Setting Up Triple Webers

[Ol_Girl_58]

Hi all,

After a few years of searching, I've finally got a triple weber set up for my FC  . Initially, the setup was on an LJ GTR Torana, so the manifold is quite tall, but it all just fits, complete with ram tubes  .

To ensure that I install them correctly and only once, I'd like to know what I will need.

Excluding my complete Weber set-up, I've got my fuel lines and t-piece etc. I was advised that I'll need an electric fuel pump, however I'm going to see how I go for the time being. Will I need a fuel pressure regulator also? A section of my firewall has also been removed, so back-fit is not such an issue.

I'm thankful for any advice. 

Cheers,

Josh

(Ol_Girl_58)

[Ol_Girl_58]

Forgot to add that the motor is a red 192 and running the standard fuel pump.

[colt]

Josh, a couple of things I've picked up on hanging around with guys that race reds with triple Webers.
They all use a standard fuel pump, they do use an electric pump, but only to provide full pressure at start up and as a back-up pump.
Yes, use a pressure regulator, this is important so the carbies have always got a good fuel supply, they also use larger fuel lines from the fuel block. This ensures a good supply at high revs.

Hope this helps a bit.
Colin.

[CraigA]

To ensure that I install them correctly and only once, I'd like to know what I will need.

First thing to do is make sure your linkage set up is of good quality, that it is adjusted correctly and that it stays that way.

Here's the linkages I use on my Weber's. Set them once and they'll stay put.



http://www.pentastarparts.com.au/sunshop/index.php?l=product_detail&p=2186

Best $225.00 you'll ever spend.

If you want to set them up yourself, then buy a carby balancer. I use the this version, robust, simple and effective.


You can get these off eBay for under $100.00.

You can also use a Unisyn like this. I had one years ago and lost it 



I use a stock black motor fuel pump (7 psi output) and then limit the carb fuel pressure to 3 psi using a Malpassi rising rate fuel regulator. This works well past 7000rpm so the set up must be OK.



Once you've set them up mechanically then you can start fiddling with the multitude of settings available in a Weber carb. If they were running OK on another engine there is still no guarantee that they will do so on yours, however there are some known baseline settings for a red six so if you have trouble after installation I can post these for you.

Here's some pics of the Weber's on my XU1.





Good luck, the sound of 3 dual throat Weber's on a Holden six is amazing.

[Ol_Girl_58]

Colin and Craig,

Thanks heaps for your input.

I'm going to run 1/4 inch fuel lines - are they going to be big enough, or should the primary (main) line be a 1/2 inch or bigger? Craig, I'm sure that I've got a pretty decent linkage setup, but I guess this remains to be seen. Thanks for your comprehesive details. I'd like to see those baseline settings, if you wouldn't mind   

So, is it a necessity to have an electric pump? I guess for performance it is. At this point, I plan to be just running on the street, but eventually I intend to drag race.

Agreed, Webers on a Holden 6 sound brilliant, and for me, are the ultimate. Getting them to fit will a sight, too. 

[colt]

Josh, if you look at Craig.s 2nd photo, you can see the top of his fuel pump. This is the one you want. Don.t use the glass top older type. You need a standard blue/black pump.
 As I said, the only reason the race guys use an electric pump is to provide full pressure at start up, so theyre not winding the engine over & over trying to get it to start.
If you look at Craig's linkages you can see the mount at each carby and the quality of the fittings. Make sure you have NO slop here as it can cause big dramas with tuning.
You may want to ask around in your club to find someone with experience with Webers.

Colin.

[CraigA]

Chokes: 36mm
Idle Jet: 45f9
Emulsion tube: F2 or F16
Pump jets: 50 with a "blocked" pump by pass jet.

These settings were provided by a guy who sets up Weber's for a living and drives a triple Webered Torana to work every day - in Sydney traffic 

The only problem I have with mine is that the rear one tends to leak after I turn the car off. This is due to the fuel expansion caused by residual engine bay heat. If you look in the pictures you'll see that I run my fuel line (3/8" O.D) across the three carbies, terminating at the rear one. To correct the fuel leak problem I was told by Dr Terry to put on to this filter:



Same type as used in the Webered Chargers. The second fitting is for a return from the last carby.

[Johns]

Guys, I have no experience with Webers on Holden motors however I have owned and raced sidedraught Weber equiped twin cam Alfas and Fiats for over 20 years. This what I have learned. Firstly, they only work effectively on engines that breathe very well and they work best at high rpm.

EVERY engine is different, on idle circuit they are difficult to set up and tend to be over rich, on main circuit they are no problem. With Webers most people seem to run either carbys that are too large, chokes that are too large or jets that are too large, or all of the above. If you do this they fuel up in the transition from idle to main, mostly around 2,000 rpm is where this happens and they hunt and kangaroo as well as swallowing enormous amounts of fuel. I suspect this (and cost) is one of the reasons GMH used Strombergs on XU1s.

Bottom line is, in my experience, that they MUST be set up on a dyno to work properly. My two litre Alfa engine with stock pistons running ported head and extractors will get down to 16 mpg on the road if driven hard and with a five speed gearbox won't exceed 25 - 26 mpg on a trip no matter how carefully its driven. Bottom line is these work superbly at high revs. To make them tractable in normal driving they need to be carefully set up for street use otherwise they can be an expensive waste of fuel.

They do sound good though.....

Cheers
John

[FC427]

For a fuel pump I usually fit to my Modified  Holden  6's is a Small Block Chev mechanical pump...The Holden 6 does need a little clearancing on the block to make it work ,but a very easy job..... the diameter of the diaphragm is much larger than the blue / black style and are under $50 new .........FC427......

[Ol_Girl_58]

Thanks for your input guys.

I didn't realise how much planning needed to go into the setup.

The car will be dynoed once the Webers are setup.

I'm still unclear on the fuel pump advice.

Questions are as such:

1. Am I able to run the stock pump? If not, why not?
2. Can I ditch the mechanical pump and go for an electric pump?
3. If I go the electric pump, is it best to go for a big or small pump? I was looking at a Malpassi pump that suited a WRX - will any pump do?
4. Should I utilise the original pump AND an electric pump for backup?
5. What diameter fuel lines should I be using? It is setup with 1/4 inch lines. Should the primary line be larger in diameter? Does the large line start at the tank?
6. With a fuel pressure regulator, what is the best type to use? I was looking at a redline dial type, it looked simple. Is it best to utilise a gauge with a regulator?

This is my first go at setting up such a thing - my questions may be simple but indeed necessary...
 

Thanks again,

Josh

Ol_Girl_58

[CraigA]

1. Am I able to run the stock pump? If not, why not?
Yes, but may not keep up with fuel flow requirements at high speeds. The later model Holden pumps are more suited. Or the Chev idea of Mark's is good and cost effective.

2. Can I ditch the mechanical pump and go for an electric pump?
Yes, no problem. That's if you like the racket an external electric pumps makes!!

3. If I go the electric pump, is it best to go for a big or small pump? I was looking at a Malpassi pump that suited a WRX - will any pump do?
Doesn't matter, so long as it will match the flow requirements which in my case are satisfied by the later Holden pump. I'm sure any pump from a fuel injected car would be OK, but it may then be useful to run a return line to the tank.

4. Should I utilise the original pump AND an electric pump for backup?
In my opinion there is no need, but as Col said there are others who do differently. Two pumps, two cranks, and mines starts no problems even when its been sitting for a month.

5. What diameter fuel lines should I be using? It is setup with 1/4 inch lines. Should the primary line be larger in diameter? Does the large line start at the tank?
Mine uses the stock lines from the tank to the pump and then 3/8" OD rubber fule hose to the banjo connectors at the carbies. This matches the banjo pipe size, which it 6mm (1/4").

6. With a fuel pressure regulator, what is the best type to use? I was looking at a redline dial type, it looked simple. Is it best to utilise a gauge with a regulator?
I haven't heard great stories about the dial type regulators, use a Holley adjustable one or a Malpassi like I've got. I bought a gauge but never fitted it - once you've set the fuel pressure there's no much requirement unless you like to fiddle around.

If you are intending to race the car (constant high revs) then the answers would be different. On a street car my setup starts easily, idles from cold, runs fine in hot or cold conditions, and has handled track days and drag strip visits without any fuel issues. The plugs run perfectly except for some minor fouling if I get caught in lots of traffic.



I run 12 degrees BTDC initial timing, 36 degrees BTDC overall. No pinging on 98 octane fuel.

You are doing exactly the right thing by asking questions and planning to get the car dyno tuned. You hear many stories of guys with tripples having no end of trouble and then ditching them in disgust.

One other thing you should make sure of is that all three Webers are of the same type (its stamped in the top body of the carbies) Will be un-tunable unless they are all the same.

I'm only giving one opinion and set of experiences though. Worthwhile to keep asking around before you fit them.

Cheers,

Craig.

[Ol_Girl_58]

Thanks again guys.

I've found a Holley pressure regulator. So, is it best to utilise a blue/pump fuel pump or a SBC pump? Which is more cost effective? Is it best to purchase a pump new, or secondhand?

Cheers,

Josh

[FC427]

Hi Josh if you wish to use a SBC pump the block need a little bit of material removed with the diegrinder so that the actuating arm does not foul this needs to be done with sump removed and preferably before engine is assembled so if your engine is already assembled just fit a blue mtr pump it will have enough volume for your needs and no modifications required ........FC427.......

[Ol_Girl_58]

Thanks Mark.

Engine is already in the car, so a blue pump it's going to be.

Thanks for your advice.

[Ol_Girl_58]

Hi guys, two questions, which I expect to have blindingly obvious answers:

1. Can I expect fuel consumption to be phenomenal?  Johns, I believe that you may have already answered this question. 

2. Do engine bay fires pose a (larger) risk? 

Cheers,

Josh

[CraigA]

1. Can I expect fuel consumption to be phenomenal?     

On light throttle they are not too bad. On full throttle they'll empty a stock FC tank in no time. In my car, at least 20+ litres per 100 kms during mixed driving, better on the freeway but only just as I'm using a 3.55 diff ratio. The best triples choice for a compromise of fuel consumption and performance on a mild street engine is IMHO the factory XU1 carbs. Easy to tune and published factory set up matched to factroy camshaft profiles. Once set up they are also very stable and reliable.

2. Do engine bay fires pose a (larger) risk?   

3 x fuel bowls, 3 x fuel lines, modified engine with extractors outputing extra heat. Yep 

If its all done properly then probably not but the risk is certainly there.