carb spacers/super sucker???

[grumpyvette]

I got asked this question ,

 

"I was wondering what one of these new Super Sucker carb spacers would bring compared to a regular 4 hole spacer."

 

 

 

Ill say right off that I have not used one of those super sucker spacers, personally, but I have seen several used,and worked on cars with them installed, look closely, at the super sucker spacers, they are NOT a true 4 hole design,like this

that maintains isolated plenum feed from each side of the carb.

they are a MODIFIED open plenum design, like this

that will have a similar effect to this in that the dual plenums are linked under the spacer,they appear to be designed to add plenum voluum to a single plane intakes plenum, and smooth the air flow transition from carb to plenum, so that will have a similar effect to this

 

I prefer the standard spacer designs,

many of the newer guys will not have done that spacer swap, and its a tuning aid, that can help some applications

Ill also add that if you have the room under the hood, adding a second phenolic 4-hole 1/2" tall carb insulator or swapping to a 1" or even a 2"phenolic 4-hole spacer may further improve the carb cooling and may help the fuel atomization slightly, but the correct spacer must be matched to the style of intake manifold

 

http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=708&prmenbr=361

 

look closely at the carb base mount area on the two intakes below

 

then think about the differance in the application of the spacer and how it will effect the airflow entering the differant intakes, the upper dual plane has TWO distinct plenums which MUST be kept seperated if your trying to maintain the maximum air flow speeds in the intake ports,the comon 4 hole spacer maintains the seperate isolated flow charicteristics, the super sucker has an open plenum area allowing cross flow between the sides, on a dual plane intake thats NOT ALWAYS HELPFUL,on a sigle plane its PART OF THE PLENUM DESIGN, Id bet the super sucker spacer gets better results on single plane intakes where additional plenum voluum is helpful but Id suspect it KILLS some low speed volumetric efficiency, in a dual plane, intake where additional plenum voluum slows the airflow speeds slightly, but aids high rpm flow due to additional plenum voluum.......now IM not saying that will or will not work, in fact an old trick on race engines was to partly remove the air dam between the sides to effectively gain plenum voluum on dual plane intakes designed for high rpm use!,similar to this but I AM pointing out the differance in application and where it will effect your engines power curve

[Oldestzguy]

What he said!

 

 

It's times like these that I know for sure how far over my head this stuff really is. I did follow it, but had to concentrate, and now I have a headache.

[Guest tony78_280z]

(Man am I in luck! Grumpy started a thread some what related to a topic that has been banging around in my head without some answers. Now I can ask him my question and since this is his thread he will be compeled to answer me. Mu ha ha ha!!)

 

This is all very interesting Mr Grumpyvette. I've been contemplating spacers for some time.

 

I'm using a stock manifold (spread bore) with an adapter/spacer to my holley (square bore) This adapter/spacer was the open design so I had the holley bores that then ended about a half inch above the spread design on the manifold. And these did not line up well at all. When I looked into the Carbs bores I could see the cross section of the manifold, and most of one of the carb bores ended in metal of the manifold.. I knew this had to be hurting my air flow, so to make a long story short, I modified the intake by grinding out the offending material and turning my intake into a open plenum, sort of. I noticed a great improvement in the seat-of-the-pants o-meter.

 

I have since spotted an adapter/spacer that is not of an open design in which the front square bores leave the carb, go down and narrow out, make a slight zag into the manifold. The Rear square bores go down widen and go into the manifold. This of course would have prevented me from needing to gut my manifold, but it brings up another good question. While I think the rear would be fine, I'm wondering how air/fuel from the front barrels of the carb would be effected by narrowing into the spread bore pattern before being dumped into the manifold. And how would that effect the tuning of the carb?

 

Surely I'm not the only guy using a stock spread bore manifold with an equal bore carb. Which of the two adapters/spacers is best?

[grumpyvette]

first some reading material

 

http://victorylibrary.com/mopar/intake-tech-c.htm

 

 

http://www.rbracing-rsr.com/runnertorquecalc.html

 

 

http://www.newcovenant.com/speedcrafter/calculators/runnerarea.htm

 

http://www.newcovenant.com/speedcrafter/calculators/intake.htm

 

http://www.bgsoflex.com/intakeln.html

 

http://www.me.psu.edu/me415/SPRING02/intake/intake.html

 

http://headerdesign.com/extras/engine.asp#Intake_Manifolds

 

http://www.team-integra.net/sections/articles/showArticle.asp?ArticleID=466

 

http://turbonation.com/intake.htm

 

 

 

ever wonder WHY intakes are designed with runners shaped like they are?

you might want to read this info

 

 

next, to answer your question,using an adaptor to put a spread bore carb on a square bore intake, or a square bore carb on a spread bore intake like youve done, is DOOMED to seeing some reduced flow.

your modification ....

 

"I modified the intake by grinding out the offending material and turning my intake into a open plenum"

 

you probably did remove some restriction to flow, but you would more than likely find that the correct intake mated to the carb would work even better.

 

"I'm wondering how air/fuel from the front barrels of the carb would be effected by narrowing into the spread bore pattern before being dumped into the manifold. And how would that effect the tuning of the carb?"

 

again its more than likekly hurting air flow, any time you change angles or reduce port size you potentially restrict flow, personally Id hit a few swap meets,ETC. and find an EDELBROCK super vic intake if the cam your using has over about 240 duration or a performer RPM if the cam you hav is under about 235 duration at .050 lift

running a correctly matched intake without the adapter is usually best

 

dual plane intakes like this generally work effectively in the 1500rpm-6000rpm range

 

intakes like this generally work great from about 4000rpm-8000rpm, but give up power below about 3500rpm

keep in mind other factors are at work and displacement,cpr,header design ETC. effect results..it does little good to put an intake that potentially flows 320cfm at 7000rpm with a cam that has .700 lift on an engine with stock cylinder heads that restrict flow to 210cfm and max flow at .500 lift like many stock sbc heads