general talk about ECU and EMS

[TurfBurn]

Thanks guys.

This is a good discussion.

Sequential >> Batch

It's kind of a circular discussion in some ways... we are working with Microtech to get the units to be full sequential. I was told this batch was going to be, but long story there... word is roughly another month...

But there are three to 4 firing modes... group, batch, semi-sequential, and full sequential. These are how I describe them, there are futher variations of them though too (like group fire can be done every 360 degrees rather than every 720, or even every 180 degrees etc).

Group - all 4 injectors fire every 720 degrees, or essentially once for the time it takes for each cylinder to fire.

Batch - 2 injectors trigger at 0 degrees, and 2 trigger at 180 degrees and then not again for another 720 degrees

Semi-Sequential - (also called batch fire as well), 2 injectors fire at 0 and at 180 degrees, and do so every 360 degrees

Sequential, one injector fires every 180 degrees (not necessarily timed to line up with intake stroke etc... common misconception).

The difference between semi-sequential and sequential is so small that they become arguable... because sequential is more "advanced" people like to argue that it is better... there is in theory a 2-3% gain in some midrange power, but that is hard to measure dyno to dyno, and also, that could be running semi-sequential/batch every 720 degrees instead of every 360 degrees... keep in mind that when run every 360 degrees, every cylinder will get one injection that can be timed to go into an open port, and one to go onto the back of the valve.... this means you get additional valve cooling and vapor charging of the intake track, as well as the high atomization for good burn from the open port injection. In some ways this is arguably superior to sequential... what happens in a stock car on sequential is typically the injector is fired so that it COMPLETES it's injection right as the valve starts to OPEN... in race cars you do it so that you complete just before the valve closes which is what people think is "normal" but is not... so obviously hitting the back of the valve is not exactly a "bad" thing..

I have to roll... but I'll add and discuss more in an hour or so.

thanks,

Steve

 

[TurfBurn]

I thought they kept the ECU's. And the MPI can do larger injectors, but it will fire them in batch mode, like the haltech, but Nick doesn't like that because you don't get the same smooth idle like you do stock.

I'm not sure what you are referring to when you say "I thought they kept the ECU's" unless you are just saying I confirmed what you thought... then I follow...

The Microtech and the AEM are the only ones that can fire true sequential. for the primaries other tha the piggy's. As I stated in my last post though... that can be a somewhat debatable point.

We have been getting very good idles overall... they are a little high (around 900-1000 rpm's I think in most cases) but are smooth and consistent. The new LT10S unit that we are working on will also have idle air control solenoid control and will allow for a very tight low and smooth idle... so that will be an improvement even further... I'm working on all sorts of add ons all the time too!

So how would you get the OBDII to work with a Standalone using switches? I guess the switches would allow the ECU to see what's doing with the engine and allow for drive cycle codes? Man if you set that up, then that would be the s***. If I were to go standalone with what's out there, I would go Microtech, I heard to much BS about the Haltech and it rubs me wrong. With all the R&D you've put in this, it sounds good, definatly better then when Spool was verkin on it. I'm sure they would have gotten there if they had time but with what they had at the time, it wasn't as practicle as it seems now.

The AEM is a bit too much for me and what I want to do. That's why I went MPI, because it's inexpensive and does everything I need it to do, and then some.

Well the trick with the OBDII that I haven't had time to work out (and part of the problem is my car is so different from everyone elses because of the stuff Terry did to it) is to basically make the car think it is idling and that's about it. If you leave the MAF in and trick a couple of sensors it becomes pretty easy to make it think it is more or less ok. How it works out over the long run etc I don't now. But it is a future project for me to build a few simulators for sensors that will trick the stock ECU in to thinking it knows what it is doing.

And make no mistake... we are WAY past anything Spool ever attempted with the Microtech... Also, Terry didn't do the stuff himself, there was some place out of Miami that was doing the actual Microtech work.. not him.

 

[TurfBurn]

Continuing some of my points on sequential/versus batch..

As you get higher and higher in duty cycle, sequential and semi-sequential become closer and closer to each other... as they both end up spraying into open and closed ports regardless because the time required to jet the necessary fuel in is longer than when the valve is open...

All in all there is very little advantage to sequential over semi-sequential. At very low duty cycles (like at idle) there can start to be a tiny bit of difference between them if the sequential is really timed properly to inject at the best valve opening period versus the semi-sequential which would also hit that, but also the closed valve once each cyle too... The difference becomes very small, and it depends heavily on port design and air velocities as to how much difference it really makes. And again, the difference in power that is sometimes found (2-3% is the high figure, some put it more around 1% if even that) is so negligible fuel quality, fuel temperature, and air temperature are enough to disguise that difference in pretty much all cases.

I'm working on injector phasing now with the Microtech's... basically setting them up so that based on rpm and duty cycle I can make sure the injectors are hitting the perfect valve open timing as much as possible during boosting for maximum power and clean burn.

Later!

Steve

 

[MPNick]

the MPI can't handle big injectors in the primary slots so thus you run secondary ones...
.

This is not true, we can run bigger injectors. up to 440cc. The problem is the bigger you go the more trade offs you have to live with, just like with any standalone systems. This is why you use the staged injectors. All of the fuel that you need and no trade offs.

 

[MPNick]

And the MPI can do larger injectors, but it will fire them in batch mode, like the haltech, but Nick doesn't like that because you don't get the same smooth idle like you do stock.

Not 100% right, the MPI will fire the injector in sequential just like stock. On the staged injector driver you will be in batch.

 

[BlkZoomZoom]

Another thing to add here is the Mpi is the only one I know of that will pass inspection in NY or any other state you have to plug in the OBD2 port. Any ecu that replaces or alters the stock unit technically "should fail" inspection. However if you no longer have the stock pcm you will not pass. I personally know that the Haltech fails inspection as I am trying to get Pretzellogic's car to pass. I also know the MPI passes without question (done 3).

--I may be way off course on the discussion...I had to stop reading Turfburns 250word responses were getting alittle too much...lol

 

[TurfBurn]

This is not true, we can run bigger injectors. up to 440cc. The problem is the bigger you go the more trade offs you have to live with, just like with any standalone systems. This is why you use the staged injectors. All of the fuel that you need and no trade offs.

What tradeoffs though? Idle, cold start, all are fine on cars like mine... if you get into very large injectors then some of the low idle opening times can be a bit too small to be effective... but that's starting to push out on the injectors a good bit...

I did not realize that you guys could run the bigger injectors... is it limited to high or low impedance at all?

 

[TurfBurn]

Another thing to add here is the Mpi is the only one I know of that will pass inspection in NY or any other state you have to plug in the OBD2 port. Any ecu that replaces or alters the stock unit technically "should fail" inspection. However if you no longer have the stock pcm you will not pass. I personally know that the Haltech fails inspection as I am trying to get Pretzellogic's car to pass. I also know the MPI passes without question (done 3).

--I may be way off course on the discussion...I had to stop reading Turfburns 250word responses were getting alittle too much...lol

Sorry... I'm wordy! LOL...

We are also going to start working on making the Microtech make it through inspections in the near future hopefully.

 

[BlkZoomZoom]

Does the microtech compensate for load at idle? Like if you switch on the a/c or rear defroster?

 

[TurfBurn]

Does the microtech compensate for load at idle? Like if you switch on the a/c or rear defroster?

Yes, you can set up the LT8S to compensate for one major load. The LT10S can compensate for 2+ loads. You can also make modifications to the maps at the load cells that also helps compensate. I haven't messed with it, but there is also a way to multiply the number of loads you can compensate for by using a stepped input on the input wires.

 

[BlkZoomZoom]

It adjusts the fuel load and the air input(like an idle air control motor)? If so thats friggin cool. It's amazing how far technology has come for the aftermarket.

Can I throw one of those on the scamp? lol

 

[TurfBurn]

It adjusts the fuel load and the air input(like an idle air control motor)? If so thats friggin cool. It's amazing how far technology has come for the aftermarket.

Can I throw one of those on the scamp? lol

The LT10S will do the air control solenoid as well.. the LT8S won't... but they both can add fuel and timing per the load. I don't even really have much past a couple minor map corrects made and with kicking that kind of stuff on I lose an AFR point and about 100 rpm's off the idle... and like I said that's essetailly uncorrected... I don't have the input even hooked up right now to make use of the corrections... that's just a couple tweaks I did to my fuel maps to deal with that stuff.

 

[Bigg Tim]

Another thing to add here is the Mpi is the only one I know of that will pass inspection in NY or any other state you have to plug in the OBD2 port. Any ecu that replaces or alters the stock unit technically "should fail" inspection. However if you no longer have the stock pcm you will not pass. I personally know that the Haltech fails inspection as I am trying to get Pretzellogic's car to pass. I also know the MPI passes without question (done 3).

--I may be way off course on the discussion...I had to stop reading Turfburns 250word responses were getting alittle too much...lol

I passed emissions in MD and AZ state with NO problems as well, that is a very big plus to running the MPI.