[DeTomaso] efi horse power gain

Ken Green kenn_green at yahoo.com
Thu Aug 13 00:28:17 EDT 2009


   Regarding direct injection, I think someone should ask Edelbrock about aftermarket upgrades.  They make a bunch of heads and EFI systems.
 
    Regarding EFI versus carburation, I can see one an advantage to a carb being smaller LSA to get more efficiency at high RPM because EFI likes a larger LSA.  Since higher RPM with everything else the same means higher HP, an 8,000 RPM carburated engine will make more HP than a 7,000 RPM engine EFI engine.
 
But EFI has the following advantages:
 
1)  maybe .5 higher CR because fuel is controlled better
2)  a dry manifold allows design freedom
3)  compensates for altitude
4)  fuel not splashing around inside a float bowl
5)  you can thumb your nose at the tree huggers.
 
    I think that if an engine is built for carburation, there won't be nearly as much advantage in switching to an EFI intake.  But if it's built for EFI and takes advantage of all the potential benefits, there is a advantage to EFI.  
 
Ken

--- On Mon, 8/10/09, boyd casey <boyd411 at gmail.com> wrote:


From: boyd casey <boyd411 at gmail.com>
Subject: Re: [DeTomaso] efi horse power gain
To: "j g" <notstock at yahoo.com>
Cc: "Ken Green" <kenn_green at yahoo.com>, wkooiman at earthlink.net, "Kirby Schrader" <kirby.schrader at gmail.com>, "De Tomaso List" <detomaso at realbig.com>
Date: Monday, August 10, 2009, 5:54 PM


Gary at TWM said that he uses weber carb manifolds and he specifically said
"from Hall Pantera" I asked him if a manifold from another source would be
okay and he said he wouldn't know until he saw it . I didn't know there was
a difference. He also said it took a substantial amount of machine shop work
to modify the manifold  for the Cleveland and that's why the Cleveland set
up was more money then the Windsor. Anyway Hall has several Weber manifolds
currently  at the machine shop ( I assume being cleaned up after being cast)
their price is $650. They said they would have some ready in two weeks.
As far as the "inside fuel rails"   I should have specified that the reason
I was given for the fuel rails to be "inside" the stacks was for the optimal
placement of the injectors and their being pointed in the correct direction
in  reference to the intake valve location.
On another point if I remember correctly the Fast XFI has the ability to
utilize  4 or 5 MAP sensors. As well as numerous optional sensors and
controls. I had made earlier mention of the benefit of a "fast " system
meaning a fast processor not the brand name "FAST."
The "FAST XFI" has been designed with software that has more optional
sensors and controls then any other sytem I am aware off. But just like
trying to multi task with an old Pentium III you will over load your
processor if you push it to hard. You need a system where the hardware can
keep up with the software. According to what I have read the new FAST system
has the ability to handle all the potential tasks possible to assign to it
through the software interface with processor power to spare. The way I
understand it , the faser the engine is running( the higher the RPM's) the
faster the other  engine parameters are changing and the faster the system
needs to be able to respond . This may be nothing more then a sales pitch
but it made some sense to me.
I have two MSD 6al units and two blaster coils and the automatic coil
selector. t Iallows you to attach the two coils to a common distributor wire
so you can switch from one MSD set up to the other in the event of a failure
of one of the MSD modules. The only things I am missing is the selector
switch , the correct  distributor and the tach adapter. I have an MSD small
cap distributor and after a crummy mechanic told me my MSD6al was bad I
bought a replacement MSD 6al for close to $300.00 ( if memory servers me
correctly) . It turns out the MSD was not bad so now having two  MSD 6AL's
and knowing MSD's reputation for dying at inopportune moments I decided to
go with the dual switchable ignition set up. It was only after buying the
extra coil and the MSD automatic coil selector  that I realized I wasn't
able to use my distributor with the switchable set up ( this may not be
factualy correc , but the sales rep at MSD seemed to think I needed to buy a
different one! ( no surprise there!). I had just spent a few hundred dollars
on the MSD small cap distributor in addition to the auto coil selector and
the extra Blaster II coil and I didn't   feel like springing for another
distributor (or anything else with the name MSD on it!) everything was now
working and my Pantera  and my "To Do " list was already longer then my
budget!  So now I keep the spare MSD6AL and the spare coil in my in car tool
kit ( along with the unused automatic coil selector) .
So in case of a coil failure or an MSD 6AL failure I can still make it home.
It is certainly not as easy as flipping a switch but it beats walking or
calling a tow truck. One of these day ( If I don't switch to a coil on plug
with a crank trigger) I will get the rest of the correct parts to utilize
the MSD switch set up. I still have to decide if I am going to bite the
bullet for the efi and if my ignition setup is compatible with whichever ECU
I wind up with (if I wind up with an EFI.) I know that many people go with
EFI for a number of reasons besides performance HP Gains  (which seems to be
a subject of some contention ) they have reasons like reliability, easier
starts, better fuel economy, but if all you were only considering  HP what
is the consensus on the difference in horse power between a weber carb set
up  and a weber "style" Stack EFI setup ? I know it's hard to make a
statement based on a "style "of EFI because there are so many variables. But
to simplify matters (if that is possible) Hypothetically if you had Weber
IDA's with the correct venturis and tuned to perfection  and you had  an
equally well tuned Weber style EFI (like a TWM) do you think there would
still be a HP difference between the two? Also The Weber IDF is supposed to
be more "Street able" than the IDA besides the absence of a choke on the IDA
what are the other differences?Does an IDF have two venturis to the IDA's 3?
The Lamborghini Miura had 6 Weber IDL's I believe this carb had 4 venturis (
as opposed to three on the IDA) Is this information correct?  Are the 4
venturis on the IDL the reason they had a reputation for being so difficult
to tune? (I suppose a 12 cylinder with 6 webers and 4 venturis each as
opposed to 4 webers  with 3 venturis each didn't help to make it any easier)
Are IDL's still available? Do people use them on Cleveland's or other push
rod ,lower reving engines (lower then 12 cylinder Itailian  DOHC , 48 valve
exotic engines) I know these are allot of questions and I want to say how
much I appreciate the feed back and opinions of those of you who have taken
the time to contribute your ideas or opinions. The only way Novices progress
to the next stage is by learning and it makes much more sense (to me) to
learn from the experience of those that have travelled down this road before
rather then try to go through my own trials of hit or miss experimentation.
I don't have the financial resources to try a plethora of different carbs ,
manifolds, heads  etc. With EFI there is the added choice of style (tunnel
ram, weber stack style , 4 barrel throttle body, then the ECU, then choosing
between batch or sequential injection) You could spend years and a small
fortune if you relied on trial and error.
II know there are allot of members of this list that have forgotten more
then I will ever know about this subject and automotive engineering in
general . I learned early in life that it was not necessary to become an
expert in every subject you were involved in to achieve success in it. It
was necessary to be able to recognize the talent and expertise in others(
and to listen to them). So by identifying the people who were masters of the
subject you were interested in you could actually achieves more then you
could by attempting to master them all yourself.  I really appreciate the
efforts and patience of those of you who have taken the time to share your
knowledge, experience and secrets.  I'm sure to some they must at times seem
like redundant and or stupid questions. I have  always believed not asking
the question was the stupid thing. So thanks to all of you for your help and
camaraderie, it is truly appreciated.

Boyd
PS. I forgot to mention Thanks for not  'grinding me into the asphalt' for
occasionaly ( or more often) making a mistake or misstating facts. I
sometimes forget to mention that I am esposing an opinion or repeating
something I have read or heard and I am looking for confirmation  or denial
of the information so I know if I'm on the right track and I am  not
pretending to be an "Expert" or :know it all" If I have an idea of my own or
a hypothesis it's a good way to find out if I have understood the concept or
theroy of what ever subject we happen to be discussing.  I don't just want
to know what works, I want to know why it works or why it is better. If I
never put forth one of my own ideas I will never know if I am still as
clueless as I was when I started. If I am repeating something that I have
read or that was told to me by a vendor or a self proclaimed expert I want
to know if I have been sold a "bill of goods" or if the information is "on
the money"
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