How much tuning really?

[dieselgeek]

At what point do you need to go to the dominator ecu instead of the hp(holley) I understand the hp has 4 input/outputs and the dominator has 8. but what type engine would use more than 4? Seems that they stopped at 4 for the kits, and the dominator is an upgrade.

Trans control is the major reason. But, the Dominator has a TON of spare inputs that can be used for all different types of datalogging. Suspension travel, wheel speed, you name it - it's configurable. The Dominator is complex just like a motec or megasquirt but if you're willing to make the effort, all those extra inputs can be used for something.

[NewEnglandRaceFan]

Lol. Anyone else here besides Alex with more questions? I don't mind answering questions from legitimate car guys.

At what point do you need to go to the dominator ecu instead of the hp(holley) I understand the hp has 4 input/outputs and the dominator has 8. but what type engine would use more than 4? Seems that they stopped at 4 for the kits, and the dominator is an upgrade.

[dieselgeek]

People have tried the same idea long ago, the reason it doesn't work is because your O2 sensor is downstream in the exhaust - by time the signal gets to your supplemental injector its too late, so you end up with a feedback loop of "too rich, too lean, too rich, too lean" and then you end up needing intelligent software to control that loop and "look ahead"

Since you are intent on keeping the carb, I'd add a single supplemntal injector but use a cheap standalone like a Megasquirt 1, because it'll actually pulse the injector in proper sync with your engine RPMs and will take your O2 sensor signal, apply a PID loop, and really let you control the AFRs the way you want to. Otherwise, without load and RPM reference, you're going to spend a lot more time and money trying to rig up something that won't work than if you'd have gone with something that's been developed already.

It's a neat idea, but think of it this way - if all the OEMs had to do was hook up a wideband and a single injector and get good AFR control, that's exactly how they'd be doing it. They are masters of figuring out how to make something work while being low cost as possible.

[Barry Donovan]

Never, IMO. The MAP is a great reference for load, the engine's fuel needs depend on that. The MAF takes that info, and refines it a tiny bit to make the engine run more consistent - that's why any modern EFI car runs its best in all weather conditions.

Lots of companies have tried "alternative methods" for fueling, and they all arrived at what we have today. It's pretty good stuff, you should look into it a bit. Barry, I am sure once you got into homemade EFI you'd be very good at it, and happy how your car runs.

I'd like to..
I am winding down on an older mechanical project.
was looking at breadboards, electronic sources.
I was going to start with a 555 timer, and one injector from a spfi Subaru (one injector did the whole engine). the one number I got is resistance from their own manual. Found a program that narrowed down some of it on a 555 setup, the rest would be a potentiometer.. and then feed it a changing o2 signal.
not exactly main stream, but seemed fun to try a backup injector if to blow through the monojet.

[dieselgeek]

I have one question, hope it is legit.

if maf creates a restriction and speed density rides a manifold pressure...

when it is time to say to the hell with both?

Never, IMO. The MAP is a great reference for load, the engine's fuel needs depend on that. The MAF takes that info, and refines it a tiny bit to make the engine run more consistent - that's why any modern EFI car runs its best in all weather conditions.

Lots of companies have tried "alternative methods" for fueling, and they all arrived at what we have today. It's pretty good stuff, you should look into it a bit. Barry, I am sure once you got into homemade EFI you'd be very good at it, and happy how your car runs.

[Barry Donovan]

I have one question, hope it is legit.

if maf creates a restriction and speed density rides a manifold pressure...

when it is time to say to the hell with both?

I really want to inject a rumbling double timing belt boxer...but wow. it purposely tries to defy the modern things going. I went back to a carb (and it is a difficult chore there too- although easier)

a set map is impossible..so restricting to a maf is the way to go?

[TC]

Lol. Anyone else here besides Alex with more questions? I don't mind answering questions from legitimate car guys.

Yap just laugh it off, though that doesn't answer my question..... But then we all know you don't have the manuals, that's why your beating around the bush...... Caught you in a lie again.......

[dieselgeek]

Lol. Anyone else here besides Alex with more questions? I don't mind answering questions from legitimate car guys.

[TC]

Yep, sure did. Every crate LS that comes with a GM ECU from Blueprint uses a calibration I developed in HPT. You should try using it sometime, that way you can share advice that may have some value instead of what you currently share.

I have used it, in fact the manual is sitting right here in front of me.... See the thing is I don't think you bought the manual and at that what manual did you buy if you did buy it, that is why I asked what you need to do before adjusting the VE tables, come on man it's only 6 things, surely you can name them.....

[dieselgeek]

Yep, sure did. Every crate LS that comes with a GM ECU from Blueprint uses a calibration I developed in HPT. You should try using it sometime, that way you can share advice that may have some value instead of what you currently share.

[TC]

Read the instructions.

I thought you did??...

[dieselgeek]

Other than disabling the MAF what else do you need to do before you can adjust the VE table??......

Read the instructions.

[TC]

In fact, the proper way to tune HPT is to first tune speed density so your VE tables, the basis of all fuel maps, are correct. Then the next step up is to tune for MAF usage (if you don't mind a little power loss with the airflow restriction, it's minor), and let the computer get back to closed loop self tuning. The car will run very nice if you go through all of this.

Other than disabling the MAF what else do you need to do before you can adjust the VE table??......

[TC]

Thank you for the confirmation. I read/listen to all replies I just give some more weight than others.
I know in the end it is up to me to do the research and find which method would work the best for
me. I said it before that I am not ready to do this now but it is something that I would love to
try but I know my limitations and don't want to get in so far over my head that I just give up.
I work only about 5 mi from DIY autotune and live just a little farther so that makes MS an
attractive option. I have stopped by there and they seem very eager to help (even when I
haven't spent any money with them). I started this thread for an education, thanks again
for the input. Amazing that without the web this exchange of information would be almost
impossible.

One more thing HPT has their own forum, it might be more beneficial to you to go to that forum and ask some of the question you've asked here and see what they have to say.....

[CDMBill]

MS is a remarkably well documented and supported system that has more users than any of the commercial systems. With Scott's help I went from EFI noob to halfway competent user. Scott also had three guys get jackets at Drag Week last year, never mind records at Bonneville and a runnerUp at Engine Masters. If you go that route you won't regret it. BTW I got my fully assembled MS3X, harness and al kinds of supporting stuff from DIY Autotune, great guys who also are here on BS a lot. You won't find a better place to get an EFI education.