTrader: (2)

i dont have the wiring in my harness i would have to add it.

i have tuned a bunch of open loop cars on megasquirt and never had the IAT sensor throwing my Air fuel off so much is the only reason i am interested in what i can do to fix it with no closed loop at all

LTstewy8

iTrader: (4)

If I plug that equation from the EFIlive description into an excel sheet to find MAT (which I assume the engine is using in its speed density calculation) and use my known bias factor from my tune, as well as my known ECT and IAT at any given point from my scan log, then the ECT will always bring the MAT value up with a bias >0. If that's the case, why would I ever want any bias towards the ECT at all? It will always make for a higher MAT calculation which will cause the PCM to lean the mixture out.

denmah

iTrader: (2)

you're right thats why i started with megasquirt cars and just did burnouts and ran 10s fairly easily,

spark cut, boost cut, anti lag, all built into microsquirt and not in the stock ECU.

its a great system for starting and racing with a glide or manually shifted auto.

I love a th400 micro car haha

soundengineer

iTrader: (16)

apparently you have not read anything in this thread...

you need the ECT bias because the fuel itself contributes to the total temperature...fule picks up heat as it travels down the fuel lines/fuel rails and into the cylinders(it even sits on the back of the valve for a bit before getting sucked into the cylinders)
andyou also need the ECT bias because the sensors get heat soaked and read hotter when there is no air movement around them

LTstewy8

iTrader: (4)

That wasn't lost on me. I understand that and agree. What I'm missing is how that equation compensates for that. It seems to have a counter-intuitive effect.

soundengineer

iTrader: (16)

its very simple... it goes back to how VE is calculated..using the Ideal gas law
PV=nRT (where P is the absolute pressure of the gas, V is the volume of the gas, n is the amount of substance of gas (measured in moles), T is the absolute temperature of the gas and R is the ideal, or universal, gas constant.)
100% VE is what this formula represents
(this is also why you cant have over 100% VE on a Naturally aspirated engine..and if you do, your tune is not correct somewhere....but that is another thread all together that I dont feel like talking about right now)

based on the Ideal Gas law which incorporates temperature...
assuming you have an LS1 pcm with a 0 to 2 scale for bias
0 = 100% IAT
2 = 100% ECT
1 = 50% IAT / 50% ECT


Lets say bias is at .75

if IAT is 70*
and ECT is 210*
its going to give you a value that is a blend of those 2.
The formula that GM Uses in the PCM is
273.15+IAT+((ECT-IAT)*factor)
all temperatures are in Kelvin. (because Engineer use Kelvin because all their formulas are in Kelvin and there's no conversion losses between units of measurement)

273.15 + 294.261 + ((372.039 - 294.261)*.75) = 596.57775 Kelvin (614* F at the point of Combustion start)


this is basically compensating for the "Heat soak" you get from the hot fuel temperatures

and again.. the air itself is moving too fast to actually gain much heat from heat soak... 1*~2* at the most at idle...if **** is really hot inside your engine bay
so any heat soak you see is the sensor itself being heated, or the fuel being heated

and any rise in IAT at idle, is either the sensor heat soaking, or actual hot air being drawn in from the engine bay

once your engine is up to full operating temperature...you can determine how much your fuel heat soak and sensor heat soak contributes to the real heat in your Air/Fuel Mixture for the VE formula, and adjust Bias accordingly

also... people who move the sensor outside the engine bay, and get away from the sensor itself heat soaking...typically see very minimal swings in AFR due to fueling calculations and Bias...
its definitely not far off once you get moving..

LTstewy8

iTrader: (4)

Dangit, that's a minus sign in that picture. I had it mistaken for a plus sign. I take it back, the equation seems to be sound. Sorry to make you type out that explanation.

Regardless, I still get a lean condition at anything less than the operating temps where my VE table was tuned at. And yes, I've retuned the VE for all the bias values I've tried. The bias table can't account for operating temps using dynamic airflow, so what would you do? For now, I've just manipulated the OLFA table to be abormally rich until it gets up to operating temp. I'm not happy with that method, but it works decently.

soundengineer

iTrader: (16)

Bias only accounts for fueling after the car is up to operating temps...

OLFA is the correct table to do Cold engine temperature Fueling..

I-H8-RICE

I just feel that its a good basic system to get your feet wet and learn how everything works, its also convinent that the software is extremely cheap for the better version, im pretty excited to get into it and see how things work out, eventually im planning to switch over to a 4l80 and a stock ECU set up.

Anyhow sorry

LTstewy8

iTrader: (4)

Haha I guess I learned that one the hard way. I did a quick reread at this thread and the others I've been referencing for info on the bias table and I don't think I saw that piece of info anywhere. It's obvious just looking at the variables- I was just expecting a miracle, I suppose. Thanks for clarifying that and putting my worries at ease, I appreciate it.