EFI tuning

[Eggbeatn ur Ass]

So after finishing my fresh top end on my motor this year, I've been working with whipple on getting my MEFI 3 setup just right. They are great to deal with and have helped me learn a few things. But, I'd love to learn how to do efi tuning on my own and I know enough to probably lean out and blow a couple motors teaching myself. Is there a way to learn how to do this without learning the hard way? I wish there was an ECU that was user friendly and something that would help people like me learn how to tune a motor. There is all kinds of products out there for the automotive industry but that doesn't help us in the marine world seeing as we can't run O2 sensors all the time. I've looked at the holley, edelbrock, fast and MSD injection systems but has anyone had any real world experience running one of those systems on a whippled 500efi or 525?

 

[DaveH]

I have wired, installed and tuned many whipple (and other types of super charged engines) using various engine management systems for nearly 15 years.

first......there really is no such thing as a self tuning system. I dealt heavily with Autronic ECU's who were one of the very first manufacturers to offer "auto-tune" over ten years ago. Any of these systems simply have you populate a table with the desired air/fuel ratio you wish to run, then take feed back from an o2 sensor and adjust the main fuel map to reach the target.

the problem with this is first, you are putting 100% pure blind faith in the o2 sensor reading. second, just because you reached your target ratio......the engine may actually run better or more efficient with a different mixture and there is no feedback or way to measure this. you really need to have power measurement feedback from a dyno to do this accurately.

second, spark is not self tuned and must be done manually.

that being said....Autronic lead the way years ago with engine airflow modeling algorithms that predicted airflow through the engine. by inputting engine parameters into the software, things like displacement, injector flow, the computers measurement of manifold pressure and temps and other parameters, the software could calculate a starting point to get the engine running reasonably well.

Motec with their new M1 series ECU's has taken this a step further. they have additional parameters modeling engine air and fuel flow and this gets the mapping even closer than other systems. Some companies claim to have self tuning ECU's......when in reality, what they have is a basic calibration file they have developed for a specific engine and offer that with the purchase of a system. For example, the popular Holley system has files for specific LS based engine that offer a "plug and play" harness and you will be up and running very quickly. Some people mistake closed loop for self tuning...when in reality closed loop is only for limited authority of the ECU to adjust mixture, and this is mainly from an emissions perspective.

getting good accurate information to do this is limited. one decent site is www.efi101.com and they offer training classes for EFI newbies.

if you want to dive into this......I would suggest finding a simpler project engine to work on. something normally aspirated, maybe a simple LS V8 and take it to a dyno and learn from there. any forced induction engine should be considered only when you are very comfortable tuning other engines first and things go very wrong very quickly. the window or tolerance for error shrinks dramatically compared to normally aspirated engines.

 

[rivermobster]

So after finishing my fresh top end on my motor this year, I've been working with whipple on getting my MEFI 3 setup just right. They are great to deal with and have helped me learn a few things. But, I'd love to learn how to do efi tuning on my own and I know enough to probably lean out and blow a couple motors teaching myself. Is there a way to learn how to do this without learning the hard way? I wish there was an ECU that was user friendly and something that would help people like me learn how to tune a motor. There is all kinds of products out there for the automotive industry but that doesn't help us in the marine world seeing as we can't run O2 sensors all the time. I've looked at the holley, edelbrock, fast and MSD injection systems but has anyone had any real world experience running one of those systems on a whippled 500efi or 525?

You can run O2 sensors all the time, you just have to have the right exhaust system. CMI welded bungs into their headers for us, when we did some beta testing for STV_Keith on a piggy back system he was building.

Learning how to tune is more of an art than a science. It makes no difference what engine you are working on, they are all just basicly air pumps! You would need a through understanding of engine building first, cam timing, compression ratios, and how all the parts in the engine all work in harmony, before you can understand how to tune.

The other issue is...

There are all kinds of Different software packages you could possibly use. Learning to use the software is a whole different issue! You'd have to use it every day to get Real good at it, just like anything else.

Still interested??

Find a laptop software package you like, buy a decent lap top, buy the software and all their adaptors, sign up and take all their classes, and you'll be on your way to be a top tuning master. After that, you can start looking for customers to pay for all the stuff you just bought!

Have fun!

 

[Eggbeatn ur Ass]

Thanks for the replies. You guys gave me the answer I didn't want to know and that its not any easy thing to learn. I'm sure I'd have a real expensive learning curve figuring it out. I have alot of respect for the professionals and the fact that it has taken them alot of trial and error to learn it too. Maybe in the future there will be a more user friendly method of tuning EFI blower motors for guys like me. But for now I guess I'll keep doing what I do best and pay someone that knows what they are doing to do it right.

 

[Trash]

I agree with all said above. BUT, you CAN do it yourself if you take your time. The only way you would lean out the motor and hurt it is IF you pulled too much fuel from the fuel tables or associated table depending on your system. You MUST use wide band as that is your only feedback as to how the motor is doing AFR-wise.

I, like you, was curious, but I dove head first and immersed myself into tuning. In reality there isn't much you have to play with as many of the scalars and constants in most case don't need to be changed.

IF you have a running motor get wideband installed and some good baseline data. THEN decide if you need to tweak things.

Get a copy of TunerPro and a MEFI 3 file. Open the file and simply familiarize yourself with the tables and parameters. You will initially be overwhelmed but fear not as the VAST majority of the tables you will not touch.

Fuel tables and spark are your main concerns.

Good luck and have fun.