Is there a significant performance improvement using two twin-venturi Webers compared to two single-venturi Solex carburetors installed on a 2,332cc motor?
Thanks!
Jason
Original Post
Replies sorted oldest to newest
There can be, if the 2332 is built to use the extra fuel and air.
If it's not, probably not.
I'm assuming you're asking in regards to the 2332 Vintage specs? We'd need the specs on the super-secret "VM2 cam".
@Stan Galat posted:I'm assuming you're asking in regards to the 2332 Vintage specs? We'd need the specs on the super-secret "VM2 cam".
I don't know the cam specifications that Greg uses in his 2,332cc motors. The performance of many 60s V8 cars could be improved by simply changing intake manifolds and carburetors and thought perhaps the same could be true for the flat four motor.
Jason
@JasonC posted:I don't know the cam specifications that Greg uses in his 2,332cc motors. The performance of many 60s V8 cars could be improved by simply changing intake manifolds and carburetors and thought perhaps the same could be true for the flat four motor.
Jason
It might be.... but you need to know if you have enough cam to make it worthwhile.
@JasonC has a point about trying to squeeze every bit of power out of V8 motors. Changing intake manifolds is helpful…but what I toyed with back in the day was equally as helpful.
My first HD was an early-70’s shovelhead 74ci V-twin. One night while monkeying around in my garage I took off the carb and intake manifold. The manifold was a simple Y-shaped bit. I noticed both the outside AND inside were rough from casting. I took a few hours to polish the inside to a smooth finish and put it all back together.
On my first twist of the throttle on that little rocket I swear I could FEEL the improvement.
Anyway…don’t forget the seemingly insignificant things going on with your motor. If you clean up the inside of your intake manifolds you may see and feel a change.
My point is I didn’t do any significant machining or change any major part and was rewarded with what I felt was a noticeable improvement. Although I must admit that 74ci only had to push a bike that weight but a few hundred pounds.
If you look at the runners on aftermarket cylinder heads and compare them to a stock VW casting I imagine the difference you see in the texture will be noticeable. There are countless reasons for this, each for a specific reason that surely improves performance. Hot Rodders don’t port and polish things for no reason.
Very interesting Rick ! I have often thought that roughing up the intakes may be a way to go. Edlebrock did some testing on this. What they found was that for gasoline it improved starting because there was more evaporative surface for the gas and Just the opposite when using propane. Better atomization ?...........Bruce
Marginal gains. That's what engine building/tuning is, a series of marginal gains. The less attention given to the ENTIRE package the smaller the likely gain, and the greater the risk of loss for any change to the package.
Greg and Pat have designed a package with a particular intent (low maintenance, good longevity, bags of torque, fun to drive). I sincerely doubt that Pat's formula can be improved upon significantly with bolt on parts short of going full electronic engine management. No exhaust or intake will make enough of a difference, even after a thorough re-jet to be worth it. It'll sound different, one's butt-dyno may say, "Wow!" But it is unlikely that it will actually make more power. Making things worse is much more likely. It would be easy to wind up with something loud and tough sounding; something unique with poor economy and holes all over the torque curve. You know, all hat and no cattle like the neighborhood kid with the rusted out '87 civic that's got a $1000 worth of wheels and a 3" diameter fart can.
When one has a considered package [Partial list: Crank, Rod length and weight, piston (diameter, # rings, weight, shape), compression ratio, combustion chamber volume and shape, Cam, valve train (push rods, rockers, valve sizes, springs), Intake tract (volume, length, intake velocity, harmonics), fuel delivery, ignition system (the list of variables on that last two is enough to fill the entire thread), exhaust system (length&volume & od of primaries, length&volume of complete system, etc.) and cooling] and that package is put together with the knowledge of someone like Pat Downs, the idea that I could go in there and swap carbs and exhaust and somehow make 20% more power...just stop. That's crazy talk. I've learned the hard way that won't work. It's like going to Las Vegas to make money.
If I really wanted something different, then I'd start with something different. That, or I'd talk to Pat and ask if a switch to dual choke carbs without changing anything else would add top end without compromising the inherent goodness of the package. The answer might be no.
I have the same engine 2332 in my Vintage Speedster - and claiming a "weak" torque at rpms below 2.000 rpm. I had choosen 2332 as I was expecting a great torque at 1300-2000 rpm - but it is not, unfortenuately. The engine needs revs over 2.000 - then it is OK, but noisy, what I do not like.
I am considering same : Away with the single venturi Solex Kadron and add 2 x 44 Weber IDF - and... certainly an exhaust system with bigger diameter ( Instead of Santana A1)
The HP or top speed is not important, but driving inside cities (Europe) with 50 km/h and countryside 80/100 km/h is just either high rev second, resp. 3rd gear too low - and 3rd high, 4th too low..
VM2 Camshaft is a mirical too to me. It would help to have inputs from others, thank you.
Great post @JMM (Michael).
@JasonC posted:I don't know the cam specifications that Greg uses in his 2,332cc motors. The performance of many 60s V8 cars could be improved by simply changing intake manifolds and carburetors and thought perhaps the same could be true for the flat four motor.
Jason
You have a point, but compare the OEM intake and carburetion on an average 60’s V8 to just about any small displacement “performance” foreign car. Rough castings, unequal length, 90° bends, vs short, straight, aluminum castings. Lots of room for improvement on a V8.
@TheMayoMachine posted:@JasonC has a point about trying to squeeze every bit of power out of V8 motors. Changing intake manifolds is helpful…but what I toyed with back in the day was equally as helpful.
My first HD was an early-70’s shovelhead 74ci V-twin. One night while monkeying around in my garage I took off the carb and intake manifold. The manifold was a simple Y-shaped bit. I noticed both the outside AND inside were rough from casting. I took a few hours to polish the inside to a smooth finish and put it all back together.
On my first twist of the throttle on that little rocket I swear I could FEEL the improvement.
Anyway…don’t forget the seemingly insignificant things going on with your motor. If you clean up the inside of your intake manifolds you may see and feel a change.My point is I didn’t do any significant machining or change any major part and was rewarded with what I felt was a noticeable improvement. Although I must admit that 74ci only had to push a bike that weight but a few hundred pounds.
If you look at the runners on aftermarket cylinder heads and compare them to a stock VW casting I imagine the difference you see in the texture will be noticeable. There are countless reasons for this, each for a specific reason that surely improves performance. Hot Rodders don’t port and polish things for no reason.
My first “real” job was as an apprentice machinist in a automated valve factory. Started out in the deburring/degreasing dept. Which gave me access to all kinds of pneumatic grinding and sanding tools.
At the time, I was driving an Austin America. Found a dual SU set up off a Cooper S to replace the stock single 1 1/2” SU and ported and polished the manifold during my lunch hour.
No idea what sort of performance gain it was, but between that and the Derrington header, it was very noticeable.
@JMM (Michael) posted:That's crazy talk. I've learned the hard way that won't work. It's like going to Las Vegas to make money.
FWIW, I made over a million dollars in Las Vegas. But I didn’t do it gambling. 
Like you say, I’m sure there’s a very good reason Pat chose the single barrel Solexes over other options. I hope it’s not just because of dependability and supply issues. I wonder if he’d do likewise if there was still good supply of Italian webers and dellortos.
@dlearl476 posted:FWIW, I made over a million dollars in Las Vegas. But I didn’t do it gambling.
Like you say, I’m sure there’s a very good reason Pat chose the single barrel Solexes over other options. I hope it’s not just because of dependability and supply issues. I wonder if he’d do likewise if there was still good supply of Italian webers and dellortos.
In the video interview Pat said he chose them because of dependability and no clogged idle jets.
@dlearl476 posted:Like you say, I’m sure there’s a very good reason Pat chose the single barrel Solexes over other options.
Kadron (Brosol/Solex) single throat carbs were chosen (by Greg) because for 20 years - all anybody could talk about on this site was the IDF's cursed plugged idle jets. It was something of a touchstone to complain about.
Kads don't plug idle jets, because every port or drilling in them is about the size of a pencil. They're simple and reliable. They'll never be as smooth or nice as individual runner carbs, but they won't frustrate the average buyer either.
Wouldn't it be cool if there was something that was as smooth and made the power of a set of IR carbs, but was as easy to live with as a pair of Kadrons?
Mike Pickett and Danny P are pointing out the way.
Makes perfect sense, with the wide popularity the cars enjoy.
Me personally, I went into Spyder ownership with the idea of it being a 1:1 scale model that besides tinkering with it, I could enjoy driving as well. I have 3 other “appliance” vehicles. Fiddling with the carbs, adjusting/bleeding the brakes, adjusting the valves, setting the timing, etc. is the raisin d’etre for my owning a Spyder.
I’ve worked on my own cars pretty much all my life, and enjoyed it. VWs, BMWs, Volvos, various BMC products. The Spyder is the only one that needs it any more.
I think @JMM (Michael) is right, and his analysis and advice is especially right for the sort of person who might find himself in possession of a VMC/Pat Downs standard issue 2332.
The engine was built with you—the turn-the-key-and-go person—in mind. Only a stock NA Suby would suit your needs better.
But, having said that, and considering the situation more fully, I do believe a set of small Webers might—if tuned properly—bring some improvement. As Pat himself testified, The Kads are there to eliminate idle jet issues. A person willing to brave those might well find the ITBs deliver improved off-idle throttle response and a little more grunt at the top of the torque curve.
Or, as @Stan Galat noted, an EFI system would be better yet, carrying that big Type 1 ever so closer to the standard set by the EJ22/25.
All it takes is money. Money and time. Time that could be spent driving the thing as intended....
As for @Kuehl's issues: Man that's unfortunate, but I don't believe any 2.3 liter 4 cylinder engine with carbs is going to give you what you want straight off idle... unless you put a turbo on it.
—which, come to think of it, might be just the thing for this particular strain of Type 1.
@edsnova posted:... unless you put a turbo on it.
—which, come to think of it, might be just the thing for this particular strain of Type 1.
Oh wow. Yeah, it'd be perfect.
As a corollary: have you seen the stuff Mario Velotta is playing with at present? He's got a 3D printer now and just made up a pair of big port-matched end pieces for a single TB turbo application. EFI with a couple of air to water intercoolers in the stacks. The target is something like 600 hp or some such.
It's breathtakingly cool stuff with little or no relevance to the conversation, except for what Ed pointed out - a nice, tamely cammed engine with decent but not huge heads would likely respond really well to a blow through turbo. You wouldn't need to go wild to make it work - you could probably fit it all under the hood and maybe even keep the temps in line.
... or not.
Either way, it's fun to spend other people's money.
@LI-Rick posted:In the video interview Pat said he chose them because of dependability and no clogged idle jets.
Interesting comment about the idle jets on Solex carburetors.
Notably, the low speed/transition/idle jet on my Solex plugged after about 200 miles of ownership. The jet is easy to remove with the carburetor in-situ, so I did and shoved a steel guitar string through it. This action dislodged some sort of hard particle from that tiny jet port and it's been trouble-free for some 1,800 miles. The jet that was installed was a #55 and and I recently installed a #60, wihch has reduced the amount of low speed popping that sometimes occurs through the exhaust system, especially on trailing throttle.
I suspect one of the reasons Solex carburetors were installed by the builders has to do with cost. A twin Solex setup is some USD700 while a twin Weber is ~USD1,200.
Jason
@JasonC posted:Interesting comment about the idle jets on Solex carburetors.
Notably, the low speed/transition/idle jet on my Solex plugged after about 200 miles of ownership. The jet is easy to remove with the carburetor in-situ, so I did and shoved a steel guitar string through it. This action dislodged some sort of hard particle from that tiny jet port and it's been trouble-free for some 1,800 miles. The jet that was installed was a #55 and and I recently installed a #60, wihch has reduced the amount of low speed popping that sometimes occurs through the exhaust system, especially on trailing throttle.
I suspect one of the reasons Solex carburetors were installed by the builders has to do with cost. A twin Solex setup is some USD700 while a twin Weber is ~USD1,200.
Jason
Cost is always a factor, but apparently the newer generation’s of the Weber knockoffs out of China seem to be working very well. There has been a bunch of positive feedback on TheSamba, with many reporting excellent results. I have not used them, so I have no first hand experience.
FWIW, I’ve never had a clogged jet on my Dells. (Knocking on wood) But then I generally go through them every year or two, whether they need it or not.
@dlearl476 posted:FWIW, I’ve never had a clogged jet on my Dells. (Knocking on wood) But then I generally go through them every year or two, whether they need it or not.
Ethanol is the reason for clogged jets these days. If you don't run fresh gas through your carburetor every three weeks or so, the gas turns to gel and clogs the small pilot jets. And the smaller the jet the greater propensity for it to clog--thanks to ethanol.
Jason
I don’t use ethanol gas. Gave it up years ago.
@JasonC posted:Ethanol is the reason for clogged jets these days. If you don't run fresh gas through your carburetor every three weeks or so, the gas turns to gel and clogs the small pilot jets. And the smaller the jet the greater propensity for it to clog--thanks to ethanol.
Jason
This is absolutely true with small engines - not so much because of gel, but because of the varnish that gets left behind when the little bit of gas in the carb evaporates. E-free gas for the eleventy-billion small engines (and I just bought 2-stroke Stihl stuff in bulk in prep for the EPA's war on lawn equipment that works) is worth the drive and the price bump.
I run E10 93 in the Speedster, from Costco if I can get there. I'm not going to claim that in 23 years of ownership I've never had a hunk-'o-love in my idle jet (or more likely, in the transition ports), but I can tell you that I've never had E10 gel on me. I've helped other guys with gelled floatbowls, but I've never had it.
Over the years, there have been many heated discourses regarding where the smutz comes from, but what I will say is that I've never had a plugged jet since I went to the turbo-hats and cone filters. I'd absolutely recommend changing your floats every 5 years or so. E10 can eat them.
I try to play the other side of the corn squeezin's debate, because if you travel at all - you'll have no choice: you will burn E10 in your car. I like to keep the tune on the fine edge. As such, I'm tuned for the gas I can get everywhere. I can shake my fist at the sky, but it won't rain E-free 93 out on the highway.
We get what we get and we don't throw a fit.
@Stan Galat posted:E-free gas for the eleventy-billion small engines is worth the drive and the price bump.
All my vehicles save the Spyder call for premium. E free around here is ±5¢ of what premium costs, depending on what the cost was when the various tanks get filled. Even when it’s 5¢ more, the extra 2-3mpg I get with e free is worth it. Even with the 88 octane vs 91.
“I try to play the other side of the corn squeezin's debate, because if you travel at all - you'll have no choice: you will burn E10 in your car.”
https://apps.apple.com/us/app/pure-gas/id454559068
I run a tank or two of E10 through my Smart in the winter to get rid of any moisture in my tank. No idea if it does that, but AFAIK HEET is basically just ethanol.
E-free is a $1.00 bump here, and a 15 minute drive.
@dlearl476 posted:FWIW, I’ve never had a clogged jet on my Dells. (Knocking on wood) But then I generally go through them every year or two, whether they need it or not.
There are at least 9 sets of Weber IDFs out there for each set of Dells which are sadly NLA(except for Chinese knockoffs). So what exactly is the point of saying how great they are? You have them, woo-hoo for you.
The problem is two-fold for carbs in general, and three-fold for IDFs.
Carbs are open to the atmosphere, and there is moisture and dirt in the atmosphere. There is nothing you can do about moisture, it does what it wants when it wants(humidity and rain or even washing the car).
If you remove and replace the carb tops/ air filters you will most probably introduce dirt.
The "problem" with Webers is there is a horizontal path in the idle circuit. Dells have a vertical path. If dirt gets in a Dell, it tends to fall back into the float bowl. If dirt gets stuck in a Weber idle circuit, it tends to stay stuck in there. For the record I've never had a problem with Webers. Occasional jet clogs happen, but especially immediately after removing air cleaners. You think there's a connection there?
Weber IDF and Dellorto DRLA are both very capable and tunable Italian carbs. Dells have 5 progression ports, Webers have 3. Other than that, they are both awesome carbs. I have plenty of experience with both.
I exclusively ran E10 93 in my carbs. I'm totally in agreement with Stan on this. The engine is tuned to run best that way, and the fuel is available anywhere in North America. I still run it with EFI.
@JasonC posted:Ethanol is the reason for clogged jets these days. If you don't run fresh gas through your carburetor every three weeks or so, the gas turns to gel and clogs the small pilot jets. And the smaller the jet the greater propensity for it to clog--thanks to ethanol.
Jason
I don't agree with this theory. It hasn't been my experience in over 15 years with E10, carbs and tens of thousand miles.
@dlearl476 posted:All my vehicles save the Spyder call for premium. E free around here is ±5¢ of what premium costs, depending on what the cost was when the various tanks get filled. Even when it’s 5¢ more, the extra 2-3mpg I get with e free is worth it. Even with the 88 octane vs 91.
“I try to play the other side of the corn squeezin's debate, because if you travel at all - you'll have no choice: you will burn E10 in your car.”
https://apps.apple.com/us/app/pure-gas/id454559068
I run a tank or two of E10 through my Smart in the winter to get rid of any moisture in my tank. No idea if it does that, but AFAIK HEET is basically just ethanol.
That app is useless in places they don't allow E free gas! 
@LI-Rick posted:That app is useless in places they don't allow E free gas!
... or on any road trip to anywhere. E-free gas one out of every 15 fill ups doesn't do you any good.
@Stan Galat posted:... or on any road trip to anywhere. E-free gas one out of every 15 fill ups doesn't do you any good.
JFC, what sort of range do you have? Like, 50 miles?
That is the map zoomed out. Just about every one of those pins looks like this when you zoom in.
Attachments
Images (3)
I have never had any trouble with my Weber DCNF carbs from Berg. I always add Star-Tron when I fill up.
Have y’all seen the new VMC speedster that Roy has on BAT?
Attachments
Images (1)
@Stan Galat posted:We get what we get and we don't throw a fit.
Sage advice for most things in life and after almost 62 years I am beginning to try.
Yes, what is a VM-3 cam shaft?
Jason
nevertheless, I give it a try, even with VM2 ;-) on my 2332 engine to solve the torque issue at low rpms ( i.e. less than 2000 rpm)
I purchased a set of Weber IDF44 (FAJS Chinese for the first try), redline airfilters with 52mm trumpets, a crossbar acceleration linkage - and special air manifolds for my 044 panchito heads.
Manifolds will be polished.
As far as I could find out the Webers should be equipped with following jets:
Idle 55, Main 150 and air correction 190-200 (200)
Further I will install a breather box (1ltr) with lines to both head covers and carbs and oil filler.
Next week I will know how it works ;-)
As I am relavively new to carburator tuning I will have to give it several tries - a synchro-measuring tool is available
Keep fingers crossed. Happy to receive comments or tips.
What CO Emission should be OK ?
Ignition timing is 7,5° before OT ?
@JasonC posted:Yes, what is a VM-3 cam shaft?
Jason
@dlearl476 posted:I’m guessing it’s something special Pat has ground for Greg. (Vintage Motorsports) Where it fits in cam world I haven’t a clue.
I'm going to guess- the VM-2 camshaft that Pat puts in Greg's 2332's is probably 234-236° @ 0.050" duration, with (in combination with the rockers) .430-.450" lift at the valves. The duration gives a 4800-5,000 rpm peak (which is about the limit of the Kadrons as well in an engine of this displacement- they're well matched!) and enough lift to make decent power with the 40x35 heads. This gives an easy to drive combo with great power- 140? hp with fantastic bottom end/lower midrange power and smoothness. This is 30-40 hp more and waayyy more driveability/street manners than any 4 cam powered car, while having almost VW-like dependability. Another way of putting it- this engine would be very easy (and fun!!!) to drive while being VERY hard to break!
The VM-3 equipped 2332 cc engines (which I'd never heard of until very recently) is for those where the above torque monster isn't enough- the cam itself will have another 10-20° duration (@ .050" lift) with (again, I'm guessing- no one knows the specs of these cams- they both seem to be closely guarded secrets) .460? .475?" valve lift, the heads will have a little more intake port volume to make more power at a higher (5500? 5800? 6,000?) peak rpm and the carbs are now 44 IDF's to match the new power output (160? 165? 170??? hp). Of course, the compression may have been raised slightly for this new combo and the exhaust may have had to be upgraded as well. This engine would still have a pile of bottom end/lower midrange torque (hey, it's got over 2300 cc's!) although maybe not quite as much as the ever so slightly tamer version- most people might not notice the difference after driving 2 otherwise identical Speedsters.
As I said, I'm just guessing...
Thank you for your "guess"; it sounds pretty good to me!
Jason