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MG MGB Technical - 38DCOE

I've seen various comments about Webers in the archives. DGV, DGAS, DCOE...

I stumbled across this auction in ebay:

But, I have never seen a comment about 38DCOE's.

I would appreciate any comments, as I am looking to upgrade from my DGV when my Crossflow Head arrives.

Tony Calleja


That seems like a rather high price for starters.
Probably because they're not 40 or 45 but 38 (I've rarely seen 38s before...).

On another note, most people seem to run 40 or 45 webers (or dellortos in my case). It already has been suggested that 45s should be ideal by some people, though my engine produces LOTS of power on 40s.
One reason for 38s could be more power in the lower regions (less 'drop' in air speed at lower engine speeds) but to be honest, I don't really think you'd notice the difference.
Of course, the other modifications except head and carbs matter too! So perhaps you could share a bit more info on this one?

Mind you, that's just my humble opinion.
There are people on this board who know lots more!

Hope to have helped though...

Alexander M

Really, I thought $650 for a pair were lower than I've seen for 40's. Given that I haven't really read much about the 38's I thought I'd ask.

I'm running +20 flat top pistons, and a DGV. The head has mild (read amateur) port work. Except for the electronic trigger and discharge, all else is stock. I'm moving to a crossflow head.

I've read with interest on the crossflow and 38DGES, so I did a search and came across those DCOE's on Ebay. The reason I'm looking at the 38DGES is to be able to swap my 32/36 during my emissions. I'd also be able to maintain the distributor advance off the carb. Otherwise, if I go DCOE's I'd have to buy two manifolds, or swap heads.

Thanks for responding!
Tony Calleja

I did not answer sooner , as I am sure there a lots of people better qualified than me , however -
Webers have 2 advantages , choke dia for choke dia they flow more than any other carb, and if you jet one of M Webers carbs , than any other unit jetted the same will perform the same . Since you are only doing this once only the first concerns us .
Now I'm sure that these units will flow a lot mare than SUs , one 45 DCOE flows more than 2 HS4s , I've seen this proved at a track day , and for street use they have to work better than the usual 45DCOEs which are optimised for flow at high RPM , esp for racing engines with a strengthened bottom end which are going up beyond 7K . One problem all fixed choke carbs have is that if you snap the butterflys open then everything in the in inlet manifold goes close to atmospheric pressure , and this makes it difficult to pick up fuel from the jets . This is known as "low speed gasp" amd over and above the better mid range performace already noted should be less noticable with these carbs .( Some Motor cycles these days have 2 butterflys to overcome this , one connected to your right wrist via the throttle cable , the other controlled via a stepper motor from the ECU.)
So for road use on a tuned car with good breathing these look very interesting , however, its your $700!
S Best

FWIW the price looks OK to me for brand new units with air filters, and that they are matched would be a great start for your X-flow, BUT remember the chokes and jets are going to add a packet to the final bill, and comparative prices for DCOE MG kits usually include their cost.
Steve Postins

If you're looking to play around with a Weber config from scratch you can and probably should look elsewhere. There are Weber sidedrafts and manifolds on sale on ebay all of the time for far less than this. I bought all of my carb bits this way, and when all was said and done I ended up spending around $350 for the whole setup (single carb) which is about $200 less than retail but required a lot of scrounging around and messing with tuning settings.
Adam Birnbaum

This thread was discussed between 04/11/2004 and 05/11/2004

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