paging mile high dcoe users

[Guest_anonymous]

Switching to dcoe's. Picked up a pair of Italian 40 dcoe 2. History unknown. Looking for base jetting at altitude.

TIA

Daron

[M3M3]

after you take them apart, replace all the gaskets, and id all the jets and choke sizes that are in them now, report back with what all those settings currently are and what state of tune your engine is in.

interesting use of socket for top strut nut btw!

[Guest_anonymous]

40 DCOE Tipo 2 :

Choke: 28

Aux. Venturi: 45

Idle: 50 F9

Air Corr: 185

E-tube: F16

Main: 115

Pump Jet: 45

Starter Jet: 60 F5

Intake Discharge: 45

Needle seat: 200

Float: 26

Engine:

9.5:1 pistons

Korman 300 regrind

135 psi compression

Stahl clone header, Ansa center, Ansa sport exhaust

037 dizzy, pertronix, msd, red coil

Non track car. street use. mostly just used to bring spare parts to throw in the neighbors pool.

@ Marshall. I spend more time and money making tools than it would be to buy them.

[M3M3]

choke is way too small for 2l engine. I would start with a 32 for street car at altitude.

rest of jets are a workable starting point. as you have probably read, highly recommended to install a WBO2 sensor. without it tuning from baseline will be painful.

your compression seems a bit low. bottom end have lots of miles? have you done leakdown test?

yes, there is something satisfying about making a unique tool for those odd jobs. as you probably have, the top of my tool box is full of things like that.

[c.d.iesel]

Daron - use " Site Search " upper right coner this page

and type in " DCOE jets high altitude " and read pages of info...

start here.....

http://www.bmw2002faq.com/component/option,com_forum/Itemid,50/page,viewtopic/t,277836/view,next/sid,bb36f03c8dfaac1534e75c4cfe7772b4/

[Guest_anonymous]

Expected comment concerning compression:

Compression Test Altitude Compensation Factors

Altitude Factor

500 0.987

1500 0.960

2500 0.933

3500 0.907

4500 0.880

5500 0.853

6500 0.826

7500 0.800

8500 0.773

Also while not as extreme as a 314 the k300 cam has enough overlap at static crank to minimize full compression readings compared to scavanging at RPM. JimK I'm sure could chime in if he has come across this thread.

New rings recently. good on leakdown.

Agreed 28 way too small from my investigations.

+1 on WB02, pain is inevitable, suffering is optional

I have compared my jets with the Haynes listing and while not far off I could use this link to start experimenting, but would like to get a narrow idea so I could order a range of jets without braking the bank. Seat of the pants then Dyno tune it.

http://www.lcengineering.com/pdf/Tuning%20Weber%20Carbs%20for%20High%20Altitude.pdf

Also: Marshall, I know you inquired about that IMSA car, ever follow up on that?

[TobyB]

Hell, try them. Small chokes and small jets will probably work fine.

And if it runs out of poop at 5500, then maybe 30 or 32 mm chokes

will help.

With bigger chokes, you'll probably go up 1 or 2 on the mains, too.

t

[Guest_anonymous]

Thanks Marshall, Toby, and once again CD.

mounted carbs after throwing a rebuild kit at the set and jetting recommended by Stephen at Pierce.. Started blowing dark smoke. I leaned out and adjusted fuel pressure. Smoke started getting more white.

Needless to say after a leakdown, #2 intake was.not seating.

Will return to post after rebuild to follow up on jetting.

Daron

[ziff73]

I'm in the throws of tuning (and learning) my 40s and just switched the 30 chokes for some 34s I had in another pair of carbs and, holy crap, it woke up! I have 150 mains (which may still be a bit rich, more to come) and I have 55F8 idles. Don't know if any of that helps, but I'll be paying attention to what others are doing...:-)

GL!

Stephen