Jump to content

14th Annual SoCal Vintage BMW Meet 2021! “All couped up”

Registration is still open. Rally from NorCal is scheduled for Friday. Post your event photos.

SoCal Vintage is Here! 

Post your photos!

DCOE 40 jet setup


Recommended Posts

I know this is a car to car setup. And this motor that I have is fairly modified. But I just put new plugs in the thing a thousand miles ago and they are black. I'll have to come back with the numbers on them, but they are what was recommended. Well the plugs are black, and the car stinks of fuel when getting on it.

Motor is cammed, turbo size valves, high rate valve springs, ported, decked, around 11:1 compression, headers, and these dcoe's. My question is what is the normal size for these jets? I just pulled mine out and found 190 air correction and 115 mains. The car idles good, but I expected much different sizes than what I found. With those sizes it sounds like it should be super lean, it most certainly is not.

Link to comment
Share on other sites

choke size? idle jets? pump jets?

that does sound really lean. my 40's were at 120/170 with 32mm chokes

45's at 140/180 with 38mm chokes on same engine.

you should hook up a wide band o2 sensor. then you would know if it is lean!

the black plugs could be from rich idle running. plug cuts only good if you start clean and pull them immediately after running them at rpm you are looking for.

Link to comment
Share on other sites

Check the fuel pressure and float level-

also check the progression jets.

If they're huge, they're giving you black plugs.

But I agree, 'normal' range would be 125- 140.

I also am the preacher of the wideband- it can

make an expert out ofanyone who isn't tuning these carbs

on a daily basis....



Link to comment
Share on other sites

alright. I'm going to look into these things tomorrow. Can someone say the specs their carbs have? Or something that my motor should have in it approximately? I'd like to have 34mm chokes. Its going to be a heavily driven car, but only revved to 6000 or 6500. I'd just like to get a good idea on how these should be set up and I haven't seen any good information for these motors.

What spark plugs should I have as well? I'm going to go get some tomorrow.

I'm looking into a controller and gauge as I already have a wideband o2. I'll have one next week for sure.

Link to comment
Share on other sites

I ordered a wideband kit today. I really wanted one anyways to cut out any guess work...

If that chart is well thought out like it says I should be pretty close then with the 115 and 190. I guess I'll know when I put in the wideband next week. I haven't yet had a chance to look at my carbs because I had a battery malfunction today. Ended up being the cable terminal...

Link to comment
Share on other sites

it doesn't take much to be really far off. 115 vs 125 is a lot less fuel and 190 vs 180 is a lot more air. ;-)

which wideband did you get? i have an innovate LC-1. x-16 guage mounted on top of dash in two unit pod with oil pressure. Jgerock has an AEM mounted on the little shelft to the left of the inst cluster. his looks much more "correct" in an 02. LOL, i got accused of having JDM style bling in my car at the track last weekend due to the lights on the x-16....

Link to comment
Share on other sites

Yeah that's very true, but it's closer than what I thought it might be.

I bought the lc-1 db kit for $166 off eBay. I really wanted the analog gauge, but didn't want to spend the extra 50 or 60 bucks on it. I'm probably going to put it in the left ledge as well. But, I've got a temp gauge mounted under the dash, which would be really nice to have with the wideband in a dual pod like your talking about.

Link to comment
Share on other sites

Jgerock has an AEM mounted on the little shelft to the left of the inst cluster.

Here is mine. The gauge is in a cup type mount, but the velcro double-sided tape will not hold it down. It just sits there. No holes drilled in the dash, just some tricky wiring. You have to remove a couple of screws under the dash to lower it just enough to get the wiring w/connectors thru a small existing opening just below the side defroster duct.




Under the car (sensor points straight up)


Existing hole in passenger side firewall


Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...