Fuel octane booster

[Hamish]

Query for all Lancisti petrol users :twisted: I'm advised to investigate fuel additives to boost the cheap unleaded fuel I get in Safeways every week :wink: after an unfeasibly large shop (those in the UK will know what I'm going on about) .
I'm told it could be unwise to run my VX on unleaded longterm so I'm using an additive (Redex) at present - what I want is a good Octane booster and lead replacement additive in one, especially as my engine will (sooner or later :oops: ) be getting a few more 'tweaks' that might demand a premium fuel.
I have used Shells 'Optimax' unleaded but there has to be a cheaper solution and I want better than pump fuel!!
Any Ideas :?:

[Wallace]

Check out http://www.racecar.co.uk/partsboardmain.htm - specifically the "Usefull Technical Info " page.

Bearing in mind that higher octane fuel doesn't necessarly give you extra horses unless the engine is tweeked to match . . . . !

[Bazza]

Query for all Lancisti petrol users :twisted: I'm advised to investigate fuel additives to boost the cheap unleaded fuel I get in Safeways every week :wink: after an unfeasibly large shop (those in the UK will know what I'm going on about) .
I'm told it could be unwise to run my VX on unleaded longterm so I'm using an additive (Redex) at present - what I want is a good Octane booster and lead replacement additive in one, especially as my engine will (sooner or later :oops: ) be getting a few more 'tweaks' that might demand a premium fuel.
I have used Shells 'Optimax' unleaded but there has to be a cheaper solution and I want better than pump fuel!!
Any Ideas :?:

Hamish - I'm quite sure that VX engines are perfectly compatible with unleaded fuel and unless you are getting pinking with 95 octane, it is perfectly safe to use.

[Hamish]

Interesting link Wallace :) I'll look into it more closely.
Bazza :P good news but I was advised that for the long term safety of the engine (and mine isn't a 'hanger queen' and gets used daily :twisted: ) that an additive would be advisable, would you agree :?:
As I tend not to hang around too much (except in the snow!) I thought a better octane fuel would - in theory at least :?: be better for the overall efficiency of the engine.
I'm (eventually) :oops: converting to a sidedraught Weber 45 so I guessed it might be better to investigate the fueling first :lol: so all input welcome :!:

[Bazza]

Bazza :P good news but I was advised that for the long term safety of the engine (and mine isn't a 'hanger queen' and gets used daily :twisted: ) that an additive would be advisable, would you agree :?:


The best way to find out for sure is to try your car on a rolling road with both types of fuel - if you find you need to retard the ignition for 95 octane but get the same power after having done that (with no loss of driveability) then retarding the ignition is the way to go. If you can't get good driveability maybe then you will have to use 98 octane or additives. Your will not need additives to protect the seats or valves.

[Hamish]

The best way to find out for sure is to try your car on a rolling road with both types of fuel -

Point taken :wink: once the 45 is in place I'll have to go to a rolling road to set it up. I can just about manage a standard VX carb with my eyes shut but this DCOE stuff is all far too complicated for a simple man such as I :!:
I'll post results here, but no-one should hold their breath :!: as knowing my luck it'll be months away yet......

[Bazza]

Point taken :wink: once the 45 is in place I'll have to go to a rolling road to set it up. I can just about manage a standard VX carb with my eyes shut but this DCOE stuff is all far too complicated for a simple man such as I :!:
I'll post results here, but no-one should hold their breath :!: as knowing my luck it'll be months away yet......

You'll find that with the DCOE you'll need bigger jets than those available from Weber - just get a selection of small drills :wink:

[Hamish]

You'll find that with the DCOE you'll need bigger jets than those available from Weber - just get a selection of small drills :wink:
Oh b****r :!: Can you give me some approximate idea of what drill sizes... :?: Is nothing ever simple with this car :?: I already assumed 'race type' jets would be tricky to acquire but I'd appreciate your 'long distance' input :oops: as you've obviously done the conversion...
Was it on 'that' VX coupe we discussed before :?:

[omicron]

drilling jets or soldering and drilling jets should be avoided if proper jets are not available, because all proper Weber jets are flow tested.

[Bazza]

drilling jets or soldering and drilling jets should be avoided if proper jets are not available, because all proper Weber jets are flow tested.

If you can't get the proper jets then what do you do - abandon the project?

I'm only talking from experience mind you :)

[omicron]

What I was saying was, that if the proper jets are available, then it is better to use proper Weber flow tested jets rather than soldering up and redrilling old jets.

However, if the jets that are required are not available, then there is little option but to resize existing jets. It is always worth checking to see if the jets you are currently using are still available, because for some reason you may want to revert to the previous setup.

If the jets required are no longer available then you have little choice do you?

[peter_coupe]

Excelent source for the Weber parts is Southern Carburettors in the UK, just ask for Steve.
I got from them many hard to find original parts for 42 DCNF, chokes, air, jets, and above all emulsion tubes which are imposible to find in OZ land.
Give them a call they will have it.

Ciao

[Hamish]

Interesting debate this :!:
Can anyone clarify what race type jets/emulsion tubes are :?: i.e: are they an off the shelf item or something you need to make up as you go along :?: My main reason for the query is as my car is a daily hack (that sounds worse than I meant it to :oops: ) I need to spend the minimum amount of time getting it 'sorted' when/if all the pieces come together... so the more I can prepare now the less dicking around I'll have to do when it's ready to be installed :twisted:
I had thought about a 40DCNF on the standard manifold but I should be (fingers crossed) getting a Guy Croft adapter manifold :twisted: in the near future hence the interest in fuel and fueling.... and dirty great sidedraught carbs with an unquenchable thirst for jungle juice :wink:

Bazza - how did you find the room for the sidedraught :?: It's going to be a tight fit with the standard radiator - I was thinking of canting it off at an angle and moving it to the left but also interested to know if you did any ducting to get cold air to the carb.... I have a cunning :?: plan to re-use the old airbox but all input (as always :roll: ) appreciated :!:

Peter - As a matter of interest what is/was the 42 DCNF fitted to?

[peter_coupe]

Hamish

I have a pair of 42 DCNF's on Alquati manifold with ANSA exhaust system and 2inch pipework, and high comp pistons, headwork, etc, etc.

It took me 6 months to sort my carbies out, most of the time I was looking for the emulsion tubes, now it's OK.
To save your self time and money you need to find a dyno and someone experienced with Twin Cams, I would guess that Bazza, Omicron or Guy Croft are more then capable and experienced in tuning TC on the dyno.

Carbies are really aspect of the car that is best left to professionals and mechanics with right tool (dyno) to set up. After that you may play with jets or air-correctors on your own.

You may couse damage to engine if you drive for too long on wrong mixture settings (detonation, etc, etc), get it done first time right.


Ciao

[Hamish]

You may couse damage to engine if you drive for too long on wrong mixture settings (detonation, etc, etc), get it done first time right.
Ciao

Fair comment :wink: but I have no reason to trust a local rolling road and the others you mention are, shall we say, at the 'other' :roll: end of the country :!:
Nevertheless I might make the effort to get it to a rolling road up my way to get it set up OK then go to someone whose reputation speaks for itself..... :!:
I was offered a 42 DCNF at a local auto-jumble for £30 (absolutely no idea what it had come off) and wish I'd taken it now :!: Might have proved an interesting alternative to the 40 and a 45 DCOE..... oh well, c'est la vie :wink:

[peter_coupe]

42 DCNF's are made for pre Biturbo Maserati and Lamborghini, that is one of the reasons for the scarce parts, some of the where also available as an after market of the shelf carb made for downdraft setup (38, 40, etc,)

P.S.
At least try to get Gunsons Colortune for setup.

Ciao

[Bazza]

What I was saying was, that if the proper jets are available, then it is better to use proper Weber flow tested jets rather than soldering up and redrilling old jets.

However, if the jets that are required are not available, then there is little option but to resize existing jets. It is always worth checking to see if the jets you are currently using are still available, because for some reason you may want to revert to the previous setup.

If the jets required are no longer available then you have little choice do you?

What I said was that the jets required are not available so you will need to drill them out - so where are you coming from?

[Bazza]

Interesting debate this :!:
Can anyone clarify what race type jets/emulsion tubes are :?: i.e: are they an off the shelf item or something you need to make up as you go along :?: My main reason for the query is as my car is a daily hack (that sounds worse than I meant it to :oops: ) I need to spend the minimum amount of time getting it 'sorted' when/if all the pieces come together... so the more I can prepare now the less dicking around I'll have to do when it's ready to be installed :twisted:
Bazza - how did you find the room for the sidedraught :?: It's going to be a tight fit with the standard radiator - I was thinking of canting it off at an angle and moving it to the left but also interested to know if you did any ducting to get cold air to the carb.... I have a cunning :?: plan to re-use the old airbox but all input (as always :roll: ) appreciated :!:

Peter - As a matter of interest what is/was the 42 DCNF fitted to?

Fitting a DCOE is very difficult - what we did was to cut up a Ford twin DCOE manifold and weld it to a plate that bolted straight on to the supercharger - we angled it down slightly so that it would fit under the bonnet cross member and moved the radiator forward so that we could make up an airbox. The airbox had a remote filter mounted behind the nearside headlight. The jetting we used is lost in the mists of time I'm afraid but it won't be too difficult to set it up on a rolling road.

[omicron]

What I said was that the jets required are not available so you will need to drill them out - so where are you coming from?

I think you'll find we're both correct!

If when setting a carb to a particular specification then I'd recommend new jets of the correct size IF AVAILABLE rather than drilling out jets. Do you agree?

It is possible that one may wish to revert to a previous specification for some reason, so keeping the old jets intact is sensible. Do you agree with this comment?

Therefore sourcing a set of very common jets to drill out to the unavailable size, would seem to be the best course of action. Agree so far?

This gives a new set of drilled out jets to the unavailable size AND the ability to easily return to the old sizes should the need arise.

[Hamish]

So in essence what you're both saying is have two sets or more of jets/emulsion tubes so that you've got a spare - right :?:
It's all getting terribly complicated, but if drilling out jets etc is necessary (and I suspect it will :roll: ) then in essence both of you (Bazza and Omicron) are in agreement that drilling (albeit without accurate flow testing :!: ) out the jets is the only way to get the carb set up 'right'.
Glad we've got that settled :lol:
I'm off to fill up with a nice 1/2 a tank ofOptimax
:twisted:

[Bazza]

So in essence what you're both saying is have two sets or more of jets/emulsion tubes so that you've got a spare - right :?:
It's all getting terribly complicated, but if drilling out jets etc is necessary (and I suspect it will :roll: ) then in essence both of you (Bazza and Omicron) are in agreement that drilling (albeit without accurate flow testing :!: ) out the jets is the only way to get the carb set up 'right'.
Glad we've got that settled :lol:
I'm off to fill up with a nice 1/2 a tank ofOptimax
:twisted:

Of course you are right Hamish and I never recommended drilling out jets to a size that is available - what I said is that you will need jets of a size that are not available so you will have no alternative but to drill them out.

[Hamish]

Of course you are right Hamish and I never recommended drilling out jets to a size that is available - what I said is that you will need jets of a size that are not available so you will have no alternative but to drill them out.

Which jets in particular would need drilling out :?: might sound daft but having not taken this route before it's best to ask potentially stupid questions :oops:

[Hamish]

Hi all,

Managed to get my hands on a digital camera for a bit (nice toy! :wink: ) and have created a gallery with piccies of the Guy Croft www.guy-croft.com VX adapter manifold - enjoy :!: