carb spacers and related intake modification



Re: carb spacers and related intake modification

Postby Wilson1 » November 23rd, 2014, 11:33 am

Ah, the great carb spacer debate. This is always an interesting and polarizing subject. Having been a drag racer for 50+ years I have a garage full of them. All the info here is technically correct, but I would caution that it does not always translate to a real world application. 4 to 8 HP on the dyno might only be .5 HP by the time it gets to the rear tires.

Now I caution all you street guys, drag racing is very different. Drag racers only care about WOT, so some of the things that work on the track, don’t in a street car, and lots of stuff that works in a street car would never translate to a drag car.

This great spacer debate started a long time ago when it was a lot harder to make horse power because of the engine parts we had. People were looking for ways to increase the effectiveness of some components that just weren’t what they are today. Manifolds, heads and cams have come so far in the past 15 years it is amazing. I say this to get you to think about putting some of these posted discussions into perspective. You can either purchase a crate motor or build one that will make way more HP than you could ever use effectively, is fuel injected, and runs like a top.

Don’t’ get me wrong, I am old school, and like street rods that have carbs, rumble and shake and need race gas to run. However, those kind of cars are for a very few. Most people want some improved performance and drivability. I.E. today’s factory hot rods and restro rods are a perfect example of what the technology of the speed industry has made available to everyone. Also lots of guys start building a street rod they enjoy driving, and in a few years of mods, turn it into something they don’t enjoy driving, but it is now one heck of a conversation piece. My point is, most of the new stuff is Fuel Injection. Carb spacers are now not part of the discussion.

If you are like me and love to mess with carbs, and are never satisfied with your combo and always want to try something else, just because it might work, or you are caught up in the trick part of the week club, first I need to extend my condolences, and second I would enthusiastically welcome you to the club. I would like to share some practical knowledge that has worked for me over the years. When it comes to carbs, find a professional, buy a bunch of books and spend the rest of your life learning. Pay for, and go to a seminar put on by a carb professional. Finding a professional and sticking with them will do a lot for you and your program. I have always worked with Gary Williams. I have purchased may a carb from him, and heeded his advice over the years. I have also thought I was smarter than him and tried different things I read about or believed would work better. In the long run, I was always back to his base line. There are many great carb guys out there today, it is almost impossible to go wrong with one.

Here is what I have learned from him over the years about spacers.

Do they work? – You will have to try it to find out. – First Rule Of Carb Spacers.

The taller the spacer, the bigger carb the motor thinks it has. (Think hard about that statement when you put a spacer on your motor and the results aren’t quite what you think they should be before you pull it off an throw it on the pile)

The spacer decreased the angle to the port – Yes it does, but that is mostly only important for Pro Stock motors.

4 hole spacers make good reversion plates if you have a reversion problem at WOT.

If you like the way it looks, and you can tune your motor to make the additional spacer effective, run it. If not, buy another one and try it. It is always cool to impress your friends when they come over to your garage with your collection of spacers. Remember, the seat of the pants dyno is a great tool to justify you spending money on that part, however, it is not a good indicator of increased HP and Torque. I don’t think I have ever spent over two hundred dollars on a part that the “seat of the pants” dyno on my street car didn’t justify the purchase. LOL

Unfortunately with the drag car, I have the time slip to prove me wrong. The point is, you tried it, it didn’t work, but did you learn something? If you did, and it sticks in your brain, someday you might be trying another idea and not getting the results you expect and have a Scooby Doo moment. That other part I tried that didn’t work, that might be just the ticket to work with this new part and give me the results I want.

By the way, this is a lifelong affliction. Enjoy.
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Re: carb spacers and related intake modification

Postby grumpyvette » November 23rd, 2014, 12:24 pm

GREAT,WELL THOUGHT THRU, POST THANKS!
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: carb spacers and related intake modification

Postby philly » November 23rd, 2014, 2:13 pm

i guess this thread is as good a place as any to post this... what is the general consensus on the velocity stacks that are sold for carbs?? one that has high credentials and testimony is the K&N piece found here:

http://www.knfilters.com/racing/stubstacks.htm

K&N Stubstack®
The K&N Stubstack reduces turbulence, improves metering accuracy. Increases the airflow by reducing restriction. Straightens and speeds up air-flow.

INSTALLATION:
The K&N Stubstack is designed to increase the airflow of carburetors, by decreasing the restriction around the choke horn. The stubstack fits inside the air cleaner housing and slides snugly down over the choke horn. Install holding nut finger tight and use Loctite or 3M to seal. When installed on some models, there may be a slight gap at the base, however this is normal and will not affect the performance of the stubstack. Due to space limitations between the choke horn and some air cleaner baseplates, the stubstack has two thin spots in the casting. These will sometimes crack or chip slightly, but does not affect the performance. Because carburetor castings vary, the stubstack will not fit all carburetors. Check the list numbers for proper application. On some carburetors that are listed, it may be necessary to alter certain areas on the stubstack. The polyurethane material is easily filed and sanded.

AIR FILTER APPLICATION:
The stubstack is designed to only work effectively with K&N Filtercharger™ elements and 360™ custom air cleaner assemblies. If the stubstack is installed in an improper housing, the performance may actually drop! The minimum height above the stack needs to be at least 1-1/2" for proper operation. See bottom of webpage for compatible K&N custom assemblies.

stub-stack-comp-final.jpg
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Re: carb spacers and related intake modification

Postby Wilson1 » November 27th, 2014, 10:47 am

Air filters and Carb Stacks. Another polarizing subject and one with lots of different opinions. Interesting thing about opinions and articles written by automotive enthusiast, engineers and manufactures is that I truly believe each and every one of them is trying to be as correct as they can be within the context of their study. Here is a link that I believe substantiates that statement.

http://www.nicoclub.com/archives/kn-vs-oem-filter.html

This is a site with several informative articles and all their facts are correct for the average guy that plans on going out to bolt on a few cool items to his hot rod. If you read thru some of them, links at the bottom, the premise is that if you are a regular Joe with a regular car then it is a waste of money. But, the people on this forum aren’t “Regular Joes”.

As “Enthusiasts” when we read articles we are many times looking for justification for a pre-disposed belief or a reason to buy a cool looking part we think might help our program. That enthusiasm many times prevents us from understanding the context of how and why a position in an article or study was advanced. Step back and understand the context of all these independent studies. Then remember, as enthusiasts and hot rodders “We Don’t Need Justification”. Go for it.

The cool thing about a forum like this one, and this is a very unique forum which I just found, is that there is a bunch of people trying to help other people with their knowledge which they have acquired thru either study or experience over the years. What I find unique about this forum is that people are publishing their experience and knowledge without any ego involved. Just how cool is that?

Back to the K&N device. I have run those in the past on my race car with no ill effects. I think the “system” which includes the air filter looks like a very serviceable unit. It couldn’t hurt. I personally believe that the best thing for a street rod is a good cold air intake. Our problem is there are not a lot of options, much less good options for older cars that are off the shelf. Most of the time building a custom on for “our” car is the only option. There are several studies that indicate running air thru a filter before it gets to the carb smoothes out the air flow in of itself and helps performance. I run a flat K&N filter below my scoop on the race car (with no oil on the filter element). Does it work? It didn’t hurt performance that I could tell, and it makes me feel good. So I do it. If you like the looks of that setup, run it. Don’t forget to report back how you felt about the change.

One K&N filter that people seem to believe doesn’t work well is the K&N with the top that is also a filter element. I have read several articles about how that kills HP…. Don’t know firsthand. Anyone with experience with that type of filter?
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Re: carb spacers and related intake modification

Postby grumpyvette » April 20th, 2015, 9:17 am

I found this bit of info on testing carburetor spacers else ware, but its certainly a good reminder that EACH combo will have different broad tendency's and air flow requirements thus theres no way to accurately predict which carburetor spacer plates will produce the best results, yes with experience you'll spot tendency's bbut theres ALWAYS a few surprises
I have some interesting airflow data. The Team at Jomar (John A and John B) asked us to flow test the leading carburetor spacer plates against their Powercone. Some of you may have already experienced these results but I thought that I would share them with the members of this forum. (with Jomar's approval).
The spacers used for the comparison were the 1" Wilson Tapered Spacer, 1" Super-Sucker, 1" Jomar (4) hole, 1" Jomar open spacer and the 1" Jomar Powercone. A standard 850 cfm Holly carburetor at full throttle position was placed on a special carburetor stand attached to a Superflow 1020 flow bench with a set pressure drop of 20.2" of water which equaled 851 cfm. This was the baseline flow setting used for all the testing. Each spacer was installed on the stand with the same carburetor and the same pressure drop (20.2" of water). An increase in airflow was reported for all the spacers, the Jomar Powercone demonstrated the greatest increase of 10.93%. The test was repeated with all the 1" spacer and a second 1" open spacer. Again, the Jomar Powercone showed the greatest gain with an increase of 14.34%. The test was repeated for a third time with the same 1" carburetor spacers and 2" of open spacer. Again, the Jomar Powercone demonstrated the highest gain with a 16.33% increase which equals 990 cfm. The total increase from the baseline was 139 cfm while maintaining the same pressure drop of 20.2" of water. Afterwards, the baseline carburetor was installed on the test stand and repeated original baseline flow of 851 cfm. Listed below are the results:

Height Carburetor Spacer Type Flow Percent Change
(in) (cfm)
0.0 Baseline 850 cfm Holley carb 851 0.0%
1.0 (4) Holes Spacer 868 2.00%
1.0 Open Spacer 921 8.23%
1.0 Super Sucker 931 9.40%
1.0 Wilson Tapered 937 10.11%
1.0 Jomar Powercone 944 10.93%
2.0 Open Spacer - 2.0" total 945 11.05%
2.0 Super Sucker w/ 1.0" open spacer 966 13.51%
2.0 Wilson Tapered w/ 1.0" open spacer 969 13.87%
2.0 Jomar Powercone w/ 1.0" open spacer 973 14.34%
3.0 Open Spacer - 3.0" total 948 11.40%
3.0 Super Sucker w/ 2.0" open spacer 976 14.69%
3.0 Wilson Tapered w/ 2.0" open spacer 986 15.86%
3.0 Jomar Powercone w/ 2.0" open spacer 990 16.33%
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: carb spacers and related intake modification

Postby Wilson1 » April 20th, 2015, 10:25 am

More practical experience with carb spacers.

This year I put a new motor in my Altered and needed to have a way of slowing it down to run an index class, and meet minimum dial at Division 6 tracks. I don’t like the old bolt under the throttle method because my carb guy – Gary Williams – tells me that because the blades aren’t fully open you get inconsistent results. So who am I to argue with Gary?

Looking around there are a couple of popular methods of doing this. One a spacer with removable plates with varying hole sizes like a NASCAR restrictor plate, and another with infinitely adjustable sliders that close off the ventuis. I decided to go with the adjustable venturis. EZ-Plate System. I chose the EZ because I didn't want a bunch of plates to keep track of, and something I could change quickly in the lanes.

Nice piece of machine work. However if you have been using spacers forever and you look down the holes of this thing you go into convulsions. Because they have four nicely machined plates that close off the venturi, the one inch spacer is open in the middle. You look at that and there is nothing smooth about it. I thought that it would kill at least .20 just because it looked like a turbulent nightmare. Guess what, with a .5 inch phenolic spacer under it for heat, it ran just as good if not better than the other spacers. Go figure.

It just goes to show, you never know… You have to try it to see if it works on your combo. You could have taken my next pay check that this would have been slower…. Not.
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Re: carb spacers and related intake modification

Postby Indycars » April 20th, 2015, 11:00 am


Thanks for the feedback!!! You are definitely right, you never know until you try it!

Is this what you are using???

http://www.restrictorplate.com/howitworks.html

ez-plate_slide_blue.jpg


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Re: carb spacers and related intake modification

Postby Wilson1 » April 20th, 2015, 11:16 am

No, sorry I mis-spoke. I am using the ET Geni.... http://www.etgenie.com/ - Getting old is not for..... Oh heck I forget... LOL
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Re: carb spacers and related intake modification

Postby 87vette81big » April 20th, 2015, 12:49 pm

Its also functioning as an anti reversion plate.
No double fuel metering through carb booster nozzles.
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Re: carb spacers and related intake modification

Postby 87vette81big » April 20th, 2015, 1:10 pm

Restriction is often helpfull.
Never convince 99.9999% of Forum guys that fact.
Just want 400-1000 cfm airflow through each intake port.
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Re: carb spacers and related intake modification

Postby grumpyvette » April 20th, 2015, 3:28 pm

87vette81big wrote:Restriction is often helpfull.
Never convince 99.9999% of Forum guys that fact.
Just want 400-1000 cfm airflow through each intake port.


ITS GENERALLY NOT THE AIR FLOW RESTRICTION,
the plate may cause,
but the equalization of the fuel air ratio distribution,between ports
and the increase in the individual intake runner ports air flow speeds
and better control over reversion pulses that can and frequently do cause air flow to momentarily reverse direction thru the carbs venturies
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: carb spacers and related intake modification

Postby 87vette81big » April 20th, 2015, 3:33 pm

I mentioned Anti Reversion above also Grumpy.
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Re: carb spacers and related intake modification

Postby grumpyvette » April 20th, 2015, 3:51 pm

yes you did! I was just trying to help some of the newer guys get a better grasp on the concepts
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: carb spacers and related intake modification

Postby philly » April 20th, 2015, 10:50 pm

by the way, wilson1 thanks for the insight.

as for the kn filter with the filter top piece, everyone i know that runs one seems to like it, and chose it based on the premise of increasing the filter area when they had less hood clearance than could otherwise fit a sufficient sized filter (everyone would love to fit a 4-6 inch tall filter unser the hood but sometimes thats impractical) so i havent heard any negative reports about those
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