MS3 on a Modified Mopar 340

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goldduster318
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Posts: 10
Joined: Sun Dec 07, 2014 1:58 pm
Location: Lake Orion, MI

MS3 on a Modified Mopar 340

Post by goldduster318 »

Hello all,

I am looking to install Megasquirt 3 with sequential fuel and spark on to my Mopar 340 engine in my 1970 Plymouth Duster.

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The engine made 470 hp @ 6000 rpm and 455 lb-ft at 4400 rpm with the Quick Fuel SS-750-AN double pumper carburetor on the Edelbrock Air Gap Manifold.

I will likely end up using the Edelbrock Super Victor EFI manifold and likely the Holley 1000 cfm 4-bbl throttle body 112-588. I already have a set of GM D585 truck coils and a 93ish 5.2 magnum distributor for the half/half crank sensor. Looking at welding a 36-1 crank wheel on the crank pulley for the engine for the crank sensor. Also will probably put an aeromotive phantom fuel system for this.

Currently, my main concerns are if I should use the MS3/MSX or the MS3 pro. Is the MS3 pro recommended for engine bay use? It seems like the 80-85c max temp might be a little bit low for that.

Also, it looks like I might need 36 lb/hr injectors for this. Does that seem right?

Thanks for your help.
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1970 Duster, 340ci/470hp 4-speed, 3.23:1, Megasquirt 3 Pro Sequential EFI with LSX truck coils
Matt Cramer
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Re: MS3 on a Modified Mopar 340

Post by Matt Cramer »

Welcome! The MS3-Pro can be mounted in the engine bay without trouble; the box was designed for firewall locations. You just need to use common sense about where you put it and not mount it somewhere that will give it too much heat or vibration.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
Rick Finsta
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Re: MS3 on a Modified Mopar 340

Post by Rick Finsta »

Your engine makes about the same power as mine on gasoline - you can do the calculations with your BSFC since it has been on the dyno but personally I'd likely step to a 40-42lb. unit to give yourself a little wiggle room on the duty cycle (I like the idea of going no more than 85% on the DC at max RPM and load) with the caveat that you'll need an injector with good low-PW linearity if depending on the number of squirts/cycle you go with.

I had to go to 65lb. units since I switched to E85.
goldduster318
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Posts: 10
Joined: Sun Dec 07, 2014 1:58 pm
Location: Lake Orion, MI

Re: MS3 on a Modified Mopar 340

Post by goldduster318 »

Okay, that's good to know about the engine bay mounting. I would mount it at the upper left in the engine bay in the photo below on the firewall. Lots of room there. It would simplify the installation a lot (no finding a spot under the dash and drilling holes/running wires through the firewall for every piece).

Image

Getting 40-42 lb-hr injectors isn't a big deal either. They're all about the same price. BSFC was between .483 at 3000 rpm and .393 at 6200. Not bad numbers. Engine is 9.7:1. Honestly, for having a big double pumper, it averages about 13 mpg city with the carb. I think it could do really well with FI because it cruises and decels very rich.

Since it's wintertime here in MI, this might be a long process!

Thanks again for the warm welcome.
Image
1970 Duster, 340ci/470hp 4-speed, 3.23:1, Megasquirt 3 Pro Sequential EFI with LSX truck coils
goldduster318
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Posts: 10
Joined: Sun Dec 07, 2014 1:58 pm
Location: Lake Orion, MI

Re: MS3 on a Modified Mopar 340

Post by goldduster318 »

I suppose I should also say I've had an innovate motorsports LC1 wideband on this for a few years. Will use this with the Megasquirt as well.
Image
1970 Duster, 340ci/470hp 4-speed, 3.23:1, Megasquirt 3 Pro Sequential EFI with LSX truck coils
slow_hemi6
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Re: MS3 on a Modified Mopar 340

Post by slow_hemi6 »

Did you get the aluminium crank pulley spacer in your part of the world? I just sectioned mine about halfway and faced off the thickness of the crank trigger wheel. The trigger wheel just locates between the two halves. Alignment and in my eyes strengthening, is done by inserting 4 x 2" lengths of bundy tube that go through the wheel and about 1" into either side of the aluminium spacer halves.
Find the Manuals up top under Quick links: Manuals. :RTFM:
Cheers Luke
goldduster318
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Posts: 10
Joined: Sun Dec 07, 2014 1:58 pm
Location: Lake Orion, MI

Re: MS3 on a Modified Mopar 340

Post by goldduster318 »

The car has the stock one piece crank pulley on it.

This is basically what I have to work with at this point:
Image

Image

I think I can fit it in between where the belt rides and my SFI balancer.
Image
1970 Duster, 340ci/470hp 4-speed, 3.23:1, Megasquirt 3 Pro Sequential EFI with LSX truck coils
Rick Finsta
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Re: MS3 on a Modified Mopar 340

Post by Rick Finsta »

That is where I put mine on my SB Olds but I had the advantage of fabricating my alternator mount at the same time so the belt lines up (I was installing a motor plate). I used one of the wheels that DIY sells and then drilled my own holes for my pattern. I like the new wheels without the slots in them, personally.
aarc240
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Re: MS3 on a Modified Mopar 340

Post by aarc240 »

Since you're going sequential spark too, you might be best off if you mount an MS3-Pro where the ignition module is/was (left front inner fender).
A little "engineerring" can put a cool air director in the rad support panel to direct air into that corner if you live in a hot place.
Put the MS3-Pro on a mounting plate and it'll even bolt on like the ignition mofule did - no extra holes.
Art,
Datsun 260z 2/2 with 280z/MS3+/5spd for the road
Datsun 240z with 280z. nearing the road again
Nissan E24 Urvan with 260z/Megajolt/5spd parts hauler - sold
goldduster318
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Joined: Sun Dec 07, 2014 1:58 pm
Location: Lake Orion, MI

Re: MS3 on a Modified Mopar 340

Post by goldduster318 »

Hi Everyone! I finally got all the parts and got around to installing the MS3 Pro on my Duster. For the most part, the install went pretty well.

I ended up using the following:

Edelbrock Super Victor EFI intake and matching Edelbrock Fuel Rails
Bosch 36 lb/hr injectors
Miller's Mule 36-1 crank target wheel with 2004 Ford Ranger 3.0 Crank Sensor
3.9/5.2/5.9 magnum distributor for a crank sensor (cap and rotor tower removed)
LSX D585 Truck coils mounted on the valve covers
GM Temperature sensors
Holley 1000 cfm square flange throttle body with stepper idle control
Aeromotive Phantom 340 in tank fuel module
3/8 feed and return line (part steel/part teflon/braided)

Here are some photos:
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1970 Duster, 340ci/470hp 4-speed, 3.23:1, Megasquirt 3 Pro Sequential EFI with LSX truck coils
goldduster318
MS/Extra Newbie
Posts: 10
Joined: Sun Dec 07, 2014 1:58 pm
Location: Lake Orion, MI

Re: MS3 on a Modified Mopar 340

Post by goldduster318 »

So I have been driving it for quite some time now and I've found that the car runs pretty decent most places.

I am having a few issues though. The first is when I cold start it. The engine basically revs up, it tries to go into closed loop idle mode, then it gets close to stalling and then comes back. I have my msq and also a datalog of this doing it.

The second issue is that at steady state at VERY low throttle openings the engine surges and the AFR varies wildly between the 12's and 16's. It's super annoying. So far I have been unable to fix this issue.

Here's the tune:
2015-10-11_10.34.30.msq
Here's a log of the starting
startup.msl
Here's a log of the surging:
surging.msl
Image
1970 Duster, 340ci/470hp 4-speed, 3.23:1, Megasquirt 3 Pro Sequential EFI with LSX truck coils
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