killershag

i got a 13b with a weber 48 dcoe sidedraft looking for the a good starting point for the jets...

AirwalkerRX7

I'm going to run the same and was looking for a good starting point too.

No one seem to ( or want to) give a clear answer. I mostly find stuff about a 12A engine's with a DCOE 45. The thread's about 48 DCOE don't say much.

After almost a week of searching and reading sites about Weber tuning I got the following.

For more fuel trough the rpm ranges till the top you have to run main jets that are greater then your air correction jets. For more "power" in low rpm ranges your air correction jet need to be higher then your main jets.

Was reading one thread where some was talking about using a bigger pump jet for the progression circuit to get rid of the bog/ hesitation at the beginning. He was also talking about using a stiffer pump rod spring and an 18 mm pump rod to make the transitions from the progression circuit to the main circuit smoother( hope i got that right)

SO.. from what i could gather:
Venturi: 42 mm
Idle jet's : 65f9
Pump Jet: 50mm/55mm/60mm (I'll have to check which one works best)
Pump Exhaust Valve : Read that soldering it shut or covering it with a rubber something would help a against stuttering.
Pump Rod: 18 mm
Main jet:210mm Air Corrector Jet:180mm
Main jet:200mm Air Corrector Jet:140mm
Emulsion Tube : F11

If your wondering about the factory setting.
Factory setting for a 48 DCOE :

Venturi: 42mm
Auxiliary Venturi: 5.00mm
Main Jet: 180mm
Air Corecction Jet: 160mm
Idle jet: 65mm (f8/f9--> ???)
Pump Jet: 45mm
Needle Valve: 2.50 mm
Float Measurement: 12mm
Pump Exhaust Valve : 100mm


This is what I have come up with after a week of research. I'm still waiting for the parts to arrived to start tuning.

Any comments and recommendations very are welcome. My 13B is a stock 6 port.

Please, stuff about Weber DCOE 48 on a 13B only. Hearing about how you successfully jetted your Weber DCOE 45 on a 12A won't help us.


AirwalkerRX7

gerald m

(( TROCHOID )) One of our senior members from what I gather is one of our best side draft guys he might help you he is very up on maxda works . and he likes that type of carb compared to some other types. he will no doubt see your thread ..

dirty-german

iTrader: (1)

I will be following this thread aswell. I have a 48 dcoe on my 13b and I'm trying to fine tune it. I've had it running and driven it but it was not drivable enough for me. For example: wot through first and second was insane but once I hit third it would bog. I've never driven it enough to get to fourth.

Dualist

I take it a 48 DCOE is the side draft version of the 48 IDA/IDF.?

If it is then this may help get you started with tubes and jets....
http://www.markus-witte.info/Wankelm...components.pdf

dirty-german

iTrader: (1)

Yes the dcoe is basically a side draft version of the ida. The jet sizes will not be the same though just because the design of the carbs are not the same. That chart I have seen before and may help as a starting point. I think the jet sizes will be different in the end though. I have a 6 port 13b and after looking at the chart I may try 40mm chokes because right now I am using 43mm chokes and I think they are too large for my stock port motor.

AirwalkerRX7

Hmmm ..then 42 mm would probably be to large to...

AirwalkerRX7

Received my F11 emulsion tube and my linkage kit yesterday. Still waiting for my other new jets to arrive...I will start setting the carb up just to see how it runs with new f11 emotube

dirty-german

iTrader: (1)

I don't know for sure that they are too large but the motor had no bottom end whatsoever, but it was breathing fire on the top end. So I would like to find something in the middle. So I'll try the smaller chokes and hopefully get some more bottom end to it with more driveability. I want my car to be a daily not a race car so I'll sacrifice some top end

Dualist

Yeah if you're running a stock port then they are way to big I've now found. A guy in the UK has a PP modded car and runs it on 43mm chokes but when he wants more power goes to 46mm....

http://www.mazdarotaryclub.com/forum...ad.php?t=61960

AirwalkerRX7

But he is running a custom 51.1 mm Weber IDA. Not the same as the 48 DCOE. IDA's flow alot better then DCOE's. A 43 mm choke on a stock port would be to much on a 13B with an 48/50 IDA setup. But since a DCOE is a side draft one would say it has different characteristics then an IDA. It should have less flow the an IDA so a 43/42 choke should not be a problem with proper jetting, for a 48 DCOE.

If only some of the Weber gurus out there would shed some light on the matter!?

AirwalkerRX7

Hey dirty-german, Any luck with those 40mm chokes. I have ordered 38mm chokes. 42 mm is to big for a stock 6 port.

snivley whiplash

iTrader: (4)

I have a bunch of jets and e tubes to sell, what do you need? pm me

dirty-german

iTrader: (1)

No luck, I will just be running the 43mm chokes that I have. I spun a bearing a few weeks ago and so I pulled the motor apart. I didn't port it but I polished the ports to get rid of the casting marks and rebuilt it this past weekend. The motor is going back in the car tonight

AirwalkerRX7

Got my car idling at a 800rpm today.
Here is my jetting and carb config. This would probably be a good starting point for a Weber 48 DCO/SP2

Chokes: 38mm
Main Jet: 210mm
Air Corecction Jet: 180mm
Idle jet: 65mm F9
Pump Jet: 55mm
Pump Exhaust Valve : 0mm (mazdatrix sells these)

I also installed Weber mounting plates with the rubber rings for a nice seal at the manifold.

No bog and revs nicely up to 7000. This setup is on a N/A S5 blok with the 5th and 6th port open. Road race exhaust open headers...revving it was very loud! Still waiting on the rest of my exhaust system...

Will post a vid soon.

airtecture

Thanks for the information.

AirwalkerRX7

@airtecture

No problem. More then glad to help others get going quicker with this..

Jhereg

iTrader: (27)

Archive please. I traded for Joe's box of weber pieces, still haven't gotten the time to open it all the way up and start seriously tuning it. Great to see some actual input. Calls to Racing Beat and Atkins were a waste of time.

Jhereg

iTrader: (27)

Ok, first attempt at tuning a carb for me. First thing I notice as I'm learning what the diff parts are, the orig owner did not have any air corrector jets on at all. Also had 1 f7 and 1 f11 e-tube. I did not have a complete kit of parts, but seems to be running really good. I'm going to order bigger ones and try that out, currently have the biggest I have on hand.

idle jets 65f9
main jets 180
ac jets 170
e-tubes f11
needle valve 2.5

I have this to mess with

main jets 135,160,165,175
ac jets 145,155,165
e-tubes f2,f3,f7,f8,a single f11, f16
needle valves 2.0,3.0

stock 13b 6port, rb road race header and upper manifold, supposed to be prima flow exhaust but I'm not sure on that to be honest.

Runs a lot better than before, but clutch is starting to go out, so I couldn't really have any fun without it slipping on me.

j_tso

iTrader: (2)

I wanted to upgrade from a 45 DCOE so I bought a Weber 48 DCO SP from another member and I'm running okay with these settings:
42 choke
195 main jet
175 air corrector
F3 emulsion tube, it's the same hole configuration as the F11 but .5 mm narrower
65F8 idle jet
65 accelerator pump jet
0 accelerator bypass
2.5 float needle
13mm float height wit plastic floats

I'm also running a Carter P60504 without a regulator. It flows 30 gph and maxes out at 4 psi, I haven't run into fuel issues on the highway or at the track (not strip).
This is all on a Series 4 13B 6 port. Port sleeves removed; I don't think this affects running much because the intake tract length is considerably reduced with the side draft manifold, my guess.

I highly recommend the Webcon linkage kit that goes on top of the carb and pushes down on throttle lever. The pedal feel is great.

In this thread a forum member got the specs for a Dellorto 48 DHLA(similar side draft design) from Racing Beat in the kit they used to sell.

Jhereg

iTrader: (27)

Could you post some under hood pics showing the linkage? Thanks for the link.

got 4 more jets in yesterday, I'm going to mess around some more. New clutch should be here soon. Hoping to get it installed before St Helens run on Sat.

j_tso

iTrader: (2)

The kit comes with a cable, but the stock throttle cable linkage even threads into the frame.

AirwalkerRX7

Nice! I also got the same throttle linkage kit.

REPU_74

iTrader: (12)

whats the price for this linkage kit???

sky_guitar

i was looking for help...seems after reading this that i don't have much to worry about. i think i already have f9s and 155 whatevers. and i guess the quarter turn till it falls is the proper tuning technique after you get your jets right. my weber has the one big airfilter on the side tho. looks a bit different. throttle is way different, but looks like it should feel real tight with what you got there. how do you tell the model?