EFI Buyer's Guide (FAST, ACCEL, BigStuff3)

Thanks for the information.

OK, I have a stupid question about this.....

How can one system be "better" than the other in the respect that they have to deliver 14.7 AFR all the way through the curve.

If that is the goal of a fuel delivery to 14.7 and a system achieves it through the RPM range, isn't that all we can expect from fuel delivery?

I understand under acceleration it drops to 12.X and could be 13.X etc.....but my point is that if each system can deliver that AFR under the same conditions, aren't they all the same? Does it come down to esoteric stuff such as software and interface?

serious question....
 
I don't think they were implying that one could control AFR better than the other. I think they are saying that one may have better support for a particular application such as "coil on plug" , "boosted" , " NOX control " , etc.
Some systems have more usable bells and whistles than others for a particular application.
 
I don't think they were implying that one could control AFR better than the other. I think they are saying that one may have better support for a particular application such as "coil on plug" , "boosted" , " NOX control " , etc.
Some systems have more usable bells and whistles than others for a particular application.

Oh, I am not saying in terms of manufacturer's claims or evaluative papers. My question is more general.

SO what you're saying is that in particular applications there's more than controlling AFR under certain conditions....that's where some shine, when based on the particular application.
 
When you get to the top of the heap with FI, you are paying for ease of use, bells and whistles and name. They all do the basics very well.
 
When you get to the top of the heap with FI, you are paying for ease of use, bells and whistles and name. They all do the basics very well.

I guess what I don't understand is what are those bells and whistles and when are they needed?

Do those bells and whistles add any demonstrable performance? Or is it a question of ease of use or specific application.

BTW, that competitive matrix in the article was useful.
 
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The spreadsheet/matrix shows the "bells and whistles".........For me, I bought the FAST system for it's data logging, traction control, EGT capability, etc. After un-boxing the system and reading the pdf, I am impressed with the quality of the hardware/documentation. For most applications, the Accell DFI VII/Thruster would do fine, and cost less than the FAST or Big Stuff systems.
 
Ok, this is going to be dangerous for me, but if you guys bear with me and realize I am an EE who has been promoted to his level of incompetence (i.e. management) and trying to describe Advanced Control Theory is a real stretch. :confused2:

In simplistic terms, Engine control up till about 2004 or 5 (for the most part) used table lookup to provide the control output needed to operate our internal combustion engines. What this means, for example, is at any instant of time, the processor looks at sensors like MAP, RPM, ECT, IAT, O2, etc. etc. and calculates the amount of fuel ( injector PW). Many of these table lookup functions are going on asynchronously (spark control, fan control, idle control etc). and are limited by the processor thruput capability. This is fraught with numerous inaccuracies. How fast are the inputs from these sensors changing and what is my ability to predict what they will be when I finally calculate and apply the desired output? Their relationships change due to many different situations, Engine wear, Fuel makeup, friction, humidity, and numerous others I don't have on the tip of my tongue. This means re-tuning or incorporating some kind of Block Learn Multiplier methodology (BLM). Accel, FAST, Bigstuff and very recent GM, Ford, (et. al.) ECUs incorporate this technology. This can be accomplished with relatively slow processors by today's standards and is their Achilles' heel. That is why I said by this time next year look out. They will be obsolete.

Very Latest GM ECM, BCMs (like E67 & E38 used on C6 corvettes and others) use much faster processors and incorporate "optimum control theory" That is, they utilize sophisticated Kalman filter algorithms to provide real time control. Transfer functions with parameter gains that calculate outputs using multiple variable inputs. In other words for example, they are taking into account the rate of change, (PID control) of inputs to enhance control by predicting the future state. This is much harder to hack and tailor to a specific application. efilive claims they have accomplish this by applying a lookup table process to calculate a new gain in the transfer function. That probably works to some limited degree. I believe the next generation aftermarket systems will come up with the ability to incorporate this enhanced control methodology with their own support software and ECU's. Now I know what you are thinking, how much real difference does all this mean. All I can say is it is significant. Just look at the performance being realized by the new C6 engines not to mention the ZR1 with Turbo charging. That presents a whole new challenge for the aftermarket. Sophisticated control of wastegate for example.

So, what does the future hold? Google on something called Model Predictive Control for automotive engines. That will blow your mind. Got to go before I get fired, so that will have to be the topic of another post.

Bullshark

P.S. Carburetors suck :lol: :stirpot:
 
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Ok, this is going to be dangerous for me, but if you guys bear with me and realize I am an EE who has been promoted to his level of incompetence (i.e. management) and tying to describe Advanced Control Theory is a real stretch. :confused2:

In simplistic terms, Engine control up till about 2004 or 5 (for the most part) used table lookup to provide the control output needed to operate our internal combustion engines. What this means, for example, is at any instant of time, the processor looks at sensors like MAP, RPM, ECT, IAT, O2, etc. etc. and calculates the amount of fuel ( injector PW). Many of these table lookup functions are going on asynchronously (spark control, fan control, idle control etc). and are limited by the processor thruput capability. This is fraught with numerous inaccuracies. How fast are the inputs from these sensors changing and what is my ability to predict what they will be when I finally calculate and apply the desired output? Their relationships change due to many different situations, Engine wear, Fuel makeup, friction, humidity, and numerous others I don't have on the tip of my tongue. This means re-tuning or incorporating some kind of Block Learn Multiplier methodology (BLM). Accel, FAST, Bigstuff and very recent GM, Ford, (et. al.) ECUs incorporate this technology. This can be accomplished with relatively slow processors by today's standards and is their Achilles' heel. That is why I said by this time next year look out. They will be obsolete.

Recent GM ECM, BCMs (like E67 & E38 used on C6 corvettes and others) use much faster processors and incorporate "optimum control theory" That is, they utilize sophisticated Kalman filter algorithms to real time control parameter gains that calculate outputs using multiple variable inputs. In other words for example, they are taking into account the rate of change, (PID control) of inputs to enhance control by predicting the future state. This is much harder to hack and tailor to a specific application. efilive claims they have accomplish this by applying a lookup table process to calculate a new gain in the transfer function. That probably works to some limited degree. I believe the next generation aftermarket systems will come up with the ability to incorporate this enhanced control methodology with their own support software and ECU's. Now I know what you are thinking, how much real difference does all this mean. All I can say is it is significant. Just look at the performance being realized by the new C6 engines not to mention the ZR1 with Turbo charging. That presents a whole new challenge for the aftermarket. Sophisticated control of wastegate for example.

So, what does the future hold? Google on something called Model Predictive Control. That will blow your mind. Got to go before I get fired, so that will have to be the topic of another post.

Bullshark

Yep, I took a look at Model Predictive Control. Very intersting stuff. Kinda like an "AI" of sorts?:cool:
 
I guess what I don't understand is what are those bells and whistles and when are they needed?

Good question Jsup. First thing I would ask is "What is your Plan".
What is your desired engine and configuration.
Do you plan/want to do the tuning or hire it done.
Do you plan any modifications in the future, if so what might they be?
Is your objective? - economy, full out race performance, street performance,
How much do you want to spend?
Auto or manual transmission?

Any other questions you should be asking yourself? Others chime in!

Do those bells and whistles add any demonstrable performance? Or is it a question of ease of use or specific application.

Yes. It goes without saying NOS, Turbo boost, and any other engine mods (cam, headers, TB) that require custom tuning will definitely enhance performance.
I believe sequential injection also helps, but that is something you will have to convince yourself of I guess.
If custom tuning is then required, then this is where some of the capabilities of the aftermarket systems really come to play.
You will definitely need UEGO - wide band O2 it compensates for allot of tuning parameter tolerance. Even if you pay to have it tuned, I maintain that the tuner doesn't vary all the parameters to optimize the tune. IAT across the temp range of 0-100 degrees F for example. wideband O2 makes up for this.
I choose to incorporate a knock sensor for my own piece of mind.

I think I just eliminated the old GM junkyard ECU's by now. :bump:

Hope this helps.

Bullshark
 
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Yeh Gene, I saw that. I tried to help him awhile back, but that got difficult since I didn't have access to an operational FAST XFI software application. He probably needs help from Big_G. ;)

Bullshark
 
Good question Jsup. First thing I would ask is "What is your Plan".
What is your desired engine and configuration.
Do you plan/want to do the tuning or hire it done.
Do you plan any modifications in the future, if so what might they be?
Is your objective? - economy, full out race performance, street performance,
How much do you want to spend?
Auto or manual transmission?

OK but I think my question is more generic. How do the bells and whistles effect those things?

Second, in terms of objective, how do the bells and whistles help to meet those objectives.

On the competitive matrix I see all the B&Ws listed, but have no idea why they are important, and secondly, how they are different than OEM ECU.


Yes. It goes without saying NOS, Turbo boost, and any other engine mods (cam, headers, TB) that require custom tuning will definitely enhance performance.
I believe sequential injection also helps, but that is something you will have to convince yourself of I guess.
If custom tuning is then required, then this is where some of the capabilities of the aftermarket systems really come to play.
You will definitely need UEGO - wide band O2 it compensates for allot of tuning parameter tolerance. Even if you pay to have it tuned, I maintain that the tuner doesn't vary all the parameters to optimize the tune. IAT across the temp range of 0-100 degrees F for example. wideband O2 makes up for this.
I choose to incorporate a knock sensor for my own piece of mind.

I think I just eliminated the old GM junkyard ECU's by now. :bump:

Hope this helps.

Bullshark

I agree on the wideband O2. I get that..and I understand it.

I also agree that forced air and NOS add performance. The disconnect I have is:

How is it that these ECUs work better with FI to produce more power? There are many FI cars and NOS cars running stock ECUs, what are they giving up in terms of performance?
 
Jsup;25617 There are many FI cars and NOS cars running stock ECUs said:
Jsup, it is not all about power. With the NOS setup for example, the Accel DFI will allow you multiple stages of nitrous or pwm control with the fuel added through the injectors. No external throttle position switch is needed as this info is provided by the tps. Nitrous enable can be set to a precise throttle position. Ignition retard is built into the program as well. Your wideband O2 sensor can provide an afr lean low limit to stop nitrous flow should you have a fueling problem, etc. As you can see there is a lot more and simpler nitrous safety with all of this integrated than with multiple pieces and the install is much cleaner. The ecm does have very sophisticated nitrous control that will improve performance as well.
 
Jsup;25617 There are many FI cars and NOS cars running stock ECUs said:
Jsup, it is not all about power. With the NOS setup for example, the Accel DFI will allow you multiple stages of nitrous or pwm control with the fuel added through the injectors. No external throttle position switch is needed as this info is provided by the tps. Nitrous enable can be set to a precise throttle position. Ignition retard is built into the program as well. Your wideband O2 sensor can provide an afr lean low limit to stop nitrous flow should you have a fueling problem, etc. As you can see there is a lot more and simpler nitrous safety with all of this integrated than with multiple pieces and the install is much cleaner. The ecm does have very sophisticated nitrous control that will improve performance as well.

Thanks, great answer.
 
I have a couple of questions about the "features" listed on page 11 off the buyers guide.

One of the features listed is "LCD dashboard" support (for Fast XFI and BS3 only). What is that, an accessory/universal dashboard they sell? Fast XFI lists EGT as an option, what is the advantage to measuring exhaust temps? Fast XFI lists accelerometer support, how would this be implemented (acceleration, lateral, braking forces)?
 
I have a couple of questions about the "features" listed on page 11 off the buyers guide.

One of the features listed is "LCD dashboard" support (for Fast XFI and BS3 only). What is that, an accessory/universal dashboard they sell? Fast XFI lists EGT as an option, what is the advantage to measuring exhaust temps? Fast XFI lists accelerometer support, how would this be implemented (acceleration, lateral, braking forces)?

EGT I have to assume has to be done on every individual cylinder, and if ti's super hot, it's lean....cold is rich....but I think that could be done by a O2 sensor much better.....far more accurate, assuming you can go rich/lean on any individual cylinder and have 8 o2 sensors....
 
I have a couple of questions about the "features" listed on page 11 off the buyers guide.

One of the features listed is "LCD dashboard" support (for Fast XFI and BS3 only). What is that, an accessory/universal dashboard they sell?

Take a look at this site

LCD dashboard

This sounds interesting though

More FAST stuff


For $800+ I will use my laptop:rolleyes:

Bullshark
 
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So to run an FI system like BigG & Bullshark have in their cars,what is the set up price? to do it all and do it correctly.
 
So to run an FI system like BigG & Bullshark have in their cars,what is the set up price? to do it all and do it correctly.
I'll probably have 3,800-4K in it by the time the dust settles. Accel DFI VII would have saved me about 1K. Don't tell my wife.:eek:
 
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