Dellorto DRLA 40 jetting guide

[askoulding]

Hi chaps,

A happy new year to you all.

I've finally taken delivery of 2 x Dell DRLA 40's and am fully aware that I need to re-jet these (they came of a 1.6 Alfa). Does anyone have a calc guide or any guidance which jet sizes I need to put in these beasts? I have the 2.0l CU Aircooled engine.

Thanks,

Andrew.

[PetenAli]

A good start would be to call Eurocarb in reading (you can Google them). They are usually pretty helpful if you tell them the spec of the engine that the carbs are going on to. Don't forget that you might (probably will) also need different chokes as well as jets. They also sell the Dellorto Superformance Tech Book by Bob Tomlinson which is a handy item to have if you're going down that route. I had a pair of DRLA 36s on an air cooled T25 and they made a big difference once they were properly sorted.

[jason k]

or jim at stateside tuning.

bear in mind this will be a base jetting you will need the services of a rolling rd asap once running

[gsmoke]

If your engine is standard, then you wont go far wrong with 30 chokes 60 idles and 130 main jets.
I cant remember pump jet etc sizes at the mo, let me know if you need them and I'll have a look at my carbs.
Good luck.

[waltraud]

I had this set up o a 2ltr in a bay before with 30- 130- 60 but then slightly wished i'd gone for a smaller choke like 28 is it?? not sure now but seem to recsall that a slightly smaller choke means a bit less acceleration but better on fuel and as its heavy can mean it will still pull well. I used an anti pulse valve in the vacuum line which i think helped (few quid) always found Eurocarb V helpful and competitively priced. If you lie the carbs and the sounds it will make remember that foot down driving with these means 15MPG but sensible driving may well give you better MPG than the orig carbs, especially as they are likely to have been worn out well before replacement. T

[askoulding]

Thanks for all your advice Eurocarbs were very helpful. Saving up for the linkage, manifolds and jets!

[jason k]

dont forget you need to boss the inlets for vaccume barbs for the servo.

no bosses= no brakes

[askoulding]

Thanks Jasonk - but you're starting to lose me a bit now...

[jason k]

ok, your stock inlets have a fitting for a vaccume take off for the brake servo.

the replacement inlet manifolds dont have the take off. hence no vaccume for the brake servo = pi$$ poor brakes

you will need to drill and fit an airtight barb for the brake servo pipe to each mainifold.

hows that?

[askoulding]

Hell yeah, that's better! Where is the best place to get hold of these boss barbs thingys?

[jason k]

any motor factor

match the size up with your stock ones, i cant remember the dia now.....

[keith2]

Do you need to do both manifolds, as the original Solex setup only had a take off on one?

[jason k]

you sure? on a 2000cc motor?

my solexs had em on both inlets with a factory balance bar linking them.

i did both for that reason.

[gsmoke]

There's no need to do both.
I tapped into one manifold and have been running that way for about 4 years with good brakes.
Theres more than enough vacum in one manifold.

[jason k]

vw boss both geraint hence why i did