Open or closed loop?

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The_blue
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Open or closed loop?

Post by The_blue »

My van has an open loop conversion, would it pay to adapt this to closed?
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Ian Hulley
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Re: Open or closed loop?

Post by Ian Hulley »

Honestly you'd do well to leave this to the proffesionals.

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The_blue
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Re: Open or closed loop?

Post by The_blue »

lol that might be true!

It was only a question, i was wanting opinion on what setups folks had and why? :)
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Re: Open or closed loop?

Post by silverbullet »

My 2.6 SA was converted recently, I'm getting 21mpg on gas with an open-loop system, keeping it legal and most of the mileage on motorways (300 miles every weekend) I will upgrade it to closed loop once I've got a new exhaust as the range on a 52 litre tank is only about 200 miles. Not enough. Can't help thinking that fuel is still going out the tailpipe.
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toomanytoys
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Re: Open or closed loop?

Post by toomanytoys »

Does your van already have lambda control?
What MPG are you getting on gas compared to what you were getting for the same driving on petrol?

Same questions for Silverbullet?

What often happens is the mpg wont get better or only by a small amount.. drivability can improve though.. but it all depends on how well set up the "open loop" is... :wink: :wink: closed loop lambda control isnt the "be all and end all".. its needed on newer vehicles with cats to ensure the cat is fed with a consistant mix, so as not to bugger it up...

Ian Hulley
Posts: 12649
Joined: 11 Oct 2005, 08:08
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Location: Wirksworth, Derbyshire ... or at t'mill

Re: Open or closed loop?

Post by Ian Hulley »

silverbullet wrote: the range on a 52 litre tank is only about 200 miles.

That sounds about right to me ... I don't know what you were expecting ?

Ian
The Hulley's Bus
1989 2.1DJ Trampspotter
LPG courtesy of Steve @ Gasure

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The_blue
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Re: Open or closed loop?

Post by The_blue »

toomanytoys wrote:Does your van already have lambda control?
What MPG are you getting on gas compared to what you were getting for the same driving on petrol?

Same questions for Silverbullet?

What often happens is the mpg wont get better or only by a small amount.. drivability can improve though.. but it all depends on how well set up the "open loop" is... :wink: :wink: closed loop lambda control isnt the "be all and end all".. its needed on newer vehicles with cats to ensure the cat is fed with a consistant mix, so as not to bugger it up...

No lambda, it's an early LT35.

It drives fine just want to make sure its as good as possible all the time.
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silverbullet
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Re: Open or closed loop?

Post by silverbullet »

Like wise, the 2.6 doesn't have lambda feedback to the ecu. I reckon that it returns about 25-26 mpg cruising at 65 on petrol, on a 150 round trip; but on gas it's returning 21, which is less than exciting for a 2wd tin-top bus (not a heavy camper) not being driven like I stole it...that's what the Scooby is for :D
The cutting out at the lights (when hot) and random blowbacks in the hot weather suggest that it's too rich.
PS the temp gauge is in the normal range for petrol. No overheating.
Also when the tank gets low (last LED) I have had the unpleasant experience of putting my foot own to overtake (yes you can do that in an SA) and the thing just fluffs and hesitates. Hasty switch to petrol and all's well again. When I pulled up to re-gas, only got 35 litres in! What's going on there then? Can't use the last 5 litres of gas either?
85 syncro Caravelle twin slider Oettinger T3200E-6
90 SA Microbus supercharged wbx/UN1 project

http://www.025motorsport.com

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The_blue
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Re: Open or closed loop?

Post by The_blue »

The cutting out at the lights (when hot) and random blowbacks in the hot weather suggest that it's too rich.

http://forum.club8090.co.uk/viewtopic.php?f=3&t=70824" onclick="window.open(this.href);return false;

Overfuling, been there, done that ;)

Blowbacks sugest timing as well. If it's firing into the carb it's because the inlet valve is still open on the up stroke.
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silverbullet
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Re: Open or closed loop?

Post by silverbullet »

The 2.6 is externally identical to the 2.5 petrol T4 motor. Motronic with batch-fired injectors, alloy inlet manifold. I cannot find out what the correct timing figure should be...any suggestions?
I know that I should optimize for LPG as petrol is only for start-up and last resort.
85 syncro Caravelle twin slider Oettinger T3200E-6
90 SA Microbus supercharged wbx/UN1 project

http://www.025motorsport.com

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