Building a MS-III system

[Cyclone03]

Ok I've scared the hell out of my Holley 870SA,and got it running ok,but I really want to build and install a Mega Squirt System.
I've read most of DIY auto tune and I want to start collecting parts to build a system.
It will go in a 68 Mustang with a stroked 390,433c.i. Edelbrock heads cam with 108 lube seperation etc (see my molesting a holley SA thread for details).
I want to do this on the lower buck side,not cheap side,and would like to select and purchase parts only once,or twice lol.
If I do it as TBI with 4 injectors,like the EZ efi system,what am I loseing over port injection?
Good fuel pump set up for NA 600hp,I want to be able to build to this. I'm right at 500 now.
Injectors?
I plan to expand into ignition control, but at first will just run fuel.
Is there a good junk yard engine harness to start with,(pic-n-pull)? I'm thinking all the correct plugs will be present even if I have to open the harness and move them.
The dual map. sensor MS sounds like the way to go,I like the idea of self correcting tune.

So I guess what I'm asking is if you where building a MS based system what parts would you use ?

BTW I'm planning to builb my own MS and the test box too.

[dieselgeek]

Re: Building a MS-III system

I would build an MS1 or mS2 on a v 3.0 PCB. not quite ready for MS3 yet, there's a lot to it and it's quite new (read: still working out the bugs, not a good "first build"). You can upgrade later, affordably.

DIYautotune.com is the place to get your parts... Matt Cramer is on here, that's where he works.


For a harness - it probably is just best to go with a premade harness from DIY. Maybe a relay board too, makes wiring pretty simple.

Re: TBI, they're really going to limit you around 500-600hp because the cam you'll run to make that power, will cause distribution problems - it's just the way TBI's work. Although a TBI is a GREAT starter EFI setup, so I 'd start with it (only if that's what you have already) then you can easily move up to MPI later on using all the same MS parts.


You can get plenty of help right here, so keep us posted and ask questions whenever you have them. I'd suggest getting input from guys like Silver Buick as the learning curve is recent enough that he'll be able to make good recommendations from the newb perspective.

-Scott

[TheSilverBuick]

Re: Building a MS-III system

I did the 670cfm 2-bbl TBI on a stock '67 428FE.

How electrical savvy are you in the relay and fuse department? To completely simplfy things I used the DIYautotune relay board and color wiring harness on my T-bird and Skylark. Really simple.

I used a junkyard salvaged GM coolant temp sensor, Intake Air temp sensor and the TBI fuel lines thats about all I can think of from the junkyard....

I've been thinking about the pertronix on my Tbird and if it would work adequately for a pick up coil to trigger the VR input on the megasquirt and use a CDI box (/MSD) as the module for timing control.

[dieselgeek]

Re: Building a MS-III system

The Pertronix modules make an *awesome* trigger for a megasquirt. We used that on the famous "Maverick" that we killed at LACR. It drove on the whole power tour, I don't think we ever had a tach spike or dropout from the first time we hooked up the pertronix. It's meant to work with the "Hall/Opto" circuit but with adjustments to the zero cross pot, it'll work on a VR input too.

Cyclone, we're talking about the "tach input" circuit on the megasquirt. They have two circuits, Hall/Opto and VR (Variable Reluctance). The Hall/Opto is meant for square wave signals, like those that come out of Optical distributor pickup sensors, or Hall types. VR is for use with the Magnetic pickups, which put out a "sine" wave voltage pattern.

This is one of the features that makes megasquirt good - it works well with ANYTHING from points to high res distributorless crank sensors.

-Scott

[TheSilverBuick]

Re: Building a MS-III system

Slight hi-jack, isn't the coil negative trigger (current hook up) the same circuit as the Hall/Opto? i.e. I should be able to just move my tach wire from the negative side of the coil to some wire inside the distributor cap?

[Cyclone03]

Re: Building a MS-III system

Well at least I allready have a Pertronics. So I'm on my way! LOL.

I'm an Aircraft Electricion/Avionics Tech so I kind of know my way around wires/relays and circuits.

Who makes a good affordable 4 barrel type TBI? I don't think Ill be junk yard crawling that part.

[TheSilverBuick]

Re: Building a MS-III system

Well you're up on me! I look at rocks for a living, grab and smash, doesn't quite work with electronics :D :P

I've only seen one 4-bbl TBI, holley's 950cfm. TBI's definately are less complicated to install (now having done both), but usually cfm limited.

[dieselgeek]

Re: Building a MS-III system

Slight hi-jack, isn't the coil negative trigger (current hook up) the same circuit as the Hall/Opto? i.e. I should be able to just move my tach wire from the negative side of the coil to some wire inside the distributor cap?

it's the same but it usually requires extra components be installed to deal with the noise that points create. Points are absolute junk, should have been outlawed a hundred years ago. There's just no excuse for running them other than nostalgia...

[TheSilverBuick]

Re: Building a MS-III system

Slight hi-jack, isn't the coil negative trigger (current hook up) the same circuit as the Hall/Opto? i.e. I should be able to just move my tach wire from the negative side of the coil to some wire inside the distributor cap?

it's the same but it usually requires extra components be installed to deal with the noise that points create. Points are absolute junk, should have been outlawed a hundred years ago. There's just no excuse for running them other than nostalgia...

Haha. The points work perfectly on my Centurion and did work perfectly on my Firebird, they never seem to loose adjustment or change dwell, so no reason to spend money to change what works. The T-bird was another story, so it got a pertronix unit. Aside from the general noise in my system (now proven to me to be how I wired the ground of the LC-1) the Tach signal was pretty clean on the coil negative triggering (with pertronix in the cap).

Word of advice on wiring, don't ground the WB Oxygen Sensor heater to the same place as any of the other electronics. Learned that one the hard way!

[Matt Cramer]

Re: Building a MS-III system

Well at least I allready have a Pertronics. So I'm on my way! LOL.

I'm an Aircraft Electricion/Avionics Tech so I kind of know my way around wires/relays and circuits.

Who makes a good affordable 4 barrel type TBI? I don't think Ill be junk yard crawling that part.

Never seen a 4 barrel stock TBI; the only ones I've commonly seen are the Holley Pro-Jection / Commander line. I've seen a couple other designs; if you're looking at non-Holley ones, watch out for designs that put the injectors below the throttle blades. These have horrible fuel distribution even by TBI standards.

[Cyclone03.1]

Re: Building a MS-III system

Thanks Matt,
Dropping the TB's with below the blade FI's all I got is Holley Pro jection TBI.
The Fast TBI's are below the blades.

So it seems at my power level Port injection is the best/only option.
That said this aaint gonna be done cheap (Remember I'm working on a Ford FE) or (hardware) easy.


Next question,I've noticed Edelbrock builds thier FE system with a Victor single plane,will a Performer RPM work as a Port injection manifold? I don't need the 7500rpm the short runner Victor will give.

I think the build it and start DATA logging will put me over on this....

[dieselgeek]

Re: Building a MS-III system

FYI, GoatRacer is using his megasquirt as a datalogger, and ignition control with EDIS wheel / crank trigger ignition. You could phase it in the way he did, and go EFI later on. I think his approach was wise - baby steps are a good idea with EFI.


I also think you should go straight with port injection. Re: manifold, I know that you don't need to worry about vacuum signal with more aggressive cams, with EFI, most guys run the single plane but I think at the 500-600hp level you might be just fine with whatever you choose...

Jay Brown might be a good guy to ask, he's a recent FE EFI convert,

-Scott

[Cyclone03.1]

Re: Building a MS-III system

Oh yea Jay says he will never have a street hot rod without FI now.
Hell who can blame him that huge Cammer idles at,what, 750rpm while he washes it! Plus it has no plenum at all!

[CDMBill]

Re: Building a MS-III system

The best manifold choice for the MPI will likely be based on which one comes with cast in bungs. The engine will not care about the dual plane vs. single plane situation at low throttle angles and you will make more power at the top end with the single plane given your c.i. and intended power output.

Dry flow manifold needs are simple compared to wet flow/ carb'd manifold characteristics and requirements. I don't think even Jay has tried multiple manifolds in an MPI setting and the massive comparison he did with traditional induction just won't apply.

I picked up significant power going from a smaller, lower, single plane manifold with an 1100 dominator to MPI EFI with a 2200 CFM throttle body on a much taller bigger cross section single plane. I did it in two phases, retaining the MSD distributor as a crank signaling and spark distribution device with the EMS Pro version of Megasquirt controlling the parl timing and fuel curve through the injectors.

One of my splurges during the build was a set of RCI injectors which have been key to getting good idle and part throttle characterisitcs as well as WOT despite the 96 lb/hr size. I couldn't have done it without the support on this board and specifically dieselgeek.

see results below.

http://www.youtube.com/watch?v=hURJ7cGE37w

[1windsor1]

Re: Building a MS-III system

back to the TB question, I've seen little information on the Wilson V-Force EFI TB with the 8 injectors (which are below the blades):


I am unsure of the variances with distibution on a V8 vs. rotary, but would be interested if anyone has heard anything on using either of these systems?...?...? ???

Sorry for the hijack.