StinkyPig
SILVER Star
Lets have a training session. I have examples as well I will donate to the cause.
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Mark W
Yep, I really don't really care that much I guess.
Would make a funny youtube short.
Round a a few drunken redneck types and go to town LOLMark...
StinkyPig
SILVER Star
brian
SILVER Star
same.
i have two.
I've had a webber on mine for 25 years with zero issues.
- Thread starter
- #27
Wow…… this thread ended up in the weeds quickly…
I’ve ordered a new accelerator pump, going to try that first. So, hypothetically if I was going to try to find an OEM carb outside of eBay, rebuilding etc. Where would I go about finding one? What about the Chicom copies?
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RevISK
SILVER Star
City racer has Japanese built carbs.
As I said before, someone put a weber on my rig without my input but it’s what on there so I’m running it until I can muster the funds and down time for a sniper. It works just fine after I dove into all the tuning stuff.
The weber haters probably know more than me but I don’t see the vitriol as being all that helpful. Amusing, yes.
Sometimes just running what you have just to get it going is enough to make you happy. I try not to get caught in the trap of hurling money at every problem just because.
Mark W
Yep, I really don't really care that much I guess.
It's not virtol. It is humor. Not meant to be helpful really... beyond saying "don't use anything but an OEM carb on a stock F/2F". Just meant to be funny.
Mark...
RevISK
SILVER Star
I get it and acknowledged it as being amusing.It's not virtol. It is humor. Not meant to be helpful really... beyond saying "don't use anything but an OEM carb on a stock F/2F". Just meant to be funny.
Mark...
Ian
- Thread starter
- #32
Thanks RevlSK! I appreciate the positive info re City Racer. As far as trolls, I used to own two firearms discussion boards. I learned to ignore them. Re: the Weber debate Clifford Performance has a 60+ year career using them to dramatically increase performance on a multitude of platforms. I have used them with great results on J**p builds in my past. (Current J**P CJ is FI). I'm not looking to make gobs of power with my FJ, I just want to get in it and drive and be dependable. If it is a Weber cool, if I have to switch back to a Japanese carb that is cool as well. Again Thanks for the City Racer tip!
RevISK
SILVER Star
To be fair, there really aren’t any trolls here. Some opinionated folk for sure, but very knowledgeable and generally super helpful.
Of all the forums I’ve belonged to, this one is leaps and bounds above for friendly help and knowledge.
I’ve consistently toyed with the idea of switching to an OE style of carb, but that’s usually when I’m dragging ass not doing things my truck actually needs.
Ian
brian
SILVER Star
oh yeah see, thats another one.....fj is frowned upon, due mainly to it not being an fj.
StinkyPig
SILVER Star
Clifford...had no idea that existed. Cool!
- Thread starter
- #37
Winner! Winner Chicken Dinner! Replaced the accelerator pump, pushed the pedal to the floor and BOOM! First lick she roared to life!
In all due fairness to the weeders, I purchased a used carb from a fellow Board member. I plan on rebuilding it and having around as a spare.
I'm in! Where's the party!
Sup fellas,
I wrote the following up a while back as I will be doing a YouTube video on this at some point. Just came across this thread today so I thought I'd share.
I originally bought into the hype and purchased my authentic Genuine Weber 38 and had it shipped down here to South America, for a nominal fee. After many days of tuning and having the top off the carb at least 10 times, trying every sort of combination imaginable to rectify the lean sag I was experiencing, I realized I had made a terrible mistake.
But, people run these carbs on straight six’s all the time without problems right?? From 4.0 Jeeps, F engine Land Cruisers, and the Legendary Ford 300 Big Six. Sure…. So have I, this Weber 38 has been installed on this cruiser since 2017.
Most people that do the conversion have drivability issues, and are instructed to increase ignition timing, and to go up in idle jet sizing. The end result, is running the carb pig rich, to compensate for the inadequacies of a carb not designed for an engine of this size.
When jetting a carb, you should be able to set the idle circuit for part throttle lean cruise, anywhere between 14.0:1 to 16.0:1. A leaner mixture like this, requires that the accelerator pump and power valve circuits are properly calibrated.
That being said, the problem lies in the accelerator pump. On Redlines website, they state specifically that the DGV series carb was designed for an engine size of 1.2 to 2.3 liters, with the Weber 38 being the “high performance” alternative. And also, that the 38mm will perform on a stock unmodified engine without any problems, it is not going to be an over carburetion situation. This is referring to using the Weber 38 in place of the progressive Weber 32/36 DGV series. So clearly, running the Weber 38 on an engine almost twice as big as the upper limit of the carb, is not only a bad idea, it is a terrible idea.
Again the Weber 32/36 and 38/38 were designed for engines no bigger than 2.3 liters. So while I can cruise at 14.1:1 AFR, and maintain a 12.5:1 WOT air fuel ratio, any time I want to mash the throttle to accelerate or merge into traffic, I get a nasty lean sag, with AFR’s shooting anywhere from 18-20.0:1. Now there will be those that claim you have to “roll into the throttle” because it’s a carb. This could not be farther from the truth. A properly tuned carb will have no sag or hesitation when mashing the throttle. Also, people claim that Webers “love” lots of timing advance, which is utter nonsense. This comes from the initial lean sag due to the Weber’s insufficient accelerator pump shot when mounted to an engine bigger than 2.3 liters. More advance allows for more consistent firing of leaner mixtures, therefor slightly alleviating the problem.
Now the accelerator pump shot is not adjustable. Only, the pump jet, which squirts the fuel into the intake when initially depressing the accelerator, until the main jets come in to play. This means that I can only control how quick the fuel shot is delivered to the engine. A bigger jet will deliver a harder hit, but the shot will be used up quickly. Vs, a smaller jet that will deliver a softer hit for longer. Basically changing the strength and duration, but not the volume of the shot itself.
A V8 carb like the Holley 350 two barrel, has a 30cc accelerator pump. You have complete control, as you can change the cams that actuate the lever to time the shot, and also the accelerator pump jet itself. Lastly, if a 30cc pump shot is not sufficient, you can upgrade to a 50cc shot.
With the Weber 38 being designed for engines ranging from 1.6 – 2.3 liters, the accelerator pump shot was sized appropriately for engine ranges of that size. Lets compare the demands of a smaller engine, to the demands of a 5.0 liter v8. For the sake of this test, we’re going to use 2.0 liters for the small displacement engine. We are also going to say that a 30cc shot is acceptable for a 5.0 liter engine, as they are installed on Ford 302’s and Chevy 305s without issues.
A 5.0 liter engine, or 5000 cc, divided by 8 equates to 625cc’s per cylinder. During the intake stroke, the cylinder will suck in as much air as possible, only restricted by valve size, intake runners, carb sizing etc. The accelerator pump must provide sufficient fuel to mix with that volume of air to achieve a 12.5-13.0 AFR during initial acceleration, until the main jets take over.
A 2.0 liter engine, or 2000 cc divided by 4 equates to 500 cc's per cylinder.
And this is where the design of an accelerator pump for a smaller engine comes in. For any given RPM, the accelerator pump will need to feed a 5.0 liter v8 or 625 cc’s per cylinder, 8 times per revolution, vs feeding a 2.0 liter 4cyl or 500 cc's per cylinder, 4 times per revolution.
Essentially the accelerator pump shot is mixing with 3000 cc’s more air volume on the V8 per revolution, during the same amount of time, as a 2000 cc 4 cylinder spinning at the same RPM.
Now that we understand that the accelerator pump sizing is not a “one size fits all,” lets see what happens when we install a carb designed for a 1.2-2.3 liter engine, on a 4.2 liter straight six.
I did not measure the shot volume of the Weber 38, so we are going to use a shot of 15cc’s for this example.
A 2.3 liter engine or 2300 cc’s, requires an accelerator pump shot of 15cc’s to mix with a 575cc cylinder, 4 times per revolution.
A 4.2 liter straight six or 4200cc’s, requires a 700 cc cylinder to be supplied 6 times per revolution. Essentially requiring just shy of 2000 cc’s more air volume per revolution to be supplied with fuel. That’s almost double the demand of what the Weber 38 was designed to provide.
Since the Weber was designed for an engine no bigger than 2300 cc’s, we are going to use it to represent 100%.
2300cc’s / 100 = 23
1% = 23cc’s
Our straight six 4.2 liter engine is 1900 cc’s bigger.
4200 – 2300 = 1900cc’s
Dividing 1900 by 23, or 1%, will give us our percentage difference between engine size.
1900 / 23 = 82.60%
Here we see an additional 82.60 percent is required from the accelerator pump. So if our Weber accelerator pump was sized at 15cc’s, multiplied by 1.82, that would bring us to a 27.3 cc accelerator pump shot to effectively supply the 4.2 straight six with what she needs.
I believe I have found my lean sag!
Part of my saving grace is that I am at 9000 feet in elevation. At elevation, there is a drop in barometric pressure, or air pressure. Essentially the air is less dense, therefore less 02 is present in the same given volume of air, resulting in the need to lean the carb based on your elevation. As a rule of thumb, you lose 3 percent of your engines horsepower for every 1000 feet above sea level. That’s a 27% loss in horsepower at this elevation. This also means, that I require less from my accelerator pump, and why I’ve been able to drive it with my desired cruise AFRs, without too much trouble. As I continue up in elevation, the undersized accelerator pump becomes even less of a problem, if at all. This is why I have continued to run a Weber 38 on my Land Cruiser, as I often climb upwards of 15,000 feet.
I wrote the following up a while back as I will be doing a YouTube video on this at some point. Just came across this thread today so I thought I'd share.
I originally bought into the hype and purchased my authentic Genuine Weber 38 and had it shipped down here to South America, for a nominal fee. After many days of tuning and having the top off the carb at least 10 times, trying every sort of combination imaginable to rectify the lean sag I was experiencing, I realized I had made a terrible mistake.
But, people run these carbs on straight six’s all the time without problems right?? From 4.0 Jeeps, F engine Land Cruisers, and the Legendary Ford 300 Big Six. Sure…. So have I, this Weber 38 has been installed on this cruiser since 2017.
Most people that do the conversion have drivability issues, and are instructed to increase ignition timing, and to go up in idle jet sizing. The end result, is running the carb pig rich, to compensate for the inadequacies of a carb not designed for an engine of this size.
When jetting a carb, you should be able to set the idle circuit for part throttle lean cruise, anywhere between 14.0:1 to 16.0:1. A leaner mixture like this, requires that the accelerator pump and power valve circuits are properly calibrated.
That being said, the problem lies in the accelerator pump. On Redlines website, they state specifically that the DGV series carb was designed for an engine size of 1.2 to 2.3 liters, with the Weber 38 being the “high performance” alternative. And also, that the 38mm will perform on a stock unmodified engine without any problems, it is not going to be an over carburetion situation. This is referring to using the Weber 38 in place of the progressive Weber 32/36 DGV series. So clearly, running the Weber 38 on an engine almost twice as big as the upper limit of the carb, is not only a bad idea, it is a terrible idea.
Again the Weber 32/36 and 38/38 were designed for engines no bigger than 2.3 liters. So while I can cruise at 14.1:1 AFR, and maintain a 12.5:1 WOT air fuel ratio, any time I want to mash the throttle to accelerate or merge into traffic, I get a nasty lean sag, with AFR’s shooting anywhere from 18-20.0:1. Now there will be those that claim you have to “roll into the throttle” because it’s a carb. This could not be farther from the truth. A properly tuned carb will have no sag or hesitation when mashing the throttle. Also, people claim that Webers “love” lots of timing advance, which is utter nonsense. This comes from the initial lean sag due to the Weber’s insufficient accelerator pump shot when mounted to an engine bigger than 2.3 liters. More advance allows for more consistent firing of leaner mixtures, therefor slightly alleviating the problem.
Now the accelerator pump shot is not adjustable. Only, the pump jet, which squirts the fuel into the intake when initially depressing the accelerator, until the main jets come in to play. This means that I can only control how quick the fuel shot is delivered to the engine. A bigger jet will deliver a harder hit, but the shot will be used up quickly. Vs, a smaller jet that will deliver a softer hit for longer. Basically changing the strength and duration, but not the volume of the shot itself.
A V8 carb like the Holley 350 two barrel, has a 30cc accelerator pump. You have complete control, as you can change the cams that actuate the lever to time the shot, and also the accelerator pump jet itself. Lastly, if a 30cc pump shot is not sufficient, you can upgrade to a 50cc shot.
With the Weber 38 being designed for engines ranging from 1.6 – 2.3 liters, the accelerator pump shot was sized appropriately for engine ranges of that size. Lets compare the demands of a smaller engine, to the demands of a 5.0 liter v8. For the sake of this test, we’re going to use 2.0 liters for the small displacement engine. We are also going to say that a 30cc shot is acceptable for a 5.0 liter engine, as they are installed on Ford 302’s and Chevy 305s without issues.
A 5.0 liter engine, or 5000 cc, divided by 8 equates to 625cc’s per cylinder. During the intake stroke, the cylinder will suck in as much air as possible, only restricted by valve size, intake runners, carb sizing etc. The accelerator pump must provide sufficient fuel to mix with that volume of air to achieve a 12.5-13.0 AFR during initial acceleration, until the main jets take over.
A 2.0 liter engine, or 2000 cc divided by 4 equates to 500 cc's per cylinder.
And this is where the design of an accelerator pump for a smaller engine comes in. For any given RPM, the accelerator pump will need to feed a 5.0 liter v8 or 625 cc’s per cylinder, 8 times per revolution, vs feeding a 2.0 liter 4cyl or 500 cc's per cylinder, 4 times per revolution.
Essentially the accelerator pump shot is mixing with 3000 cc’s more air volume on the V8 per revolution, during the same amount of time, as a 2000 cc 4 cylinder spinning at the same RPM.
Now that we understand that the accelerator pump sizing is not a “one size fits all,” lets see what happens when we install a carb designed for a 1.2-2.3 liter engine, on a 4.2 liter straight six.
I did not measure the shot volume of the Weber 38, so we are going to use a shot of 15cc’s for this example.
A 2.3 liter engine or 2300 cc’s, requires an accelerator pump shot of 15cc’s to mix with a 575cc cylinder, 4 times per revolution.
A 4.2 liter straight six or 4200cc’s, requires a 700 cc cylinder to be supplied 6 times per revolution. Essentially requiring just shy of 2000 cc’s more air volume per revolution to be supplied with fuel. That’s almost double the demand of what the Weber 38 was designed to provide.
Since the Weber was designed for an engine no bigger than 2300 cc’s, we are going to use it to represent 100%.
2300cc’s / 100 = 23
1% = 23cc’s
Our straight six 4.2 liter engine is 1900 cc’s bigger.
4200 – 2300 = 1900cc’s
Dividing 1900 by 23, or 1%, will give us our percentage difference between engine size.
1900 / 23 = 82.60%
Here we see an additional 82.60 percent is required from the accelerator pump. So if our Weber accelerator pump was sized at 15cc’s, multiplied by 1.82, that would bring us to a 27.3 cc accelerator pump shot to effectively supply the 4.2 straight six with what she needs.
I believe I have found my lean sag!
Part of my saving grace is that I am at 9000 feet in elevation. At elevation, there is a drop in barometric pressure, or air pressure. Essentially the air is less dense, therefore less 02 is present in the same given volume of air, resulting in the need to lean the carb based on your elevation. As a rule of thumb, you lose 3 percent of your engines horsepower for every 1000 feet above sea level. That’s a 27% loss in horsepower at this elevation. This also means, that I require less from my accelerator pump, and why I’ve been able to drive it with my desired cruise AFRs, without too much trouble. As I continue up in elevation, the undersized accelerator pump becomes even less of a problem, if at all. This is why I have continued to run a Weber 38 on my Land Cruiser, as I often climb upwards of 15,000 feet.
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brian
SILVER Star
Awesome write up, but will still fall on deaf ears.
