A/F ratio Jetting on stock Pony Carb

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MPGmustang

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i'm posting this here as i'm not sure...

My current A/F ratio is 14.1:1 according to 20 dyno runs... I think it's evident that I should change the Jet in the carb. but to what?

I've taken off the cover and looked at it and it reads 50E or 59E... It's kinda partly misprinted... I've taken pictures I'll try to find one that is readable and link it...

But If was wanted to acheive A/F ratio of 12:1 on my new engine I think I would look for a bigger Jet. but what size? is there a "rule of thumb" to go by? if anyone else has done this on the 1100v let me know your findings...

The reason I want to go to a bigger jet is simple,

1) More Gas, less heat in the head
2) cooler car, cooler A/C (at the expense of mpg)
3) less heat, longer longevity
4) More power no? ;)


thanks
Richard
 
okay, so i called up John at Pony Carbs, and related what I wanted... he said best A/F ratio is 12.5 to 12.8 and if I go from a 59f (he corrected me on the size) to a 62f it should get me to 13 A/F ratio... or if I take a .625 drill bit to it... (that seams huge????)


any way's Just wondering what others think...
 
JackFish":11zpqq64 said:
I will add that drilling is bad.
The jets have a beveled edge that gets destroyed if you do that.
Click to expand...

I'm thinking the same... so where can I get these jets? i'll try local shops like wilkes, lopers, autozone, (napa didn't have anything), checker...
 
or if I take a .625 drill bit to it... (that seams huge????)
Click to expand...

Yeah the fuel pump would have trouble keeping up with a 5/8 inch hole. :rolflmao: Probally should have been .0625 drill size :unsure:
 
bubba22349":2gxgbtuy said:
or if I take a .625 drill bit to it... (that seams huge????)
Click to expand...

Yeah the fuel pump would have trouble keeping up with a 5/8 inch hole. :rolflmao: Probally should have been .0625 drill size :unsure:
Click to expand...

yes that's what i thought... but anyway's reading more on this forum, and finally getting the search to show results, I found that more ppl with the 1100 or 1101 like the jet size 64f, i'm thinking I should be safe getting a 65f or a 66f for summer, and use my 59f for winter...
 
MPGmustang":1nk1nwgg said:
bubba22349":1nk1nwgg said:
or if I take a .625 drill bit to it... (that seams huge????)
Click to expand...

Yeah the fuel pump would have trouble keeping up with a 5/8 inch hole. :rolflmao: Probally should have been .0625 drill size :unsure:
Click to expand...

yes that's what i thought... but anyway's reading more on this forum, and finally getting the search to show results, I found that more ppl with the 1100 or 1101 like the jet size 64f, i'm thinking I should be safe getting a 65f or a 66f for summer, and use my 59f for winter...
Click to expand...
You need to put in the 62 jet & check the A/F ratio with a wideband tester or dyno it again.
For winter use you might have to go 1 jet size larger. You have its backwards, cooler weather & less humidity you richen up, hot weather & high humidity you lean.
 
alright so I'm now again looking for Jets again.

I'm looking for Jet numbers 61, 62, and 63.
Lately I've been doing alot of "seat of my pants" testing on the new engine, it likes the 64 jet, but it seems (smells) too rich. I bet if I held a flame near the tail pipe it would propably light...
besides the testing I would also like them before I dyno again, so I can get the best A/F mixture possible. Changing them on the spot would be Ideal.

what is the best A/F ratio for our engines? I've heard 12.5-12.8 to 1, can others confirm that?

next question is where can I get these? in these sizes. I've searched all the local places but they don't have these numbers or don't carry autolite/motorcraft jets. any help on where to find them I'd really appreciate.
 
IIRC, my Holley 1946 had a 61 size jet in there stock.
I swapped it out to a 66 with the new engine as I was afraid of being lean.
 
JackFish":1u7h1yx2 said:
IIRC, my Holley 1946 had a 61 size jet in there stock.
I swapped it out to a 66 with the new engine as I was afraid of being lean.
Click to expand...

sadly holly jets are too small

69.5Mav":1u7h1yx2 said:
Do you have any carberator shops in your area?
If not try langdons stovebolt.
Click to expand...

I've googled but the one that does, didn't have the numbers I want. maybe i'm blind but stovebolt didn't have any jets on the online catalog
 
MPGmustang":2hne4lbd said:
69.5Mav wrote:
Do you have any carberator shops in your area?
If not try langdons stovebolt.

I've googled but the one that does, didn't have the numbers I want. maybe i'm blind but stovebolt didn't have any jets on the online catalog
Click to expand...

Call Langdon and ask him. He keeps a stock of jets for his weber 5200 carb.
 
Howdy MPG and All:

"what is the best A/F ratio for our engines? I've heard 12.5-12.8 to 1, can others confirm that?"

Jetting is not a "one-size-fits-all" deal. What jet is ideal for an engine in Ohio may not be be the same for an engine in Colorado. Elevation and temperature are just two of the variables in selecting the best jet for an engine. Engine combo's and condition also mix the mix. That's why dyno tuning is a good thing. It can be specific to each engine combo as well as to the locale. A good dyno tech will not only fine tune jetting, but will also add ignition timing to the mix. Since John is not far from you, and since you asked him, I'd go with his suggestion- then head for the dyno shop with a good timing light and a pocket full of jets.

On finding jets, a good practice is to look for 1100s and 1101s at swap meets and garage sale. They can usually be picked up for a few bucks. Then strip the jets and keep them for ???? Or, to save time, and possibly money, buy them from John. He may be expensive, but he is providing a product and service by maintaining the availability of 1100s and 1101s, as well as jets. That's got to be worth something.

On drilling out jets. It may not be the ideal way, but it works. It will not ruin the flow, but the flow will no longer be reflective of the stamped indicator or comparable to any other jet size. It also ruins the jet if you want to go back to what you had. If you do drill, use a hand drill, set up a fixture to hold the jet and do you best to align the drill bit angle to the original hole. Go slow. Finding a precision drill bit set will set you back more than a few bucks too.

A way to refine your butt-o-meter testing is to use a repeatable test foremat and use a stop watch. Try to use the same section of road, at the same temperature/wind direction and speed, and with the same vehicle load (ie gas level, passengers, freight). All testing should be at WOT for evaluating the main jet. It is easiest to repeat a test from say 20 to 70, than 0 to 60. If your car is a manual trans, try testing in in a higher gear. Also try to use the same rpm range- 3,500 to 5,500 for example. Start the stop watch and stop the pedal at the same time. Stop the clock at the predetermined speed/rpm and then let off the gas. It takes a little practice, but will give more objective info than a Butt-o-meter. Please be safe!

Thanks for sharing your quest.

Adios, David
 
thanks David!! that's a great idea, will do and post my findings to compare on when I dyno it with the jets.

Well I guess I'm just going to bite the bullet and order the 3 jets from pony, I'll do so on my next paycheck after I get school books.
 
Back to this thread... topic...

falcon1963":2t410bou said:
You need to put in the 62 jet & check the A/F ratio with a wideband tester or dyno it again.
For winter use you might have to go 1 jet size larger. You have its backwards, cooler weather & less humidity you richen up, hot weather & high humidity you lean.
Click to expand...

Okay, so i've been thinking about this... I think I see the light now...
recent drive up in higher elevation I was able to run more timing, and the car ran cooler, is that because when cooler you can run more advance, because heat is easier to get rid of, and there for you can burn the fuel longer?
so in hotter temps, you need less fuel to burn, because you can't get rid of the heat as easily.... I know i'm dipping in my heat discussion, but i'm trying to understand the complete logic with summer = smaller jet and winter = bigger jet

AZ is dry all year long, never (unless it rains...) have humidity
 
Okay, so i've been thinking about this... I think I see the light now...
recent drive up in higher elevation I was able to run more timing, and the car ran cooler, is that because when cooler you can run more advance, because heat is easier to get rid of, and there for you can burn the fuel longer?
Click to expand...

Yes to when cooler you can run more advance but also the air is thiner at High Elev. so you loose power :shock: you could also run more compression and or more advance too :unsure:

so in hotter temps, you need less fuel to burn, because you can't get rid of the heat as easily.... I know i'm dipping in my heat discussion, but i'm trying to understand the complete logic with summer = smaller jet and winter = bigger jet AZ is dry all year long, never (unless it rains...) have humidity
Click to expand...


Jetting rich was and is used for safety to cool combustion chamber temps on high compression/high performance engine (prevent detonation). With more heat fuel atomizes better too. Running lean will make more power but engine temps also rise. If you have access to an Ex. Gas Analyzer can get closer to perfect tune. :nod:
 
What leads you to want to richen up the mixture? Under what conditions? Idle, full load, WOT, coast, cruise?

AF ratios will move all over the place depending on load and speed. There just isn't a single ratio that's "best".

For my car, 14:1 AF under cruise is actually a little rich. Observing my EGO gauge on the Megasquirt, I hit 15.5 - 16.5:1 under no-load sometimes. 14.5:1 is normal cruise. I only get to 12-13:1 under full load and WOT.

If you drill the jets, you will only run richer, use more fuel, and may not make any more power.
 
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