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Tue Nov 10, 2020 6:23 pm

just curious what y'alls opinions are on carbs for off road? best one you've used and maybe even worse, and why you think so. give some specifics like, do some work good mounted one direction but like crap mounted another direction? etc etc
prefer not to get on the efi subject here, thanks.

Tue Nov 10, 2020 6:50 pm

Typical carbs found on VWs, probably the Zenith NDIX series. Available in 32mm, 36mm, and 38mm. 32mm are far and away the most popular. Good fuel control in the bumps and Work well in a centermount configuration on mild engines.

Outside of VWs, I have to say that I have been super impressed with the SU HIF series carbs. They run just fine at STUPID angles, and with the later anti-stick “stay up” float design they seem to be almost immune to rough going. They are a side draft carb, but technical specs suggest mounting the carburetor between horizontal, or with up to 40 degrees of down draft. Closest thing to EFI I have ever seen from a carb.

Wed Nov 11, 2020 3:41 pm

What engine?

Thu Nov 12, 2020 7:36 am

Wulfthang wrote: What engine?

Could you be more specific? What engine for what?

Thu Nov 12, 2020 8:22 am

Vanapplebomb wrote: Wulfthang wrote: What engine?

Could you be more specific? What engine for what?

I believe he's asking the OP what engine he is needing a carb for.

Thu Nov 12, 2020 8:52 am

What kind, size and mods done to the engine are kind of important to determine the best carb. Driving type and style are important too. Yeah yeah I know that this is a VW site but there are many people who power their buggies/rails with something besides a VW engine.

My rail is powered by a naturally aspirated Ford V6 that I did some hyper work on. Headers, matched and polished intake and exhaust ports, 5 inch intake riser, hotter ignition, more ignition timing dialed in, etc. It runs very well with a Holley 4412 Series carb.

It's a 500 cfm two barrel with a multitude of settings and adjustments to fine tune it. It was designed by Holley as a racing carb so it's not emissions legal if you have to worry about that. Linkage hookups are pretty easy. I've run it at low rpms crawling up an old shale mining road and down the interstate at 90mph. It handles rough terrain pretty well with no hiccups and is smooth the entire time. Fuel economy seems pretty good too. I'm happy with it.

Thu Nov 12, 2020 4:14 pm

the post is a general question about ppl's experience with carbs offroad, theres no need to get hung up on technicalities about the engine that just getting off subject. i mean if someone ran a small block with a 671 and dual holleys and someone else thinks they can apply those same carbs to a vw, then they get what they get

Fri Nov 20, 2020 11:12 am

richardcraineum wrote: the post is a general question about ppl's experience with carbs offroad, theres no need to get hung up on technicalities about the engine that just getting off subject. i mean if someone ran a small block with a 671 and dual holleys and someone else thinks they can apply those same carbs to a vw, then they get what they get

Richard... You asked which carb and Wulfthang was absolutely correct. The engine and the use make HUGE difference in which is "the best" carb for offroad.

A guy I knew many years go built a 2110 VW aircooled engine for his Baja Bug that he liked to crawl Jeep trails with in the Sierras and the Rockies. He was VERY happy with the Solex 30 PICT1 carb he built for it. He put an external float bowl vent on it and blocked the stock vent. He was using it for low RPM torque. He talked about wanting a little larger carb like a Solex 34 PICT-3, but he didn't like the carb and the overly complex circuitry in it.

I know other guys who like big sand dunes like Glamis and love to climb huge steep faced dunes at wide open throttle. They've preferred dual 48 IDA Webers. And even better with a turbo.

Others with 1450 off road race trucks with 700hp V8s use Holley 4 barrels.

Different uses. Different engines. Different carburetion. There is NO one size fits all carb for all uses and all engines.

The best shoes for a track sprinter are not the best shoes for a guy hiking the Pacific Crest Trail and neither of what is best for those work for a ball room dancer or a quadriplegic.

Fri Nov 20, 2020 9:48 pm

The 4412 Series Holley that I'm running on my Ford V6 powered Trail Rail is technically a little to large for trail running on this size engine. It's a 500 cfm 2 barrel carb so "just a little bit of throttle to power up this trail" means the butterfly's are barely open. It's not progressive so both barrels operate together. That causes the mixture to come out of the carb base at an extreme angle. Not good for drive-ability since it causes surges, etc.

I solved that with a 5 inch riser between the carb and the manifold. That extra length allows the mixture time to straighten out and mix better. I can motor up and down trails all day long at 1000 rpm and it's very smooth. Plus, the extra sized carb allows me to run on the interstate at 80mph and still have plenty of acceleration.

Yeah engine size, type and driving stye have a major effect on carb choices.

Sat Nov 21, 2020 8:14 pm

dustymojave wrote: richardcraineum wrote: the post is a general question about ppl's experience with carbs offroad, theres no need to get hung up on technicalities about the engine that just getting off subject. i mean if someone ran a small block with a 671 and dual holleys and someone else thinks they can apply those same carbs to a vw, then they get what they get

Richard... You asked which carb and Wulfthang was absolutely correct. The engine and the use make HUGE difference in which is "the best" carb for offroad.

A guy I knew many years go built a 2110 VW aircooled engine for his Baja Bug that he liked to crawl Jeep trails with in the Sierras and the Rockies. He was VERY happy with the Solex 30 PICT1 carb he built for it. He put an external float bowl vent on it and blocked the stock vent. He was using it for low RPM torque. He talked about wanting a little larger carb like a Solex 34 PICT-3, but he didn't like the carb and the overly complex circuitry in it.

I know other guys who like big sand dunes like Glamis and love to climb huge steep faced dunes at wide open throttle. They've preferred dual 48 IDA Webers. And even better with a turbo.

Others with 1450 off road race trucks with 700hp V8s use Holley 4 barrels.

Different uses. Different engines. Different carburetion. There is NO one size fits all carb for all uses and all engines.

The best shoes for a track sprinter are not the best shoes for a guy hiking the Pacific Crest Trail and neither of what is best for those work for a ball room dancer or a quadriplegic.

the problem here is that you two are reading into my question and assuming im asking ppl to recommend a carburetor for me to use, that wasn't what i wrote at all. i just asked what ppl liked , didnt like and why.

Sun Nov 22, 2020 8:30 am

I like dual WEBER IDF's or HPMX's.... Simple enough?....

Dale

Sun Nov 22, 2020 9:35 am

richardcraineum wrote: the problem here is that you two are reading into my question and assuming im asking ppl to recommend a carburetor for me to use, that wasn't what i wrote at all. i just asked what ppl liked , didnt like and why.

Well in that case...since engine size, use and driving style don't matter.... I'll have to choose the WT-1048 with the WT-257 running a close second. Neither one has a float bowl, only a fuel chamber so there's no splash over. Yeah, they'll run in any position. Banging down, slamming up, running flat out, etc. they don't care.

The WT-1048 is a dedicated high performance carb and will require a lot of tuning to get it to run right but once it does, it does! It's used in boats, aircraft and off road vehicles although I only run it on my tunnel hull race boat, The Whiskey River. Here she is with me driving running down the back straight running in the mid 70's mph.

Sun Nov 22, 2020 10:18 am

Wulfthang wrote: richardcraineum wrote: the problem here is that you two are reading into my question and assuming im asking ppl to recommend a carburetor for me to use, that wasn't what i wrote at all. i just asked what ppl liked , didnt like and why.

Well in that case...since engine size, use and driving style don't matter.... I'll have to choose the WT-1048 with the WT-257 running a close second. Neither one has a float bowl, only a fuel chamber so there's no splash over. Yeah, they'll run in any position. Banging down, slamming up, running flat out, etc. they don't care.

The WT-1048 is a dedicated high performance carb and will require a lot of tuning to get it to run right but once it does, it does! It's used in boats, aircraft and off road vehicles although I only run it on my tunnel hull race boat, The Whiskey River. Here she is with me driving running down the back straight running in the mid 70's mph.

Used to do that years ago.... Ran Deep VEE's (off shore styles) mainly....

Dale

Sun Nov 22, 2020 10:54 am

Yeah, I used to run deep vees when I was running the big Nitro engines .OPS 65's and 90's. Then the fuel got to be to expensive so I switched over to the big block gasoline engines. Nowadays, I run a Zenoah 30cc with a hyped up ignition system and intake system blowing out thru a tuned pipe. It sounds like a giant sized really PO'd Hornet! I design and build my own hulls to match what I want it to do. It's fun!

Tue Nov 24, 2020 11:31 am

OK I will bite but has no VW application that I Know of. The best offroad carb out there is a Rochester Quadrajet running 4 or less PSI fuel pressure. We have been using those off road in our early Broncos from sea level to 8,000 feet elevation from freezing cold to 115 dessert heat. just keep good gaskets under it. it is very impressive what it is capable of. next step up is a couple grand of fuel injection conversion.

Tue Nov 24, 2020 6:35 pm

Over the decades, the most overall wins in the unlimited classes of offroad racing, including Class 1: single seat buggies with unlimited engines; Class 2: Same as Class 1, but 2-seat cars; Class 5 for Baja Bugs with engines unlimited to size except they had to be VW aircooled engines was a Zenith carb. For all of those classes the most common setup was 2180cc, 82mm stroker crank, 92mm cylinders (thin wall...HAH! no problemo dude) and a single Zenith 32NDIX carb. For decades!!!! this was the wining setup.

I myself used a single Weber 40DCNF-12. Same carb used on many Ferraris. Used it on the street/offroad in my Baja for years before I put the engine in my Hi Jumper. Most told me that it wouldn't work offroad because of the float bowl vent. But I blocked the factory vent opening and put a vent fitting in the top of the float bowl. Won races and a championship that way. Beat lots of bigger engines too.
Cool

In the mid 1970s, I was making a living modifying carbs for Man-A-Fre for Toyota Land Cruiser 4x4s. Those were Rochester 2G carbs. I set one up for my Baja to test it on. It worked OK. I liked my Weber better. More responsive and less sensitive to altitude changes, and wider power band. Adjustments were with oversight by Harold Graves, founder of Man-A-Fre, who was famous for his multi carb setups for hot rods. One of those carbs I set up for my friend's Buick V6 in his WW2 Jeep GPW is still there and still working fine. Good carb for that engine and application.

My Baja has been running for about 20 years with a pair of Solex Kadrons. Again...a carb setup that many say won't work offroad because of teh float bowl vent into the throat. But I fixed that with a curved brass tube up into the throat. I works well, so Jeff Laine of Kaddie Shack took the idea and offers a kit for Kadrons with a steel tube welded to the air cleaner stud mount crossbar. When the brass tube in one of my Kadrons broke from fatigue last year, instead of bending another brass one, I bought an offroad kit from Kaddieshack. Works great. I can drive my Baja at race speed on an offroad course like at Barstow, commonly considered the roughest place desert racers race on, and it works great, never floods out from float bowl overflow.

My Favorite carb for offroad???

Still say it depends entirely on the car, engine and how it's used.

Tue Nov 24, 2020 7:16 pm

Wulfthang wrote: richardcraineum wrote: the problem here is that you two are reading into my question and assuming im asking ppl to recommend a carburetor for me to use, that wasn't what i wrote at all. i just asked what ppl liked , didnt like and why.

Well in that case...since engine size, use and driving style don't matter.... I'll have to choose the WT-1048 with the WT-257 running a close second. Neither one has a float bowl, only a fuel chamber so there's no splash over. Yeah, they'll run in any position. Banging down, slamming up, running flat out, etc. they don't care.

The WT-1048 is a dedicated high performance carb and will require a lot of tuning to get it to run right but once it does, it does! It's used in boats, aircraft and off road vehicles although I only run it on my tunnel hull race boat, The Whiskey River. Here she is with me driving running down the back straight running in the mid 70's mph.

How about pressure feed carburetors used on old airplanes? That’s pretty off road...and you could pull negative G in those suckers. :lol:

Tue Nov 24, 2020 9:19 pm

Dusty, can you elaborate more on what you tended to see with those Zenith carbs? Did they tend to be the plenum type cast manifolds, or the individual runner manifolds usually made of mandrel bent steel?

Also, do you know what the "usual" cam was in an engine like you describe?

Tue Nov 24, 2020 9:31 pm

Vanapplebomb wrote: Wulfthang wrote: richardcraineum wrote: the problem here is that you two are reading into my question and assuming im asking ppl to recommend a carburetor for me to use, that wasn't what i wrote at all. i just asked what ppl liked , didnt like and why.

Well in that case...since engine size, use and driving style don't matter.... I'll have to choose the WT-1048 with the WT-257 running a close second. Neither one has a float bowl, only a fuel chamber so there's no splash over. Yeah, they'll run in any position. Banging down, slamming up, running flat out, etc. they don't care.

The WT-1048 is a dedicated high performance carb and will require a lot of tuning to get it to run right but once it does, it does! It's used in boats, aircraft and off road vehicles although I only run it on my tunnel hull race boat, The Whiskey River. Here she is with me driving running down the back straight running in the mid 70's mph.

How about pressure feed carburetors used on old airplanes? That’s pretty off road...and you could pull negative G in those suckers. :lol:

Those old carbs were really more like fuel injectors than carbs. The engines were running on Nitromethanol. I used to run the big marine OPS nitro engines...the .65's and .90's but I modified them very heavily. I machined my own exhaust and intake manifolds and heads for them. The stock carb/injectors were not large enough so I machined them too. They ran pretty good but were fule hogs big time. The price of fuel is what convinced me to switch over to big block gasoline powered marine engines.

I used to fly airplanes...uhhh ok ok, I used to crash them a lot! Like all of the time. I got tired of taking them home in garbage bags so now I just run the boats. A major high speed crash requires drying out the engine and that's usually it. Most of the time, the physical damage is very minor.

Wed Nov 25, 2020 1:00 pm

No no, not little RC nitro engines. I’m talking the WWII era aircraft, like the big V12 or Radial cylinder engines with the gigantic pressure feed carbs. Very clever design. Surprised it didn’t catch on in more applications.