Very interesting I have never played with IFR beyond adjusting the injector flow rate for the injectors.Combine this info with BSFC and you'll see the model screaming at you in bright red ink.

 

RedSupra- I respect what your doing,did the math stuff years ago and tried to make it work but went in circle's. Now I just use what works for me.

 

Yes there is, but to me, IFR tuning isnt right since, to me, it would throw off IDC since the computer doesnt even know the true size of the injectors to base IPW and such off of. Does it work, yep. Tuners have been doing it for years, but with a tunable MAF, why not just tune it instead..

 

No it doesn't, and if I'm not mistaken, the explanation is a few pages back in this thread.

 

If the variables for IDC are IPW and RPM, then IDC should be a straight calculation. IPW is simply the amount of time the injector stays open. If it's open too short of a time or too long, the AFR is going to be rich or lean - regardless of how the amount of fuel needed was calculated (IFR, VE, MAF, etc.). It's just milliseconds.

Marcin - As I said earlier, I haven't abandoned or given up on anything. Like ZL1 said, there's more than one way to skin a cat. Curiosity got the best of me the past couple of weeks and I'm trying to keep an open mind. The truth is, this is a fun hobby. But, there will come a time when I want to stop tuning my car and enjoy it. Here I am with two years of EFI Live under my belt still futzing with the car I bought back in August. What's important to me is what pushes the car down the track the fastest consistently regardless of how it does it. If I can do that in one day with an IFR tune, then what's so bad about it? I'm trying to keep an eye on the side effects of what I'm doing. So far, nothing glaring has popped out at me. If it does, I will share the bad with the good and the indifferent.

 

I was discussing the BSFC a few pages back. you could do this fiarly easily BTW.

number of Injection events in one sec at say 1500 rpm "rpm/60= 25 "call this term F

Amount of Fuel delivered per injection event Call this term FA

"injector Constant" Grams Second Flow / 1000 = FA


Airflow in Grams per second per cylinder Call this term B

F x FA= W is the total amount of fuel delivered in 25 injection events in 1 second at 1500rpm

B/w= AF in chamber or total delivered fuel and air ratio.

 

But, when I looked up BSFC for some general descriptions on the net, they said you really need a way to measure torque output to determine the optimum BSFC. Otherwise, it's just a calculation that will vary with fueling. Now, my butt dyno is ok. But, no where near accurate. Either way, that's something I'd need to observe to learn well. I still feel it's over my head.

 

Do you have a shop local to you with a larger high power capacity Mustang or superflow chassis dyno?. Not that the BSFC number would be transparent but it would be alot easier to find out MBT. Also you could relatively easily figure out drivetrain loss if you car has a manual transmission.

What i was suggesting in the method above was sanity checking your fueling amounts. Thats an easy way to make sure that its not overly rich or lean.

 

This just occured to me for those interested in doing this. If I recall, this won't work (chnaging the bias 100% to IAT) on 98-99 PCMs. Is that correct? As in we have the table but changing it doesn't work...

 

With EFILive, switching to an '02 operating system is a cake walk.

http://forum.efilive.com/showthread....9956#post49956

Latest update...

 

Your low end richness is a bit confonding since I never see that. doens't look to aweful. Try working the VE table a little bit here and there.. I know you moved your blending point but its still going to see some use on detla throttle transistions.

 

As stated earlier, the MAF only tuning method works great until you have to work with a large overlap cam that needs to be leaner or richer in certain areas for driveabilities sack. Specially when tuning an M6 car.

 

Are you saying that even though I dropped the blending threshold down to 400 rpms, it still looks at VE? That was the point of the change - to turn off the VE. I didn't notice a difference after I dropped the threshold. I had my SD VE still loaded and then switched it to a stock VE.

 

Your moving the blending disable point but it could still be looking there at large thottle deltas. Its hard to say what else is in there that even with the info i have is avaiable. The primary purpose of the Ve table was to perform throttle deltas.

 

it's simple to test, if VE doesnt' do anything according to jeff's theory, just set it to 100 everywhere, and go romp on it

 

(that's right - no VE tuning!)[/QUOTE]

how does your car run in open loop without changing your VE table?
mine was untouched by a tuner , and when i went into open loop
i was super rich at idle as lean at wot.

 

" With EFILive, switching to an '02 operating system is a cake walk."

With HPTuners, it's simple as pie to change but I have to buy another 'year' to go on the software.

 

It's based on the MAF sensor being accurate. If you have a stock screened MAF (or in my case a screened SLP MAF), the MAF curve should be accurate. Change the blend threshold so the VE isn't used and it should run just fine. The thing is, you have to adjust fueling some. It's not going to be perfect. I did it with the IFR table.

LS1curious, my throttle deltas are sometimes rich and sometimes a little lean. I haven't started studying them closely yet. When I was saying it's rich down low, that's steady state throttle I'm talking about (i.e. 1400 RPM will be high 13's). Now that I have the IFR table pretty much dialed in, I'm going to try and tweak the MAF table +/- 2% or less to get it dialed in the rest of the way. Then, try and figure out how to backfill the VE table to deal with the transients. As for now, the thing runs like a top. I could throw it in closed loop and be perfectly happy.

 

I can tell you that I've had problems with lower map/rpm cells being rich all the time doing VE tuning. Then I re-enabled the MAF and got rid of that problem to open up new cans of worms. With all the talk going on in this thread and about 3 others between here and the Live forums I've decided to take my own way and have managed to start seeing alot of improvement on my tables and the actual power from the engine. This all with being way rich across the board. Using Jeff's VE table in SD the lower map/rpm cells I was having problems with are now even or a hair leaner than the rest. I still have alot of logging to do to confirm my findings but what I've done makes sense to old school tuning of the carb days.

I have also found that maybe it's not the 42lb injectors being to big or the cam overlap causing my lower rich concerns. The delphi injector is a quicker reacting injector than the greentops from everything I've read and are showing to be more tunable than others have led me to believe.

I agree with the idea that the VE table is like a wetting wall but also believe that when changing the intake and exhaust efficiency that it will still need adjusted accordingly. Cams are just to inefficient at low rpms for the stock VE to handle. We adjust MAF(which in a Marcin word,automagically, adjust for the transients) to mask the problem. The same goes for tuning with IFR tables. Although they work, you are just backing off fuel for the problem areas. IFR takes care of 4000rpm and below and scaling the MAF helps get above 4000rpms in line. There should be a way to tune the VE table in SD mode and have little problems which in turn should also give excellent results in CL once OL is finalized. The problem is getting SD in line without the amount of problems different people see on different cars. If this way I have began to play with works out then maybe I can pass it on to Marcin for the mathmatical part of the explanation and proof. I'm not one for calculus and all those equations. You guys put them up and I'm at a complete loss of what to do with them. Maybe I should take a quick course at learning the meaning of the equations themselves.


I'm not sure how much skin this cat could possibly have left.

Back to Marcins' bus for the VE..........

 

With Live there is no other license to buy. Change over and keep on rockin with your tunin.