Alfa 147 1.8 Twin Spark LPG Conversion

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Alfa 147 1.8 Twin Spark LPG Conversion

#1 Post by scottyf » Mon Oct 06, 2014 11:07 am

Okay all. Today I fitted the following...

toroidal tank
48 Litre is the largest Torodial tank you can get in.
630 x 200 in the 147 (Sits above the boot a little though due to the shape of the wheel well.
The 156 boot is a bit bigger so you can get more in.

multi valve to tank
Filler point. Not hidden though so might change to a normal UK one instead of an m10 hidden. Don't think it'll pass cop 11 without one.
Ran 6mm faro from tank to front of the car. Followed original fuel lines and brake lines as there is a rubber holder that you can tuck everything into as there are spare clips. Saves to drilling loads of points under the chassis. Same when you pull it up through the fuel lines.

Installed the vapouriser over the nearside front arch.
This seemed to be the only place I could fit it and have enough space.
Then T section for the water. One before the thermostat. Then one after the thermostat. Removed the air filter for more room.

The pipe after the thermostat is a little thicker than standard 16mm water tube. So just made sure it was bloody tight.
Vapouriser works best lower in the coolant highest point circuit. That way you get less chance of air lock.

Then I drilled a map sensor directly in the plastic manifold after a few practices with a spare inlet I had. It's wise to practise I feel given if you balls it up. Your car will sick too much air after the throttle body. Meaning it will run incorrectly. Same goes for the four injectors.

Now the twin spark although has a plastic manifold the injectors are in a metal inlet. So you need a good drill bit.
In order to get cylinder one I had to remove

coil pack
Rocker cover
Variator solenoid

I then also fashioned a make shift vacuum piece to such swarf as I drilled and tapped.
This was the scary point. As drilling your inlet is a one time only thing really. You need the correct angle. Enough space to put in the injectors. Correct angle of spray and also close to the original injector but with enough room it doesn't kink anything.

I used a 6.3mm drill piece. M6 tap and Helicoiled a thread into it. I used a glue to take up any thread difference which seemed to work okay.
Added all four injector points and all the tubes from hana injectors to gas entry points. Again more glue to make sure it's air tight. Hopefully.

First time starting it was a bit scary as it took a while. Think it was sucking air from the tank until it got to pressure.

Anyway seems okay now. So that's this weekend done. Although i only did half days and sat reading and trialing things out. I could do what i did in the weekend in one day if i tried. But a lot is prep.

Now all i have left is the electrics and installing the ecu somewhere and then tuning. So probably another weekend. Then testing really.

It's an okay job. It's not hard it's just making sure you plan it out and where things can go that'll work correctly. Can't wait to get it hooked up and see if it runs okay. I'm not expecting miracles though.





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Re: Alfa 147 1.8 Twin Spark LPG Conversion

#2 Post by scottyf » Mon Oct 06, 2014 11:11 am

Looking at that though I will be able to make the injector lengths smaller but I used the max equal length for the moment.
Those are currently 25cm in length at the moment. I know the max is about 30cm.

So I will try cut this down to closer to 15-20cm - As far as I know this helps with the mapping.

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Re: Alfa 147 1.8 Twin Spark LPG Conversion

#3 Post by billynoband » Tue Oct 07, 2014 9:06 pm

Old wifes tale. It does'nt make any difference.

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Re: Alfa 147 1.8 Twin Spark LPG Conversion

#4 Post by LPGC » Tue Oct 07, 2014 9:36 pm

billynoband wrote:Old wifes tale. It does'nt make any difference.
You're having a laugh, right?

Not only do pipe lengths make a difference but also pipe diameter. How well do you reckon the sequential system would work with injector pipes 10 yards long the diameter of gutter pipes?

Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,

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Re: Alfa 147 1.8 Twin Spark LPG Conversion

#5 Post by scottyf » Fri Oct 10, 2014 11:54 am

So if there any more tips - I can get more photo's of the install. Tackling the electrics this weekend.
Then setting up the fuelling hopefully. Should be interesting.

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Re: Alfa 147 1.8 Twin Spark LPG Conversion

#6 Post by scottyf » Thu Aug 13, 2015 9:57 am

Been running LPG now for over 12k.
Two coil packs failed and one LPG filter.

I've currently saved so far £804 Conversion cost £500 Give or take a few pence.
That saving also includes any petrol fill up's.

I also changed my LPG filler from a smaller M10 thread to a normal UK filler. Although to be honest I never actually had any issues with the smaller M10 tread - Despite it not conforming to UKLPG working practices.

I still never bothered getting it certified and it went through MOT without issue. Also went through Emissions fine.

I get an average of 28mpg on LPG. 34mpg on petrol same sort of journey.
However I've changed jobs now meaning my 20k mile a year travel is now only 8k.

But it has made a huge difference to the amount of money I spend on fuel. Even now my commute doesn't warrant a conversion I'd look to convert any car because it just makes worring about fuel a thing of the past.
The world feels like I can travel the globe for pennies.

Only thing I would do again if I had the option is to buy single injectors so I could position them closer to the manifold.
Bigger cylinder tank so I could get more of a range than 200-230 miles between fill ups.

Those are small niggles though. The tank one being the bigger one. But again its not a huge issue. It just means I fill up more often.
Small price to pay for a car that does 75 mpg petrol equivalent cost.

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Re: Alfa 147 1.8 Twin Spark LPG Conversion

#7 Post by LairdScooby » Thu May 12, 2016 2:07 am

Nice! I don't do many miles each year but am in the process of converting mine - running at the equivalent cost per mile of 50-70mpg on petrol makes a huge difference to my budget so arguably speaking, even though you say you only do 8k miles it still make a difference to you as well?
Either way i'd rather pay 48p/L than 118p/L - bit of a no brainer in those terms! :D

Somewhere in Suffolk with a Jeep, 2 Rovers and a V6 Volvo


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