Outer Limits 4x4 Board

just woundering if anybody knows how to setup the mixer on a 4 bl holley that i have on a 4.4 (p76) engine.
at the moment at 100km and put the foot down it sounds like it wants to go but has a slight sergeing feeling and a backfire from time to time.
also it idles fine and revs with no load fine except on full open throtle.
Thanks rick.

What sort of system are you running ?

Rangie Thing wrote:just woundering if anybody knows how to setup the mixer on a 4 bl holley that i have on a 4.4 (p76) engine.
at the moment at 100km and put the foot down it sounds like it wants to go but has a slight sergeing feeling and a backfire from time to time.
also it idles fine and revs with no load fine except on full open throtle.
Thanks rick.

Had a 650 vac secondary on a 4.4 taken out to 5.0 litres a few years ago running a WillPower manifold ... it used to cough and backfire through the carb a lot ... like it was running lean but when we took it to a dyno to sort it out, it turned out there wasn't enough manifold vacuum. Ended up going back to a smaller 2 barrel manifold and carby to keep the manifold vacuum up. The guy tuning thought the cam was not suited to the big manifold and carby.

Anyway, I guess your problem sounded a bit the same ... you need to make sure it's got enough manifold vacuum to warrant such a big carby and venturi. If the cam is wrong or worn out then you probably won't be getting enough vacuum. I won;t go into the issue of flooding when off-roading as I am assuming you don't take the Rangie off road .. cos if you do then you really shouldn't be running a 4 barrel Holley as you will struggle to stop it flooding.

Food for thought.

Cheers
Simo

When you said mixer i assumed it was an lpg problem, what size holley have you got, could be the power valve is the wrong size and the accelerator pump isnt squirting fuel down the throats when it gets off idle.

it is a 450 holley with no lpg.
will see if i can check the vac after work today engine was done up not to long before i got it.

What sort of manifold are you using? i will interested in the outcome as i have a 450 holley that will be fitted to my 4.4.

it is a stock manifold that has had the old 2 bl boss removed and a 4 bl boss welded to it and the water and vac points removed too.
the carby is a 450 4bl with mac secondrys ( i think its a john cain setup) it has the fuel bowl in the middle like an elbrock type.
if i don't have any luck with it soon i think i will go with fuel injection soon!!!

Do you know the history of the carb, i had similar probs when i first put the 350 holley on my 3.5, power valve was wrong size and would splutter just off idle. Also check the needle and seat and the float. I have the same one.

will have to check the power valve size as it came of a highly modifyed engine and the carby is new only 600km.
also tomorrow i will check the timing and will change the crank case breathers as one side still comes the base of the carby and maybe upsetting the vac of the carby.

Changed the crank case breathers but still the same only better drivability around town and also checked the timing i think my dizzy has a problem because with the vac line off it advances with revs.
I think that saturday i will look into fuel injection again.

EFI ing a 4.4 can lead to all sorts of problems, forget about using the lucas crap start off with a programmable ecu. I would steer clear of using the rover manifold and spacers (unless you already have them) as too many people have had air leakage problems. I plan on using a ford ea-eb tbi unit on the original manifold with a Megasquirt ecu. Its simple and a carb can be swapped back in 5 mins.

yep i will be going to use an ford ea single point setup with standed ecu for now.
just have to get a 8 window shutter for the dizzy and work out what fuel pump to use.
I had a fuel injection bloke do the sums and said it will keep up and he said that he can make me up the dizzy if i needed him to. (but look simple to do)
so hope to have it ready easter.

I have heard that the tbi's dont use as high a pressure as other efi setups, so if you find a suitable pump let me know.

Regards,
Nick.

Loanrangie wrote:I have heard that the tbi's dont use as high a pressure as other efi setups, so if you find a suitable pump let me know.

Regards,
Nick.

Thats correct, you could always use the intank pump from an EA or an adjustable fuel presure regulator

The pump is about half the pressure of the other ones so i hope that i can use a regulator or it might be a custom surge tank fitted with standed pump.

Pumps are usually capable of a much greater pressure than is used in the rail, the pressure is governed by the regulator which relieves back to the tank. so in theory there is no reason you couldn't use a Bosch external as long as the reg. is capable of relieving such a great excess of fuel.

Don't take it to heart, but why use such a crappy EFI system, you will get a good power gain using a multi point and better economy. only advantage i see is obvious, angles. but why if going to the trouble and expense use the antiquated setup?

Agreed multipoint is better, but there are so many problems with using rover efi manifolds and spacers that it would negate the benefit. Anyway unless you are using sequential injection there is no real benefit.

i have looked at other efi systems but the ea is cheap, simple and lots of them around for spares.
also i can make this system for about the cost of a tank of fuel.
and can be converted back to carby quickly.

Fair enough, i'll be inerested in how it works out for ya

Rangie Thing wrote:i have looked at other efi systems but the ea is cheap, simple and lots of them around for spares.
also i can make this system for about the cost of a tank of fuel.
and can be converted back to carby quickly.

Same reasons i am doing it, are you going to use the ford ecu ?

will use the ford ea ecu to start with, but might go to an after market chip and get someone to program it to suit the engine later on.
Well until the next engine swap anyway.

never thought about useing cfi off a falcon before thay are prety simple and reliable

Anybody out there with a p76 4.4 know what the ignition timming should be set to.
P.S. ea loom in, Dizzy setup and relays and ecu in. tomorrow will setup oxy sensor.

Rangie Thing wrote:Anybody out there with a p76 4.4 know what the ignition timming should be set to.
P.S. ea loom in, Dizzy setup and relays and ecu in. tomorrow will setup oxy sensor.

6 to 8 degree's probably more, depends on when you start to suffer pre-ignition (ping) and also depends on how the EFI advances timing and what fuel your running i.e. premium, regular

Rangie Thing wrote:Anybody out there with a p76 4.4 know what the ignition timming should be set to.
P.S. ea loom in, Dizzy setup and relays and ecu in. tomorrow will setup oxy sensor.

Great, can you post some pics ?

yeah definitly pics. if it works i may do the same to recover the use if my duel fuel. what manifold are you bolting the ford tb to ?

Hope to get pics on wed as i will be out tomorrow, oxy sensor in today.
Im leaving the 4bl manifold on and making a plate for the ford tb.
Also just running regular fuel ( it drinks to much to put the good stuff in )

i see so i would need a 4bbl manifold

Na you would be able to use the standed one but you will have to drill holes in the ford tb like i was going to do, but i could not be bothered swaping it back. ( i'm just a bit lazzy )

i have a twin stromberg manifold at the moment . dont realy wanna change over cause the heads and shit have been machines and manifold to suit