Lotus Elan

DCOE: Fuel Lines

PostPost by: TWebb » Wed Jun 08, 2022 10:43 pm

Would love to see how folks are running their fuel lines to the dual 45s.

In process of running -6AN lines and would like to see what others have done.

Thanks in advance.

Tim
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PostPost by: Slowtus » Thu Jun 09, 2022 12:05 am

TWebb wrote:Would love to see how folks are running their fuel lines to the dual 45s.

In process of running -6AN lines and would like to see what others have done.

Thanks in advance.

Tim


Whatever you DO use - and in case you haven't looked at the Carbs and their associated lines and pipery - get the BEST and inspect visually AND using your olfactory organ because if and when they let go and depending on which Lotus you have, this can be the result.

Seriously, ignore at your potential peril...

After1.jpg and
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PostPost by: 661 » Thu Jun 09, 2022 7:55 am

IMG_6515.jpg and
s-l1600d.jpg and
IMG_2122.JPG and
IMG_2183.JPG and
IMG_1212.JPG and
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PostPost by: 661 » Thu Jun 09, 2022 8:00 am

I used Earl's hoses throughout.
The push on hose weber connector is replaced by an AN- connector.
Mine is the light blue one.
I have many pictures of engine bays but most of the picture files are too big for straightforward uploading
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PostPost by: TWebb » Thu Jun 09, 2022 12:38 pm

Graeme,

I have only used Earls in the past. Plan on doing so again with the Elan.

I don't see a fuel regulator. Is it hidden in this photo or somewhere other than in the engine compartment.

As to the throttle linkage is that a bespoke unit or is that something off the shelf?

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PostPost by: 661 » Thu Jun 09, 2022 1:47 pm

The throttle linkage is a Sytec's one.
https://www.glencoeltd.co.uk/sytec-heri ... nkage-kit/
I preferred the routing to the TTR one.
It has been modified a fair bit. 3mm off the base plate , angled skim off the top corner ( to not foul the bonnet, and the pivot position has been changed to that it has more leverage so that the throttle cable travel to WOT is about 3/4 of what it would normally be.
The pressure regulator is in the boot, but the pressure sensor is at the carbs.
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PostPost by: TWebb » Thu Jun 09, 2022 5:54 pm

Graeme,

Thanks
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PostPost by: rgh0 » Thu Jun 09, 2022 10:00 pm

661 wrote:The throttle linkage is a Sytec's one.

The pressure regulator is in the boot, but the pressure sensor is at the carbs.


Hi Graeme
what sort of regulator is that with a remote pressure sensor?

cheers
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PostPost by: TrevorJones » Thu Jun 09, 2022 10:05 pm

Not the best pictures (show what you want if you can zoom in) The system is all goodridge parts, fittings, Hardline and 200 hose. The hardline runs from the boot along the original route and clipped to prevent rubbing, it terminates at a small bracket to the rear of the engine mount and then up to a T below and front of the no1 carb.

The pump is a Bendix Redtop and feeds the carbs via a Filter king regulator modified to accept the Goodridge 1/8" BSP -6 fittings. You may notice the fuel filler vent which I have fitted C/W roll over NRV valve. FIA like the cars to have a fuel cap that will not leak if inverted and has some form of lock, I wanted to retain the look of the cap so had to find another route for ventilation.

IMG_1903.JPG and


IMG_1904.JPG and


IMG_1906.JPG and


I hope this helps, good luck with your routing.
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PostPost by: 661 » Fri Jun 10, 2022 9:01 am

rgh0 wrote:
661 wrote:The throttle linkage is a Sytec's one.

The pressure regulator is in the boot, but the pressure sensor is at the carbs.


Hi Graeme
what sort of regulator is that with a remote pressure sensor?

cheers
Rohan

It's not automatic! It requires a manual twist of the knob.
You can see the regulator in the boot.
IMG_1241(1).jpg and

The sender in the engine bay is connected to a Stack pressure gauge
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PostPost by: Andy8421 » Fri Jun 10, 2022 9:22 am

Graeme,

Thank you for positing the pictures. Excellent quality work.

A question;

The argument for co-locating the pressure regulator with the carbs is twofold -

1. Under heavy flow conditions, there will be a pressure drop along the fuel line which the regulator can compensate for.

2. Under heavy braking or heavy acceleration, the 'column' of fuel in the pipe needs to be accelerated or decelerated leading to spikes and dips in fuel pressure - again having the regulator at the carbs allows this to be compensated for.

As you have a pressure monitor at the carbs, do you detect any of these effects when driving?

Thanks,

Andy.
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PostPost by: 661 » Fri Jun 10, 2022 10:01 am

Andy8421 wrote:Graeme,

Thank you for positing the pictures. Excellent quality work.

A question;

The argument for co-locating the pressure regulator with the carbs is twofold -

1. Under heavy flow conditions, there will be a pressure drop along the fuel line which the regulator can compensate for.

2. Under heavy braking or heavy acceleration, the 'column' of fuel in the pipe needs to be accelerated or decelerated leading to spikes and dips in fuel pressure - again having the regulator at the carbs allows this to be compensated for.

As you have a pressure monitor at the carbs, do you detect any of these effects when driving?

Thanks,

Andy.

Yes!
It is noticeable. I have been running about 4.5psi static ( tried 4 psi, but lower pressures were occasionally noticeable) and I don't see drops below 3psi. ( where my gauge is set to warn me of low pressures) At Brands last week I had just put the engine back in and for some reason I noticed I was running 3psi before the race ( In the assembly area, so too late to change it) . I noticed quite a few momentary lower pressures during the race ( ie the gauge flashed red ). No power loss and I would guess ( my eyes were generally elsewhere) no reduction of pressure below about 2.5psi.
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PostPost by: nmauduit » Fri Jun 10, 2022 12:10 pm

661 wrote:
Andy8421 wrote:Graeme,

Thank you for positing the pictures. Excellent quality work.

A question;

The argument for co-locating the pressure regulator with the carbs is twofold -

1. Under heavy flow conditions, there will be a pressure drop along the fuel line which the regulator can compensate for.

2. Under heavy braking or heavy acceleration, the 'column' of fuel in the pipe needs to be accelerated or decelerated leading to spikes and dips in fuel pressure - again having the regulator at the carbs allows this to be compensated for.

As you have a pressure monitor at the carbs, do you detect any of these effects when driving?

Thanks,

Andy.

Yes!
It is noticeable. I have been running about 4.5psi static ( tried 4 psi, but lower pressures were occasionally noticeable) and I don't see drops below 3psi. ( where my gauge is set to warn me of low pressures) At Brands last week I had just put the engine back in and for some reason I noticed I was running 3psi before the race ( In the assembly area, so too late to change it) . I noticed quite a few momentary lower pressures during the race ( ie the gauge flashed red ). No power loss and I would guess ( my eyes were generally elsewhere) no reduction of pressure below about 2.5psi.


the way I understand it is the carbs operate from a constant level in a bowl that is at atmospheric pressure : as long as that level is correct, the fuel line pressure (or even flow) would not matter imho. In order to obtain optimal carbs operation at all times, one does need to ensure that the bowl level is met at all time with minimal variations (ps. under heavy deceleration the fuel requirement is likely to be minimal - and most fuel regulators are of the "cut" type, they would not actively compensate flow by other means than re-opening the fuel tap, wihtout any fuel reserve to push back in, like an accusump would do for oil).
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PostPost by: 661 » Fri Jun 10, 2022 5:29 pm

nmauduit wrote:
661 wrote:
Andy8421 wrote:Graeme,

Thank you for positing the pictures. Excellent quality work.

A question;

The argument for co-locating the pressure regulator with the carbs is twofold -

1. Under heavy flow conditions, there will be a pressure drop along the fuel line which the regulator can compensate for.

2. Under heavy braking or heavy acceleration, the 'column' of fuel in the pipe needs to be accelerated or decelerated leading to spikes and dips in fuel pressure - again having the regulator at the carbs allows this to be compensated for.

As you have a pressure monitor at the carbs, do you detect any of these effects when driving?

Thanks,

Andy.

Yes!
It is noticeable. I have been running about 4.5psi static ( tried 4 psi, but lower pressures were occasionally noticeable) and I don't see drops below 3psi. ( where my gauge is set to warn me of low pressures) At Brands last week I had just put the engine back in and for some reason I noticed I was running 3psi before the race ( In the assembly area, so too late to change it) . I noticed quite a few momentary lower pressures during the race ( ie the gauge flashed red ). No power loss and I would guess ( my eyes were generally elsewhere) no reduction of pressure below about 2.5psi.


the way I understand it is the carbs operate from a constant level in a bowl that is at atmospheric pressure : as long as that level is correct, the fuel line pressure (or even flow) would not matter imho. In order to obtain optimal carbs operation at all times, one does need to ensure that the bowl level is met at all time with minimal variations (ps. under heavy deceleration the fuel requirement is likely to be minimal - and most fuel regulators are of the "cut" type, they would not actively compensate flow by other means than re-opening the fuel tap, wihtout any fuel reserve to push back in, like an accusump would do for oil).


That's my understanding too. It is interesting to see the pressures vary but they obviously keep the float chambers well supplied.
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PostPost by: nmauduit » Fri Jun 10, 2022 5:59 pm

what I meant is as long as the pressure does not go down to 0 for some time (to be defined) there should always be the proper fuel level in a well operating carb (i.e. you may set your warning to 1psi if it gets annoying)
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