TheSamba.com :: View topic - Holley 94 vs Holley Bugspray- 200cfm

Thu Nov 04, 2021 1:45 pm

HI, Im new to the forum, Ive had my first bug for about 8 months now. Its a 1971 VW Superbeetle with a 1600 and a pict 34. The only mod I've done is an empi exhaust and a chrome aircleaner. I am car guy though, so I did my research and found out that these little motors are very restricted in the intake and the exhaust. I already did the exhaust so now its off to the intake. I have a Holley 94, the reg 94, flows about 185cfm from what I could find. I know the pict 34 flows about 115cfm from what I could find. The intakes for the 1600 look very simple just a pipe with a tee and flange. I have adapter to mount the holley 94 on the regular intake, but I was wondering has anybody used a holley 94 and/or made an intake or similar to get it to work. IS there any real difference between the holley 94 and the bugspray other than the base? I can make an intake out of copper plumbing fittings, I have them laying everywhere. Ive gotten lots of great info from this forum and this is defiantly the pace to ask this question. This is a great forum.

Thu Nov 04, 2021 9:32 pm

I like Holley Bugsprays for nostalgic look and good power on the cheap. They are old and parts are sometimes hard to come buy and may have vacuum leaks especially on the throttle shaft.

I've used different types of intake manifolds for them:

The most recent one I had was 1 5/30, but I do remember using a 94 and I think the other was a 210? not sure.

You will get great acceleration but idle will be rough and rich to keep it running.

Fri Nov 05, 2021 1:25 am

THe deano/racetrim plenum manifold like above seems to be about the best of it's kind, and the best carb to put on it might be a weber DCN with very small venturis or something like that.
This manifold and carbs usually used on it are really too large to work with a near stock 1600, including the 200cfm bugspray. It was a little too big to work right in 1971 and not much has changed. A two barrel carb that only flows 150cfm is not easy to find. So why use a two barrel carb? who knows why they thought of it, maybe same reason you did? LOL But at the core there are a few reason it works pretty good, and if you understand that then you might have something, and could make a minature version of that.
And if you don't get why it works then you will end up wasting your time.
Not every combination of some carburetor atop any random combo of plumbing fittings is going to have the same flow characteristics and wet flow benefits, ect.

Working on the handlebar intake has gone a lot of nowhere in three generations of motorheads trying everything, but it is understandable because ultimately it is limited.
No carburetor tricks and No amount of enlargening or reshaping of the junctions can fully overcome the drawbacks of using the overly long "handlebar" intake.

Connecting the tubes in that particular way just does what it does. If you like it, great. If you don't like it.... your never going to like it. You can put any carb or any fuel injection system ON there it's still going to be what it is. Putting a turbo in place of the stock carb seems to be the best strategy to make that thing work, but that too is limited, out of style these days.
If you have to have an intercooler and fuel injection then it kind of defeats the elegance of just ramming hot fuel and air into that handlebar intake with a impeller :wink:

So what is the next alternative to feeding all the cylinders with one carb/plenum?
Would be what we call an isolated manifold. The left and right sides are separate. Gets rid of over half the "monkey motion" in the system but actually makes the length problem worse. Even so, it will be the superior set-up in the 2500-4500 rpm range. Since a stock engine is done by 4500 it would be the better choice, although with a cam and some headwork that limit goes away quick.
What the V8 guys don't seem to get is when you divide the manifold then that's a totally different CFM requirements. Using each side of the carburetor only 60% of the time, then you need a carburetor at least 66% larger than if BOTH barrels feed everything. And that's how the bugspray kits were engineered to work officially.....on an isolated manifold, before being re-arranged in every possible way with varying results. But it wasn't great anyway because that carb is pretty crude circuits and lacks the adjustability to really get it jetted right for that kind of application, so it isn't really the best unit FOR that job. They had a "balance slot" cut in the throttle body that connected the two sides in what was apparently just the right size to make the jetting right, and by right I guess right enough for 1970 is a little more lax than today.
The european carbs so popular now end up being better when you are feeding one or two cylinders with each barrel because they are designed FOR that, they are designed for IR intakes (independent runner).
The best single carb isolated manifold setup IMO is a 40 dellorto on a CB low profile intake. And jet again there are a handful of details of both the intake and the carb that make it a very good setup, which aren't clear at first glance.

The next logical step past that, (to get rid of the length problem) is dual carburetors, or port fuel injection.

There are other possibilities not commonly tried, but pretty much everything has been tried at least a few times by now.

Got the "holley sniper" discussion right next door..... I'm staying out of that.
They think any FUEL INJECTION atop any random arrangement of plumming fittings will be the cats ass....... we'll see. Not saying YOU think that either, just a funny example of how some seem to think. In some sense it's thanks to such bullheadedness that we can learn what every combination does.

Fri Nov 05, 2021 2:17 am

Well that was more tangent than answer but, anyway.
Most of what changes holley made to the carburetor.... the slot between the throttles, eliminating the power valve, and whatever else I can't recall, were mainly for adapting it to work on an isolated manifold.
Copying this would be a period correct accessory and it worked Ok.

Putting it on a plenum type manifold most of this would not be needed, so you might be better off to just give it a shot and see what happens and adjust as needed BUT in that configuration it's rather too large for a near stock engine.

Fri Nov 05, 2021 6:55 am

modok wrote: THe deano/racetrim plenum manifold like above seems to be about the best of it's kind, and the best carb to put on it might be a weber DCN with very small venturis or something like that.
This manifold and carbs usually used on it are really too large to work with a near stock 1600, including the 200cfm bugspray. It was a little too big to work right in 1971 and not much has changed. A two barrel carb that only flows 150cfm is not easy to find.

You know, it's funny you mention that being the best.

A few years ago when I was less knowledgable and more stubborn ( :D ) a buddy wanted help on a new purchase- a 63 Baja Ragtop with a 1915 and some really nice old school parts- a mallory mechanical advance distributor, Delta mark 10 CDI, a bugspray on a Deano setup just like the one shown above- along with deano valve covers, hurst shifter, mustard brown carpet, ford mustang wheels, and seats from some other 70's car. A real time capsule of a car. We took some time getting it all dialed in and that car ran very well, even with a cheap bugpack bobtail header with as-shipped preheat. It wasn't a high RPM screamer, but I was very surprised at how torquey and strong that car was.

I'm still mad he wrecked it after a night of drinking. Dumbass :evil:

Fri Nov 05, 2021 9:09 am

Hi, thank you all very much for the information. I’m not looking to re-invent the wheel, but I understand the limitations of the “handlebar” style intake manifold. From my years of playing with different combinations of V8 intakes and carbs I kinda understand why the bugspray doesn’t like the open plenum manifold but does make power once in the gas running up in the higher rpm ranges. I’ve looked online for the cfm ratings of kadrons, webers and other such carbs and the cfm rating is way above what the single Holley 94 is. I read that the cfm rating of the 40mm Kadron is 165 cfm, that’s just for 2 cylinders not 4 because there are2 of them one for each bank of 2. If I was to extent the mounting flanges so the kadrons would be mounted side by side in the center, then it would be a combined total of 330cfm for the entire 4 cylinders. Im a bit perplexed as to why this amount of cfm works but a 200-300 cfm bugspray does not. Is the handlebar style intake “that” terrible that it just doesn’t have any good flow characteristics at all no matter how nicely designed a better flowing intake looks? Could it be timing? Could it be lack of compression? Could it be intake manifold flow velocity? Any ideas? Being a relatively new 1st time bug owner this little car has captured all of my curiosity.

Fri Nov 05, 2021 10:54 am

Lets say you have a three similar engines

-1 cylinder 500cc engine
-2 cylinder 1000cc engine
-3 cylinder 1500cc engine

They all use the same carburetor size.
no matter if they have 1 carburetor, or one carburetor on each cylinder
because the carburetor is sized to the peak flow that occurs during the intake stroke and not the average flow.
There is no real flow when the intake valve is closed. In the three cylinder only one intake valve is open at any given time. So several cylinders can share a carburetor just fine if they take turns.

With four cylinders the intake pulses overlap slightly so then it can get more complex, and go either way. if the intake manifold acts to SMOOTH the flow then the peak CFM demand is lower, if the intake strokes overlapping and "stacking up" makes for high peaks then the peak CFM is higher.
But even so close enough. A kadron is about the right size no matter if you use one on each cylinder or one for the whole engine. This is why carb companies don't use CFM to rate carbs for 1 and 2 cylinder engines, they just go by the size of the venturi and throttle bore, which is easy to compare to the intake valve size and port throat size. One cannot flow more than the other if they are directly connected.

Fri Nov 05, 2021 3:34 pm

Because the Bug spray was one barrel was for 1&2 and the other was for 3&4 and because of the pulsing booster ventures were added above the butterflys to recapture the air/fuel mix being blown out the top and send it back down acting like a power valve. Holly still has parts and Hollys are completely adjustable to fit a lot of applications. I have a set of Dual Deno manifolds for Holly Bug sprays and two Bug sprays that came with them, I made some adaptors for then to fit my 356 heads and can't wait for the weather to warm up to put this together.

Fri Nov 05, 2021 4:11 pm

Does anyone sell rebuilt/new Bug sprays? I had one years ago on my first stroker, loved it. What year cars were they on, or trucks?

Fri Nov 05, 2021 4:25 pm

chrisflstf wrote: Does anyone sell rebuilt/new Bug sprays? I had one years ago on my first stroker, loved it. What year cars were they on, or trucks?

They were for 40 HP single port motors so you need to make a manifold. there are two models 200 and 300 cfm. EBay or classifieds here.

Fri Nov 05, 2021 4:37 pm

The holley 94 was used on a lot of flathead fords, so they were lots of them made.

In the 70's and 80's a weber carb was 4x more expensive than an old holley.

Fri Nov 05, 2021 7:02 pm

a holley bug spray carb . WHY ???? THEY WERE A JUNK CARB back in the 1970s .with all the new carbs that are being sold now a days that will make more power than any bug spray carb . oh well you will find out for your self .lol lol your running the wrong intake . to start with . you will have to jet the carb rich .to run that intake you better set the dizy up for 12degs intal.all in by 32degs total never use a vac. disy run 1LB to 1 1/2 lbs fuel pressure good luck you will need it spencerfvee

Fri Nov 05, 2021 7:36 pm

Boy spenserfv must have hade to use the #1 cob because holly used the #3 and took the #2 with her.

Fri Nov 05, 2021 8:06 pm

I Really like the orange manifolds. Looks great.

Fri Nov 05, 2021 8:13 pm

chrisflstf wrote: Does anyone sell rebuilt/new Bug sprays? I had one years ago on my first stroker, loved it. What year cars were they on, or trucks?

Try Dave at Bug City in CT.
Talk to him. He can steer you straight.

Fri Nov 05, 2021 10:32 pm

From what I have read Holley changed the Pilot circuit and the Emulsion passages to get a Bugspray to work on a VW, The three I have all have power valve plugs in them does a 94 have a power valve in it? Speedway Motors sells rebuild kits for 94's and it has a 4 bolt gasket so it should work in a Bugspray too, they also have new throttle shafts that can be used in a bug spray with a little work.
Also so you know a Kadron velocity stack will fit a bug spray...

eQ

Fri Nov 05, 2021 11:21 pm

Here's the vid of the one running:

PM me if you're interested in this set up

with some extras from a sacrificed bug spray included

I would go to Bug shows in the 80s-90s and grab holley bugsprays from the swap meet area any where between $5-$100 because parts.

I was extremely satisfied on the power delivery compared to my 40 dual Webers on the 1904cc; the worst thing was the idle after coming off of a high speed run, it would load up a bit and die, but also running it on a buggy it's very cold, even with heat risers it would chill and freeze, especially the large plenum. I couldn't find a dual plenum when I was recreating the '69 look from when we bought the buggy so went with the single.

Sat Nov 06, 2021 11:38 am

Wow a lot of good info. Ive been thinking a lot of what you all say in that it works good but the idle is kinda crappy, but better on a dual runner style but still not great. This has me thinking, in the V8 world, whenever I put a holley 650/750 or whatever on top of a single plane open manifold it ran like hell but had a crappy idle unless ran a bit rich and it would stall on occasion when taking my foot off the gas after a run. I could get around this by using a 4 hole spacer under the carb and this would extend the barrels/venturis another 3/4 to 1 inch amplifying the weak signal the carb was getting because of the single plane intake. has anyone ever though about using the bug spray on a thin spacer with tubes on it that extend the carbs ventures into the open plenum a bit to give the carb a better signal so it meters correctly at idle? a full spacer would probly bring the carb up too high.

Sat Nov 06, 2021 12:21 pm

The idle problem came from no manifold preheat tube on the early manifolds so most people kept the idle high to keep the gas vapor from falling out of suspension and stalling the motor. With a properly heated manifold idle should be no problem.

Sat Nov 06, 2021 2:54 pm

I'm with Spencervee on this one.

I ran Bugsprays for many years as a kid in my only car, daily driven.

Of course I had to run the bugspray because it was a performance item.

They leak fuel after shut down. Inlet valves cannot take much fuel pressure so they drip gas down the intake and out the throttle shafts. Washing the rings right out of your fresh motor.

You gotta set the fuel level lower in the bowel or it will flood out with a hard stop down a hill.

it drops 2 cyls under hard cornering.

Horrible flat spot just off idle that kills milage.
The accelerator pump seals would harden up and just stop working. New seals worked great for about a few months, then the flat spot is back.

I remember the day I installed my dual 44IDF Webers and gave away the bugsprays forever. ( I had a box of them and all kinds of spares).