Weber dcoe 40 jets for 1.9CIH

[kiekmer]

Hello everyone,

Last week I bought 2 dcoe40 18" for my Opel GT, but I`m not sure what jets to use for a stock 1.9CIH engine. I used the calculations on this site: hometown.aol.com/dvandrews/webers.htm and came to the following values:

Main venturi 32
Barrel size (32 * 1.25) =40
Main jet (32 * 4) = 128
Emulsion tube F16 or F2
Air crrector (128 + 50) = 178
Idel jet 50 F11
Pump Jet (72) 40
Exhaust bleed (75) 50
Needle valve EW 150

Does anyone know if this is correct????


My other question is: do I have to hamer the bodywork to fit the Webers???

Greets from Holland,

Roel

[spdkilz02]

u may have to cut out some of the heater box for them to fit, just depends what manifolds u have to go with them...

[GTJIM]

Welcome to the Opel Community, Kiekmer

The only intake manifolds that don't need the heater box to be hammered or cut away are the Irmscher short ones. Anything else needs major surgery.

Here is the jetting another set of 40 DCOE jets running on OpelDean's GT

http://www.opelgt.com/forums/75302-post14.html

With a standard 1.9L you will be better to use 30mm venturis (chokes)
The jetting depends upon many things: compression ratio; exhaust system; any other modifications; even height above (or below!) sea level etc. etc.
What ever you start with the carbs need to be individually tuned to your motor.

For more info just put "40 DCOE Weber Jets" into the Search Box on the home page.

[kiekmer]

Thank you for your info! I don`t have the Irmscher short ones , bit I really don`t want to damage the heater box.

Does anyone know if these manyfolds are still available, and how much they cost???

[GTJIM]

Originally Posted by kiekmer Does anyone know if these manyfolds are still available, and how much they cost???

The Irmscher intakes are only available 2nd hand - you will have to search German EBay for them. They sell between E150 and E300.

The Irmscher "shortie" is a very short manifold - there is also a 'long' one used for Mantas. If you can find a set with the special water outlet that is needed - so much the better.
Here is a pic of a short one beside another type of longer manifold and a pic of the special water outlet with a set of dBlis manifolds which are just about as short.
Have added a pic from Nobody's collection with measuring tapes on a set of Irmscher 'shorties'

[kent]

exactly how tall are those shorty's?and how much clearance do they leave?I have a dsd manifold that I'm trying to figure the clearance on

[kiekmer]

The ones i`ve got are 9.5 cm (3.74 inch), but i`m not sure if these are the short or the long ones

can anyone tell me which intake manifolds i`ve got? The brand is c/t...

Gr. Roel

DCOE intake.JPG

[kiekmer]

Hi,

I tried to install the webers on my GT, but it is a very tight fit at the heater box. I think I`ve got the short intakes, they are (9.5 cm/ 3.74 inch), but i`m not sure.

I added some pictures:

weber heater box 1.jpgweber heater box 2.jpg

I really dont want to cut/hammer the sheet! How can I solve this problem????
- Are there even shorter intakes???
- Can I install the Webers with only 3 trompets???

Gr.

[Lasse H]

I think there should read "Irmscher" on the upper side of Irmscher shorties near cylinder head. I can't see that in your pictures and those look somewhat different otherwise too.

If this is a street car, have you considered small air cleaners instead of trumpets? With stock heater box there is really little space for that 4th cylinder trumpet/cleaner anyway... I think using 3 trumpets out of 4 is probably worse than using 0 trumpets, makes engine run uneven?

In my picture gallery there is a couple of pics from DHLA 40 carbs, short Irmscher intakes and little air cleaners. Heater box is slightly modified, but there still is not too much room! I dreamed of trumpets before but soon realized that is not possible without fairly big work with that heater...

Maybe you could move engine a little bit left to make more room? I don't know the best way to do this (or how much extra space is achievable?), but it should be possible in some extent.

Btw. in your pic there appears no any kind of insulator between carburetor and intake manifold. This might increase risk of carb flange breaking and also improves heat and vibration transfer to carb... Too bad a proper damper also adds some millimeters to the total width of the package.

[opelwasp]

It also appears you have EFI installed in your GT. Why are you going to dual webers? If you are looking for increased performance then buy/build a MegaSquirt programable EFI computer. Look it up, there is some pretty wild stuff you can do. All you need is the manifold, throttle body, injectors, and an O2 sensor. I'd bet you could get clse to if not more potential power(i.e. turbo/super charger) from that setup then the carbs.

[Crusher]

I have the DCOE on my car.
If you can find a manifold so you can use only one carb, it would probably work just as well for you....Reason is I raced a guy with dual DCOE 40's against my single DCOE. He had a 2.2L engine, mine is a 2.0L ported head, cam and ballanced....It was basicly a dead heat, and both cars ran the same.
The single carb with a longer manifold will give you better low end power than the shorter manifolds, and it will fit without damaging the heater box.
I tried the jetting formula but the car couldn't get above 4000 rpm and it just ran bad...I thing that jetting formula is for the dual arrangement.
For the car to run right I had to put 180's for the main jets and 200's for the air correctors. everything else was the same as yours.
I measured the O2% in the exhaust at idle and on the freeway..the levels ranged from 1% to 0.5% O2 which is just where it should be if the carb is jetted right.

Good Luck

[RallyBob]

Originally Posted by kiekmer I really dont want to cut/hammer the sheet! How can I solve this problem???? - Are there even shorter intakes??? - Can I install the Webers with only 3 trompets??? Gr.

You need to use very short air horns. Something like this: 12mm air horns

Not much room in a GT!

[kiekmer]

The manifolds I`ve got are some kind of replica`s. They have 'C/T' as a brand name.

I`m looking for someone who can tell me how long these shorties from Irmscher are. So when there are no shorter then the one`s I've got there is a chance of doing this without damaging the bodywork, otherwise I have to think of someting else to spice up the engine...

Gr.

[opelbits]

kiekmer-

The really short trumpets used in conjunction with an airbox would probably be best. The box would act as a plenum for the carbs and allow mounting a filter ahead of the radiator support, to catch the cooler air.

I say this, because, 1- you need a filter and 2- if you are sitting in traffic, that back carb throat (cylinder #4) may run hot drawing in the hotter air from the back of the engine compartment. The rear cylinder may run rich from either not being able to draw as much air or from the hotter air being less dense.

[soybean]

Originally Posted by opelbits kiekmer- The really short trumpets used in conjunction with an airbox would probably be best. The box would act as a plenum for the carbs and allow mounting a filter ahead of the radiator support, to catch the cooler air. I say this, because, 1- you need a filter and 2- if you are sitting in traffic, that back carb throat (cylinder #4) may run hot drawing in the hotter air from the back of the engine compartment. The rear cylinder may run rich from either not being able to draw as much air or from the hotter air being less dense.

Here's a link to MantAsconas photo gallery showing his cold air intake. http://www.opelgt.com/photos/showpho...0/ppuser/11162 Very nice setup check out the other photos as well.
I believe it is a TWM Air box. http://www.twminduction.com/airbox.htm. They also sell the Velocity Stacks.
Also a link to OpelDeans Twins. http://www.opelgt.com/photos/showpho.../photo/4709Hth, Jarrell

[soybean]

Originally Posted by kiekmer The manifolds I`ve got are some kind of replica`s. They have 'C/T' as a brand name. I`m looking for someone who can tell me how long these shorties from Irmscher are. So when there are no shorter then the one`s I've got there is a chance of doing this without damaging the bodywork, otherwise I have to think of someting else to spice up the engine... Gr.

The picture that GtJim posted in this thread (nos. 5) is pretty much correct. Hth, Jarrell

[opelbits]

Originally Posted by soybean Here's a link to MantAsconas photo gallery showing his cold air intake. http://www.opelgt.com/photos/showpho...0/ppuser/11162 Very nice setup check out the other photos as well. I believe it is a TWM Air box. http://www.twminduction.com/airbox.htm. They also sell the Velocity Stacks. Also a link to OpelDeans Twins. http://www.opelgt.com/photos/showpho.../photo/4709Hth, Jarrell

The TWM boxes are pretty nice, but they look too big. If you can't fit the airhorns, the box won't fit either. The only solution is to make on out of fiberglass. It's not really that difficult and it can be made to fit the contours of the GT engine bay (build a mock-up out of that blue or pink insulation board from Home Depot, coat it with wax and mold release, then glass over it. Once it cures, pull the foam out). Basically, a flat panel that bolts to the carbs with a box that bolts to the panel. The box would have a round flange on the end nearest the radiator to connect a flexible air duct.

I keep thinking about getting some short sidedraft manifolds to mock it all up and make the airboxes.
Alfa used to make some really nice airboxes, some were sheetmetal with round filters inside, others were cast aluminum with a remote filter. I'll dig up some pics.

[kiekmer]

Originally Posted by Crusher I have the DCOE on my car. If you can find a manifold so you can use only one carb, it would probably work just as well for you....Reason is I raced a guy with dual DCOE 40's against my single DCOE. He had a 2.2L engine, mine is a 2.0L ported head, cam and ballanced....It was basicly a dead heat, and both cars ran the same. The single carb with a longer manifold will give you better low end power than the shorter manifolds, and it will fit without damaging the heater box. I tried the jetting formula but the car couldn't get above 4000 rpm and it just ran bad...I thing that jetting formula is for the dual arrangement. For the car to run right I had to put 180's for the main jets and 200's for the air correctors. everything else was the same as yours. I measured the O2% in the exhaust at idle and on the freeway..the levels ranged from 1% to 0.5% O2 which is just where it should be if the carb is jetted right. Good Luck

Where can I look best to get a single DCOE manifold? And do you have pics from the carb on your car?

Gr. Roel

[opeldean]

in my gallery is an audio file. My heater box is uncut, I have no trumpets,it runs great and has for 7,000 miles..at least.

looks like you have the same room as me...before I hammered in the box at the back corner, I cut the screen and let the foam filter rest againt the metal wall of the box ..no problems...

[soybean]

Originally Posted by kiekmer Where can I look best to get a single DCOE manifold? Gr. Roel

You might try alfa1750 on Ebay. Gabrielle (sp?) usually has parts for sidedrafts and others and might be able to find one for you.

On the other hand, Adam, (spdkilz02) has a set of carbs and the matching Webers for sale in the classified section here. Hth, Jarrell

[GTJIM]

This is by far the best type of Single Side Draft intake manifold to find:

[kiekmer]

Originally Posted by opeldean in my gallery is an audio file. My heater box is uncut, I have no trumpets,it runs great and has for 7,000 miles..at least. looks like you have the same room as me...before I hammered in the box at the back corner, I cut the screen and let the foam filter rest againt the metal wall of the box ..no problems...

Hmmm so maybe the solution is in the filters, cutting the screen so the foam can rest against the metal wall, didn`t think of that What type of filters do you have, and where can I get them?

Gr

[GTJIM]

They are Lynx "RamFlo" filters made in Australia - distributed by Weiand in the USA.

http://www.lynxcorp.com.au/main.php?idx=home

http://www.racetep.com/ramflolynx.html

That is some good info for you.

[opeldean]

the length of intake is 3 inches
i will get my jetting for you later,its awesome

[tekenaar]

Originally Posted by kiekmer Where can I look best to get a single DCOE manifold? And do you have pics from the carb on your car? Gr. Roel

Best SSD (40DCOE/DHLA40) manifold for GT is Steinmetz . . . only available used. No cutting of heater box necessary and can use short trumpets (15mm) inside an angled airbox to feed carb cold, filtered air!



With cold airbox installed:



To answer your SSD40 jetting question, go here for both Weber and Dell'Orto.