219 replies to this topic

[SA EH]

Good stuff OJ, appreciated.
I'll apply the same expertise getting some more su flow figures shortly.

[SA EH]

All the more encouraging for anyone with 1 3/4" then....

Including me that is.

[warrenm]

I could lend you a 2", if your interested.

[LC-GTR-1969]

I could also supply a 2 inch SU... I could lend the weber but its on the car and need it etc... however if it was planned out I could whip off the weber, test it and put it back on...

 

Anyone else have a 45dcoe sitting on a bench?

[jd lj]

Yeah I've got a spare damaged body that could be used for testing, but I guess you'd also need a good range of different choke sizes and an auxiliary ventruis to do the test.

[LC-GTR-1969]

I have some 36s sitting on my bench JD. Happy to supply them for the test... 

[greens nice]

Some nice data there OJ, can the HSR's be found locally in useable/rebuidable condition?

If it helps, I have an assortment of 2 in SU's in unmolested and tickled condition as well as some 45 dcoe's & various chokes.

My flowbench is a pitot style with digital manometer, repeats to <1%.

You have me curious now, using the pitot sensor to the bottom of the jet tube we could see what effect modifications to the slide & jet bridge have on fuel metering

[LC-GTR-1969]

great info here! well done...

[orangeLJ]

I've got some 40mm webers laying around.

But you're out west are you oj?

Also some 48mm dellortos

[N/A-PWR]

Hi Oldjohnno,

 

I would say the information will make people feel at ease with their own set-up,

 

given the comparison vs other carburettors,

 

and can also give members an insight into which way they would like to spend their money,

 

for capacity per dollar value.

 

In saying that, we would need to have the motor modifications needed to accept the carburettor sizing,

 

added to the chart.

 

I've got a question for you guys: suppose we compile a table listing the flow rates of all the carbs that we think might work OK.

 

What are you going to do with it?

[SA EH]

I've got a question for you guys: suppose we compile a table listing the flow rates of all the carbs that we think might work OK.

What are you going to do with it?

Well I don't know what everyone else is doing with the info, but for me comparing su's actually relates to my engine so I appreciate getting a 1 3/4" baseline flow rate. I'll be flowing all of mine regardless & providing figures when I do, then see what sort of power difference it makes.
For my own personal pleasure of course, and a few interested parties.

[SA EH]

Lol

[N/A-PWR]

Hi All,

 

All the information in these pages are of great value,

 

so I have numbered and lettered them for the carburettor flowbench discussion.

 

See what you think is needed to add, for a cross-examination graph,

 

which I don't mind helping out with:-

 

1-Flowbench

a-maximum flow

b-head port size

c-valve size

d-valve lift

e-duration

f-orifice size

g-cylinder size

h-standard pressures (1.5" or 3"hg)

j-12" water (about 0.8" hg)

k-digital manometer

l-pitot style 

m-pitot sensor

n-sweet spot

o-midrange performance

p-short ramp

q-tapered tail

r-CFM

s-flow figures

t-gulp factor

u-at WOT

 

2-FUELS

a-fuel pressure

b-AFR/rich/standard/lean

c-vent the bowl

d- fuel type

 

3-Engine size/ V8/ V6/ L6/ L4

a- standard/ warm/ hot/ max rpm

b-138

c-149

d-161

e-173

f-186

g-202

h-253

j-308

k-327

l-350

m-lift/ duration curve

n-aspirated/ forced

o-manifold/ plenum

 

4-Carburettor

a-unmolested

b-traditional

c-mods

d-popular mods

 

5-SU

a-2 inch

b-1 3/4 inch

c-1 1/2 inch

d-generous radius

 

6-Weber DCOE

a-48mm

b-45mm

c-40mm

d-36mm

e-Max fixed choke/dcoe

f-40mm-45mm

g-35mm

h-34mm-40mm

j-30.5mm-38mm

k-auxiliary ventruis

l-jet tube

m-jet and UP Needles

n-slide & jet bridge

o-fuel metering

 

7-Dellortos

a-48mm

 

8-Holley

a-4bbl holley

b-750

c-600

d-465

e-450

f-390

g-2bblHolley

h-500

j-350

 

9-Mikuni

a-HSR42s

b-HSR

c-TMX

d-PWK

e-VM40

f-VMX38

g-38 TM

h-36 TM

j-32mm

 

 

 

Or what needs changing around - this is just a start list.

Edited by NA-PWR, 01 March 2016 - 01:25 PM.

[N/A-PWR]

Hello Grant,

 

did I forget to mention deleting anything too?

 

I say Oldjohnno has already explained a few flow figures which will be in the chart,

 

and has offered to do a couple more.

 

All I was merely doing was putting in other specifications that are talked about by others,

 

and if any of them were mentioned in a test, the chart would show.

 

Sorry if I started something to big.

 

helping out, starter list  - OMG- that's not simple there dave.

 

Old Johono will have to employ a full time staff member  to sort through that list and test.

 

Could you Imagine the amount of plasticine he would have to purchase, his local toy shop would start to look at him a bit strange.

 

jesus - lets stick to - about 4 or 5  carbs as we are only trying to establish the following

 

" air flow through a shaped opening". 

 

lol 

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