HemiTronix

-
Hey Joe , I have been reading some more of the info at DIYAutotune & Megasquirt , I could be reading for weeks yet :study:
I think I could manage kit assembly ok , what scares me a little is the wiring to the engine etr , what scares me alot is setting perameters and creating a base tune from scratch , if I can't manage that I fear most tuners wouldn't want to touch it seeing as it's not a common of the shelf unit .
 
Wiring up the sensors and stuff is really pretty straightforward I think. Think of it like plumbing, "stuff" flows down the line between pieces. If you can follow lines on a piece of paper you should be able to wire up the Megasquirt. They have some pretty nice schematics and pinouts for the plugs and label stuff quite nicely (especially with a relay board), they just have one big plug that's hard to keep track of where the pins are. Putting connectors on for all the sensors could be difficult too depending on how you want to do it. The easiest way would be to cut them off a stock harness and just splice them on the ends of the Megasquirt harness and use a relay board (don't have to put wires into the large 40 pin plug this way). The better way would be to actually try to track the connectors down unassembled and manually crimp the pins on the end of the harness, but good luck finding the connectors.

I agree on the setup though. I was pretty much flying blind when I first tried to get my car to fire on the Megasquirt. There are some pretty good guides for parameter setup at least, and if you start with a simpler setup (like batch fire and only fuel, no spark), it's not too bad and there's not too much you have to setup. The tuning was also pretty challenging. The base tune is for a 350 Chevy (what the computer was originally built for), so I figured it would run okay on a 345 Hemi since they are roughly the same size...wrong. They do have a calculator though were you can put in your estimated peak horsepower, torque, and respective rpms and it will spit out a pretty decent base map. It made my car run way smoother when I started over with it.

The important thing to remember is that you don't have to try to set up everything at once for the first go. You can turn off lots of stuff like O2 correction, IAC control, etc. and just try to get the car to start and idle (crank pulse, fuel map tuning) then start adding and tuning features as you go. You can modify tons of stuff like afterstart enrichment, warmup curves (basically like a choke), accelerator enrichment, etc., but the base settings generally work pretty good for a plain jane tune. Once you get it running you can slowly tweak the settings to work better with your engine.

It's definitely not the plug and play solution that a lot of people want, but it's really one of the most poweful options out there because of what all it lets you tune. I've tried to get a thread going on the forums here with tune files for different computers for people that are interested in the swap, but somewhat hesistant because of the tuning. I know I really would have liked a known running tune to at least reference when starting, but couldn't find any. I've posted a version of my working tune for anyone that's interested over in that thread. I was hoping as more people got them running they would add to the thread.
 
What Map63Vette said.

One of the key issues with setting up MS on any motor is the fact that it is a universal fuel and spark management system. It can be modified to work with almost ANY internal combustion motor. As a result the manual, known as the "Megamanual" covers a huge series of options that you won't be using. Unfortunately you don't know enough about how fuel injection works to know what you won't be using and you can simply skip over.

The reality about reading for weeks is simply true. I started reading about MS a couple of years ago and decided it was the way for me to go simply because I didn't and wouldn't have the money for a system from AEM, FAST, or BigStuff. I also didn't want the limitations of the factory computer. Don't get me wrong, some have had great success with the factory computer and others are very happy with FAST et al, I simply couldn't afford it.

I think the decision to go MS is simply one where you have to evaluate time versus money. If you have plenty of money and no time. Call FAST and be done with it. It will come with a base tune, you can then drive the car to a dyno, and have a professional tune it. If you have plenty of time and little money than MS is a better alternative.

As far as wiring, it is funny, I too was scared of wiring the car, but once you break it down into bite sized chunks, it starts to make sense and that bundle of fifty wires is really just a bundle of about 10 different functions. Once you understand what those functions are that wrist size bundle of wires looks a LOT less intimidating.

For example, you'll need a bunch of sensors to tell the computer what the motor is doing so it will know how much fuel and spark to send to the motor and precisely when.

Here are just three of the sensors you'll need.

Crank Position Sensor- Chrysler abbreviates this the CKP- it has three wires, one provides five volts, one provides a ground, and one provides a signal to the computer. It basically tells the computer how fast the engine is spinning and the position of the crankshaft.

Camshaft Position Sensor- Chrysler abbreviates this CMP- it also three wires, one provides five volts, one provides a ground, and one provides a signal to the computer. It basically tells the computer whether the engine is on the compression or exhaust stroke.

Intake Air Temperature Sensor- or IAT sensor, it has two wires, one is a signal to the computer, the other is a ground for the sensor. This tells the computer how hot the motor is running. It doesn't need power because a change in temperature generates the voltage.

So with three sensors we have a total of 8 eight wires already. Once you start to break it down like this it becomes very manageable. The key is to break out each circuit.

It all comes down to the old adage:

"How do you eat an elephant?"
"One bite at a time."

I'd also think about ordering this book:

[ame="http://www.amazon.com/Performance-Fuel-Injection-Systems-HP1557/dp/1557885575/ref=sr_1_1?ie=UTF8&qid=1337810304&sr=8-1"]Amazon.com: Performance Fuel Injection Systems HP1557: How to Design, Build, Modify, and Tune EFI and ECU Systems.Covers Components, Sensors, Fuel and Ignition ... Tips, Aftermarket ECUs, and EFI Convers (9781557885579): Matt Cramer, Jerry Hoffmann: Books[/ame]

It's written by Matt Cramer and Jerry Hoffmann. I believe Jerry owns DIY Autotune, and Matt is an employee, the reviews of the book are positive, and unlike the Megamanual it is probably better laid out. The book might be helpful regardless of the fuel injection system you use.

The book should provide some information regarding initial setup and tune.

Regards,

Joe Dokes
 
I was in the Portland area last weekend so I stopped by Nutter Racing Engines to talk to him about the Hemitronix system. For what it's worth, AC was extremely knowledgeable and struck me as a stand up guy.

He said that his shop rarely, if ever builds a carbureted motor anymore. He had several LS motors and multiple states of build. I saw the motor used in the Mopar Action article. He told me Mopar Action didn't want him to do anything to it before he ran it on his dyno so he didn't. He showed me all the parts involved in the swap and I got to check out his dyno and the rest of his shop. I came away impressed and I am eager to pick up a motor to swap into my Dart.

In the end, the proof is in the pudding but after my visit I feel comfortable spending my money on this kit. As always, your mileage may vary...
 
You must log in or register to reply here.
-

Back
Top