Zach's Carbs to Microsquirt conversion thread, 7/20/18 update Options

[VaccaRabite]

I am retrofitting this thread to be my full on conversion thread, documenting my change from dual 40 Webers to MSII fuel injection.

Here is what I have so far, and what I need:
HAVE:

• MSIIv3.52 pre-built box.
• JimStim board for testing the MSII box
• V3 main Board wire harness.
  
  Will soon have:
  Injection system off a 1.8 914, from which I will use
• Throttle body
• Intake Runners
• Fuel Injectors (unless I find they don't flow enough fuel)
• Fuel Rail
• Fuel Pump (maybe - Joe may still need it for himself)
  
  Stuff I need:
• TPS or MAF sensor
• 4 wire O2 sensor
• Bung welded into exhaust
• Fuel Pump (Maybe, see above)
• Other stuff I don't know about yet

The engine is a 2056, particulars as follows:
Built on 1.7 heads.
Jake's 9530 cam (carb cam similar to Web 494)
Mallory optical ignition
ACCEL (UltraCoil) coil.
SSI exchangers for exhaust.

My goals for this project are to have near stock intake noise volume, better cold starting - especially in cooler weather, negate the bad effects or Ethanol on carbs, teach myself something about fuel injection.

Since I already have a pretty good ignition system, I am not going to go after crank fired ignition at this time, but I am not ruling that out for the future.

Before I begin the conversion, I am going to pull the engine and do a little refreshing and cleaning, including:

• Fixing an oil leak at the front of the engine
• cleaning under all tins (not that I exect to find much, but its a good thing to do)
• Fix some cooling tins issues that I have been living with for the past 2 years
• Open up holes in the tins I welded shut so I can replace heater tubing and heat my cabin!
• Check for battery acid leaks or rust appearance in the engine bay. Neutralize.

I am getting ready to start my conversion form carbs to EFI.

My goal is to use as much stock EQ as I can, but replace the sensors and such with modern, easy and cheaper to find stuff. Plus, since my car has a cam, the stock FI will not work.

My engine has 1.7 4 bolt heads.
1) are the 1.7 and 1.8 intake runners the same?
2) Is the intake runner inside diameter smaller then the 2.0 intake runner ID?
3) is the throttle body for the 1.8 smaller then the throttle body for the 2.0?

If the 1.8 TB is smaller then the 2.0, can the 2.0 TB be swapped in?

Are 1.8 injectors high or low impedance?

I am asking this as I will be able to get Joe's discarded 1.8 bits when he pulls his engine and starts going down the 2056 route.

Zach

[underthetire]

1.7 and 1.8 runners are not the same, 1.8 is slightly bigger, but won't match up to the 1.7 plenum. I have no 2.0 stuff to compare. The 1.8 runners will bolt up to your heads, that much I know. I always thought the 1.8 injectors were high, but several here have actually measured them, and found them low just like the rest.

[Krieger]

I pretty sure the stock throttle body bore for a 2.0 is 45mm.

[McMark]

Yup, none of the intake runners are the same or interchangeable with other plenums, although I have cut and reoriented intake runners. Specifically getting a set of 1.8 runners to match a 2.0 plenum.

All 914 injectors are low impedance. L-Jet uses a resistor pack to 'emulate' high impedance injectors. If you want to use stock injectors with MegaSquirt, you can get one of those resistor packs to do the same.

The 2.0 throttle body has a flat bottom, and the 1.7, 1.8 have taper/cone bottoms. You could look into the size of the bus 2.0 TB.

[Valy]

Since you want to use newer parts, L-Jet (1.8) is the way to go.
The air plumbing is not interchangeable. The J-tubes for 1.8 and 2.0 are the same diameter but different length. 1.7 are a bit smaller.

There are many cars fitted with L-Jet so you can rip parts from them.
Ont thing you should pay attention to is the Air flow sensor. Older L-jet (like the 914) have a potentiometer that has a linear relation to the air volume. Newer ones are not linear (to save manufacturing cost) ant the ECU compensates for linearity.

[VaccaRabite]

If the 1.8 and 2.0 intake runners are the same ID, are the throttle bodies also the same ID? Will I be starving my 2056 using the 1.8 throttle body?

Zach

[7275914911]

In the research I did it looked like the Bus plenum/TB worked/flowed better in a 2056 setup w/L-jet. IIRC that comes from discussions on Jakes site and Shoptalkforum...

[FourBlades]

If you are going to megasquirt, is there a plenum and set of sensors from a
common, modern car with a MAF, like a newer VW that would work?

Not using ITBs would allow you to use a lot of stuff from a more recent car.

John

[r_towle]

If the 1.8 and 2.0 intake runners are the same ID, are the throttle bodies also the same ID? Will I be starving my 2056 using the 1.8 throttle body?

Zach

the ljet system can run a 2.4 liter motor.
You obviously will need to tune the A/F map that you use, but the throttle body should work.
You will need a different throttle position sensor for the aftermarket EFI...the ljet one is an on/off switch for Idel and WOT only...

I believe the Ford focus or fiesta one fits and works, and it has the additional curcuits for you.

Rich

[edwin]

what carbs do you have now? why not use them and weld in injector bungs to the manifolds?

[VaccaRabite]

My primary goal is to kill the roar of running dual carbs. Get to a point where I don't need earplugs to go on a longer drive.

All the other benefits of EFI come second to this sime creature comfort. Otherwise I'd just keep the carbs.

Zach

[scotty b]

How about getting a TPI setup from a Chevy V8 and cutting it down to 4 cylinders (IMG:style_emoticons/default/rolleyes.gif) (IMG:style_emoticons/default/poke.gif) (IMG:style_emoticons/default/poke.gif) (IMG:style_emoticons/default/poke.gif) (IMG:style_emoticons/default/poke.gif)

[VaccaRabite]

How about getting a TPI setup from a Chevy V8 and cutting it down to 4 cylinders (IMG:style_emoticons/default/rolleyes.gif) (IMG:style_emoticons/default/poke.gif) (IMG:style_emoticons/default/poke.gif) (IMG:style_emoticons/default/poke.gif) (IMG:style_emoticons/default/poke.gif)

What's this? The pot calling the kettle black?
(IMG:style_emoticons/default/rolleyes.gif) (IMG:style_emoticons/default/poke.gif)(IMG:style_emoticons/default/laugh.gif)
Zach

[r_towle]

My primary goal is to kill the roar of running dual carbs. Get to a point where I don't need earplugs to go on a longer drive.

All the other benefits of EFI come second to this sime creature comfort. Otherwise I'd just keep the carbs.

Zach

On the cheap....
look at this setup.
then think about doing it with two turbo covers and a type1 aircleaner box...
The filter is easy to get over time.
The covers can be had at CB performance
Hoses can get gotten lots of places.

You would have a nice quiet setup for short money.

http://www.csp-shop.com/cgi-bin/cshop2/fro...sort=0&all=

Rich

[Dave_Darling]

You can probably build an air-box for a lot less than that. Heck, just build it around your current air cleaners! Dyna-mat it (and make a long-ish intake snorkel pointing somewhere back away from you) and it should absorb a lot of the sound.

--DD

[FourBlades]

I finished building this same thing recently in the quest for quiet plus better low
end response. I need to post some pictures...

I tried it with and without dynamat on the runners and stuff and found it made
little difference.

I welded up the carb tops and made a dual 3 inch / one 4 inch center plenum then
added a $25 cone air filter. Think I spent $60 total on it.

It feels a lot quieter but my sound meter does not show much improvement DB wise.

I'll post pictures when I get home.

John

[VaccaRabite]

There are a lot of other advantages of EFI, especially for cars that sit for long periods of time like mine. Both my 914 and the v8 in my jeep are going EFI though it would probably be easier just to do the carb.

Zach

[jsayre914]

cant you just redrill the intake flanges and bolt the whole shabang on there? Sound like it can handle your engine with a bit of adjustment.

(IMG:style_emoticons/default/idea.gif)

[dlee6204]

I finished building this same thing recently in the quest for quiet plus better low
end response. I need to post some pictures...

I tried it with and without dynamat on the runners and stuff and found it made
little difference.

I welded up the carb tops and made a dual 3 inch / one 4 inch center plenum then
added a $25 cone air filter. Think I spent $60 total on it.

It feels a lot quieter but my sound meter does not show much improvement DB wise.

I'll post pictures when I get home.

John

(IMG:style_emoticons/default/popcorn[1].gif) Please do!

[76-914]

Hey Zack, Will you be our "FI Poster Boy" when the next great "Carbs vs. FI" debate comes around, again? (IMG:style_emoticons/default/happy11.gif)