In the stock BBZB bin the 2D BASE BOOST vs MAP table has zeros as the first few entries. Does this mean that for 100-130kPa, no additional fuel is added due to Manifold Pressure? I realize there would be PE and AE due to deltaMAP or deltaTPS, so does the stock v6 rely on consistant PE/AE conditions for low boost fueling?

I've read that:
BPW= f(BPC,MAP,T,AFR,VE,F33C,BLM,DFCO,DE,CLT,F77)[correct if its wrong]

The BPW is a function of those variables and table entries. I have the actual function pretty much developed for 20-100kPa, but I don't fully understand how the boost vs MAP table is used by the ecu for boost fueling. Does it just take the BPW as if MAP were 100kPa and multiply that calculated PW by the value in the 2D table? If that is correct, doesn't it seem dangerous that additional fuel is not being added untill MAP is 140kPa (almost 6 psi)

thanks in advance for any help

 

As you stated it is a multiplier. I have not looked at stock cal for a long time. Should be 1.0 at the lowest setting, which adds zero extra fuel, as boost rises multiplier typical will go up.

Yes it takes the last VE from F29 and then multiplies.

 

Thats correct, it doesnt add fuel until 140kPa............

/N.

 

Is that = doesn't add extra fuel ratio (over commanded stoich or PE ratio) until 140 kPa, or doesn't add ANY fuel above 100 kPa until 140 kPa? I'm assuming since it's VE*MAP, so that the extra pressure still adds fuel in a linear way (MAP is increasing) in order to maintain the same A/F (i.e. just being in some low boost doesn't mandate a richer mixture, according to the calibration). Then once boost builds above 140 kPa, it gets richer.

 

that is basically my question, better stated.

 

The boost multiplier table takes the lowest value and uses that multiplier for all conditions below that #. Stock is 100kPa I believe and a 1.0.

So the main VE table is multiplied by 1.0

Once you get into boost and maps rise, the multiplier will change accordingly per #'s in table.

 

thanks for the replies. That helped me create this excel sheet. You can copy and paste your $58 tunerpro VE tables and Base BOOST vs MAP table into it and it calculates a bunch of stuff. Its not too complicated, but pretty cool.
Just click cancel if it asks for a password

 

Nice work.
Interesting seeing it all mapped out like that.

 

Interesting spreedsheet and timing on a project me and couple other guys are working on in regards to $58 code.

Confirms some things I have seen.

Stay tuned for some new $58 developments.

 

Defintely a neat excel setup there.

Nice work.

I'm mulling boosted 383 or LS swap? I want boost though lol

later
Jeremy

 

Thanks for the compliments. Suggestions for change are welcome, also feel free to make changes on your own. if your changes are any good, post them.

Something I learned:
Even if the absolute HP numbers are off, but the relationships are correct, from using this sheet I found that its not worth going low compression unless you plan to crank the boost.
9.4:1 = 470hp@11.7psi (170kPa)(extreme max boost)
8.5:1 = 470hp@14.7psi (200kPa)(not max, but getting close)
The lesson is: you need almost 3psi to make up for low compression.

 

Mind explaining the logic behind it a bit.

Where did the actual AFR come from, a log?

How did you calculate the BPW. I see formula includes AFR.

 

What it does: It uses the airflow of your engine(VE) and calculates how much fuel is needed to achieve a given AFR in units of ms. The AFR would have to be from a log.

It assumes: AFR(by mass)=Ma[mass flowrate of air]/Mf[mass flow rate of fuel]

4 stroke engines take 2 revs for one VE cycle(thus the .5 in front of the next). CID is the Cubic Inch Displacement of your motor.
Ma[lb/rev] = .5(VE[%]/100[%])*(CID/8cyl)*(1.225[kg/m^3]) = mass of air per cylinder per revolution

[] denote units
IFR = single injector flow rate in lb/hr
PW is in units of milliseconds of injection per revolution(syncronous)

Mf[lb/rev] = (PW[ms/rev]/1000[ms/s])*(IFR[lb/hr]/3600[s/hr]) = mass of fuel injected per cylinder per revolution

so... it solves for the PW required to obtain a given AFR after all of the unit conversions (and the assumed density of air = 1.225kg/m^3). I guess I could add a calculation for IAT to get a more accurate density of air.


This sheet is only truely accurate if your VE tables are dialed in to those AFR. The thing is, your afr will change in any given location because of other parameters and modifiers not taken into account, like AE, coolant, Vbattery, IAT, etc. PE is basically accounted for in the AFR table(more ideas or change arising).

Also, the thermodynamic efficiency of an engine is not constant for different cells (or for the same cell at two points in time for that matter). So that is another approximation by assuming it is constant.

After all of the assumptions, I'd say the power/torque numbers are only accurate to 15%.

Also, I added a second page to the excel sheet for drivetrain calculations if interested.

 

ttypecamaro I like the sheet.

Can you add Cylinder select (4,6,8)? I was going to but I couldn't figure out how you came up with the value (0.0993670593) in the formula for the Open loop synchronous fueling PW (ms) Table. I know it has something to do with the number of cylinders but not sure what you divided 8 into to get that number.

 

I think you can use the pulse width chart for a 262 V6 as long as you leave the cubic inches as 350 (262 being 3/4 of a 350) The pulse width is based on calculation for each cylinder volume. The HP numbers would have to change by 3/4.

 

you can just multiply the .099XXXXXXX by (8/6) for a 6 cylinder. Only multiplication and division were used to get that number.

bore, stroke, and cylinder select added...

 

;*====================================================
;* Boost BPW Table
;* Value Multiplies BPW

Just as a FWIW, this is what's worked well for me.
;*====================================================
BoostBpw: FCB 0 ; row offset, RPM/25
FCB 0 ; col offset, 3 bar ADC
FCB 12 ; cols per row
; Kpa 100 119 138 156 175 194 213 231 250 269 288 306 ; RPM
FCB 108, 108, 108, 108, 108, 98, 98, 98, 98, 88, 88, 88 ; 0
FCB 108, 108, 108, 108, 104, 98, 98, 98, 98, 88, 88, 88 ; 400
FCB 108, 108, 108, 108, 104, 98, 98, 98, 90, 88, 88, 88 ; 800
FCB 116, 116, 108, 108, 104, 104, 96, 96, 88, 88, 88, 88 ; 1200
FCB 128, 126, 124, 122, 122, 122, 124, 124, 124, 124, 124, 124 ; 1600
FCB 128, 128, 128, 128, 130, 132, 132, 132, 132, 132, 132, 132 ; 2000
FCB 128, 128, 130, 138, 140, 142, 144, 144, 144, 144, 144, 144 ; 2400
FCB 128, 132, 134, 140, 142, 146, 146, 146, 146, 146, 146, 146 ; 2800
FCB 128, 134, 136, 142, 146, 146, 148, 148, 148, 150, 150, 180 ; 3200
FCB 128, 134, 138, 142, 146, 148, 148, 150, 150, 152, 152, 180 ; 3600
FCB 128, 134, 138, 144, 148, 150, 150, 152, 152, 154, 154, 180 ; 4000
FCB 128, 134, 138, 144, 148, 150, 152, 152, 154, 154, 156, 180 ; 4400
FCB 128, 134, 138, 144, 150, 152, 154, 154, 154, 156, 158, 180 ; 4800
FCB 128, 134, 138, 146, 150, 152, 154, 154, 154, 156, 160, 180 ; 5200
FCB 128, 134, 138, 146, 150, 152, 154, 156, 156, 164, 164, 180 ; 5600
FCB 180, 180, 180, 180, 180, 180, 180, 180, 180, 180, 180, 180 ; 6000
FCB 180, 180, 180, 180, 180, 180, 180, 180, 180, 180, 180, 180 ; 6375

Might note how the PW get shortened in the low RPM areas, so that an idle, off idle sneeze doesn't flood the motor. Or at an over boost or over RPM conditon goes extremely rich....

 

Thats a good idea to go way rich on overboost. From experience, way rich in boost makes loud bangs out my exhaust, that'll get my attention in case of overboost. Another good idea to stay lean on the idle side, but I can't think of a time I'd be in boost below 2k. Is it possible? maybe.

Does that mean 288kPa (~28psi) only adds 60% to your 100kPa VE value?

 

I like the spreedsheet in see some value in it.

I did notice when I put in a syty chip info with known horsepower output the estimated power is far from correct.

It showed a steady upward hp curve, when actually a stock syty peaks around 3600 then drops suddenly. As you said it has some error in it, but even the trend wasn't close.

I am sure the math behind it is sound, just the math -vs- reality never matches up that close.

Is a good sheet and good work.

 

Depending on the intake tract volume, and during a sudden throttle lift you can have boost in an otherwise *idle* condition.

I tune for what the engine likes, so %wise I don't pay any attention. BTW, those numbers are for 60PPH injectors on my 231. So where talking about a fair bit of fuel there...

 

Grumpy, you still running the 7749 ecm or did you swap to something else?

Or what is the percentage you are running on each ecm you use?

 

Yeah, there are so many things you can't account for. For example, stoichiometry: lowering the AFR will increase your horsepower to no end in the spreadsheet, when in reality the engine would lose power. you have to assume that your AFR is tuned to max power.

 

I'm back to my ROMless 1227148 (SEFI)...
The correction table was about the same between my 749, and 148.

 

I added some new sheets to my above Excel book. you can find the link in my previous post above.

I may start a new thread to ask this, but does a 92 z28 with a manual tranny use a magnetic or optical speed sensor?