Carburetors- Weber vs. Twin SU's

[RoseRoyce]

My '77 MGB has the original Zenith Stromberg carburetor. Many of my friends have made the switch to Webers or to twin SU's to improve performance. I am trying to determine which is best? Most of the people I know made the choice based on availability...incidently all of them are happy with the improved performance.

 

[Baxter]

Read this:
https://shadetreemg.com/carb_choices.htm

 

[adam90009]

Also read this: https://bellsouthpwp.net/a/d/adam90009/performance.htm My MGB made a 0-60 run in aobut 12.5seconds starting off in a little bit of gravel. I only tried it once. That's with my horible compression and low oil pressure....etc. My intake manifold and header maybe up for sale soon(V6 conversion).

 

[coldplugs]

[ QUOTE ]
....Webers or to twin SU's....

[/ QUOTE ]

I'm sure you'll find advocates for both options - some prefer the Webers & some the SU's. I've had experience with both (though only with SU's on an MGB) and lean towards the SU's, especially for road use.

Webers are great carbs primarily because they're simple and so "configurable" for various applications (I presume you're considering twin sidedrafts?) but just about every road car I've seen with multiple Webers seemed overcarburated for the street. They all seem to be pretty unresponsive at low revs, probably due to the low air velocity through the bores - they also like to spit back through the carbs & backfire now & then.

I've always wondered about the effectiveness of four barrels of Weber hooked up with a cylinder head with siamised intake ports.

Lotus used Webers on their Elan engines for several years until switching to 2 Strombergs towards the end of their production. Although enthusiasts expected performance to fall off, it didn't, and in many ways the Stromberg setup worked better than the Webers. One theory is that a very effective crossover pipe caused a smoother intake airflow and provided better "internal aerodynamics" in the manifold.

So, I lean towards the SU option for an MG.

 

[Baxter]

Coldplugs, you're going to confuse him.. there is no twin weber setup commonly available for the stock MG head (and it would be way too much carb even if there were). I imagine he's talking twin SUs or a DGV, with maybe a DCOE or DGS in the back of his head... the link above pretty much outlines ALL of the readily available choices, but here it is in a nutshell (and I've actually dealt owned and driven (daily) cars with weber dgv, dcoe, SUs and ZS)...

SU - probably best all-rounder. Cool looks, good performance, decent reliability and economy.
DGV - can't be beat for economy or reliability. While not a performance carb by any stretch (despite what the catalogs tell ya) it'll still easily trounce a ZS-equipped MGB.
DCOE - the most versatile, flexible carb out there. If you love to tinker and know what you're doing. Mere mortals may not want to tackle the learning curve. Still, rock solid if they're set up right, and CAN be anything from a fuel-miser to a full-race carb.
DGS - May provide the best compromise between DGV and DCOE, but I haven't played with one myself.
ZS - not impressive on Triumphs, Jags or Volvos, an utter nightmare on a B, with that rotten manifold.

 

[coldplugs]

[ QUOTE ]
Coldplugs, you're going to confuse him.. there is no twin weber setup commonly available for the stock MG head ......

[/ QUOTE ]

You're right, of course. I was half asleep when I wrote it and the original question referred to "Webers" so 2 side drafts came to mind.

 

[ICESWH]

When i bought my 80-B it had a webber setup. I hated it. It ran like crap. Hesitated terribly. The timing had to be set way off just to get it running. My mechanic put a new twin SU, HS-4 setup on it, and it was worth the shirt off my back that i had to give. I always recommend the SU's.

 

[RoseRoyce]

Thank you for the information and the useful links. I guess the Twin SU set up is the one for me...I was being mesmerized by the hype on the suppliers' web site...now I have the proper information. I am new to all this, and find that the support of groups like this make the adventure of owning the MGB that much more enjoyable.

 

[humoo]

My 77 MGB has the original ZS carb and it sounds like an upgrade to the Twin Su HS-4 is in order. What should I expect to pay for the parts? thnx