How to Megasquirt your 3G Hemi

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A friend of mine bought a 68 Valiant and a 5.7 out of an 07 truck. He wants me to help him with the wiring. I'll have to watch this post to do that. Right now I'm building an older hemi with a Megasquirt and have gutted a Joe Hunt mag except for the rotor and coil. It will be driven by an MSD system. I've seen dragsters with belt driven distributors and suggested to him that I could machine a unit to act as a distributor and be belt driven and used just to distribute the spark. He's rather anxious about his engine because of the 8 coil system and the extensive wiring used. I thought maybe the distributor deal could ease his worries a little. What do you think? Also, is there a way to locate the missing tooth on the crank trigger wheel without pulling the pan? Thanks, Bill
 
You could probably pull the crank sensor and stick your finger in the hole and feel for it while rotating the engine? Do it however you want but I think a little extra wiring is a whole helluva lot simpler that machining a distributor drive.
 
The megasquirt wiring is very straight forward, especially of you follow my 'how to' at the beginning of the thread. A distributor drive would be significantly more work.

FYI- don't remember if I put it in this thread or not- I marked TDC and put a timin light on the motor- actual timing was 1-2* retarded vs commanded (at 15-18 degrees). Within my margin of error.
 
Bill- what's the purpose of you physically locating the missing tooth? The MS has it right when you use the correct wheel settings.
 
I don't spend a lot of time over here. I hand some time to read through this tonight. It is a very interesting build. Have you had it on the dyno yet? If so what did it make at the wheels? I have tuned several individual throttle body setups. They have all kinds of issues fueling and metering air evenly on a per cylinder basis. It can really give you fits trying to make it balance from side to side. I don't know that I agree with your fuel and horsepower assumptions. I will just leave it at that. I would love to see some dyno runs. I dig the MS3 setup.
 
I don't spend a lot of time over here. I hand some time to read through this tonight. It is a very interesting build. Have you had it on the dyno yet? If so what did it make at the wheels? I have tuned several individual throttle body setups. They have all kinds of issues fueling and metering air evenly on a per cylinder basis. It can really give you fits trying to make it balance from side to side. I don't know that I agree with your fuel and horsepower assumptions. I will just leave it at that. I would love to see some dyno runs. I dig the MS3 setup.

Dyno runs were posted in another thread.

The math I posted for VE should've been close, but I don't think these 6.4 injectors flow what I assumed they did, skewing the numbers.

I have not had much issues with the ITB's. The linkage has adjusted itself more than once, and the airflow could use more balancing at idle, but it's plenty fine for everything I'm doing.

I have since killed this motor at the Texas mile. Ran it lean at 7200 rpm. Battery cable ground itself to chassis. 4 melted pistons. I put a bone stock 6.1 in for now, and will build a stroker to replace it.

Here's the dyno numbers from the 5.7. Peppy little motor. RIP



Finally dyno tuned my motor today. I'm very pleased. Picked the car up A LOT driving it home.

Quick breakdown:
1973 plymouth duster
forged 5.7, 11.6:1 compression, 03-08 GTP Extreme heads, Hilborn intake, custom shorty headers welded by me (around P/S box), 218/224 on 113.5+2 (xfi exhaust lobes- very mild)
TKO600 standard tranny, ford 9" floater rear, 3.60:1 gear with locker, heavy wheels all around.
Megasquirt 3x engine management tuned by me.
straight 30 weight conventional oil for all pulls.

We started the day in the 370's (rwhp) using a modified stock 5.7 timing curve. We kept adding timing until it dropped power, and backed it down 2* to the previous higher point. Ended up with more timing in the higher rpm range than most. I wanted more peak torque, but I am very pleased with where we ended up. ~300 rwtq from 3,000-7,000 will do just perfect for road racing.

All on 93 octane unleaded. No knock sensors. Craig at Bumbera's was listening, and I was doing the same through a microphone clipped to the knock sensor point on the block. Neither of us heard any knock the entire day, including when we tried 2* on top of our final curve just because (dropped power across the board, did not knock though).

Honestly, I did not expect the motor to pull this high with this little cam. I expected the hp peak to be below 6000 rpm, as that's where this cam peaked on 5.7's & 6.1's with a normal intake. Guess not with my build.

A couple back to back runs at the end:


And my timing curve. DON'T YOU DARE use this curve and expect it to work - way too much timing for most - you'll blow your motor ;)

Point worth noting: I marked TDC on my balancer and put my timing light on the motor to verify what the MS3x is commanding is what the motor is seeing. I found 1-2* of retard (light vs commanded) at 15-18*. That is within the range of measurement error, though it's very possible that the engine sees timing at 10% less than commanded. All I want you to take away from this curve is adding timing after peak torque was VERY beneficial for my motor. Further, this is the actual MBT for my motor on 93 octane, and MBT was reached before knock. Every motor is different so what worked on mine may not work on yours. Disclaimer: I'm not liable if you blow your motor trying to run 30*+.

 
I see your disclaimer on timing down below. Combustion on the g3 is significantly more efficient than the old school motors. In fact, even more efficient than the LSx motors. Most of them make the best power and torque about 25 degrees all in.

Posted via Topify using iPhone/iPad
 
I see your disclaimer on timing down below. Combustion on the g3 is significantly more efficient than the old school motors. In fact, even more efficient than the LSx motors. Most of them make the best power and torque about 25 degrees all in.

Posted via Topify using iPhone/iPad

We were expecting 22-24* all in. But she kept adding power so we kept adding timing.

FYI for those reading - please don't add timing past 20*! ha
 
I see your disclaimer on timing down below. Combustion on the g3 is significantly more efficient than the old school motors. In fact, even more efficient than the LSx motors. Most of them make the best power and torque about 25 degrees all in.

Posted via Topify using iPhone/iPad

We were expecting 22-24* all in. But she kept adding power so we kept adding timing.

FYI for those reading - please don't add timing past 20*! ha
What helps a lot is factory knock sensors. I know the new ms3pro and the fast both support them.

Posted via Topify using iPhone/iPad
 
What helps a lot is factory knock sensors. I know the new ms3pro and the fast both support them.

Posted via Topify using iPhone/iPad

They support them, but I don't know anyone who had used that yet (knock sensors on either of those two boxes).

I have the knock board in my ms3x. May try to wire up the knock sensors.

The issue is the hemi knock sensor isn't 'tuned'. So, the tuning needs to be done in the computer. If you want to tackle it, I've got the frequencies somewhere I can send you...
 
For those who are 'new' tuners and reading this thread to tune their cars, I ran into an interesting situation last night worth telling about.

I was experiencing a lean spike at 4,000 rpm. I mean, 16:1+ AFR. I couldn't figure out what it was until I looked at the MAP reading. Historically I've had the VE table with the left columns reading:
100
95
90
85
80
etc etc

I used to have the VE numbers the same in the 95 & 100 rows, but that was causing a rich issue at part throttle. Well I allowed tunerstudio to 'self tune' at part throttle, and it drastically reduced the VE number in the 95 cell.

Anyway, what I came to find out was that under full throttle, the MAP reading drops to 95 at 4000 rpm. So, the MAP reading under full throttle (95) and part throttle (close to 95?) was the same at 4000 rpm, so I either was lean at WOT (16:1+) or fat at part throttle (9.5:1 AFR).

My solution was to add rows:
100
98
95
93
90
85
80
etc etc

Anyway, that helped. That allowed me to put the WOT VE in the 95, 98, 100 cells for 4000 rpm, and put something more appropriate in the 93 cell. I've still got a little fat issue at one small throttle position, but I'm not sure I could improve on this tune unless I stepped away from speed density.

So- lesson for the day:
If you've got a lean or fat issue you can't figure out at WOT, check the MAP reading to make sure it's referencing the cell you think it is!
 
HOW TO ADD GENERIC SENSORS:

The megasquirt box comes with three pre-wired generic 0-5 volt sensor inputs (additional available with internal wiring jumpers added).

There are a number of sensors that generate a 0-5 volt output. I'll be using these inputs for logging oil pressure to make sure I never lose oil pressure on a road course.
Oil pressure 1 (between oil pump and check valve)
Oil Pressure 2 (between check valve and accusump / engine)

Other 'generic sensors' that can be used here:
Pressure sensors of any kind (fuel pressure, nitrous pressure, etc)
Vacuum sensors / MAP sensors
Temperature sensors
Mass Air Flow sensor
Linear potentiometer (measuring suspension or pedal travel)
etc

Step 1: Wire the sensor. Three wire hookup.
Red: 5v feed (use pin 26 on the main megasquirt harness - already feeding your TPS, Cam sensor, and Crank Sensor)
Black: Ground (Use a Megasquirt box ground)
Blue: Sensor output. Connect to Pin 21, 22, or 23 on the MS3x harness

Screen shot of the '3x 0-5V analogue in' pins:
[ame]http://i1271.photobucket.com/albums/jj629/uhcoog1/ACF0E027-7745-4F4B-9E15-5101CE536A83_zpsyq3ylp5f.png[/ame]

I used the following pressure sensors ($18/each):
Pressure transducer or sender, 100 psi, stainless steel, for oil,fuel,air,water
[ame="http://www.ebay.com/itm/261260635816?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT"]Pressure Transducer or Sender 100 PSI Stainless Steel for Oil Fuel Air Water | eBay[/ame]

Screen shot of the 'description' indicating the linear output for the sensor:
[ame]http://i1271.photobucket.com/albums/jj629/uhcoog1/C0F9A789-0F82-4D60-A481-16816D45DB7B_zpsk43lcn1l.png[/ame]

Set-up within tuner studio:
Go to: Advanced Engine / Generic Sensor Input


Tunerstudio will automatically log these sensor inputs for you once you set them up in the Generic Sensor Input window.

Screenshot of log (middle log), showing sensor 1 and sensor 2. In my case, sensor 1 is the engine / accusump side (red), and sensor 2 is the oil pump side (green). The first half of the log was running a clockwise skidpad in 2nd gear. The second half of the log is running a counterclockwise skidpad in 1st gear. Needless to say, the oil pump pressure stayed at or above the engine/accusump pressure, which tells me I never sucked the pump dry.


References:
http://www.msextra.com/doc/ms3/genericsensors.html
http://www.msextra.com/doc/ms3/hardware.html#wiring
 
Very informative thread. It really has me thinking of using the MS3 system on my 5.7L duster project. I cant tune the OEM dodge ECU for the turbo's I want to run.

Thank and keep the info flowing.:burnout:
 
Great write, I've been meaning to read the GEN III section on Mega forums. I'm glad you posted up your experience. This will certainly make my swap easier when I get under way on my dart. Thanks for taking the time to share your experience.
 
See if this works. I had lost track of this interestin' thread, until tonight I accidently found this on th' tube:

AWESOME. Must give the 'Vette guys twitches to look in the mirror and see a crappy old Duster!!1

Wade Koehl

 
See if this works. I had lost track of this interestin' thread, until tonight I accidently found this on th' tube:

AWESOME. Must give the 'Vette guys twitches to look in the mirror and see a crappy old Duster!!1

Wade Koehl



Glad you enjoyed the video! Ha- yes always fun chasing down 'faster' cars
 
hey i have a question about the tuning of megasquirt. i have an 05 5.7 hemi and i got the gold box with harness and it also came with default tunes on a flash drive i had to install via laptop.the tune it has is a 6.1 VVT (mine has no vvt so i turned that to disabled). it fires up fine but my problem arises when i use the throttle. i have a vacuum gauge hooked up and when it idles it sits at around 19-20 of vacuum. if i go right to throttle hard it loses all vacuum and dies but if i slowly go into the throttle and watch my vacuum gauge and dont let it go to low i can get it to rev.
 
VVT is a 09 and later for the 5.7L hemi and NEVER appeared on the 6.1L Hemi.

So I don't think the VVT setting is your problem. I would look at your enrichment setting in MS Tuner Studio.

Regards,

Joe Dokes
 
yeah i dont believe it was VVT. just stating all the details on my tune that efisource sent me on the flash drive
 
I haven’t read the entire thread yet, so maybe this has been mentioned. Has anyone tried the MS3 Gold box from EFI Source? It is a MS3 box for $800 and a plug and play Hemi harness for $495. To me it looks like you’d have the same setup with a plug and play harness!
MS3 Gold Box – EFI Source
 
I haven’t read the entire thread yet, so maybe this has been mentioned. Has anyone tried the MS3 Gold box from EFI Source? It is a MS3 box for $800 and a plug and play Hemi harness for $495. To me it looks like you’d have the same setup with a plug and play harness!
MS3 Gold Box – EFI Source

You are correct. I wrote this before mike released the gold box. EFI Source is arguably the best way to go if doing megasquirt and 3G hemi these days.
 
and the fact that tunerstudio has a 'self-tune' setting that will adjust the fuel tables to match your specified air/fuel ratios.
...Buy Tunerstudio & MegaLogViewer software: $60

Buyer beware that MS3 Does not auto-tune by itself with the free Tunerstudio. You MUST buy a Tunerstudio license for that to work. That where the $60 must have gone. MS2 used to say that in the MS2 update literature until I called them on it and said you had better mention that you need to buy the license for megatune/Tunerstudio for that to work. Just an FYI. Excellent write up.
 
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