Killer Bee Fan

Hello everybody.

Last week I started my project of rebuilding my 45mm DCOE Weber carb so I bought from a well known shop the parts that I needed.
I got a new rebuild kit, .300 neddle and seat.

Well, now it is finished and installed in my car but the carb is giving me a lot of trouble, it has a nice idle between 900-1000 RPM and it works great on idle but when you push hard the accel pedal it will reach fast to 4800 RPM and when the secondaries open the carb sounds like he is not getting the right amount of fuel...
I know I need to change my fuel pump but the gas filter is always full and under hard acceleration in only gets down a little bit, he gets to 3/4 of the total amount of fuel inside it.

My car has a 12A with streetporting and bridgeport only in the intake secondaries of the engine, MSD Blaster 2 Ignition coils, Accel High Performance Plug wires.

My jetting right now is:

38mm Venturies
160 Air correction jets
200 Main Jets
f16 e Tubes
f9 65 idle jets
0 Bypass.

I was trying to use the carb with 190 Main Jets but he did not work well and with the 200 is the same problem. I am thinking to put in my car a DLIDFIS upgrade as a side project, to have a better ignition system but I don´t know if it will work well I will need help with the wiring too.

If anybody has a an idea about what i have to do with my carb please post it here because is horrible to have a nice great look 7 without the real power he needs to move...

d0 Luck

38 venturies seem small to me; hence you not getting enough fuel towards higher RPM range. try upping it to 40 or 42 and see if that works

Siraniko

iTrader: (13)

Use larger idle jet for much more aggressive take off.

38 venturies are too small for that application. Run the carb without it venturies. Give it a shot, you will be surprised.

Air/Main set up will make it lean out on how RPM. Use smaller air jet or bump the main.

Killer Bee Fan

I tried two times with 40mm venturies but he gave the same trouble...

I don´t know what else to do since here in Guatemala City we do not have a real expert in weber carbs...

20 days ago somebody killed one of my friends and he was a great carb tuner...

Killer Bee Fan

A more larger idle jet will not affect my idle when I start the car??

I´m surprised about that you are telling me to take off the venturies of the carb and run it like that, ok I will try this weekend to know what happens with it...

When you tell me to give a bump to the main, you are trying to tell me to hit the main as somthing can be jamed or blockage???

seanrot

iTrader: (2)

4800 RPMs describe what the car is doing, your description of a sound doesnt do much. Is the engine bucking and popping or running sluggish with the little venturies you have its going to have more pull down low. bigger venturies will give you more up top. So descride the actions sounds the engine is making and see if that make it a little easier. BTW i'm sure its a 2 barrel carb, sorry no secondaries.

also are you running a fuel pressure regulater, is it still the stock fuel pump. if it is the stock pump you probably dont have enough fuel pressure to feed the carb over 4800 rpm and its drying out.

Was it on the car before the rebuild?, if so time to take it apart and see what got changed.

Siraniko

iTrader: (13)

here's a link to a good reading material. this will give you a better idea on how they interact

http://www.aircooled.net/gnrlsite/re...es/jetting.htm

Killer Bee Fan

Ok here we go:
1.- The sound that I mentioned is like bucking and popping like he is getting having to much fuel in it, he continues accelerating but he accelerates very hard until 6, 7 or 8000 RPM.

2.- You are correct; I made a mistake in what I said; there are no secondaries, is when the carb uses the mains when trouble comes.

3.- I´m not running a fuel pressure regulator; I have right now in the car a Horrible Facet Pump (Round One) that worked well before with the little Nikky. I don´t think the carb is getting dryed out, because the fuel filter is always full of gas...

4.- No, the carb I got it from a friend (Not a Good Friend); he was using it in a 13B Bridgeport Engine, the carb had the Venturis really bad bored to 40 mm and the neddle and seat did not matched the carb... Thats why I buyed the .300 neddle and seat for the carb...

Killer Bee Fan

Thanks for the help, going on reading...

seanrot

iTrader: (2)

bucking and poping is going lean and incorrect timing, too much fuel is sluggish. change your pump get a regulater. Drive like bat out hell.

the carb is running outa fuel in the float bowl not the filter. You will always see fuel in the fillter engine doesnt suck gas from the filter. your engine is sucking your carb dry and you pump cant keep up.

I think the average around here is 4 to 6 psi of fuel pressure around here on webers. I have a Jay Cee Ent glass ball needle seat and run 7-8 psi in mine. Jay Cee seats are good to 9 psi before I get flamed.

Siraniko

iTrader: (13)

Yes, you're right on that. Im using Jack's glass needle/seat and its able to keep up @ 9 PSI. Im running MSD F/I pump with and old mallory 4309 and fuel jet on the return line. I cant lower the fuel pressure less than 9psi as the older mallory had stiffer springs than the newer ones (thats the info I got from robert @ rotaryshack). No flooding problem. I just started using this old mallory after several years of sitting in my shelf.

on the side note, Jack was the first in the VW group to knock out the wall on a 48 IDA.

Siraniko

iTrader: (13)

killer bee
before doing anything else, if a holley pump is not available in Guatemala, you can run two pumps. Hook them in parallel set-up meaning, there is "WYE" from the main fuel line to the inlets of the pumps. And this apply to the outlet also.

Ditch the fuel filter in the carb. Im referrring to the one in the inlet fitting below the banjo bolt. enlarge them as well - see my mod on a IDA below. this mod will ensure that there is no restriction.

Work in your idle jet first, then the main.

Killer Bee Fan

Whta kind of pump and regulator do you recommend??

I was going to buy a Holley blue pump with regulator from summit racing or maybe a Carter; I have read that for rotarys is better if you use a fuel regulator from 1 - 4 psi; is this good or bad?? or maybe get one from 4 - up psi ??? And the fuel filters wich ones do you recommend me??

Killer Bee Fan

Thanks for the help; I don´t have any hurry to get it running with two pumps; I can wait for the Holley or Carter fuel Pump (Which one do you recommend me at last and which fuel press regulator do you recommend me to buy ). I am going to buy it from Summitracing Equipment so I can wait, but what else do you recommned; I need to know the best Spark Plugs that I can get for my engine too...

Siraniko

iTrader: (13)

holley red and use a thick rubber insulation to reduce the noise.

seanrot

iTrader: (2)

Fuel pump- I'm running a special beast. Turbo 12a with a accel 74701 and a mallory 4309 fuel regulator. If you plan on staying naturally aspirated get a carter or holley. (you can use the search function on here for ungodly amount of info) 4 psi and up regulater would be good. seeing that the webers run 4-6 on average. I can t remember exactlly but I think the little nikky only needed 3 psi (believe that is where you got the rotary is better #'s 1-4).

Fuel filter i would run a stock one and a clear one before the regulator.

JoseReyes

According to the weber manual. All weber side draft require a fuel presure of no higher than 2.5 and no lower than 1.5 psi

I run the following on my 45DCOE 12A Street Port 1982.

Idle Jets 60F9
Main Jets 200
Emulsion Tube F11
Air Corrector 180
Pump Jet 50
Chokes 40
Auxilliary Venturies 4.5
Needle & Seat 200

Carter Fuel Pump, fuel pressure at 2.5, headers, RB Muffler system. Jacobs Electronic Ignition with Direct Fire setup.... 2nd Gen spark plugs

With this setup I'm pushing 136hp at the wheel at 3300rpms Haven't try any higher due to engine being new (less than 1500 miles)

Then again, every engine is a slightly different...

d0 Luck

still loud since i myself was there to hear it..
what u can do is insulate it yourself

but for the buck and performance u can't beat it

Siraniko

iTrader: (13)

Try it with a IDA. Its like night and day.

Siraniko

iTrader: (13)

because you were listening on the wrong car. check the RX-4.

seanrot

iTrader: (2)

no joke there.

the main reason for raising the fuel pressure is to keep the float from dropping very far. the higher the fuel pressure the more stable the level of fuel will be in the float bowl. The fuel will flow in faster and keep the fuel level in the carb from dropping. granted this is as long as you have a needle and seat that can handle the higher pressure. with a new 300 seat you shouldnt have a problem with 4-6 psi.

Killer Bee Fan

Ok seanrot; Can I handle this for DCOE too?? This means if I have a nice fuel pump with regulator at 4psi the carb will always have enough fuel to work good?? I´m asking this because there are many rotor heads that saids that for DCOE on rotary you only need 2.5psi as max pressure???

All of my friends only have IDA on their cars and they use 4psi as well for them.

Robert from Rotary Shack told me to get the Holley street pump that delivers 5psi without using a fuel press regulator???

Killer Bee Fan

Thans man... Another question: Can you tell me the difference between the Holley Blue and the Red one Fuel pumps??? Which one is better for a rotary?? (ONE DAY I AM GOING TO CHANGE THE 45 DCOE FOR A 48 - 51 IDA)
And what about the Carter Fuel Pump?? I was going to buy weeks a go this one:

Vendor Carter
Product Line Carter Universal Rotary Vane Electric Fuel Pumps
Free Flow Rate 72 gph
Maximum Pressure (psi) 8
Inlet Size 1/4 in. NPT
Inlet Quantity Single
Inlet Attachment Female threads
Outlet Size 1/4 in. NPT
Outlet Quantity Single
Outlet Attachment Female threads
Quantity Sold individually.
Notes (Not Specified)


Vendor Holley
Product Line Holley Blue Electric Fuel Pumps
Free Flow Rate 110 gph
Maximum Pressure (psi) 14
Inlet Size 3/8 in. NPT
Inlet Quantity Single
Inlet Attachment Female threads
Outlet Size 3/8 in. NPT
Outlet Quantity Single
Outlet Attachment Female threads
Quantity Sold individually.
Notes Includes regulator.


Vendor Holley
Product Line Holley Red Electric Fuel Pumps
Free Flow Rate 97 gph
Maximum Pressure (psi) 7
Inlet Size 3/8 in. NPT
Inlet Quantity Single
Inlet Attachment Female threads
Outlet Size 3/8 in. NPT
Outlet Quantity Single
Outlet Attachment Female threads
Quantity Sold individually.
Notes (Not Specified)

Siraniko

iTrader: (13)

the red is 7 psi max. blue is 14-18 IIRC. With the carter, I, including my friends, have similar experience of inaccurate fuel pressure despite running new power line and such. I personally dont have (or heard) any bad experience with the holley red. also, the holley F/P/R comes in two settings: 0-4.5 and 4.5-9 (I prefer the 4.5-9)

Killer Bee Fan

Ok, so you recommend me the Red Holley Fuel Pump. What do you mean for Holley F/P/R ??