James' EFI Saloon Thread

[James]

Filter arrived - do you think it's big enough

 

Weber Alpha - so should be good

[James]

Swirl pot bits.

 

Not sure where I am going to route the fuel lines yet - I might make them go under the floorboards in which case I'll replace the the two top ones with banjos.

 

Plan is...

 

Inlet that goes through the filter - in from the tank

"Outlet" that goes up through the centre of the filter - return from fuel rail

Drill and tap hole in the bottom and fit banjo - to the fuel pump

 

I need a return back to the tank in case the whole thing gets pressurised - not sure to use the secondary inlet or outlet. Or would it just end up going backwards via the feed from the tank?

[James]

Airbox and filter now installed... weather too nasty to be fitting electric fuel pumps though

 

Excellent fit

 

Might just make up a simple heat shield to attach to the rad/engine side

 

The rubber around the aperture is just a length of fuel hose sliced along it's length - perfect

[DaveNotSoSideways]

Nice job. Love the filter Proper one.

[James]

It is a nice filter - if I need some cold air I could just wrap the rear part of the filter with something so it just sucks in from the front and front/sides. It's big enough that I doubt it would make any notable effect

 

Going to wire in the electric pump today - happy I have a late Mk1 with PI body shell - holes in the right places

[James]

I am thinking of using clear pipe for the in-boot low pressure side of my fuel system - can anyone think of a downside? I like the idea of being able to see the fuel for bubbles etc

 

http://cgi.ebay.co.uk/CLEAR-PVC-TUBE-HOSE-PIPE-FUEL-AIR-OIL-WATER-8mm-5-16-/300428150215?cmd=ViewItem&pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item45f2e9c5c7#ht_815wt_1137

[Nick Jones]

In my experience that stuff is not properly resistant to petrol, goes hard and eventually cracks.  Wouldn't have it on my car.  Proper fuel hose required and that isn't it, whatever it says in the ad.

 

Like the air filter     Wish I had room for one that size!

 

Nick

[James]

Ok - I'll cross that one off the list...

 

Here's what I plan to do with the filter/swirl pot... does it make sense?

 

I figure the return from the fuel rail can feed the swirl pot - and if it over flows then it'll go back to the tank.

 

[Nick Jones]

Well, that is likely the simplest way so well worth a try.  You may (or may not) have issues with fuel temperature as, at low speed in traffic, you will only be recirculating a small volume of fuel and it will get hot.   You may also get issues with bubbles.  Ideally the tank would be part of the recirc loop but there probably aren't enough connection points?

 

Nick

[James]

Thanks Nick.

 

I presume that in traffic the return is pretty much full pressure and full flow?

[Nick Jones]

Well, yeah at idle and low load, pretty much all the fuel that goes up front will come back, but warmer.  Shouldn't be under significant pressure if you got your plumbing right though .  Thing is, if you keep sending the same litre or so of fuel up front it will soon get get quite warm - which might become a problem in say Andorra in summer - or even London.  I notice with mine, even using the whole tank as a recirc pot temperatures can go up by 20+ degrees which can lead to embarrassing overflows when filling up on top 1/4 tank of hot fuel (the new fuel grows a surprising amount as the heat transfers!).  Not had any running issues even in fairly extreme conditions (Andorra last September) although the pump does get noisier.

 

Nick

[James]

Updated diagram - the top ones aren't connected - makes more sense to use it as a return to tank.

 

Though I'm not sure _where_ to return it to the tank.

 

There is a short piece of pipe close to the filler cap - I could put a T piece in to that and feed it back in that way.

 

I'm not sure what it actually does, it connects the base of the filler hose to the middle of the filler hose. There is a vent pipe on the other side of the tank, so it's not for that.

[spitNL]

Just thinking out loud, but if you turn on the fuel pump, is it going to prime properly?

I've no experience with it but it looks like it's just going to suck air from the "return from rail" and/or "to tank" connections?

[James]

Hmmm

 

The "to tank" acts just like a vent - allowing the air out so the filter fills up from the inlet.

 

The return from rail should have a reasonable supply of fuel - but if not the tank supplies it.

[spitNL]

Or does the "to tank" go to a fuel line which vents below the fuel level?

[James]

The idea was to go in to the tank above the fuel level.

[motov8id]

isn't it common to have a high pressure filter on the output side of the pump then return to the top of the tank? pressure temp. and volume are all proportional. as temp rises volume rises when increasing volume pressure and temp decreases.maybe a larger diameter line will decrease fuel temp as it returns to the top of the tank. AT EFI pressures any air will be compressed and should not be a problem unless you  are out of fuel.

[Nick Jones]

James,

 

If you have the means readily available to return directly to the tank then I would do so. A vent from the swirl pot/filter to the top of the tank would be good to have but not essential.

 

Nick

[mk2vitesses]

James, I don't know if you have already sorted the temp sensor out. I have had three of these adaptors made, there will be a spare if you need one.

 

Si

[James]

Hey Simon,

 

I found a Lucas sensor with 5/8 thread - has same ohms as the typical Bosch type (there is a profile in the Tuner software)

 

the only issue is that the thing is quite long so will need a couple of thick washers as spacers. Or else I am wondering if I could just cut 6mm of the brass part - not sure how they work.

 

(you around this afternoon? I might go for a run-in drive- need to add miles)

 

James

[mk2vitesses]

Yes I am in till 6.30 PM

[James]

Got the fuel pump and seat in today - going much better already

 

The seat needs reclining though - it has a hole for adjustment at the back of the mount but the metal near the lap strap hole gets in the way so I need to lop that off to use the lower hole. It's only 15-20mm lower so not sure it will add much angle.

 

Amazingly the Facet Posi-flow pump doesn't seem to over flow the SUs - which is an odd but a happy accident. It may be that I am still using the 6mm fuel line all the way to the front. It's the middle of the range 180bhp pump rated at 4 to 6 psi - I thought SUs liked a more gentle 1.5psi or so. It's also very quiet - I know it's in the boot and the saloon is well  soundproofed - but nice not to hear a constant clicking as I have experienced in other cars with similar pumps.

[James]

This may be a silly question - but should I have air in my fuel system?

 

I put a big fat clear filter before the pump, then there is the pump with it's smaller built in filter, then the pump, then it goes forward to the front where there is another filter just before where the mechanical pump was, then it goes to the carbs.

 

There is air in both the filters.

[Nick Jones]

Unless you mount the filters vertically with inlet at bottom and outlet at the top, air will be trapped.  Will compressed air in the outlet side filter so will seem less.  Doesn't matter.

 

Nick

[James]

The one that was just before the mechanical pump is vertical and has air... hmmm..

 

Trying to work out why it's still having issues with pulling - nowhere near as bad as it was. It would just almost die and you'd have very little power. Now that has gone but it's hesitating and mildly misfiring and just not climbing up the revs cleanly.