Need some help with offroad airbox intake setup

[ORANGECRUSHer]

Hi guys, been a bit. I've made some changes to the intake system that I'm trying to get a handle on and I'm hoping I can get some experienced input on how to go about adjusting my carburetors in the most intelligent way possible.
engine stats:
2110 with dual chinese IDF44's, Empi runners, 1/2" bobcat exhaust

I was wanting better filtration for this car which is meant to run offroad so I fabricated some aluminum airboxes from which I could plumb two Donaldson Power Core filter housings. They are similar to the boxes that can be had from Kartek for a few hundred dollars except mine have a 3.5" inlet that is offset in order to clear my baja bodywork.

This is how they look on the car today.

The issue that I didn't think about before I started this project and is now a very big pain in my butt is that carb adjustments are no longer and easy task. The new intakes have made re-jetting neccessary. I've gone leaner as I think I have more restriction than before. I could have been a little rich before anyway. I went down in my main as well as my idle, but I have a big flat spot right in the transition so right now I'm preparing to go up in the AIRs to bring the mains down in the RPMs.

This is where my problem comes in.

I have to pull the engine in order to do any main stack adjustments. The first time I tried to remove the airboxes with the engine in the car turned into a 4 hour profanity-fest. I can't reach the nuts that hold them on easily. I even cut a 10mm boxend and re-welded it with a 90 to try to reach the nuts better. I've found it's easier to just pull the engine and work on it that way.

Syncing the carbs is also a problem. I have to do this with the airboxes off, and a spare set of airhorns installed. The engine needs to be temporarily installed. That ends up being two engine pulls.

I know plenty of other people have run these things and had the same issues and I'm wondering what they figured out works best. Granted, a lot of them are probably on tube frame rails which makes it a whole lot easier proposition, but some of the problems still remain.

Is there another way to sync besides using a snail in the venturis?? Perhaps using vacuum gauges on the vacuum ports?? I have vacuum ports in all four of my runners used by my Megajolt system. Could I use these somehow? They are after the carbs so I'm not sure how that makes a difference. Measuring vacuum at each runner and making them equal would be something I could do without having to pull the engine. And it's so easy to loose my balance when I'm tuning and adjusting the idle speeds on separate carbs.

I'm really curious if anyone has anything interesting to share that I haven't thought of. I'd also like to discuss what kind of changes people think I may experience in the operation of this engine now that I have this new intake installed. Seems like the increased velocity stack alone could cause it to want to run better in the high end rather than where I need it in the low end....
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Brian H.

OrangeCrushERBerrien Warrior-2.4L Quad4-2x3 arms-1.5Fox coilovers-094-930CVs
LAZY MARY1970 Baja 2110cc-82mm CB forged crank-AA pistons/cylinders-Grant rings-1.1 vw rockers-CB serpkit-CB chromoly PRs-CB maxiflow filter pump-wix51515 filter-Dual 44IDF-cut/turned front beam-AEM wideband-Auber CHT-Donaldson Dual PowerCore filters-custom AL air boxes

[Brian_e]

Nice work on the boxes. I can see how they would be tough to work on.

On the flat angled panel, could you make an access cover? Even a 2"x2" bolt on cover looks like it might allow just enough room to get to the jet stacks in the middle of the carb?

You can sync them with vac. no problem, and it works very well. There are some really cool 4cyl motorcycle sync tools out there, but most are kinda $$.

With my first set of kadrons, I used a 3' long 2x4 with about 9' of 3/8 clear plastic tube. The plastic tube ran down the upright 2x4, and made a U at the bottom. Each open end hooked to the kadron manifold port. I used 2 stroke oil in the tube for the fluid. Fill the tube till the level is about half way up the board in both tubes. Fire up the engine, and adjust the carbs till the levels in the two tubes were even. It worked great. I never did it, but putting a main jet, or a welder tip in both hoses would probably slow the pluses down and make it a little more steady and easier to read.

Brian
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[rayjay]

Fab up an idle speed adjusting screw mechanism that mounts in the center of the hex bar and remove the 2 idle speed adjusting screws from the carbs. Now your synchronization rarely needs messing with.

Yes, you can use a manometer to check synchronization. Google "carb sticks". All you need is a vacuum port below the throttle blades.

Multicylinder motorcycles have been doing the above since the late 60s. Archaic carb sync procedures and distributor advance curves are probably the main 2 areas where ACVW technical know how is drastically lagging.

[67rustavenger]

[chrisflstf]

I cant help. but I like those filters. They are huge!. Look at how small the distributor looks

[ORANGECRUSHer]

Great suggestions! thanks

I used to sync motorcycles all the time. I have an old Kawasaki manometer from probably the 90's. It came in a kit from Kawasaki. It was a plastic device with four glass tubes and lengths of vacuum hose. You had to assemble it and then measure equal amounts of mercury into each tube. There were places to park the ends of the tubes on the back of it when you were using it so that it softened the pulses. I still have it leaning against the wall behind a toolbox, but overtime it developed gaps in the mercury from being moved around and probably inadvertently falling over. It was $75 which I thought was expensive at the time. I always wanted the one that was black and had the steel bearings in it instead of the mercury but it was about twice the price. I don't know why I was so cheap with my tools when I was younger??

I suppose I could give that a try again.

Brian I like your idea for a removable plate to get at the stacks. However, I built this to be as dirt proof as possible. I don't get clogged idles like I used to. If I made doors that would be one more entry point I'd have to worry about. I just may have to do it though. Pulling the engine is going to wear out that poor little transmission.
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Brian H.

OrangeCrushERBerrien Warrior-2.4L Quad4-2x3 arms-1.5Fox coilovers-094-930CVs
LAZY MARY1970 Baja 2110cc-82mm CB forged crank-AA pistons/cylinders-Grant rings-1.1 vw rockers-CB serpkit-CB chromoly PRs-CB maxiflow filter pump-wix51515 filter-Dual 44IDF-cut/turned front beam-AEM wideband-Auber CHT-Donaldson Dual PowerCore filters-custom AL air boxes

[EVfun]

[ORANGECRUSHer]

Yeah I don't see how you could completly remove the idle screws and have nothing to sync with from side to side...
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Brian H.

OrangeCrushERBerrien Warrior-2.4L Quad4-2x3 arms-1.5Fox coilovers-094-930CVs
LAZY MARY1970 Baja 2110cc-82mm CB forged crank-AA pistons/cylinders-Grant rings-1.1 vw rockers-CB serpkit-CB chromoly PRs-CB maxiflow filter pump-wix51515 filter-Dual 44IDF-cut/turned front beam-AEM wideband-Auber CHT-Donaldson Dual PowerCore filters-custom AL air boxes

[ORANGECRUSHer]

[67rustavenger]

Mmm K. How about if, you box in the lower section around the velocity stacks and create an access hole through the upper filter housing and the lower velocity stack housing to access the main jet stacks?
You could use a spring loaded screw starter, like this one.

It's a Cornwell tool I buy from pawn shops here when I need one.

Just thinking things through here.
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[ORANGECRUSHer]

[rayjay]

[rayjay]

[modok]

I'm not seeing the vent hole for the jets and float bowl.
Maybe it's there, I'm just not seeing it?
Did you drill a hole in the side or something?

[oprn]

The air cleaners on my street Buggy cannot be serviced with the carbs in place due to a lack of head room. The carbs have to come off. This means that the carbs have to be re-synced every time I clean the air filters. And of course all that makes it impossible to use any kind of "snail" device to sync them.

This is what I built out of two juice bottles and a bit of 1/8" plastic tube. Water with a bit of food coloring and hook it up to the ports below the throttle plates. It works excellent!

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Our cars get old, we get old but driving an old VW never gets old!

[esde]

What nuts are you using to secure the airboxes? They make nuts for an M8-1.25 stud that have a10, 11, or 12mm flat, so that you have more room for the wrench. Situations like this is where they shine
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modok wrote:
Bent cranks are silent but gather no moss. I mean, ah, something like that.

[ORANGECRUSHer]

[ORANGECRUSHer]

[ORANGECRUSHer]

I'm super glad now I installed these ports for a MAP sensor.

[url]


Not really crazy about butchering my new boxes to add doors to them right now. I think I'll just put up with it for the season. Maybe next winter I'll fab up a new set with improvements. Be nice if I could get someone to laser cut them and make them real nice.[/url]
_________________
Brian H.

OrangeCrushERBerrien Warrior-2.4L Quad4-2x3 arms-1.5Fox coilovers-094-930CVs
LAZY MARY1970 Baja 2110cc-82mm CB forged crank-AA pistons/cylinders-Grant rings-1.1 vw rockers-CB serpkit-CB chromoly PRs-CB maxiflow filter pump-wix51515 filter-Dual 44IDF-cut/turned front beam-AEM wideband-Auber CHT-Donaldson Dual PowerCore filters-custom AL air boxes

[ORANGECRUSHer]

I think I would also try to source some thinner stack tubing to give more room for turning the mounting nuts.
_________________
Brian H.

OrangeCrushERBerrien Warrior-2.4L Quad4-2x3 arms-1.5Fox coilovers-094-930CVs
LAZY MARY1970 Baja 2110cc-82mm CB forged crank-AA pistons/cylinders-Grant rings-1.1 vw rockers-CB serpkit-CB chromoly PRs-CB maxiflow filter pump-wix51515 filter-Dual 44IDF-cut/turned front beam-AEM wideband-Auber CHT-Donaldson Dual PowerCore filters-custom AL air boxes