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TinCanFab
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Joined: April 04, 2006
Posts: 2743
Location: Waterford, California
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 Posted: Sat Dec 13, 2014 9:05 am Post subject: Megasquirt ITB cold start options |
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Hey guys, I am setting up my N/A 2 liter engine swap for my driver 60 single cab. I am new to custom EFI and trying to set up all my plumbing for a Microsquirt system (mostly because I want to mount it in the treasure chest, and it is not moisture proof). I know shoptalkforums has a lot of info, but I try to register and I keep getting invalid email errors.....
I am using CB IDF manifolds and welding injector bungs into them. Each runner is tapped 1/8" NPT ready for vacuum hookup that I will run to a small plenum and then to a GM MAP sensor.
What hardware are you guys running for cold start mode? I've read posts where some guys just feather the idle untll the engine warms up. Some people have stated they've done that in the past, but upgraded to fast idle valve, stepper motor, etc and liked the change. I want to do it right but I don't know where to go from here.....
Can I tie something into the MAP sensor plumbing? I planned on using -3 AN teflon hoses for a clean install. Are 1/8" NPT ports large enough to make a valve work properly? Can I program Microsquirt to do the same thing that a valve does? Megasquirt has so many options and has changed over the years and other threads have me confused as if hooking up external valves are more for the older EFI systems that didn't have the control the new EFI systems do. I really don't want too much clutter in the engine compartment if it's not necessary.
Opinions and pics would be awesome.
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clonebug
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Joined: January 29, 2005
Posts: 4027
Location: NW Washington
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| Posted: Sat Dec 13, 2014 9:13 am Post subject: |
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I have MS-2 with a single TB without a cold start idle valve. I can fire it up right now and it will idle without stalling just on the tune I have although it runs pretty slow.
I have spent very little time on the cold start due to the short window you have while the engine warms up.
It takes less than 30 seconds for me to have a throttle pedal free idle the way it is.
You with your ITB's will more than likely be able to tune it with some cold idle advance and a couple blips of the pedal before heading down the street.
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My Megasquirt Fuel Injection Turbo Buggy Build
Water/Alcohol Injection
Audi TT intercooler
Upgraded to MS3Pro-Evo
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http://www.shoptalkforums.com/viewtopic.php?f=3&t=127936 |
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DeathBySnuSnu
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Joined: August 25, 2012
Posts: 1183
Location: MS
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| Posted: Sat Dec 13, 2014 9:13 am Post subject: |
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Mine is not together yet.
So anything I say is conjecture.
I plan on using a Ford pwm idle air valve and plumbing it in like the map sensor but seperate.
I think the older stuff mentioned in the manual is not idle air but a fast idle switch.
With the micro I think it can do stepper motor idle air. |
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raul arrese
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Joined: July 23, 2006
Posts: 1329
Location: miami florida
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| Posted: Sat Dec 13, 2014 9:17 am Post subject: |
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Hello, I dnt run a stepper motor on my builds cause I don't run a.c. but it wont be a problem getting one to work , the itb's is the trouble , I would think you need to run bigger lines to all 4 throttle plates so the idle motor can control your idle speed better , im sure some one will chime in that has done it .. is it turbo or N.A ?? you would have to dump it back in or run a filter on the stepper if its N.A. ??? I do run a plenum on mine with a .040 jet feeding the map sensor , made a world of diffrenece .
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Northof49
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Joined: July 22, 2013
Posts: 1759
Location: Winnipeg, Manitoba, Canada
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| Posted: Sat Dec 13, 2014 9:36 am Post subject: |
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I would hesitate to tie it into the map sensor plumbing, for fear of getting an inaccurate reading. That said, feeding auxiliary air to all four runners is going to get messy. What are you running for throttle bodies?
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raul arrese
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Joined: July 23, 2006
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Location: miami florida
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| Posted: Sat Dec 13, 2014 9:40 am Post subject: |
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| Northof49 wrote: |
| I would hesitate to tie it into the map sensor plumbing, for fear of getting an inaccurate reading. That said, feeding auxiliary air to all four runners is going to get messy. What are you running for throttle bodies? |
That's what im saying , that's why I don't run it on my ITb's messy as hell
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" Bug Jam best motor and best paint "
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TinCanFab
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Joined: April 04, 2006
Posts: 2743
Location: Waterford, California
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| Posted: Sat Dec 13, 2014 9:59 am Post subject: |
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| Northof49 wrote: |
| What are you running for throttle bodies? |
At the moment, my IDF Webers with 32 ventiri's. The plan was to break in the new cam and lifters with the carbs since they are already setup with a good jetting starting point.
The engine is still out right now. This is the only time I'll have good access to the firewall for mounting stuff: MAP sensor, fuel pressure regulator, pressure and return line bulkheads, any hard lines, etc. The great thing about the trucks is the nice firewall panel behind the engine, instead of a gas tank shelf like a normal bus has.
Was thinking about these:
http://www.summitracing.com/parts/aei-13109/overview/
http://www.summitracing.com/parts/dfp-ps10075/overview/
I'm not concerned about all out performance, just a clean and simple install. I've got the plumbing handled, since I work for one of the largest West Coast performance hose and fitting shops. Most of my plumbing is XRP. For the rest of the stuff I'll need, I'm not against junk yard shopping. I already pulled some high impedance fuel injectors off a Ford truck. 
Here's my truck:
It's already cool as hell, but EFI would make it that much more different.
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Steve Arndt
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Joined: August 01, 2005
Posts: 1780
Location: Boise, Idaho
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| Posted: Sat Dec 13, 2014 10:49 am Post subject: |
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If you want to add idle air with ITBs then they need independent plumbing from your map sensor plumbing. Four taps, to a small plenum with the idle air solenoid/motor. Make the plumbing 3/8 ID for the idle air. For the map sensor 1/8 ID is standard.
I've ran ITBs for about 9 years now in extreme weather here. It only takes around 15 seconds to holding the pedal to get a decent idle. Pretty much the same issue as with carbs. My ECU does idle control with timing but that only "helps" it doesn't cure it.
For best results position your idle air bypass ports near where your injectors spray. The mixing is improved that way.
steve |
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clonebug
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Joined: January 29, 2005
Posts: 4027
Location: NW Washington
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| Posted: Sat Dec 13, 2014 10:50 am Post subject: |
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Most IAC's have a 1 inch hose feeding the intake so you will need a fair amount of air for each runner.
Pop a pm or email to Mario at thedubshop.net....he has ITB's on his 1600 and he will know if you need to mess with a cold start valve.
I don't think you will have a problem.
All you do is set up the cold idle to be a little rich and some advance until the temps climb and you can pretty well get in and go.
I start my buggy.....plug in my phone...turn on the music and latch my seat belt and it is ready to go.
It takes off smooth as silk.....I screwed it up once by trying to lean it out a bit at cold idle and ended up having to reload a saved tune...... 
Mario has a nice coolant sensor that bolts to the top of the heads at the cooling tin bolt that works really good for warmup.
_________________
| vwracerdave wrote: |
Take a good long look in the mirror and report back on what you see. |
| Paul.H wrote: |
| That one line on that chart is probably better info than you can get from this place in a month |
My Megasquirt Fuel Injection Turbo Buggy Build
Water/Alcohol Injection
Audi TT intercooler
Upgraded to MS3Pro-Evo
EcuMaster PMU16
ECUMaster ADU5 Digital Dash
http://www.shoptalkforums.com/viewtopic.php?f=3&t=127936 |
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raygreenwood
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Joined: November 24, 2008
Posts: 21512
Location: Oklahoma City
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| Posted: Sat Dec 13, 2014 11:37 am Post subject: |
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| Steve Arndt wrote: |
If you want to add idle air with ITBs then they need independent plumbing from your map sensor plumbing. Four taps, to a small plenum with the idle air solenoid/motor. Make the plumbing 3/8 ID for the idle air. For the map sensor 1/8 ID is standard.
I've ran ITBs for about 9 years now in extreme weather here. It only takes around 15 seconds to holding the pedal to get a decent idle. Pretty much the same issue as with carbs. My ECU does idle control with timing but that only "helps" it doesn't cure it.
For best results position your idle air bypass ports near where your injectors spray. The mixing is improved that way.
steve |
Steve is right on here.
Essentially...with ITB's...just like twin carbs....what ever you feed to one TB must be fed to the other. Set up a balance tube....just like carbs...running to both manifolds dumping in at the port. They need to be exact equal length from a small airbox (plenum) in the center that T's to the stepper.
You shoould not need much volume. Maybe 3/8"- 7/16" hose. Ray |
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Northof49
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Joined: July 22, 2013
Posts: 1759
Location: Winnipeg, Manitoba, Canada
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| Posted: Sat Dec 13, 2014 11:39 am Post subject: |
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Can you ditch the twin throttle bodies and instead plumb it all into a central plenum, use an existing automotive tb with iac. I don't see the advantage of twin throttle bodies if they are not delivering the fuel.
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mcmscott
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Joined: March 12, 2010
Posts: 4856
Location: sanger ca
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| Posted: Sat Dec 13, 2014 12:01 pm Post subject: |
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Gm iac feeding two throttle bodies, clean enough?
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67 T-1
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TinCanFab
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Joined: April 04, 2006
Posts: 2743
Location: Waterford, California
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| Posted: Sat Dec 13, 2014 12:52 pm Post subject: |
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| Northof49 wrote: |
| Can you ditch the twin throttle bodies and instead plumb it all into a central plenum, use an existing automotive tb with iac. I don't see the advantage of twin throttle bodies if they are not delivering the fuel. |
I totally agree, but twin throttle bodies gives me a few advantages: Less fab work, less cost, I like the look, they fit great underneath the extremely short engine compartment, no custom air filter setup needed, they already flow well and are match ported to my big valve heads
The top of the fan shroud barely fits under the bed sheet metal. It actually sits between two crossmembers. The stock 40 hp carb and filter setup barely even fit.
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Check out my truck brought back from the dead... http://www.thesamba.com/vw/forum/viewtopic.php?t=420762&highlight=sprayed+blood
They're never really ever finished 58 rag build...
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TinCanFab
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Joined: April 04, 2006
Posts: 2743
Location: Waterford, California
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modok
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Joined: October 30, 2009
Posts: 26781
Location: Colorado Springs
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| Posted: Sat Dec 13, 2014 1:02 pm Post subject: |
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HECK NO, keep the IR throttles! it will idle better cold and hot.
You'll get a better MAP signal without a plenum; use the feature where you read map at a particular crank angle.
Since there is no cam sensor probably tie 2 and 4 for the map sensor then read at tdc-30 after.
NEVER use a plenum as it will have horrible throttle response if there is any lag in the map signal.
If you have other things to connect such as fuel pressure regulator, blow off valve, vac advance, fast idle, these need to be on a separate line than the map sensor.
A fast idle solenoid would be handy but it is probably the least important thing.
I'd go simple on/off rather than a stepper or pulsewidth solenoid!! |
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mcmscott
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Location: sanger ca
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| Posted: Sat Dec 13, 2014 1:29 pm Post subject: |
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| roachdub58 wrote: |
| mcmscott wrote: |
Gm iac feeding two throttle bodies, clean enough? |
Very nice! Can you give me some details? All I see are the injectors |
When I built this I didn't want to use the f/a hoses but the customer insisted.
It is a 2110 with a 120, and one of the last set of pancheato heads. CB ecu, crank fired with idle controls, and harness built by me. This thing pulls like a tractor.
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There are no stupid questions, only stupid people,
68 Ghia
67 T-1
65 Notch
02 Mexican beetle
74 Thing
15 Long travel rail
07 Nomad
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Northof49
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Joined: July 22, 2013
Posts: 1759
Location: Winnipeg, Manitoba, Canada
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| Posted: Sat Dec 13, 2014 1:54 pm Post subject: |
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| modok wrote: |
HECK NO, keep the IR throttles! it will idle better cold and hot.
You'll get a better MAP signal without a plenum; use the feature where you read map at a particular crank angle.
Since there is no cam sensor probably tie 2 and 4 for the map sensor then read at tdc-30 after.
NEVER use a plenum as it will have horrible throttle response if there is any lag in the map signal.
If you have other things to connect such as fuel pressure regulator, blow off valve, vac advance, fast idle, these need to be on a separate line than the map sensor.
A fast idle solenoid would be handy but it is probably the least important thing.
I'd go simple on/off rather than a stepper or pulsewidth solenoid!! |
I respectfully disagree. Unless you have some cavernous plenum, you will have excellent throttle response with a plenum that connects the four intake ports. Look at the various factory vw fuel injection systems. Single TB and a plenum connecting both sides.
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modok
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Joined: October 30, 2009
Posts: 26781
Location: Colorado Springs
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| Posted: Sat Dec 13, 2014 2:18 pm Post subject: |
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| Northof49 wrote: |
| I don't see the advantage of twin throttle bodies if they are not delivering the fuel. |
The difference is vaccum at valve overlap, as in, there is none. Oe apps keep overlap under 20 degrees and in that case it can work well.
| roachdub58 wrote: |
I am using CB IDF manifolds and welding injector bungs into them. Each runner is tapped 1/8" NPT ready for vacuum hookup that I will run to a small plenum and then to a GM MAP sensor.
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BTW this was the plenum I was referring to
Last edited by modok on Sat Dec 13, 2014 2:23 pm; edited 1 time in total |
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TinCanFab
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modok
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Location: Colorado Springs
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| Posted: Sat Dec 13, 2014 2:34 pm Post subject: |
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If you mean a plenum for the map sensor yes. All you need is to connect it with a hose.
There is some natural tendency for guys to imagine this is needed but..........it isn't. It could only make it run worse 
It might be a good idea for the fast idle solenoid! But not for the map sensor |
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