Just read a thread comparing the virtues of different carb setups and came across a link for a company selling duel single Kadron carb kits for the type 4 engines.

http://www.shop.kaddieshack.com/BRAND-NEW-...20L-43-4520.htm

I'd never really heard anyone on this board talk much about the duel single-choke carbs as a viable option. It sounds like a nice compromise between the efficiency of a stock D-jet and power of duel twin-choke Webers or Dells.

Has anyone used this setup for a 2.0 engine before and if so what cam did you use?

Thanks,

John

Actually, Porsche did fit the 914 with dual Solexes at one time ( I think it was the ROW 1.8), so they can certainly work.

The carb position over the ports would alleviate the problems caused by the center mounted carb, and they should be able to be balanced easily. Though the power may not be comparable to that found by the dual setups, they should be OK. Unless you've changed the camshaft, I don't know how much switching to carbs really helps (unless the original, good working, fuel injection system is kaput and can't be repaired).

Back in the day, I sold a ton of those things for T1s, and they worked great. They're a descendent of the 40mm Solexes found on the 356 1500 Super. In my experience, and other shop owners have agreed with me, they're not all that good on a T4.

The Cap'n

Does anyone have any pictures of a 914 with dual carbs from the factory?
Never seen one and I can't imagine they are all gone, if in fact they ever existed...

Rich

I don't have a pic of them installed in a 914 but here is what they look like ...

Not that rare, exact same set up came on the 1.8 carbed buses.

I put them on a 1.8 and loved them. We put them on a 1.7 in Linda's Horne's car and it seemed a little down on power but she didn't mind, and she got great MPG. I now have the same carbs in my bug on a 2110. It is fun to drive.
This car has duel Soles's singles on it.

Click to view attachment

http://www.914world.com/bbs2/index.php?sho...102737&st=0

There's an inherent problem with dual singles on a flat four engine.
The intake pulses aren't timed properly for good balance of the air/fuel charge.
This becomes really apparent if any sort of performance camshaft is installed.

The engine firing order, being 4,3, 2,1 means one carb does 2 intake pulses sequentially and then waits one full crank revolution for the other carb to do its 2 intake pulses.
The result is that the forward cylinders (2 & 4) run at one mixture and the two rear cylinders (1 & 3) at a very different mixture.
This is exacerbated by reversion from any cam overlap which will further screw up the second pulse on both carbs.

Combined with the rather short intake runners typical of a dual carb installation, an engine with a performance cam and dual singles can not be tuned to run well.

That makes a TON of sense.

One has to remember that VW already had FI (D-jet) for the type 4 and going to carbs was obviously a cost cutting measure. They only used this for a couple of years before changing the 1.8 bus (and next the 2.0) to L-jet.

That's called the "Kadron Syndrome" and is spooky, you can pull off the either 2 or 4 spark plug wires and the engine keeps idling the same, doesn't seem to notice. Not just Kadrons, it happens with any dual-single setup, even the OEM. It's an odd phenomenon, but happens only at idle, at anything above idle the mixture velocity is higher and it disappears.

On T1 engines Kadron/Solex/Bocar/Brosol equipped cars perform nearly as well as IDF cars on the dyno, are equal through mid-rpms, but don't flow quite as well at high-rpms so give up a few horsepower. If you look on The Samba or google you should be able to find some comparison dyno charts. Kadrons do much better than centermount carbs and are much more driveable day-to-day, though neither compares with the driveability of stock fuel injection or Weber IDF's. If you're at all dubious about high performance Kadrons look at AJ Sims (Lowbugget), who's famous in VW circles for building giant killer Kadron drag race cars that are often faster than the IDF/IDA competition. There are a lot of T1 people who could afford anything that are very happy with AJ's products, simple and fast. That's relevant because acceleration is kind of like a moving dyno, a relatively pure measure of horsepower.

There's a lot more variety in carburetor combinations available for T1 engines, and a good summary comparison from John Connolly of Aircooled.net at http://www.aircooled.net/vw-carburetor-opt...-selection-101/. Not all those options are available for 914's, so you need to keep that in mind as you read. What complicates things is that there were an awful lot of slow VW buses built with T4 engines, lots more than 914's. Unfortunately that means the bus T4 engines get more attention than 914's but they're generally less performance oriented.

With all that being said it seems to me the best combination for a stock car is the stock fuel injection. No question. For a modified car it's IDF's or Dellortos. If you're hugely budget restrained and can't go the few hundred extra dollars for the IDF's then there are the Kadron/Solexes. And in last a two-barrel centermount, but only when you've found one for free that your brother left in a box in the garage and it's the only way you can get your car running. OK, I may be opinionated about the centermounts, but it's a free country.

AJ and Berg were people I looked up to when I built my 1776. Dual Kadrons were great on my Type 1. They were much easier to maintain than the dual 42 Webers.

I miss this car...

did you run a balance tube between intakes?

question is for anyone with kadron experience.

Yes you must run the balance tube. Back then they used to give you aquarium line and it use to collapse and than run like crap.

The procedure for balancing the carbs required you to crimp the balance tube and than set the timing (from my failing memory)

Porsche used the balance tube on all the pushrod engines prior to the 1600, and we never closed off the balance tube for any reason, nor does that procedure appear in any of the literature I've seen.

The Cap'n

Ill check the GB liturature when I get home I distinctly remember (this is 15 years ago) needing to crimp the tube when setting the butterfly opening on each carburator

Crimping a steel tube carries with it certain collateral damage, seems to me .............

The Cap'n

I did not have a steel tube, I upgraded form the aquarium line that came with the kit to flexible air hose line

I think the 356 Solex carbs used a metal balance tube, the newer Kadron/Solex kits use a standard rubber vacuum hose. I don't know the official explanation, but for me the balance tube (hose) was a kind of cheat to balance the vacuum signals between the carbs so the engine would still run smoothly when the carbs were slightly out of sync. The racing Kadron guys don't use them, but they're constantly adjusting and syncing carburetors. For a street car it makes a mechanic's life easier if the car doesn't suddenly run like crap because the carbs have gotten slightly out. My best guess. I always used it, never saw a reason not to.

I've got a client with these on his 2056cc 914. They run O.K., but that's about it. Much better carbs on a bug.