SE5a Scimitar with Essex V6 running on LPG

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Gilbertd
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Re: SinglePoint open loop essex v6 - timing query

#21 Post by Gilbertd » Thu Apr 19, 2012 11:22 am

MikeyBikey wrote:However there is a misfire at low rpm. There was one in petrol days but rather than spend a long time sorting it i thought of converting to lpg then if the misfire was still there to pursue it.
If it misfires on petrol, it is only going to be worse on LPG. LPG needs a stronger spark and the air/fuel ratio is a lot more critical.
'96 Saab 900XS, AEB Leo, sold
'93 Range Rover 4.2 LSE, Lovato LovEco, sold
'98 Ex-Police Range Rover 4.0, Singlepoint AEB Leo, my daily motor
'97 Range Rover 4.0SE, eGas multipoint, a project.....

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MikeyBikey
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Re: SinglePoint open loop essex v6 - timing query

#22 Post by MikeyBikey » Thu Apr 19, 2012 1:40 pm

Gilbertd wrote:
MikeyBikey wrote:However there is a misfire at low rpm. There was one in petrol days but rather than spend a long time sorting it i thought of converting to lpg then if the misfire was still there to pursue it.
If it misfires on petrol, it is only going to be worse on LPG. LPG needs a stronger spark and the air/fuel ratio is a lot more critical.
As part of the lpg conversion i did uprate the coil and add iridium plugs. The only thing missing is decent set of ht leads (magnecor??) but that will be next months budget !!

tom-madbiker
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Re: SinglePoint open loop essex v6 - timing query

#23 Post by tom-madbiker » Fri Apr 20, 2012 8:11 am

i fitted an electronic box to tthe dizzy improved acceleration and fuel economy about 25 quid on ebay

MikeyBikey
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Re: SinglePoint open loop essex v6 - timing query

#24 Post by MikeyBikey » Fri Apr 20, 2012 1:50 pm

tom-madbiker wrote:i fitted an electronic box to tthe dizzy improved acceleration and fuel economy about 25 quid on ebay

yes, I fitted accuspark and it's very good. The difference over points was immediate.

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Re: SinglePoint open loop essex v6 - closed loop query

#25 Post by MikeyBikey » Thu Apr 26, 2012 9:53 am

I've already posted in the 'how far for a tenner' thread just how far I'm not getting. :?

Getting about 13mpg and yes have driven carefully. It's currently single point open loop.

The scimitar is due to go in for an MOT and LPG System overview / certification next week. As part of that the lpg garage is intending to fit a regulator in the mixer gas supply (between OMVL and the mixer) so that he can adjust the supply.

Would I be better off fitting a lambada / closed loop. Before I fitted the kit i don't research and there seems to be a definite split (feedback from experienced fitters), between those that always fit closed loop sensors and those that think they're a waste of time.

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Re: SinglePoint open loop essex v6 - closed loop query

#26 Post by rossko » Thu Apr 26, 2012 10:19 am

MikeyBikey wrote:As part of that the lpg garage is intending to fit a regulator in the mixer gas supply (between OMVL and the mixer) so that he can adjust the supply.
That's a good plan, difficult to set up without an adjuster fitted. And you wonder why mpg is poor ... ?
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Re: SinglePoint open loop essex v6 - closed loop query

#27 Post by MikeyBikey » Thu Apr 26, 2012 12:34 pm

rossko wrote:
MikeyBikey wrote:As part of that the lpg garage is intending to fit a regulator in the mixer gas supply (between OMVL and the mixer) so that he can adjust the supply.
That's a good plan, difficult to set up without an adjuster fitted. And you wonder why mpg is poor ... ?

Well it wasn't in the original 'kit' and so it was only when I visited him for a fill up it was identified... Due to be fitted next week. But would you think the lambda would be a better course of action or do this first?

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Re: SinglePoint open loop essex v6 - closed loop query

#28 Post by rossko » Thu Apr 26, 2012 1:34 pm

Why not discuss it with the man?
Although if an manual adjuster is in the £2.50 league and a lambda control system in the £100 area, plus same again for sensor and boss, removing exhaust for modification, extra wiring, etc ...
Perhsps a cost/benefit approach would be best?
www.blazegas.com

Gilbertd
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Re: SinglePoint open loop essex v6 - closed loop query

#29 Post by Gilbertd » Thu Apr 26, 2012 4:58 pm

MikeyBikey wrote:Well it wasn't in the original 'kit'
You only got 2/3rds of a kit then. Open loop consists of a vaporiser, a mixer and a power valve. Of the three, you can get away without a mixer (using a spud pipe straight into the intake) but you can't get away without either of the others. I'm surprised it actually runs to be perfectly honest.
'96 Saab 900XS, AEB Leo, sold
'93 Range Rover 4.2 LSE, Lovato LovEco, sold
'98 Ex-Police Range Rover 4.0, Singlepoint AEB Leo, my daily motor
'97 Range Rover 4.0SE, eGas multipoint, a project.....

Proud to be a member of the YCHJCYA2PDTHFH club.

MikeyBikey
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Re: SinglePoint open loop essex v6 - closed loop query

#30 Post by MikeyBikey » Thu Apr 26, 2012 8:42 pm

Thank for the advice

Gilbertd
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Re: SinglePoint open loop essex v6 - timing query

#31 Post by Gilbertd » Sun May 06, 2012 10:59 am

dj_ad1200 wrote:obviously people are gonna start screaming at me in a minute but just a quick question ..........
When the car was brand new did it come with iridium plugs ? If it did then put them in if it diddnt then take them out and use them as fishing weights
You expected it so you are going to get it. The car didn't come with higher compression pistons, (9.8 : 1), high lift cam, big valve head, tubular manifolds, and to supplement the ht side it's got electronic ignition and uprated sports coil either. Are you going to suggest he takes them off as well? We are talking about a 40 odd year old car, Iridium plugs didn't exist 40 years ago so of course it didn't come with them originally.

It's a reliant Scimitar, the wiring looked like that when it was brand new, that's standard (except that it's had a fusebox that takes modern blade fuses added in place of the original). How many Essex engines have you converted, or Cologne, or Kent? Or do you even know what they are, I suspect not.
'96 Saab 900XS, AEB Leo, sold
'93 Range Rover 4.2 LSE, Lovato LovEco, sold
'98 Ex-Police Range Rover 4.0, Singlepoint AEB Leo, my daily motor
'97 Range Rover 4.0SE, eGas multipoint, a project.....

Proud to be a member of the YCHJCYA2PDTHFH club.

MikeyBikey
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Re: SinglePoint open loop essex v6 - closed loop query

#32 Post by MikeyBikey » Fri May 18, 2012 8:38 am

Hi Folks, just thought I'd add an update.
The car was suffering from a long term misfire and getting poor mpg (regardless of fuel). This was before and after the conversion. Eventually tracked it down to the inlet manifold gasket. After fitting a decent quality one, and using the manual adjuster between reducer and mixer, the car is running very very well.

I generally only use LPG, and have adjusted the timing accordingly. (odd occasion on fuel to keep the carb and pump fresh)

She pulls like a train and now return up to 28 mpg depending on driving style. Even spirited driving on these cornish roads returns 21 :D

And have started to completely tidy the installation.

Have investigated fitting on my daughter's mk1 golf but need to do a carb conversion first. Bit of work involved so will pursue in the summer hols when she's finished teaching.


thanks for your help.

Zebedee
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Re: SinglePoint open loop essex v6 - closed loop query

#33 Post by Zebedee » Mon May 21, 2012 4:01 pm

28mpg doesn't sound bad to me. Hell, I'd even be pleased with 21.
What sort of power is your Essex making now? They were a shade under 140bhp from the factory weren't they?

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Re: SinglePoint open loop essex v6 - closed loop query

#34 Post by mat_fenwick » Mon May 21, 2012 5:28 pm

Is that a real 28mpg or the cost equivalent of 28mpg on petrol?
Another member of the YCHJCYA2PDTHFH club

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Re: SinglePoint open loop essex v6 - closed loop query

#35 Post by MikeyBikey » Fri Jun 08, 2012 7:16 pm

Zebedee wrote:28mpg doesn't sound bad to me. Hell, I'd even be pleased with 21.
What sort of power is your Essex making now? They were a shade under 140bhp from the factory weren't they?
Apols, Haven't logged in for a couple of weeks.
Not sure of bhp. The engine has been completely rebuilt with fast road components. Would like to get it on a rolling road but at £100 per hour i've got other things for the car i need to spend my money on.:?

The mpg is actual mpg

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Re: SinglePoint open loop essex v6 - closed loop query

#36 Post by MikeyBikey » Tue Jun 26, 2012 10:14 pm

Hiagain. As per my other thread,
http://www.lpgforum.co.uk/viewtopic.php?f=33&t=11232
I've been using Simon's notes and made a feedback system however I have now gone slightly further and bought a Air Fuel Ratio guage to match up the lambda sensor that is now welded into the exhaust just after the three downpipes converge into one (on one side if the v6) and lo and behold it's all working.
P1050241.JPG
P1050241.JPG (139.65 KiB) Viewed 1926 times
b
However I have a query regarding tuning the system using this feedback guage.

I have fiddled and adjusted the power valve and vapouriser but the guage does read Lean most of the time.

When driving it will go into Optimum under load and Rich under heavy load (accelerating or going up hills.)

When the car is stationary and i hold the revs even it stays lean. When i blip the throttle it swings round.

Is that right ?

If i make it much richer she holds onto the revs at tickover and stays at 1200 rpm rather than 600.

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Re: SinglePoint open loop essex v6 - Tuning with lambda qry

#37 Post by MikeyBikey » Tue Jun 26, 2012 10:29 pm

And can you recommend a feedback / closed loop upgrade. I've the omvl 90e vapouriser with single point system.

Thanks

Gilbertd
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Re: SinglePoint open loop essex v6 - Tuning with lambda qry

#38 Post by Gilbertd » Wed Jun 27, 2012 12:07 am

MikeyBikey wrote:And can you recommend a feedback / closed loop upgrade. I've the omvl 90e vapouriser with single point system.
Bigas Pegaso from Tinley Tech. It's a rebadged AEB Leonardo which is generally regarded as one of, if not, the best. You'll need to change your wideband lambda sensor for a standard narrow band one though.
'96 Saab 900XS, AEB Leo, sold
'93 Range Rover 4.2 LSE, Lovato LovEco, sold
'98 Ex-Police Range Rover 4.0, Singlepoint AEB Leo, my daily motor
'97 Range Rover 4.0SE, eGas multipoint, a project.....

Proud to be a member of the YCHJCYA2PDTHFH club.

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Re: SinglePoint open loop essex v6 - Tuning with lambda qry

#39 Post by SimonHobson » Sat Jun 30, 2012 8:45 pm

Yes, AEB Leonardo (or any rebadged version of it) would be a good upgrade. Get yourself the cable and software to go with it.

Does that meter use a narrowband or wideband sensor ?
With a narrowband sensor (as is used for almost all vehicles) then you tend to get either "lean" or "rich" and seldom in between. That's because of the way they work and have a very sharp transition so it's incredibly difficult to get them "in the middle".

From your description, I;d say you need to adjust the bias screw a bit more - increase the output pressure a little and close the power valve a little to compensate. If you refer to the diagrams on my tuning page, you want to lift the line up a bit (turn the bias screw to richen mixture) and rotate it clockwise (close power valve to weaken mixture).
Land Rover 110 V8 LPG
Land Rover 90 petrol (no longer diseasel :D), still awaiting V8 & LPG
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Re: SE5a Scimitar with Essex V6 running on LPG

#40 Post by MikeyBikey » Thu Nov 16, 2017 8:41 pm

Long time since visited but still a constant lpg / dual fuel user in my racing scimitar se5a. I run around on open loop lpg then sprint / race on bleddy expensive shell v max.

Omvl 90e rated 150 bhp+.
Venturi on each mixer is 38mm.
Two mixers

Since the demise of photo bucket what's the easiest way to post some pictures. I'd like to show you my latest project, converting the old Essex v6 to run off twin throttle bodies from an omega v6. and a mixer on top of each tb. And a flute feeding each mixer. It's a bit basic but I've a wideband afr with gauge, and a decent vacuum gauge. She runs fine but nowhere near the oomph I was expecting.

Ps I have a modified dizzy that has the vacuum gubbins removed and throws lots of advance early on.

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