Nova SPi to carb

[Aragorn]

ok
my car is currently running a 1.2 spi

ive got a 1.4spi engine in the shed from my old car

what i want to do is convert it over to carbs then install it in my car

so im gonna get a 1.3carb and 1.4 inlet manifold for the 1.4 engine

but i need to work out the fuel system

the spi uses an electric fuel pump like the mpi engines whereas the carb uses the mechanical jobbie
ive been told to use a regulator by someone but i spoke to micky on IRC today and he said its better to fit the mechanical fuel pump
but if i do that i'll need to change stuff at the fuel tank end

so anyone know what the best option?

what needs to be done at the tank end for mechanical pump and/or how much will a regulator cost and where can i get it

thanks

[carltoncrazy]

well there probley an easyer way but this is how i would do it,
transfere a carb feult tank and all pipes and mec feul pump,
but im not really sure,but to me it would seem a easyer meathod

[MC]

Just use a regulator. Its the easiest way. You might aswell just by a 1.4 carb and manifold complete. The carb is the same as the 1.3. Or if you want even more power, fit the 1.3 head, manifold and carb. The head and manifold flow much better, and the combo of the 1.3 head with 1.4 bottom end will raise the compression to around 10:1. It'll be much better.


MC.

[carltoncrazy]

one of those feul things for sale on parts,

[Aragorn]

yeh well i was gonna buy the head too BUT the scrapyard wanted ?40 and thats no garuntee that everything works and the valves and shit are in good order - head also means skimming which is another ?50 at least

i dont have this kinda money right now so im gonna buy the 1.4 inlet manifold and 1.3carb (1.3 carb has bigger jets) just now and get the engine installed and running then when ive got moer money i can buy the inlet and head from a 1.3 and get more power :P

ok so i need a regulator - i had a look in demon tweeks and they have one listed in different pipe sizes - so is this adjustable and if so what do i set it to?

secondly if im dumping the ECU im goin to have to rewire the fuel pump as im guessing its currently controlled by the ecu - would wiring the relay on to the switched live from the ignition work? if i did this would there be an issue with the car sitting with ignition on for long peridos of time (ie listening to the radio at a cruise or wotever - i dont really want the fuel pump running for hours on end cant be good for the pump or the battery)

also is there any other circuits i'll need to rewire? ignition coil for example?

i suppose this is kinda like fitting twin 40's to say a GSi in this respect so any wiring tips or guides on what i need to change??

Thanks

[MC]

Bigger jets do not equal more power! They will just fuck up the mixture, and you'll loose power. Quote the jet sizes to me. A larger main will give more fuel accross the range, and a smaller air will give more at peak. It aint as simple as you think. You're better off having the correct jetting for the engine, i.e. 1.4.

MC

[Anonymous]

Power from an engine is basically determined by one thing, how much air you can get into.
Other factors like how hard you squueze it (CR) are an issue, but it all comes down to getting air in really.
Putting more fuel in witout more air will result in a loss of power as you will be running too rich.

IF you get a 1.3 head it wont need skimming for CR or anything, all you'll need is something like a 2 thou clean up to make sure its flat, that shouldnt cost more than 20 quid.

As far as the fuel supply goes, get a regulator on your existing setup.

Wiring the pump into the ignition via a relay is fine.


Chip

[Aragorn]

ok now what about ingition timing

the SPi uses a electronic ignition system which im pretty sure wont work on the carbed engine due to the lack of feed back from certain sensors (ie MAP sensor , lambda probe ?)

if the original electronic ignition wont work then what do i need from the carbed engine to make it work contact beaker stylee and i'll do it that way

thanks again :)

Aragorn

[Aragorn]

as for the carb specs:

13SB: Primary Secondary

Main Jet: X97.5 X112.5
Air corr Jet 80 100
idle fuel jet 37.5
idle air 130

14NV:

Main Jet: 95 110
Air Corr 117.5 90
idle fuel 45
idle air 130

so which is better?

[carltoncrazy]

m8 b4 u sed u dont have 50quid to spend,
so im woundering y r doing all this????????
no afence but its gonna cost and well b blunt,
money ur spending u culd get a 1300 or 1600 gte lump for about the same.
im workin on the idea gte lumps r bout 100 quid,coz ive seen a few for that price.
no afence but carb 1.2
1.6 mpi
no which 1 id do

[Aragorn]

the final car will be a 1.4 carb - and as u well know the insurance on a 1.6i (ie GTE) is MUCH higher than a 1.4 carbed saloon (group 6 vs group 11 iirc)

and i do have enough money to get the carbs etc online and what uve got to remember is i'd need to do all this work anyway if i was fitting a 1.6i as all the ecu shite would need to be redone so it is cheaper in both initial costs AND running costs (ie insurance) by getting a 1.4 carb setup

now what would u rather have?
a 1.2i with a whopping 45bhp or a 1.4 with 75

i know what i'd rather have and for the small amount of money its goin to cost me in parts it should be well worth it - so lets iron out these niggles and i'll have a decent motor (kinda :P )

so ignition system: methinks the best bet would be to get the dizzy and coil from the same car im getting the carb from but how should i wire it up? is it just a case of attachin a 12v feed to the coil and the green tacho wire and the HT lead on the top?

[Anonymous]

yeah take the dizzy/coil off the same car, and it should wire in as you described, just make sure you get the connectors out of the donor loom too as i know some vauxhall coils are different to others.

Chip

[Aragorn]

ok so i feed 12v and gnd to coil and connect the green wire

what does the contact breakers?!? do and do i have to do anything with the wiring for these?