Board logo

Single point injection or suggestions?
pewe - 12/8/13 at 02:58 PM

The Lancia engine on the F27 has always suffered a flat-spot on right handers.
This is because the engine was East/West but turned North /South to fit the chassis.
That means the carb float chamber faces the wrong way and being relatively narrow on right corners it allows the fuel to surge away from the main jets.
I've tried various baffles and pressures without success so would really like a proper fix.
Someone suggested single point injection.
The set-up already includes a high pressure fuel delivery and return as well as in-tank swirl pot.
I can probably pick up a throttle body from a bigger engined Volvo but there my knowledge stops, though I'm aware I'll need a crank position sensor and some electrickery.
Was there a PPC article covering that type conversion or any suggestions as to published sources?
Thanks in advance, Pewe10


minitici - 12/8/13 at 03:08 PM

You might as well go down the bike, multiple throttle body route and megasquirt shouldn't be much more cost than singlepoint.


whitestu - 12/8/13 at 03:22 PM

As above, the most expensive bit will be the ecu, so you might as well get some TBs whle you are at it.


pewe - 12/8/13 at 03:35 PM

Thanks guys.
I should probably have said that the engine is supercharged and AFAIK it'snot possible to use throttle bodies, which is a pity because I like their simplicity.
Cheers, Pewe10


britishtrident - 12/8/13 at 03:54 PM

In the USA they were always more into single point injection than on this side of the pond, that is where I would search for info.

However you could drill the existing manifold for 4 injector pockets which you can weld in and convert the existing carb to use as throttle body.

The pitch of the cylinders may match another engine so you may be able to use an off the shelf fuel rail.


MikeRJ - 12/8/13 at 04:58 PM

Presumably this is a "suck through" installation (i.e. fuel and air pass through the supercharger)?

How much power is the engine making? A single point system on a powerful engine will need a high capacity injector, or possibly multiple injectors. Apart from that there isn't much difference to port injection in terms of the set up. Obviously you'll need a system that uses a MAP sensor for engine load rather than just throttle angle.


mark chandler - 12/8/13 at 06:05 PM

Have you tried altering the float shape?

It's the way these things were addressed before injection, what you do is cut the float into a wedge shape, point at the bottom with the removed material on the side that the fuel builds up on.

It works because on hard bends the fuel sloshes away from the float, the float now drops allowing in more fuel so the jets do not get uncovered.

If you have copper floats its easy enough to do, just unsolder, reshape and solder back up if plastic then araldite becomes your friend.

[Edited on 12/8/13 by mark chandler]


pewe - 12/8/13 at 08:42 PM

MikeRJ, yes suck through and not huge amounts of power.
I think originally they only quoted 135bhp.
They sold the Volumex cars in Coupe and HPE versions to homolgate the engines for use in the Type 037 rally cars so weren't really bothered about ultimate power for road cars.
With bigger carb and free flow exhaust I reckon it might struggle to 150bhp.
Just thinking about what might be available I thought Volvo 960 single point injector should be adequate.

However as a locost fix Mark Chandler's suggestion has got to be worth some thought as I have a spare, part dismantled carb in stock.
Only question about doing it - is Araldite un-leaded proof?

Thanks for all the suggestions.
Cheers, Pewe10


britishtrident - 12/8/13 at 08:52 PM

Another low-tech work around could be to tilt the engine to the right.


BaileyPerformance - 13/8/13 at 08:00 AM

I would just use a very large single high pressure injector (as used in mulitpoint) close to or in the throttle body. We did a turbo mini on megasquirt with a single Jenvey in place of the SU. We did the same on a turbo X flow. You need about a 1000cc injector