Maybe, just maybe an end to SD issues?

[MeentSS02]

Hence either relocating the IAT sensor or tuning it out, so to speak.

[Billf6531]

so yes ... 1.0 and be done with it for now unless a better solution comes up ...

Scott, my hat is off to you, or 'you da man' in what I gather is current vernacular.

I, too, was frustrated when changes in day-to-day temperature pushed the VE table all over the place. I finally had a chance to test your theory. My IAT sensor is in the stock location on my C5.

I set the bias to 1.0, took one of my best VE tunes, smoothed it once, and multiplied the complete table by 1.12, plus an extra 1.04 from 4K to redline.

Three short tuning sessions on the street, and the VE was back to +/- 1%.

Many thanks for your efforts.

[SRPerformance]

What about placing the IAT just before the throttle body, any comments?

Joe

[S2H]

I dont see that as a problem either..as long as it sits down into the airstream a little....

my issue is that I dont have anything in front of my TB...just my air filter directly on the mouth of the TB...so it went in the Intake

I also noticed that my VE table smoothed out a lot...

[S2H]

Hence either relocating the IAT sensor or tuning it out, so to speak.

well..you cant really "tune it out".....if you set the bias to 2.0 it would be all ECT....which would lead to some damn inaccurate fueling due to no compensation for IAT temps...and setting it to 0 gets you no ECT...but it way iver/undercorrects with the extreme of each...
1.0 sems to work great...

there are some things coming up that will allow m eto dive into it further and se if theres a better value..but 1.0 looks pretty dam good tome so far

[WS6FirebirdTA00]

I was going to put mine in the MAF bypass pipe before I wired it into the pot. Seemed like it may be a good place.

[SRPerformance]

To help me and others do you want to post your 'Cylinder Charge Temperature' Bias and Filter settings.

Joe

[S2H]

well..my cylinder bias temp is 1.0 across the board for nowand I'm slowly adjusting it to match for higher and lower airflows

sometimes simplifying is a lot better than trying to use thier Complex methods

[MeentSS02]

I can't wait to try this...

[SSUte01]

I am also keen to give this a crack when I find time. Out of interest to those that have done it did you find that it had a major effect on fuelling or minimal or dependent on conditions. The reason I ask as I am curious as to what effect (if any) changing the bias to 1 across the board and nothing else would have - Just curious

[SRPerformance]

I am also keen to give this a crack when I find time. Out of interest to those that have done it did you find that it had a major effect on fuelling or minimal or dependent on conditions. The reason I ask as I am curious as to what effect (if any) changing the bias to 1 across the board and nothing else would have - Just curious

yes, this would be a good test as soundengineer needed to move his IAT due to the air filter setup.

BTW: the over the radiator cold air intake we use (OTRCAI) does respond very quickly to air temperature changes. I have fitted a probe, connected to the dyno, and scan/watched the IAT come down very quickly to match the probe. Where as the maf pipe/air box takes quiet a while to come down and never matches the probe.

[S2H]

well..as you move towards your ECT you will find that it leans out the mixture
in general...which is why you have to add to the ve and maf tables respectively...

in the end I still use the same amount of fuel..I actually get better gas mileage from having fueling more consistent from day to day...

and my VE shows higher #'s and appears smoother looking in general

being 1 bar SD I dont have any isues with running out of dynamic cyliner air in the spark tables..but I can see how some FI setups would easily max it with a 2 br and need to do some IFR table trickery to get that back in check as it seems that teh VE values are about 10-15% higher on my car with the bias set to 1.0 across the board..

[SSUte01]

Thanks Soundengineer.

Interesting to know. I have a funny feeling my VE is a little high at the moment. I haven't done any decent tuning on the VE in ages due to my particularly crap Laptop battery, holding out for black box logging. That said I haven't really changed anything that would affect the VE dramatically other than weather - It was pretty close. I have a day off tomorrow I may just have a play with the bias set to 1

On weather can someone settle this debate I have at the moment.

I believe when running SD that your tune will run rich during hotter temps ie less air density, same amount of fuel = rich and during nice cold nights actually leans out due to more air, same fuel = leaner. Am I right or did I lose this one.

[S2H]

you got it backwatrds there
with the bias more towards the IAT(like many many many stock calibration) hotter days you will run leaner ..cooler days you will run richer...
which is why people say to get tuned in the summer and not the winter
...
of course those people dont know the bias trick either..
I have had a couple of weeks of odd weather...
everything from dry to wet and from 60* to 98*...plus heatsoaks of up to 145* to test this on...
I am seeing less than 2% change in fueling from day to day and it hovers right around perfect all the time

[SSUte01]

What about if you don't consider the bias, just based on the fact fuel is constant at a given MAP and air is dependent on density, is my theory then correct or am I still ass about tit.

I am getting more keen ot try the bias set to one.

[S2H]

well..IF I set it to be all IAT..meaning bias 0.00000
or if I disbale the complex charge filter completely
it leans out when it gets hot and richens up when it gets cold..

[SSUte01]

Right-o so I have it back to front. Without considering bias as you described or using the charge model at all, why will it lean out during the heat (less air) and richen up during the cold (more dense). Sorry if that sounds daft, but I have it backwards in my head for some reason

[S2H]

in theory it would if nothing else changed..but our vehicles over compensate..so no charge bias means its all IAT and for some reason our vehicles are lean with more heat and rich with less heat...

or atleast thats the way it appears in every log in every vehicle I tune...and I do lots of them..LOL

[SSUte01]

Cheers

I just thought I must be going and all the laws I had ever learnt pertaining to pressure and temp and density must have been wrong

Appreciate your clarification - that is the concenus I get from everyone and i was all confused

Now I understand thanks for the help

[esr]

Meents.....you must be thinking of protein shakes or something.....

Did someone say something about a blender?