Weber jetting for 20S engine

[kummel]

Hi i just got my self a 2 45Dcoe webers, the engine is standard 20S from Rekord E, ive installed a martelius exaust and thats all. What jets should i use??
Thank you

[Crusher]

Well...I've got the same side-draft carb on my 2L Opel.
I have a larger cam and ported heads with lots of air flow.
I tried the recomended jet sizes for a stock engine of that size but it would run at an idel and not when you open the throttle...too lean, probably because my engine has alot more air-flow than stock.
With an O2 analyzer reading of 1 percent O2 in the exhaust, I finally ended up with 185 jets in an f8 tube...ya, it sounds big, but you can see for your self... My car runs great !

p.s. The DCOE series I've found has a slight flat spot during acceleration...Just the nature of the beast.

[tekenaar]

Originally Posted by Crusher Well...I've got the same side-draft carb on my 2L Opel. I have a larger cam and ported heads with lots of air flow. I tried the recomended jet sizes for a stock engine of that size but it would run at an idel and not when you open the throttle...too lean, probably because my engine has alot more air-flow than stock. With an O2 analyzer reading of 1 percent O2 in the exhaust, I finally ended up with 185 jets in an f8 tube...ya, it sounds big, but you can see for your self... My car runs great ! p.s. The DCOE series I've found has a slight flat spot during acceleration...Just the nature of the beast.

Though I wrote this primarily for SSD applications, might be worth looking at for twin SDs, if you've exhausted all other jetting options for your engine.

[Crusher]

Your right, there is no means of adjusting the transition mixture on the DCOE.
I've been sort of leary of drilling on my carb

Kummel - I hope we've added some insight to your carb project.

Steve

[tekenaar]

Originally Posted by Crusher You're right, there is no means of adjusting the transition mixture on the DCOE. I've been sort of leary of drilling on my carb Kummel - I hope we've added some insight to your carb project. Steve

I think there's a small misinterpretation of terminology here . . . you CAN, in fact, adjust idle/transition MIXTURE (idle jets and air bleeds) and idle mixture VOLUME by the idle adjustment needle. But you CAN'T adjust transition mixture VOLUME, as it's controlled by a series of fixed orifices just above the throttle plates. The ONLY way to alter transition mixture VOLUME is to enlarge these orifices (holes).

That's why the term idle jets and idle air bleeds are such a misnomer . . . they only cover HALF their functionality! And why do you think Weber offers a range of DCOE40 and 45 "types" and it's always recommended that you use the same "type" on an engine? . . . because they were originally designed for engines of a specific displacement and breathing efficiency.

[kummel]

Could those 45dcoe be to big for my stock engine or can i change the jets to fix that.??
What cam whould you recomend for that setup??
Im bilding a every day car, with some extra power.

[GTJIM]

For an "everyday" car the standard cam will be OK as it makes peak power above 5,000 rpm and the DOCEs' will allow better power anyway.
Just keep the venturis down in size (30 to 34 mm) for better low end response. This may restrict your hi-rev power but most everyday drives operate at the low rev range most of the time. So just "tune" those 45s' to the rev range most often used.

[RallyBob]

Jim is absolutely right, the choke (venturi) size is very important. You can use the 45 DCOE on a standard 2.0 but you should run a small venturi for good torque and mixture signal. I would probably use 32 mm. If you have long air horns (trumpets) then that would be better too for road use.

Make sure that your exhaust pipe diameter is not too large as well. I would not go larger than 2.25" (58 mm), but you may be better off with 2" (51 mm).

Bob

[kummel]

what emulsion tube should i use?
I m planning to order some stuff from finland and i want to get everything.
I have fuel and air jets, im planning to go for 34mm chokes. because im planning
to work with head also. Today i got a new clutch, you can also use 2 liter kadett GSI clutch and senator 2,5 disk. it has 6 polts instead of original 4 polts