Progressive Warm air intake fix

[Ozzaholic]

A couple years ago I decided to go the progressive route, put everything together in Winter and immediately had troubles with icing.
After reading here and other sites I came up with a cookie tin fix that worked pretty well but was flimsy. It ran on the car for about 2 months with no troubles before the car died.

Now a year and a half later i got my new project with progressive going right during the coldest week of the year.
I read this thread, http://www.thesamba.com/vw/forum/viewtopic.php?t=386388&highlight=weber+progressive.

I changed my pre heat set up so one goes to the collector and came up with this hot air intake box to pre heat the carb air. I think this could be used on other carbs also.

A $22 electrical junction box, 2 heater tube rings, Heater tube.

Used the air cleaner bottom, and ring to mark the bottom of box and cut out.

Silliconed the air cleaner base to the box and bolted to carb. Don't forget to put in your air cleaner clips , I found 4 works best.

Welded one heat tube ring to the exhaust near the collector.

With the cold weather we are having lately I hope this helps someone.
In the warm weather I plan on disconnecting the hose from the collector and run it else where or just take the hose off.

So far with just a couple short drives it works great, my carb and manifold are warm to the touch when they used to be covered in frost.
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We have Desert in Oregon too

'68 Baja swing stock RIP cancer
'74 Baja IRS stock RIP Big rock, cancer
'71 Baja 002, raised current project

[joescoolcustoms]

Now that is thinking!

Nice job.
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Bad News Racing 2018 NORRA 1000 3rd in Class
Best Day Ever Racing 2022 NORRA 1000 2nd in Class and first All Female team to complete the race

Everyone is gifted. Some just do not open the package.

Looks like it was painted with a live chicken,polished with a brick and buffed with a pine cone

[Ozzaholic]

Thanks, I was looking into a tractor air cleaner and try to modify the same set up, but just the cleaner housing was $98 and then $30 for a filter.
I think this works just as well and fits better.
_________________
We have Desert in Oregon too

'68 Baja swing stock RIP cancer
'74 Baja IRS stock RIP Big rock, cancer
'71 Baja 002, raised current project

[2RL]

i like it. have you noticed any restriction/loss of power sucking air through a smaller intake like that? your box idea has me thinking of a similar idea for duals.... but for an entirely different reason.

[Ozzaholic]

That is one thing I have been thinking about. I didn't have a problem last time I ran it but that was with a tired motor and I didn't really push it hard.
I will be testing that and see if there is a restriction. I'll run it with the lid off and see if there is any difference.
Worst case I run another hose to the other side of the collector.
So far the plastic box is rigid, I think it would sit on duals, and they come in different sizes.

Thanks for the input.
_________________
We have Desert in Oregon too

'68 Baja swing stock RIP cancer
'74 Baja IRS stock RIP Big rock, cancer
'71 Baja 002, raised current project

[dixon_cass]

im thinking that would work great to re route the intake to higher ground. im thinking run the tube to the top of the vehicle to get cleaner air.
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http://www.thesamba.com/vw/forum/viewtopic.php?p=5224965#5224965

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[2RL]

i wonder if theres a way you could adapt a thermac (thermostatic air cleaner )setup from something like an older chevy or ford air cleaner to the box . the idea would be to just have the preheat active when you need it most, then it would switch itself over to cold air once things get up to temp.... it might work, but it'd take some trial and error for sure. heres some food for thought on the subject
http://arrc.epnet.com/autoapp/9110/9110CH04_Thermostatic_Air_Cleaner__THERM.htm

[Ozzaholic]

To route to higher ground you could cut the hole on top or side with no problem, I thought about a snorkel set up also.

The box is strong enough that you could mount one of those units to it, That ran across my mind also.
From information I got from a respected source, I should be able to run it with the heat on till about 90 deg, which isn't till late Summer here.
_________________
We have Desert in Oregon too

'68 Baja swing stock RIP cancer
'74 Baja IRS stock RIP Big rock, cancer
'71 Baja 002, raised current project

[joescoolcustoms]

I was thinking about a rubber flap to operate like a reed valve. At low air flow it stays shut pulling the warmer air in, but in wide open throttle a negative pressure inside the box would pull the flap open increasing the air flow to the air filter.

Or a manual choke wire operating a slider that the driver can pull open when performance is needed exposing an additional opening.
_________________
Bad News Racing 2018 NORRA 1000 3rd in Class
Best Day Ever Racing 2022 NORRA 1000 2nd in Class and first All Female team to complete the race

Everyone is gifted. Some just do not open the package.

Looks like it was painted with a live chicken,polished with a brick and buffed with a pine cone

[Ozzaholic]

Both excellent ideas, I think I will experiment with the rubber flap idea.

Got a sick boy at home so I can't experiment yet, maybe this weekend.

Thanks for the ideas.
_________________
We have Desert in Oregon too

'68 Baja swing stock RIP cancer
'74 Baja IRS stock RIP Big rock, cancer
'71 Baja 002, raised current project

[Ozzaholic]

I was finally able to get out and play this weekend. Took a nice high speed 45 mile gravel road loop.

YES there is restriction.
I didn't notice it in town, but on the way home there are a lot of long straight stretches.
I took the top off the box and did notice some acceleration gain, and gained 5 MPH all out.

So I immediately started to implement one of Joescoolcustoms ideas I had been thinking about.
Here's what I came up with.

The tube hole is 2", the new relief hole is 1 1/2". The carb intakes are both 1 1/2".

I used a piece of truck tube and it just lays there for now, I will see how it works and if I need to rivet the other side down.
I have a remote camera I am thinking about mounting either inside or underneath the box to watch how this works, We'll see how ambitious I get.
_________________
We have Desert in Oregon too

'68 Baja swing stock RIP cancer
'74 Baja IRS stock RIP Big rock, cancer
'71 Baja 002, raised current project

[veeweeman]

That's a pretty sweet setup...it's good to see some ingenuity using modern day products...do you have factory heat riser tubes hooked up?

VeeWee

[Ozzaholic]

Thanks. I have the heat riser attached on the one side (R), and the other goes into the collector.
It draws the exhaust through better. I have a cheap manifold.
_________________
We have Desert in Oregon too

'68 Baja swing stock RIP cancer
'74 Baja IRS stock RIP Big rock, cancer
'71 Baja 002, raised current project

[twomonkeysayoyo]

Okay, school me on this:

I thought you wanted cold air (high density) on the intake, and to keep it gaseous on it's way through the manifold. With this setup aren't you just pumping in hot air (less dense) as a workaround for the long manifold length instead of using manifold heat to keep cold air/fuel mix just this side of liquid?
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Looks like trouble.

[Ozzaholic]

I am by no means an expert, I am experimenting with ideas I have picked up from reading this and other forums, and limited experiences with the progressive.
That being said, Here is what I have learned, Please add to or correct me if I'm wrong.
This article [/url]http://www.thesamba.com/vw/forum/viewtopic.php?t=386388&highlight=weber+progressive.[url] confirmed a lot of what I had thought and found through trial and error.

This seams to be more of a problem with the progressive, but I have seen it on other carbs, although eventually the pre heat is enough to melt it off.
Most cars use pre heat that is routed through a thermostat that opens to cool air when the engine is warmed up. They are also surrounded by metal and insulation, so when the thermostat opens to cool air, most of the components around it in the engine compartment are warm and getting warmer, so it is still drawing warm air to a degree, specially on hot days.
On a Baja the engine is surrounded by cold air and with the progressives amount of fuel air flow, along with the thick aluminum intake and long run, It needs a lot of warm air to keep the fuel suspended.
With out the pre heat the fuel puddles up and runs into the cylinders.
Some manifolds have the pre heat go up to the base of the carb, the cheap ones (like mine) don't.

The stock manifold pre heat doesn't work properly with after market exhaust. Instead of flowing through and heating it pulses back and forth doing nothing really. To fix this run one pre heat tube to the collector of the exhaust this draws the exhaust through and heats the manifold really well.

But as thick as the progressives manifold is the pre heat doesn't warm the top, and the cold air/ fuel takes over causing icing.
That's where the warm air intake comes in. The warm air heats the carb and top of manifold and warms the fuel making it easier to suspend in the air mix.
With the whole intake warm the fuel stays suspended and doesn't cling and puddle in the manifold.

I have read in a post a concern about too much hot air causing detonation and over heating problems. I can believe that in a hot climate ( you probably aren't reading this, or think I'm nuts). But when you think about that hot engine surrounded by hot insulation on 110* day, how hot is too hot?, and all I have to do is disconnect the hot air tube.

Also on the air density, I live and drive at 4500' and above, so that might help me, I'm not sure. I thought that is what the jets and air correctors were for, but as I said I'm no expert.

Long winded but I hope it helps, someone
_________________
We have Desert in Oregon too

'68 Baja swing stock RIP cancer
'74 Baja IRS stock RIP Big rock, cancer
'71 Baja 002, raised current project

[joescoolcustoms]

[veeweeman]

You know another mod you can try I just thought of would be to tap into your oil supply and run some rubber hose around the intake and through a oil cooler...this could actually serve well, it could keep your intake from icing up in the winter and if you installed a bypass valve you can just shut it off in the summer...so the oil would run from the engine, wrap around the intake to keep it warm and return to the engine or run it through a cooler...then in the summer warmer weather just detour the oil flow from the engine, through a cooler and back to the engine...just a though I just came up with...I still like your intake box ideal a lot...here where I live we get a lot of sand dust storms and our filters get dirty really fast...your box ideal would cut down on the direct contact to the air filter.

VeeWee

[Ozzaholic]

I had thought about wrapping the manifold with a copper tube and run the oil through, but then I read about the reaction with Copper and oil, and the limited space around the manifold ruled that out.
I have found a few people that run oil through the preheat on the manifold.
I would think about that with a newer manifold or one you cleaned out really well. It would be my luck a giant carbon plug would break loose and cause problems.

With my first box made of a metal, the whole idea was for the pre heat. I was trying this time to use a remote filter box like a tractor and incorporate the hot air, the cost of the tractor box was way too much, and had no place to mount close enough.
Then while walking thru Home Depot I found this box and it all clicked.

It protects the air cleaner very well. I have been out and had so much mud on the air cleaner it wouldn't run, not a problem with this set up
_________________
We have Desert in Oregon too

'68 Baja swing stock RIP cancer
'74 Baja IRS stock RIP Big rock, cancer
'71 Baja 002, raised current project

[Vanapplebomb]

Thread back from the dead.

I was cruising youtube and came across this video which reminded me of this old thread. The first 45 seconds or so shows how this guy hooked is weber progressive to the busses factory air cleaner for preheat. For those of you who don't care for oil bath air cleaners you can substitute a paper or cotton/gauze filter. This mod has been done here on TheSamba to this exact air cleaner. You could easily rig something up like this for progressive carbs.


Link

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1800 Type 4 Berrien 295

http://www.thesamba.com/vw/forum/viewtopic.php?t=487021

[ORANGECRUSHer]

I made a heat riser for my Weber years ago. IMO it's not even worth the thought. You can't polish a turd. Progressives are cheap for a reason.
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Brian H.
I may not know everything,but I will try to help if I can
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