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Old 14th August 2008, 22:58   #1
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Default My Experience of using Carburetor Spacer

Dear all,

I wish to share another successful experiment with you.

After adding free flow exhaust I was thinking of doing something to my intake systems but was not sure what to do as I have no inputs regarding this.We know with free flow we can have gain in torque across rpm band depending upon its design.Stock systems are restrictive.Sosame is with intake systems.Air intake systems play crucial role but we dont have much to do excpt for those in racing circuit.FFE is more populer and easily available.

I was thinking of doing something thats cheap & can be easily adopted having substantial benefit.And I came across Carburetor Spacers.I went ahead and applied my own by simple method and beleive me result is so good.

I m finding increased torque in lower to mid range.Pull in 3rd gear from 20 onwards is so good now and flowless.It feels as if there is free flow at intake end.

I have added 1.25" spacer made of normal plastic below carburetor.This is nothing but carb flange of thicker size.Almost double the thickness of nornal flange.I used 2 such flange & changed intake manifold studs.Above intake manifold I sandwitched both flange & put carb above it.Initiallly idling was reduced because of increased air.I just adjusted it.Nothing changed so far.Car is definitely showing increased mid range torque.Not tested upper end but seems its also improved.There is slight sluggishness from standstill but once I crosses 20kmph car is pulling so nicely.I was able to pull in 2nd gear up to 85 so effortlessly in lpg.

Adding spacer increases the plenum height of intake manifold.So air fuel mxture from carburetor has more time hence more mixing.This also increases velocity of air travelling from carb to intake valve.There are numerous spacers available of different materiala like plastic,phenolic,aluminium,cast iron & wood.There are so many designs & concepts with each methods.

We have plain spacers,tappered one & combinations of both.Each has their own advantage.Spacer is just a tuning instrument to change the torque curve of an engine.Which suits to our engine need patience & trial & error method approach in the absence of dyno facilities.

Apart from lifting manifold,spacers also cools down air fuel mixture because of increased travell.This too has beneficial effect of dense air.

Here are links for further reading.Input from members appriciated as we still have thousands of carbed cars running.

Wilson Manifolds - Tapered Spacers

Throttle Body Spacers: Hubcaps Plus After Market Parts and Accessories For Cars, Trucks and SUVs

Spacing block - Google Patents

Merged Carb Spacers - Speed Talk

Jomar High Performance parts - The new Jomar poerformance Power Cone Phenolic Carburetor spacers to increase horsepower of up to a 40 horsepower gain

Benifits of a carb spacer? - Monte Carlo SS Message Board

Airflow spacing plate - Google Patents

Here is the wonderful article about Spacers.

Carburetor Spacers - Open And Four-Hole Spacers - Circle Track Magazine

Looking at all above information one find this is very old technique to improve power.This infact increases FE too as mixture is leaned out but not yet tested.

Last edited by finetuning : 14th August 2008 at 23:10. Reason: Arranging links
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Old 14th August 2008, 23:48   #2
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When carburetor butterfly is partly open is deflacts the air fuel mixture in sidewalls and at full opening it guides entire mixture right to the bottom of manifold opening from where air fuel mass turns 90 degree moving towards intake valve through intake runners.

This butterfly valve is restrictive in the manner it deflects the air and fuel.By raising carburetor above intake manifold opening we are improving the directional defects caused by partially opened throttle.Air fuel mixture has more time to travel which gives not only better mix but better flow towards manifold opening.With spacers at partial throttle even mixture is deflected,we get streight flow because of increased height.

When intake stroke starts,because of rapid movements of pistons vacuum is created.That vacuum signal guides the flow of air from manifold opening to all intake valves.If manifold is raised we get strong & distinct vacuum signal which aids in better flow towards intake valve.


If there is tapper at the bottom end of spacers that guides flow of mixture well on both sides,it improves all round performance.

It costed me just Rs 200 for this work.

Further reading.

Tuning With Carburetor Spacers
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Old 17th August 2008, 14:56   #3
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Quote:
Originally Posted by finetuning View Post
I have added 1.25" spacer made of normal plastic below carburetor.
should it read .125" thats +3mm

the spacers that you have installed have you noticed if they are leak proof as these things should be proper machined or clean face for install.

do also let us know from where u got them.

Last edited by Jr Godzilla : 17th August 2008 at 14:58.
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Old 22nd August 2008, 13:10   #4
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Sorry for the delayed update.

Also read size of spacer as 12.5 mm and not 1.25".I used two 6mm thick carburetor flange sandwitched togather.Nothing else.Its available at any autoparts shop.Ask for thicker flange used in maturi zen.Its having same hole diameter & size.Its made up of some special plastic(phenolic plastic?).Instantly i had to increase idling speed a bit.

Adding spacer changes torque delivery across rpm ranges.I m feeling more pulling power in mid range.Its quite noticeable.

This encouraged me to add more height.I was always thinking of 1"+.So I fabricated a wooden spacer having same size & hole diameter of normal carb flange.I made it from hard teakwood block.Its measuring 1.25" exactly.Reason I opted for wooden is easy to fabricate,change shape & size by me.Removed older one & added this tall wooden plate.I was not able to place by lpg pipes as air filter asembly is so tall that I couldnt close bonnet.So I tested car in petrol only.Still running wooden spacer.

There is remarkable difference in the performance.No hesitation from stand still up to 80kmph.I dont have rpm meter.Car is pulling so fast in 2nd & 3rd above 80+.I wish to retain the same setup but having practicle difficulties.

I will be trying this add on in another total stock car & will share result.

Can any one suggest what to do with this setup?I wish to retain 1.25" spacer.I can later on fabricate spacer form plastic or metals like aluminium.
When I add lpg setup my bonnet doesnt close.

Enjoying ride now.One thing is sure.This doesnt decrease FE as I do not intend to upjet nor change air fuel ratio.So if driven as before this setup will increase FE a little bit.

This is turning out to be extremly simple yet very effective addition to my car.

Last edited by finetuning : 22nd August 2008 at 13:17. Reason: addition
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Old 22nd August 2008, 14:35   #5
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@FT, another one from you !

Pls post some pics of the mod you have done. Unlike the previous threads, this should be easy (to show). TY !
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Old 22nd August 2008, 16:43   #6
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@finetuning

Very interesting.
And all this for just 200/- ?

How much for the hardware ?
From where was it sourced ?

Also pics please...
I have a FFE so this really sounds interesting...
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Old 22nd August 2008, 17:39   #7
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Ha.. Ha...

Finetuning one more from you.

Pls do put pics of your flawless experiment for all to see.

There is hardly 2 mm gap between the airfilter and the bonnet, how do you raise it so much, there will be lot of rattling and grinding below the bonnet with this mod.

Just polish your intake manifold, thats more than enough.
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Old 22nd August 2008, 20:04   #8
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Will soon post photos. That will clear all doubt.

Those having free flow in carbed car this will help more.If you are not running with any lpg/cng setup that has connections above carburetors then this is so tempting mode.

pawan, there is sufficient gap between bonnet & top of filter in my car.I think it depends upon manufacturing year of car too.I m having lpg inlet above carburetorthen also its not touching. But with this 1.25" spacer I just cant shut the bonnet.I m so tempted to continue using this. But I have to cut bonnet/modify.I m feeling torque of swift diesel
.
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Old 22nd August 2008, 22:28   #9
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Here are photos. Wooden spacer was too thick to use with lpg hence today I removed it but couldn't take photo.

See how much thick it is.We are normally using one carb flange which is extreme left in first photo.I used 2 flange with green packing which is on right of wooden spacer.
Attached Thumbnails
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My Experience of using Carburetor Spacer-dsc04020-large.jpg  

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My Experience of using Carburetor Spacer-dsc04022-large.jpg  

My Experience of using Carburetor Spacer-dsc04028-large.jpg  

My Experience of using Carburetor Spacer-dsc04032-large-2.jpg  


Last edited by finetuning : 22nd August 2008 at 22:31. Reason: Addition
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Old 22nd August 2008, 22:43   #10
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Quote:
Originally Posted by yzfrj View Post
@finetuning

Very interesting.
And all this for just 200/- ?

How much for the hardware ?
From where was it sourced ?

Also pics please...
I have a FFE so this really sounds interesting...
Hi,

Its really dirt cheap mode.I tried teak wood block lying around my house bcz it can be easily machined.I took it to carpentary machine shop & drilled hole.We can use good quality plastic that is heat resistant.We can try adding more thicker flange. All this depends on how much space our car has above filter.
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Old 23rd August 2008, 15:45   #11
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Dear pawan,

Can you tell me more about intake manifold polishing?Is it to be polished from top surface or from inside?and what may be benefits?My esteem manifold has 2 holes of different diameter one being smaller which are just beneath carburetor butterfly valves.

This 2 hole intake manifold is better for day to day street driving I think.
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Old 7th September 2008, 21:16   #12
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Finetuning,

It is really interesting. You are doing good modifications. Also searched the spacer in the Bangalore shops (non-standard thickness) not available. could you pl. tell how to get these spacers ? may be posting to you because i have esteem model 1999.

My Advance thanks !!
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Old 11th September 2008, 17:08   #13
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Hi fanteen,

I m doubtful about availability of spacer for esteem. You can easily use carb flange of maruti zen shown in my first photo extreme right. Left one is normal esteem flange. if you are not running with lpg/cng then use 3 thicker flange. You need to buy 4 manifold studs of bigger size. With 3 flange height your idling might get reduced(may not) so after fitting just increase it without touching anything.DO not forget to use paper thin gasket below & above these 3 flange.

You will have plenty of low to mid range torque coming so early which is so boon in city traffic.

Else you can make your own from simple wood block.

Last edited by finetuning : 11th September 2008 at 17:11.
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Old 15th September 2008, 17:08   #14
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hi finetuning,

I use my esteem with LPG. I checked up the gap between the air filter and bonnet is less. can i use zen spacer + esteem spacer ? or i need to try out with possible combinations. I will reply to the forum, once the modification done !!
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