quote:Originally posted by comp2:
The Innovative motorsports LM-2:
http://www.innovatemotorsports.com/products/lm2.php
I have an earlier version, the LM-1 I have used on many vehicles including my tractor. A few cars I actually added a O2 gauge and a vacuum gauge.
@ Comp2. Thanks for the info.
@4v & Proud.
There are several inaccuracies in Dan's statement in that post.
The secondary meter plate is interchangeable but that really doesn't matter.
What you do is you remove the pressed in brass bushings/jets then thread them for allen set screws which in turn are drilled in a jet size. It's quite easy.
There is a curb idle screw to set rpm with.
The annular discharge venturis are only on the primaries. Secondaries are standard venturis.
The primary metering body has an "idle fuel jet" pressed into it and is located under the main fuel jet.
The idle set screws ARE hidden under hardened brass caps that need to be removed and ARE allen sockets adjusted with an allen key wrench.
They are set at 3/4 turns BUT only control the volume of atomized fuel. So that does not richen the idle mixture, it only will give more atomized fuel (mixed with a pre-set a/f ratio) and thus only raises or lowers the idle rpm.
To richen the mixture at idle, you need to "change the jets" which is EXACTLY the concept done in Weber IDA's but there is no provision for them to be changed here in these carbs because they were locked for emissions reasons on the original application, YOU have to modify the carb to make them changeable.
It is originally supplied with two stage power valves yes, but you change them just like in any other Holley carb.
Close tolerance jets? Yes but they change out to any Holley jet you want.
2x4 Holley idle. Here it doesn't matter. There is a primary carb and a secondary carb. Not two primary carbs.
The engine idles on the primaries in the primary carb. It idles clean. Too clean and that's the problem.
The typical Holley provision of a minimal idle circuit to circulate fuel through the bowls is there. Yes. That's all they do.
The value of a 2x4 Holley set up is that it is completely progressive unlike a 2x4 Carter, AFB or Edelbrock system since that set up has mechanical secondaries.
The car runs on only two barrels of the Primary carb up to about 3200rpm when the secondaries primaries begin to open.
Those are all in by about 6,000 rpm.
The secondaries are vacuum operated and open on engine demand.
The intake manifold is designed to be a 180 intake and has characteristics of both a 180 manifold AND a tunnel ram at WOT.
Because the engine is running most of the time on the primaries of a single 600 cfm vacuum secondary carb, you are getting about 20 mpg out of this setup as opposed to using a single 780cfm Holley which would give you about 12mpg.
These set ups will dyno at a solid 25 to 30 hp over the single holley as well.
You can run it with two 465cfm carbs but I find that the 600's are smoother all along and make more power on top.
Call these 595's if you want to but that is just because Ford always rated the carbs at a different vacuum drop than Holley.
I suppose "you" could re-phrase what I am trying to do here as arrive at a good idle mixture by reading the exhaust temp of the headers rather than measure a/f ratio through the exhaust with an exhaust analyser, which I do not have.
In a way it isn't that difficult to do. Just keep making the idle richer until the headers stop glowing?
Pictures are in the link I posted in a previous post.
Here is the link again.
http://www.ifsja.org/forums/vb...wthread.php?t=165441
Nothing like short answers, huh?
