for an aluminum head, and triple DCOE's, which size is best? also, are all DCOE 45 the same, etc? so you don't have to worry about them matching, or is there something you need to look for?
Which DCOE's?
- Thread starter Invectivus
- Start date
Invectivus":3se171dk said:
40DCOEs are good up to 34mm chokes, above 34, use 45DCOEs. All 45's are not the same, mostly in the number of enrichment holes in the body. If you purchase DCOEs, try to get a set with matching numbers, or numbers that are close, ie. three 45DCOE 9; three 45DCOE 28; or a set numbered 45DCOE 150, 45DCOE 151, and 45DCOE 152.
The newer Weber DCOEs are made in Spain, and are not as good as the Italian made ones.
Be prepared to spend sometime tuning them, either on the road or on a dyno. Use a O2 sensor and have alot of different emulsion tubes and jets.
Hope this helps.
Inital DCOE selection is as rocklord says. Get three DCOE's all the same type number.
Be aware that there are 38, 40, 42 and 45 DCOE's, and very rare DCO's in 48 and 50 mm sizes.
First, you have to pick up the choke size that suits your peak rpm power band, and the cc's of one cylinder, or else the set-up will never run right. Use the Weber chart attached.
Curves only exist for high rpms like 6000, 8000, 10000 rpm etc, but most of us are only interested in the 4500 to 5500 rpm band, so the graph is a little bit limited, and you have to guestimate the choke size if the cam maker says power is at 5000 to 5500 rpm.
A 144 is 378 cc; 3 x DCOE 40 Weber with 28 mm chokes 144 cid Ford Falcon six reving to 5000rpm could use six 115 micron Weber jets as a start
A 170 is 463 cc; 3 x DCOE 40 Weber with 31 mm chokes 170 cid Ford Falcon six reving to 5000rpm could use six 125 mircron Weber jets as a start
An Argentine 187 is 511 cc and an Aussie or Argentine 188 is 512 cc; 3 x DCOE 40 Weber with 31 mm chokes would suit 187/188 cid Ford Falcon six reving to 5000rpm, and jet selection start point is still six 125 mircron Weber jets
A 200 is 545 cc; 3 x DCOE 40 Weber with 33 mm chokes 200 cid Ford Falcon six reving to 5000rpm, use six 135 micron Weber jets as a start.
An Aussie or Argentine 221 is 603 cc; 3 x DCOE 40 Weber with 34 mm chokes for 221 cid Ford Falcon six reving to 5000rpm, with six 140 micron Weber jets as a start
A 250 is 682 cc; 3 x DCOE 45 Weber with 38 or 40 mm chokes for 250- cid Ford Falcon six reving to 5000 rpm, with six 145 micron Weber jets as a start.
If you have a 200 cammed for making power at 5000 rpm or nore, then DCOE 40's with 34 chokes will be worse than DCOE45's with 32 or 33 mm chokes. It's better to use 45's than 40 or 42's if the choke size from the Weber Independent runner chart comes up with over 32 mms choke size.
After that, all you need is a good intake manifold and then trial to jet 1/25th of the choke size. A 34 mm choke would require a six 1.36 mm or 136 micron jets as a trial start, then adjust up or down via an oxygen sensor or dyno air fuel sensor.
Be aware that there are 38, 40, 42 and 45 DCOE's, and very rare DCO's in 48 and 50 mm sizes.
First, you have to pick up the choke size that suits your peak rpm power band, and the cc's of one cylinder, or else the set-up will never run right. Use the Weber chart attached.
Curves only exist for high rpms like 6000, 8000, 10000 rpm etc, but most of us are only interested in the 4500 to 5500 rpm band, so the graph is a little bit limited, and you have to guestimate the choke size if the cam maker says power is at 5000 to 5500 rpm.
A 144 is 378 cc; 3 x DCOE 40 Weber with 28 mm chokes 144 cid Ford Falcon six reving to 5000rpm could use six 115 micron Weber jets as a start
A 170 is 463 cc; 3 x DCOE 40 Weber with 31 mm chokes 170 cid Ford Falcon six reving to 5000rpm could use six 125 mircron Weber jets as a start
An Argentine 187 is 511 cc and an Aussie or Argentine 188 is 512 cc; 3 x DCOE 40 Weber with 31 mm chokes would suit 187/188 cid Ford Falcon six reving to 5000rpm, and jet selection start point is still six 125 mircron Weber jets
A 200 is 545 cc; 3 x DCOE 40 Weber with 33 mm chokes 200 cid Ford Falcon six reving to 5000rpm, use six 135 micron Weber jets as a start.
An Aussie or Argentine 221 is 603 cc; 3 x DCOE 40 Weber with 34 mm chokes for 221 cid Ford Falcon six reving to 5000rpm, with six 140 micron Weber jets as a start
A 250 is 682 cc; 3 x DCOE 45 Weber with 38 or 40 mm chokes for 250- cid Ford Falcon six reving to 5000 rpm, with six 145 micron Weber jets as a start.
If you have a 200 cammed for making power at 5000 rpm or nore, then DCOE 40's with 34 chokes will be worse than DCOE45's with 32 or 33 mm chokes. It's better to use 45's than 40 or 42's if the choke size from the Weber Independent runner chart comes up with over 32 mms choke size.
After that, all you need is a good intake manifold and then trial to jet 1/25th of the choke size. A 34 mm choke would require a six 1.36 mm or 136 micron jets as a trial start, then adjust up or down via an oxygen sensor or dyno air fuel sensor.
sweet, thanks. i don't have the engine yet, but i'd like to have a plan to help me keep my eye on the ball, and look for opportunities.
