I am heading out of town today to hang out with HumpinSS. When I get back I will make the noted changes to the sheet and see if I can't improve a couple of things as well.

 

I agree the MAF table does work great.

 

yup, i've had ~20 people IM/email me about their good results, and i've done 4 cars myself, so i know it works well.

 

Nice to see that it is working good for those that are using it!!!!

 

I tried out RedHardSupra's spreadsheet about 2 weeks ago and it worked great for me. This weekend I'll try yours out, Black02SS, and compare the 2. Good job guys

 

the concept should be the same, i did it in pure excel, he did it in VB, so his is faster, but mine works without macros, and i've seen it run even on old excel 97

it would be nice to run the same set of numbers though and compare the results, just to verify the math though...any volunteers?

 

Anybody have a log we can look at? Even just a good screenshot of the STFTs and LTFTs would be nice.

 

you mean for 'before and after' or logs to do the testing with? actually i got both, i just tuned my friend's 01SS for headers last night...

 

I don't suppose you could send them my way? Or I can download them if you post them somewhere. Please?

 

So is this the right order?

1) Mafless Tune the VE with PE disabled till all values 0 to -2
2) Plug back in MAF/ Re-enable PE and use this spreadsheet to adjust maf using MAF table till values are same as prior to MAF installation.
3) Then tune PE with a wideband!

 

actually, you can combine VE and MAF tuning into one step, as long as you're in SD. the reason for it is that in SD you are gathering MAF data (for MAF calibration), but ignoring them for VE calculations.
so:
step 0:
SD mode

step 1:
do a full table VE tune, like you were trying to stay MAFless (gather good data for MAF ironically enough)

step 2:
put in your new VE and MAF tables, might as well throw in PE in there too, as that's just pure math.

step 3:
drive around some more in SD, to validate your VE, and gather up some more MAF data (as you can compound data from different runs in version 2.5 of my spreadsheet)

step 4:
put in your final MAF and VE changes (usually very minor, consider it 'smoothing')

step 5:
back to MAF mode, and go scan again, everything should run as well as it did in SD (as that's what MAF calibration does, makes calculations agree with sensors).

v'oile!

note: combining VE and MAF calibrations really cuts down the time, twice this week i already did a full tune for two different cars, and they both run perfect now (well, i never touched timing, but that's a whole different ball of wax). took about an hour each man, if i could only get paid for this stuff...




Another_User:
either PM me your email account, or just talk to me on aim/yahooIM/icq, they're all in my profile.

 

Hey Guys I was able to use the doc to calculate the P/N RAF but I went back and grabed a scan from cold to operating temp while in gear and when I got to run it the sheet just locks into a never ending calculation loop and I have to end task on it.

I've downloaded new sheet several times and made new scan logs and it keeps doing the same thing. Can you tell me what I'm doing wrong now verses the first time when it worked? Thanks guys!

 

Dup post

 

I have had a lot of **** going on lately and haven't really had a chance to look into it. I will here this week sometime. sorry.

 

you know, you can always use the original MAF calibration spreadsheet that doesn't go into infinite loops simply because it has no loops www.allmod.net/hpt

 

I used RedHardSupra's V25 spreadsheet the other day and the table that it came up with was pretty close to the Monaro. I'm going to do some hand work with it to extrapolate the numbers that it gave me to complete the high and low ends where I had no data. I'll post my results when I get something decent.

My thinking is that if I pick values that emulate the shape of the Monaro table to complete my table, then 3rd order curve fit it, then input the frequency into the equation and solve for airflow, it should give me a very nice smooth curve. Right? (The curve that the spreadsheet output wasn't as smooth as the example curves.)

While I'm here, how do I get data above 9kHz? Just go faster? (Or will that not matter? 9kHz was about 80mph and 80kPa MAP. Maybe I'll have to log some drag strip runs this weekend to get better data...)

 

1. get more data, if the calibration is 'choppy' that means you simply haven't logged enough. use the 'historical compounding' function, in few days you can build a really awesome table.
2. what i do is use my new calibration points (assuming i got a good calibration from LOTS of samples) I graph these new points on XY graph, put a trendline through it (polynomial, 3rd order) and tell it to give me the equation for the best fit line. the equation is usually _very_ long, so you might wanna crank up the 'decimal resolution' on the displayed equation (to the full 30digits preferably, you'll see why) and use it to create the values for points that you haven't it yet. I consider this to be a more academic point, as if we haven't hit it in testing, we probably won't hit it in real life, but just in case, i'd rather have my calibration full and without any jerkiness to it. give it a spin.
best yet, talk to me on AIM, i'll show you more tricks. btw, i love that vette of yours!

 

RHS:

1. Ok, I'll log more and get more samples. My first attempt was just using about 25 minutes of mixed driving. I was pleasantly suprised to see that the data trended very closely to the Monaro table (which I was using before I started SD tuning).
2. That's what I was planning to do. I guess I didn't explain it well. I'm Scooter70 on AIM. I'll add you to my buddylist and talk to you when I have more data to sort thru. We're going to the drag strip on Saturday so I should have more data between now and then. (And I'll get a chance to see what this car will do...) Thanks for the kind words. It was a very interesting learning experience. My next project should be even better.

-Matt

 

Here's an interesting trick ( to me, anyway ) to get the VE info for your engine. Allot of times, we just think of the AFR as a quality of combustion. But it is also the physical ratio of air flow vs fuel flow.

i.e. if the AFR is 14.7 and the fuel flow is 100 lbs/hr, then the mas airflow is 1470lbs/hr.

100lbs/hr x 14.7 = 1470lbs/hr

Once you have airflow in lbs/hr, you can compute standard CFM.

1 standard cubic foot of air weighs .0745lbs.

so, 1470lbs/hr / 0.745 = 19730cf/h , 1973cf/hr / 60 = 329CFM

With that, RPM and your engine displacement, you can get V.E. directly.



To do this, you need a wideband that can keep up with fast airflow changes (LM-1 or LC-1), and to log RPM and injector duty cycle.

If you can log your MAF sensor output, you can map its output and get CFM/V or CFM/Hz.

If you have a rising rate fuel pressure regulator, you will need to log fuel pressure also. Good idea to log TPS too; since your really only want WOT data.

Fuel flow can be calculated from the standard formula.


I put the fomulas here: Still working on the formatting.

http://67.43.173.134/StupidWidebandTricks.htm

If it seems like allot of math, we are automating it and putting this all into Logworks 2.0

 

oh wow this is cool! why didn't i think of this? i have a spreadsheet that is one step away from this! alright, i'm off to update it with this formula of yours