Yet another theory on how to tune...
#61
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.
Originally Posted by SSpdDmon
It just sounds like we're trying to reinvent the wheel with complex models. Last year it was trying to figure out interpolation (which I don't think we ever did). I reverted to an IFR approach because it was very quick, not very complicated and the results (so far) have been well within the realm of acceptable. When correlated with the MAF, the IFR isn't as flat (or two dimensional) as it appears to be. At least, not with the results I have after futzing with it for only 6 hours. Who's to say it's too far off either? At the height of decel (75kPa of manifold vacuum), my SVO 30's, which were designed for a 3-bar system, flow like 50lbers according to my 'worked' table. Is that unrealistic? We've got a slow injector working under added fuel pressure with a 75kPa vacuum pulling the fuel out on the other side. Linear would look pretty, but would it be right? Does this mean I've abandoned VE or SD tuning? No. It's just a different way of going about things.
#63
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Originally Posted by ZL1Killa
there are just toooo many ways to skin a cat...what way is right?
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Originally Posted by Frost
No it doesn't, and if I'm not mistaken, the explanation is a few pages back in this thread.
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.
#66
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.
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.
Originally Posted by SSpdDmon
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.
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.
#67
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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.
Last edited by SSpdDmon; 06-22-2007 at 09:46 AM.
#68
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.
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.
Originally Posted by SSpdDmon
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.
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Originally Posted by Viper
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...
http://forum.efilive.com/showthread....9956#post49956
Latest update...
#71
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.
Originally Posted by SSpdDmon
With EFILive, switching to an '02 operating system is a cake walk.
http://forum.efilive.com/showthread....9956#post49956
Latest update...
http://forum.efilive.com/showthread....9956#post49956
Latest update...
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Originally Posted by LS1curious
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.
#74
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.
Originally Posted by SSpdDmon
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.
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Originally Posted by shoemike
(that's right - no VE tuning!)
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.
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.
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.
Last edited by SSpdDmon; 07-11-2007 at 12:39 PM.
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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..........
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..........
Last edited by Violatorno1; 06-24-2007 at 08:58 PM.
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Originally Posted by Viper
" 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.
With HPTuners, it's simple as pie to change but I have to buy another 'year' to go on the software.
With Live there is no other license to buy. Change over and keep on rockin with your tunin.