engine and drivetrain Weber Sidedrafts Wooohoooo

[KFunk]

Anyone on here daily drive a car with sidedrafts? What's it like?

 

I've been daily driving (for the most part) with DCOEs since around '07.  I often switch back and forth between the 02 and my truck and motorcycle though, and put the 02 away when salt is on the road.  

 

It's pretty uneventful for the most part.  It fires up pretty easy (just pump the gas and it goes) and idles relatively smooth every day.  Maybe not perfect if you get it out of tune (but well driveable).   I've had a few hiccups when my fuel level was a little off, but once I figured out how to set that properly it was great.  I had my pump jet o-rings go out at some point too, but those were probably 30 years old and rotten, and real easy to replace.

Edit:  Oh, and  had some issues with throttle linkages that were poorly built.  Now that I have the top mount linkage from IE, I'm pretty confident that it's working great and holds up much better.

It's mostly just fun being a jackass and spinning the tires taking off at every stop.  We have a lot of brick streets here, and I can drift all over without squealing.  I would say the biggest problem is trying to resist being an idiot with them.

Mileage isn't too bad actually, for being an old sloppy carbed car.  I get anywhere from 21 MPG around town, to 27+ MPG on the highway.  

Edited May 2, 2014 by KFunk

[76ohtwo]

I've been daily driving (for the most part) with DCOEs since around '07. I often switch back and forth between the 02 and my truck and motorcycle though, and put the 02 away when salt is on the road.

It's pretty uneventful for the most part. It fires up pretty easy (just pump the gas and it goes) and idles relatively smooth every day. Maybe not perfect if you get it out of tune (but well driveable). I've had a few hiccups when my fuel level was a little off, but once I figured out how to set that properly it was great. I had my pump jet o-rings go out at some point too, but those were probably 30 years old and rotten, and real easy to replace.

Edit: Oh, and had some issues with throttle linkages that were poorly built. Now that I have the top mount linkage from IE, I'm pretty confident that it's working great and holds up much better.

It's mostly just fun being a jackass and spinning the tires taking off at every stop. We have a lot of brick streets here, and I can drift all over without squealing. I would say the biggest problem is trying to resist being an idiot with them.

Mileage isn't too bad actually, for being an old sloppy carbed car. I get anywhere from 21 MPG around town, to 27+ MPG on the highway.

Sounds good. I can't wait to get my engine all sorted and rebuilt with 40s.

[KFunk]

For comparison, I was just thinking about any hiccups I had when I was running a 32/36DGV (which I did from '05 to '07).  In that two year time span, I had some issues with the throttle shaft leaking fuel onto the manifold.  I had to install a choke cable (never did that for DCOEs), and had to fiddle with getting the throttle linkage to stay together and open both barrels fully with WOT.  The throttle linkage bound up and held the throttle wide open in Death Valley.  The tube with the brass opening in the venturi got spun upside down somewhere in Nevada, and it ran like a dog at WOT, and I had to JB Weld it back in place somewhere in Illinois.  So in my experience, the classic 32/36 isn't quite as amazing as everyone thinks. 

[Brendan]

So, is the HP/ seat of the pants improvement due to the short intake runner or carb/ venturi bore size, or both?  Or are the two bbl downdraft intakes just poor flowing designs?

 

I ask because I'm doing a fuel injection swap this summer, and I wonder if going to an ITB setup is going to yield the same joy that you all are experiencing with the sidedrafts.  

 

 

Thanks,

Brendan

 

[visionaut]

Brendan - it's both.  The straight shot per cylinder (where intake length affects powerband location - shorter not necessarily better), and the venturi/bore diameters (which affects airflow volume/speed, thus how much fuel you can burn).  Obviously there's more to it all - airhorns/air restrictions at the inlets, valve sizes/cam timing, ignition quality, matched exhaust, etc. for the final result.  You'll definitely get a lot of similarity with ITBs.

 

Tom

[KFunk]

I've got a Warneford manifold (fairly long), with velocity stacks and uni pod filters from IE, and I believe 32mm venturis if I remember right.  I won't even begin to claim they make more peak horsepower than anything else (I'm a trained scientist, so of course I can't ever make any claims without numbers to back them up).  All I can do is speculate and say they're kick-ass.  I know I tend to spin the tires off the line a whole lot more with the 40 DCOEs.  I won't even begin to compare to a 38/38, since I've never used one, and I never thought to try one because nobody approached me on the street and offered to sell me a 38/38 for cheap (thats how I got my 40s).

I'm wondering if the 4 individual pump jets help the seat-of-the-pants feel quite a bit of the dual sidedraft setup.  That's a lot of fuel going straight into each each cylinder right when you push on the gas pedal.  If the pump jets lose pressure (as I've felt when their o-rings go out), then the engine falls flat on its face as soon as you hit the gas.  A good downdraft setup probably flows as much fuel theoretically and could make similar peak hp, but that initial take-off I would bet feels a lot better with the dual sidedrafts.

Edited May 2, 2014 by KFunk

[TobyB]

It's the sound.  Really.  They just SOUND like they make a lot of power.

 

 

even when they don't.

 

 

t

[KFunk]

It's the sound.  Really.  They just SOUND like they make a lot of power.

 

 

even when they don't.

 

 

t

 

Sorry Toby, but even as a scientist, I do not believe you (and my rate of rear tire consumption doesn't either).  My truck also makes awesome sounds when I take off, but it only makes 67hp at most, and it shows.

[GirtAllerton]

Thanks Guys, Will stick to the 40 DCOE plan. Still looking for a good set of Italian 40s 151 - Anyone have an extra set for sale to help me out??  Also have a wanted listing in the classifieds.

Girt

Edited May 3, 2014 by GirtAllerton

[TobyB]

 

 

even as a scientist, I do not believe you

Jeeze, I would think a scientific background would make me even LESS credible...

 

...EFI all the way, baby!

 

hee

 

t

[KFunk]

I tried googling a few times, but I still can't find decent dyno comparison charts.  I'd like to see some dyno charts that compare a 32/36, 38/38 DGAS, and 40 DCOEs on similar engines.  I would bet there's more torque at low RPM with 40s, then it becomes more comparable at high RPM, but I dunno.

With the 40s, you get 4 individual pump jets squirting fuel when you first hit the throttle, and I would bet that's a lot more aerosolized (or atomized?) fuel than you can get from 1 squirter in the 32/36 or 38/38.  It's kind of like fuel injectors, but sloppier and lacks metering and just dumps extra fuel.  After initial throttle and you're just holding the pedal down, then the main jets and venturis take over and all the real power is made.  I'm just talkin out my hind quarters, though. 

 

EFI is cheating!  I don't like compooters.

Edited May 4, 2014 by KFunk

[TobyB]

I think the main gains are volumetric- there are a lot less pumping losses with DCOE's wide open

than with a 40/40 wide open.

 

It would be a neat comparo- you'd have to compromise both tunes a bit to get them as equal as possible.

 

In theory, the longer manifold would out- torque the sidedrafts, but at full chat, I wonder....

 

...probably all comes down to tuning, at the bottom line.  You can make a LOT of power out of a 40/40...

 

t

[76ohtwo]

40/40 downdraft? Aren't those rather hard to find? I haven't come across one yet anywhere online.

[M3M3]

It's kind of like fuel injectors, but sloppier and lacks metering and just dumps extra fuel. 

 

any carb is just device to loosely control a fuel leak.   DCOE's just leak in more places....  

 

i don't like computers in old cars either...so i hide the three computers that manage the engine in my 2002... under the passenger side footwell....