Carb spacers: Are they worth it?

[Slide]

I have been looking at the carb spacers on the wall in the "performance" section of the local parts counter. Are these things worth a durn?

If so, which is better, one big open hole, or 4 smaller ones? I'm sure each type is has it's advantage in different situations, so what's the deal?

[Model A Vette]

I think it is better to use one with holes that match the carb to the manifold. That prevents the air/fuel mixture from getting screwed up.
As far as using a spacer: I think the theory is that a higher carb moves the power rpm range a little higher.
Along the same lines: the newer versions of Edelbrock street manifolds have a notch cut between the left and right sides of the manifold divider. I think that is supposed to give you more power overall.

[Smokin Joe]

You just said it. Each type has it's advantages.
Both types will cool the carb which is an advantage in itself.

[Flat Ernie]

The 4-hole type will provide a slightly stronger signal to your carb - helpful on a single-plane for off-idle tip in tuning.

If you've got a dual plane, an open spacer will move the power band up ever so slightly.

Each has its place...

http://www.jalopyjournal.com/ubbthreads/images/graemlins/cool.gif

[bradberry00]

My motor guy told me that every intake should come with one....

in my f-100 i have a edelbrock aluminum intake and matching 4 barrel...

the motor started like shit when it got warm...

so i threw a spacer on.....runs and starts way better....easy cheap fix...

as for performance....maybe? probably not much HP increase...but they are cheap so throw one on!

[Slide]

[ QUOTE ]
The 4-hole type will provide a slightly stronger signal to your carb - helpful on a single-plane for off-idle tip in tuning.

If you've got a dual plane, an open spacer will move the power band up ever so slightly.

Each has its place...

http://www.jalopyjournal.com/ubbthreads/images/graemlins/cool.gif

[/ QUOTE ]

Interesting. Some things I was reading would suggest that the 4-holer would be better for the dual-plane, and the open one for single-plane. But what I was reading wasn't clear anyway. What you said makes more sense in my head. http://www.jalopyjournal.com/ubbthreads/images/graemlins/crazy.gif

[Scotch]

I've tested quite a few of these and have never lost power. It's always beena matter of how much is gained, rather than if any gain can be found. They do work.

My favorite designs are those sold by HVH and Wilson Manifolds. They are a tapered 4-hole-to-open design and by funneling up to the throttle plates, we've seen two things: A better vacuum signal at idle (according to the designers, this is due to the funnel-type design being able to provide a crisper signal to the throttle plates), and better mid-range power (due to a larger plenum area).

Different height spacer plates offer different levels of benefit, but the best results have been from the 2-inch plates regardless of intake design.

Look at what HVH and Wison Manifolds offer. I'd get 1.5 and 2-inch plates, and test both. Run what works best and sell or save the other.

Scotch!~

[Bass]

[ QUOTE ]
we've seen two things: A better vacuum signal at idle...and better mid-range power.

[/ QUOTE ]

Scotch, so are you saying these two things hold true no matter what manifold they're bolted to in most cases? Single plane or dual plane makes no real difference?

Now I'm curious...In your opinion, how would a pair of spacers act when bolted to a dual quad manifold? Would they move power up the rev range, or just add a little extra where it already is?

Thanks!

-Brian

[Slide]

[ QUOTE ]
My favorite designs are those sold by HVH and Wilson Manifolds. They are a tapered 4-hole-to-open design and by funneling up to the throttle plates, we've seen two things: A better vacuum signal at idle (according to the designers, this is due to the funnel-type design being able to provide a crisper signal to the throttle plates), and better mid-range power (due to a larger plenum area).

...but the best results have been from the 2-inch plates regardless of intake design.

Look at what HVH and Wison Manifolds offer.
Scotch!~

[/ QUOTE ]

I haven't seen these, but that shape does make sense. I have the space for a 2" (I have that much spacing the air cleaner up now to clear the HEI.) Them WIlson ones are pricey, tho. WOW!

So do these things do anything for/against fuel mileage?

[Jey]

i like the carb spacer because i was having a problem with my intake overheading my bowls and boiling the gas in the carb. so i threw on a 1/2" spacer to get it up off the heat.

seems to work pretty nice. but had to cut a hole in the brace for my cowl to cear my air cleaner http://www.jalopyjournal.com/ubbthreads/images/graemlins/frown.gif

[Yo Baby]

The four hole 2" spacer picks up the low end and low mid range power and the open 2" picks up power from about 5500 on. I tried both on an open plenum intake and the tapered four hole picked uyp about 2.5 hundredths of a second in the 1/4 shifting a 427 at about 6000 in a 1475 lb. car,so basically if it's a low rpm deal Ie. under 7000rpm of usable power the 4 holer is best all around. http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif

[Slide]

So for a car that never gets raced, would one of the regular (non-tapered) phenolic ones do the deed, or is it worth it to spend 3X as much on one of them fancy Wilson CNC deals?

I'm just trying to make the car a little more efficient, not trying to win any races.

[Scotch]

Slide-

The funnel effect is what you gain, so the "fancy" ones will help most down low, and as I said, off-idle and even at idle. They crispen up the vacuum signal to the base of the carb a bit, and once the engine is close to redline, it sees a little more plenum. But, yes, they are pricey right now as they are new. I hear plastic parts are on the way and will be cheaper yet. The insulation factor of raising the carb height is also part of the gain. The aluminum, phenolic, or plastic spacer sheds heat, and keeps some away from the carb (vs. the same setup minus a spacer. There's also additional gaskets (which also shield off heat) and some guys run 2 or 3 gaskets under the plate to see even more of this. So, yes, there is some benefit to be found almost regardless of carb setup (Actually, I'd be curious to test on a dual-quad setup- I bet a "low-rise" dual quad setup would see good gains, compared to maybe a high-rise or tunnel ram..hmmm..?). Anyway, these well-researched parts now seem to add something in most carbureted applications. Some see more, some less, but as I said..I've never tested a tapered four-hole-to-open spacer that didn't gain somewhere. Whether or not it's worth it depends on how much you gain, and where, and how much you spent...but these good spacers do work. If you've got the hood clearance (2 inches is ALOT to some of us), run one if you can afford it.

Opposing viewpoints welcomed! These opinions are my own.

Scotch!~

[Hot Rod To Hell]

I called wilson and ordered a 1.5" spacer right before I puked the motor in my car. The guy I talked to about what I needed was VERY informative, and his words to me were:

"If you have a carbureted engine that operates anywhere between 500 and 15000 RPM, I GUARANTEE that you will see an improvement with one of our tapered spacers."

And to David Henninger (Local speedshop dyno guy & NATIONAL Tuner) I asked:
"So are these wilson manifolds spacers worth the dough???"

and he Replied:
"If wilson manifolds tells you you need it, it's worth any price they ask"

Good enough for me!

[Max 460]

One significant advantage is isolating the carby from heat. The cooler, denser charge mix gives better atomization = more complete combustion and more power.

The best spacers are ones made from an insulating material, usually a phenolic resin or sometimes laminated woods.

There's also relatively new types of cnc machined spacers that have a taper macined into the 'venturi' that is supposed to create a swirl effect and further engance atomisation. Theory is sound, though I have no personal experience with them.

[Flat Ernie]

Insulation is a good thing, but I'd be careful stacking gaskets - too easy to break a mounting ear off the carb base if you're not careful.

When those stacked (moroso?) heat shields were all the rage in the 70s-80s, I saw loads of Holleys w/broken mount ears...

...not saying don't do it, but be careful.

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[John Copeland]

I run an Edelbrock dual quad intake with two 500 CFM Edelbrock Performer carbs, in a 40 Ford the heat in the engine bay is pretty difficult to deal with and it had a huge effect on how hot the carbs were getting. When I shut the engine off after running for a poriod of time, the gas would boil and eventually evaporate. The Edelbrock 2X4 intake is a dual plane, very low design, which adds to the heat issue. A good friend of mine milled two 1" phenolic spacers for me to use under the carbs. It changed the entire disposition of the engine. It now starts very easy when its hot, the gas stays much cooler and the low end response is excellent. The reason we made the spacers rather then buy them is because that particular intake only has the inboard set of studs and off the shelf hardware was not available at Jegs. All they had was aluminum and I needed something that would reduce the heat.

John

[Slide]

Man, who'da thought a part seemingly so simple could have so much to research. Thank you all for your input! Looks like I'll try something, just not sure which one just yet.

[48_HEMI]

I haven't dyno'ed it yet but I changed the intakes on my 235 chev from a passenger car with a 1.5 inch rise, to truck intake with a 3 inch rise and picked up an instant 7 rpm on top end and from the seat of the pants it feels like a .04 horsepower increase also http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif

[Hot Rod To Hell]

Wow 48... I must need to diet. My butt can only pick up a .1 HP difference...

[4t64rd]

I know it's a 2 year old post, but it just became relavent for me.

I see that I'll probably need a pair of phenolic 4 holers for my low rise Offy intake with 2 holley Qjet style 450s on a SBC 350. For no other reason than to clear the linkage and thermo housing.

Here's the new question, why the huge differences in prices?

They range from about $20 to $100. Is one better for reasons not explained?

Also since this is a low rise, will 2" spacers be to much for a street car? I'm in FL so heat is a problem and a blessing, no choke worries, but plenty of heat for gas boiling.

[chopperimpala]

Just a question, and NOT a sarcastic one, a lot of comments are saying that the rise of the spacer will cool off the charge, carb fuel...etc., but what about when the engine gets up to operating temp. and all the heat has finally "soaked" its way into the spacer? Now the spacer is just as hot as the rest of the manifold, it is also transferring its heat to the carb, so aren't you back at the temp. before you put the spacer on? I have no idea how they work, and am interested in them...Ken

[Betruger]

I know it's a 2 year old post, but it just became relavent for me.

I see that I'll probably need a pair of phenolic 4 holers for my low rise Offy intake with 2 holley Qjet style 450s on a SBC 350. For no other reason than to clear the linkage and thermo housing.

Here's the new question, why the huge differences in prices?

They range from about $20 to $100. Is one better for reasons not explained?

Also since this is a low rise, will 2" spacers be to much for a street car? I'm in FL so heat is a problem and a blessing, no choke worries, but plenty of heat for gas boiling. When we were using Q-jets we used to gut old worn out throttle plates, J/B Weld the holes shut and run it under the carb- solved alot of heat issues

[ray]

Just a question, and NOT a sarcastic one, a lot of comments are saying that the rise of the spacer will cool off the charge, carb fuel...etc., but what about when the engine gets up to operating temp. and all the heat has finally "soaked" its way into the spacer? Now the spacer is just as hot as the rest of the manifold, it is also transferring its heat to the carb, so aren't you back at the temp. before you put the spacer on? I have no idea how they work, and am interested in them...Ken

it's not all the same temp. you have air flowing over the engine from the cooling fan and vehicle speed. 2" of space will open up a lot of airflow around the carb.

and again, the double gasket thing. insulation works much better in multiple layers of thinner insulation, so two 1 inch spacers with a gasket between them would cool a little better than a single 2" job.