Lancia Beta Forum

Technical stuff => Fuel System VX => Topic started by: VXdeMayo on June 05, 2012, 10:21:22 AM

Title: Uprating the VX engine + VX wiring diagram anyone?
Post by: VXdeMayo on June 05, 2012, 10:21:22 AM
Hello guys,
great weekend at Norwich, and good to put so many faces to names etc.
Firstly, Eric you were most helpful on the subject of uprating the VX engine as I wished with a DCNF and i.e inlet cam, CSC stainless exhaust and lastly a 21T pulley which I think would be good. I said at the time that I would remember the mods you pointed out, but you've guessed it.... I havent!

Could you please when you have a moment put finger to keyboard and post a list of what you recommended to me, improvements wise. (I am sure it will be of great use to others as well).

Also does anyone have a Volumex wiring diagram so I can chase this gremlin I have with "Lulu".

That would be a great help.
Chas and Anne,

Title: Re: Uprating the VX engine + VX wiring diagram anyone?
Post by: WestonE on June 05, 2012, 03:51:34 PM
I will try to do this justice but I reserve the right to miss something. Firstly My VX wiring diagrams are with Darren at Monte Servicing hopefully to be swiftly returned. On this the HF Turbo technical book has some nice descriptions of the OE VX systems and a guide to things like setting the SC belt tension correctly so try to get one of those!
As a basic principal engines that produce power like cold dense air with as little flow restriction as possible i.e. a straight flow of air with minimal changes of direction. The OE VX design is a disaster in this respect. Naturally aspirated engines benefit from tuned length inlets with pressure wave reflection, but pressure charged engines do not need this. Hence Guy Crofts high performance VX engines use a DCOE side draft carb directly on the front of the Supercharger.

The OE VX has the same fuel tank and pump as the Fuel Injection Beta IE but uses a carb which adds a lot of complex plumbing. I have very successfully removed a lot of this un-reliable complexity and used a Facet Silvertop competition pump at the rear with a filter between the tank and pump. A Filterking filter regulator is located in the engine bay set to 3PSI. The return fuel pipes are plugged ( bolts & pipe clips).  These cylindrical pumps are designed to run and stop continuously and are very well proven provided they are protected from clogged fuel lines so clean out the tank if in doubt and you must have a pre-filter. These bits are available from Fuel Systems Enterprises.
NB Keep the electrical thermo-valve and the hot shut down vapour pump looping this into the water hose routed from one end of the inlet manifold to the other. Initially keep the cold start manifold warming plumbing (vacuum valve thermo switch on the side of the inlet manifold and vacuum controlled water valve).  You can test the effect of not having this by disabling the switch so the manifold stays cold and decide if it is worth having for quicker warm up and smoother running in warm up.  I would remove it, but please test it and make up your own mind.  Just make sure it is not stuck so the manifold is still getting hot water once the car has warmed up as this will ruin the result from jetting the carb.

On the air intake side heat insulate the underside of the airbox with stick on heat insulation as it is in a crazy location for picking up heat and use a K&N filter in the housing. Find an airbox from an IE and use the pipe input piece with the round pipe section. Visit Europa Spares and buy the Revotec Cold Air feed Kit and route this to cold air at the front NS of the engine bay. This will remove the often free floating thermostat flap that can cause havoc and restrict power whilst making little difference to warm up when the airbox is sat at the hottest part of the engine bay.

On camshafts leave the Exhaust one just as it is other than checking it is not damaged and has the right valve clearances (higher lift or duration just wastes fuel). On the inlet side fit a Beta 2000 inlet camshaft from a Carb or IE model or if you can afford it a Guy Croft 3A cam. Obviously if you buy a GC prepared cylinder head in place of a well used 27 year old one you get a better result but also budget for head bolts and a decent head gasket if you decide to do this.

Fit your 21Tooth pulley sourced from Allan Young engineering taking the opportunity to clean and re-grease the rear bearings and change the oil on the VX SC. Guy Croft publishes a nice guide to this so I have included a link to this on his website. Make sure the pulley lock nut is correctly torque tightened and fit a new belt and tensioner if it has not been recently changed.
Find and fit a 40DCNF carb with jetting as published in GCs book as a starting point. Go for a very high quality carb as time worn and battered items will give endless trouble even with a carb overhaul kit fitted.  On anything used fit an overhaul kit as a matter of course to save yourself misery later.

VX FI Monte project & Volumetrico FI Beta Spyder ( ( ( ( (

Title: Re: Uprating the VX engine + VX wiring diagram anyone?
Post by: VXdeMayo on June 05, 2012, 09:05:17 PM
Dear Eric,
thank you so much for that. Having it "on paper" so to speak means I can tick off the mods one by one, and know I have not missed anything along the way! (I have been trying to get a copy of Guys book at a non stupid price for a while, but to no avail).
I will try to find the HF Turbo book you mention, but in the meantime if your copy of the VX wiring diagram come back to you, please let me know. That would be most helpful.
I have recently purchased a DCNF 40 via ebay, and although it looked slightly dirty in the photos, I had a look before purchasing and took a chance. On cleaning it up it revealed what looks like a good example, that I am sure has been subject to a clinical stripdown and rebuild just before sale, as the gaskets and diaphrams look new and "uncompressed" by engine heat. So after rejetting to the favoured spec I hope it will be a reliable unit in it's new installation!
Once again many thanks.
Chas and Anne,
(VXdeMAYO). :)