(dramatic music)
- This manifold right here is part of what comes
with a complete Holley HP EFI package that you can buy.
It's right around 3,000 bucks for a small block
Chevy whether you've got Vortec or a TPI type
cylinder head pattern or the classic pattern.
And it comes with everything you need
as far as wiring, sensors, computer, manifold,
rails, pre-bent lines, the whole shebang.
The only thing it doesn't come with
is the fuel pump, and the injectors themselves
because those things need to be sized towards
how much horsepower you're planning on making,
so you'll want to buy those separately,
and just FYI we're running 38 pound-per-hour
injectors on this deal at 45 PSI.
We tried to run a carburetor on this manifold
that comes with the Holley kit,
and basically it was really bad,
which brings up a really good point,
which is that multi-point EFI is only flowing
dry air through the intake manifold.
There's no fuel suspended in it,
and that opens up the intake manifold design,
and it's really one of the major benefits
that we're not realizing here.
That's why OE manifolds have big, long runners in them
that fuel would never make its way through,
but dry air will.
So we're not realizing those advantages here,
but it is a really solid A/B test
on how these things are going to perform
on the same manifold, and here's what we're using.
On the engine and the dyno cell,
we've got a Victor Jr. that's been modified
with bungs for injectors.
Edelbrock now sells this Victor E manifold,
which is very similar,
but comes pre set-up for injectors,
and they've got rails for it also.
And I noticed Trick Flow has a new manifold
for small block Fords that you can also buy rails for.
And if you've got that situation
you can also buy a Holley kit that
does not include the hardware,
but that does have everything that you need
to put a throttle body and the EFI itself on your engine,
just not the hard parts.
So there's kind of what we've got going on here,
before we move on here,
to the old organized fuel leaks.
The dinosaur implements known as carburetors.
So, the 4-barrel throttle body
that we're running on the EFI
is advertised at 1,000 CFM.
So there's two things that I wanted to do
in order to compare that to carburetors.
One of which is run a 750 CFM carburetor,
this one being a Holley XP,
because this is really typical as to what a guy
would run on the street, on that 383, in the real world.
But I also wanted to run a carburetor that
more accurately was sized to the throttle body
we used with the EFI so this quick-fuel technology
4150 series carburetor flows an advertised 1,050 CFM.
So that's going to give us a real accurate A/B test
changing nothing but the air door,
and the carburetor,
and the fuel pump.
Let's go find out right now what we're going to do
with this 750 before we move on to the 1,050.
We have the dyno measuring the manifold
air temperature which is going to be really interesting.
I want to see if it's colder-- - We've got a temperature
probe right here.
And kind of what we're looking for there
is the difference in the vaporization of the fuel
with the carburetor to see if it actually lowers
the air inlet temperature significantly.
- [Steve] Any predictions here Freiburger?
- I don't think the 750 is going to make
more power than the EFI.
- [Steve] You don't?
- [Freiburger] No.
- [Steve] You want to re-think that?
(laughter)
- I love knowing and watching - I know.
- you guys banter. - I hate it
when you know.
Brule already pre-tuned all this stuff
so that we would be set and be able to do this quickly.
- So this is really streamline, right?
- Yeah look how much lower that is in the carburetor,
it's an advantage for hood clearance.
- And notice there's not booster venturi inside there
to obstruct airflow.
- Yeah, that's 1,000 CFM
- [Steve] Yeah.
- This is 750 with a booster and junk in the way.
- But basically we just took this off and put that on.
- Yep.
- [Steve] And changed nothing else but the fuel pressure.
- Nothing else, even the ignition timing is still
being handled by the Holley EFI so the only
change is the carburetor and the fuel pressure.
Okay, now we have the Holley 750 double-pumper
on there, 4-barrel carburetor.
And we're going to see what happens.
I bet it probably makes two or three numbers
at peak and the rest is the same.
That's my guess.
- Oh, you think it's going to make more power?
With the carbs way smaller than the throttle body though.
- Barely.
- [Freiburger] Yeah.
- It is a lot smaller.
- Yeah, I think it's going to make less.
- But does the engine even need the CFM that
the throttle body offers?
We'll find out.
Once again we're going to do three pulls.
(dramatic music)
(engine revs loudly)