IR Manifold with MAP & IAC

For discussing injector selection,manifold modifications, throttle bodies, fuel supply system design and construction, and FIdle valves and IACs.
Forum rules
Read the manual to see if your question is answered there before posting. Many users will not reply if the answer is already available in the manual.

If your question is about troubleshooting, configuration, or tuning, you MUST include your processor type (MS-I or MS-II) and code version in your post. If your question is about PCB assembly or modifications, you must also include the main board version number (1.01, 2.2 or 3.0).

If you have questions about MS1/Extra or MS2/Extra code configuration or tuning, please post them at www.msextra.com Such questions posted here will be moved to: a temporary MSextra sub-forum, where they will be removed after 7 days

The full forum rules are here: Forum Rules, be sure to read them all regularly.
Post Reply
pcf_mark
Helpful Squirter
Posts: 56
Joined: Thu Mar 25, 2010 10:37 am

IR Manifold with MAP & IAC

Post by pcf_mark »

Newbie to the forum and I have been reading everything I can. I am trying to plan my project but before I get too deep I want to see if I am on the right path. I have been reading but is bewildering the amount this product and site have grown in a short amount of time!

Engine is a big block Chevy displacing 7.4L/454 cu inch with large ported cylinder heads, solid roller camshaft with about 14" idle vacuum making about 550 HP at 6,500 rpm.

My current plan based on what I have read is:

1) MS-II to control fuel and spark
2) Enderle Indivdidual runner manifold with 8 throttle blades and runners with velocity stacks and air cleaners on top
3) Ford EDIS like solution used in this link http://www.DIYAutoTune.com/catalog/mega ... -p-65.html because I can get the parts cheap and it looks rock solid
4) I want some type of idle control for better cold start running and idle control when it gets hot
5) Innovate wide band O2 (already using to tune carb)

Question 1: Do I need to build a vacuum log from each individual runner to a central location and feed that signal to the MAP for MS-II to work correct?
Question 2: If I build a block like the Jeep version that uses a GM stepper IAC will this give me good start and idle stabilization when combined with the cold start enrichment?
Question 2A: If I build a vacuum log to signal the MAP can I just plumb the IAC into this circuit? If so how big does the vacuum line need to be? 1/4"?
Question 3: When using a wasted spark dual coil set up where do you get a tach signal?
Bernard Fife
Master Squirter
Posts: 475
Joined: Thu Oct 29, 2009 12:54 pm

Re: IR Manifold with MAP & IAC

Post by Bernard Fife »

pcf_mark,

1. You will probably need to link the cylinders together to get a stable MAP signal, and tuning will likely work much better that way.

2. This will work, but only if plumbed to all cylinders (you can likely use the same plumbing as for #1, if there aren't significant restrictions (i.e., the line inside sizes are big enough, etc.). This is going to be a matter of experimentation, but as a guide the IAC passages are about 3/8 to 1/2 of an inch or so. However you would be dividing that by 8 cylinders, so the lines could be much smaller (3/16" or so, though there are wall effect restrictions...). If I was doing this, I would start with 1/4 inch lines.

3. See this: http://www.megamanual.com/ms2/EDIS.htm#tach

Lance.
"Never wrestle with pigs. You both get dirty and the pig likes it.” - George Bernard Shaw
pcf_mark
Helpful Squirter
Posts: 56
Joined: Thu Mar 25, 2010 10:37 am

Re: IR Manifold with MAP & IAC

Post by pcf_mark »

Thanks Lance. I am going to build the vacuum log to help with tuning and IAC all in one function. You hit it with the vacuum signal split across 8 runners - I'll try 1/4" to meet both functions and see how it works out. I may sketch it out and post for feedback before I drill too many holes. I think I'll put the vac. port above the injector so it does not draw in any fuel vapor if possible.

Next up - finding 45# - 50# injectors without going broke!
Post Reply