[DeTomaso] Vacuum source on IR manifolds
Ed Mendez
edducati at mac.com
Sat May 26 01:58:35 EDT 2018
Here is a picture of mine. I have a line going to each runner then all to one small common block for brakes and MAP. I am running indexed speed density mode on my FAST XFI 2.0, I have have two MAP sensors one for manifold absolute pressure and one for barometric pressure, it takes a reading form both and adjusts for elevation. I am not running an IAC because as the article states below you would have to have two lines plumbed to each port.
Here is a section from a forum when I was doing research.
======
Perhaps add a vacuum reservoir to act as a "shock absorber" and give a more even MAP reading, go speed density for the tune. For the map signal, you need a vacuum feed from each port, tied into a common "metering block" and then to the map sensor. You cannot take a vacuum signal from a single port, needs to be from all of them. You also don't want to share that vacuum source with the iac or anything else. They make nice remote mount iac's, but again they need their own separate lines to each port. Think of something like a port-injected nitrous system with the stainless hard lines going to each port in the intake and tieing together in a billet aluminum block. On mine, there were two lines to each port hidden underneath the manifold just like a hidden nitrous kit. Then after the block where they came together we put two bulkhead fittings in the rear of the intake (one for iac and one for map) so there was a connection from the top of the intake. Totally hidden, very clean looking and works perfect.
Using a SMALL plenum for the vacuum is a requirement - not an option - otherwise you have nowhere to take the MAP reading. There is very very little vacuum signal from these types of intakes. I would advise you to use the plenum for ONLY the MAP signal. I was trying to remember - but think I could only get 4 or 5 inches of vacuum reading at my plenum. The pulse signal is soooooo weak without having a large common plenum of the dual plane / single plane intake....
To help tune the idle circuit -- in the efi maps -- you make smaller incremental
grids in the idle vacuum and rpm map.... then you can tune out the lumps easier with finer control... and also using the idle spark add or subtract.
IMHO, a guy that's GOOD with these ECU EFI systems can make anything/combo run like a swiss watch.
I just finished helping a buddy with his 8 stack (Imagine Injection) install - using Fast XFI on his 454 big block. It started the FIRST TIME - in about 3 rev's - once I tweaked the distributor timing to actually match the ECU - it purred... and there's nothing like the sound of air being gulped one cylinder at a time.
======
In reading this however, I have the single lines to each port “the black lines in the picture” I have them going to a tiny plenum and have my brakes and MAP going to it and have no issues at all.
I suppose this depends oil if you have a huge cam or not, in that case Don Byars makes this bitchin vacuum pump setup the for brakes that fits underneath and in front of the radiator.
Ed
> On May 25, 2018, at 22:28, Robert Stroj <npdrs at maui.net <mailto:npdrs at maui.net>> wrote:
>
> Hi, I am in process of installing IR fuel injection, using Fast Xfi 2.0.
> Would like to hear from someone running similar setup how did you plumb vacuum source manifold.
> Was planning to use just one common manifold (connected to all 8 runners) and then connect servo brake tube, MAP sensor and vacuum regulated fuel pressure regulator all to that manifold.
> Would that work fine or will signal from MAP get wrong readings when breaking (booster maybe reducing vacuum)?
> If this is fine, is there some rule on how to size this manifold?
>
> Thanks, Robert
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>
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-------------- next part --------------
Here is a picture of mine. I have a line going to each runner then all
to one small common block for brakes and MAP. I am running indexed
speed density mode on my FAST XFI 2.0, I have have two MAP sensors one
for manifold absolute pressure and one for barometric pressure, it
takes a reading form both and adjusts for elevation. I am not running
an IAC because as the article states below you would have to have two
lines plumbed to each port.
Here is a section from a forum when I was doing research.
======
Perhaps add a vacuum reservoir to act as a "shock absorber" and give a
more even MAP reading, go speed density for the tune. For the map
signal, you need a vacuum feed from each port, tied into a common
"metering block" and then to the map sensor. You cannot take a vacuum
signal from a single port, needs to be from all of them. You also don't
want to share that vacuum source with the iac or anything else. They
make nice remote mount iac's, but again they need their own separate
lines to each port. Think of something like a port-injected nitrous
system with the stainless hard lines going to each port in the intake
and tieing together in a billet aluminum block. On mine, there were two
lines to each port hidden underneath the manifold just like a hidden
nitrous kit. Then after the block where they came together we put two
bulkhead fittings in the rear of the intake (one for iac and one for
map) so there was a connection from the top of the intake. Totally
hidden, very clean looking and works perfect.
Using a SMALL plenum for the vacuum is a requirement - not an option -
otherwise you have nowhere to take the MAP reading. There is very very
little vacuum signal from these types of intakes. I would advise you to
use the plenum for ONLY the MAP signal. I was trying to remember - but
think I could only get 4 or 5 inches of vacuum reading at my plenum.
The pulse signal is soooooo weak without having a large common plenum
of the dual plane / single plane intake....
To help tune the idle circuit -- in the efi maps -- you make smaller
incremental
grids in the idle vacuum and rpm map.... then you can tune out the
lumps easier with finer control... and also using the idle spark add or
subtract.
IMHO, a guy that's GOOD with these ECU EFI systems can make
anything/combo run like a swiss watch.
I just finished helping a buddy with his 8 stack (Imagine Injection)
install - using Fast XFI on his 454 big block. It started the FIRST
TIME - in about 3 rev's - once I tweaked the distributor timing to
actually match the ECU - it purred... and there's nothing like the
sound of air being gulped one cylinder at a time.
======
In reading this however, I have the single lines to each port "the
black lines in the picture" I have them going to a tiny plenum and have
my brakes and MAP going to it and have no issues at all.
I suppose this depends oil if you have a huge cam or not, in that case
Don Byars makes this bitchin vacuum pump setup the for brakes that fits
underneath and in front of the radiator.
Ed [cid:BB9234B6-5F88-4571-A521-3C6B9693C26D]
On May 25, 2018, at 22:28, Robert Stroj <[1]npdrs at maui.net> wrote:
Hi, I am in process of installing IR fuel injection, using Fast Xfi
2.0.
Would like to hear from someone running similar setup how did you plumb
vacuum source manifold.
Was planning to use just one common manifold (connected to all 8
runners) and then connect servo brake tube, MAP sensor and vacuum
regulated fuel pressure regulator all to that manifold.
Would that work fine or will signal from MAP get wrong readings when
breaking (booster maybe reducing vacuum)?
If this is fine, is there some rule on how to size this manifold?
Thanks, Robert
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