More LPG questions

[Piers1989]

Along with some other mods I'm considering having my VR4 converted to LPG. I know several members have theirs running LPG, and I've had 3 LPG cars before so I'm not new to the scene!
I did some searching but all the threads I could find were upwards of 5 years old, some significantly more so!

Theirs a place in Durham - CLS Dual Fuel - who have a great rep and converted one of my cars before. Leigh the director is very helpful and has years of experience.
I discussed this with them a couple of years ago on my second VR4 but sadly the car was in bad shape and had to go!
They are a BRC authorised installer and it would be a BRC kit with their SuperMax Yellow injectors and a high pressure regulator.

So, I have a few questions for the LPG owners on here and probable Foxdie too!

1. How long have you had the system, what system is it, and have you had any issues?
2. Do you have valve saver / flashlube, and is it necessary for this engine?
3. Since I have a 7202 ECU, can I map it with a ROM that can take the "LPG on" output from the LPG ECU and run a more aggressive map due to the higher octane rating (and go back when on petrol)?
4. Should I have any extra concerns since my engine sometimes smokes and runs rough after starting when left to cool for half an hour or so (possible valve stem seals?). I have an AFR gauge and its running massively lean at idle when this happens, but sorts itself out as soon as you start driving. I set it to run rich in these cells in the map but it hasn't made any difference. Otherwise the car makes good boost and doesn't smoke when hot. Garages haven't been able to reproduce / find an obvious problem.

[Confused]

@adaxo will be able to help regarding the LPG - we're actually installing LPG to my Legnum in a few weeks, with a selection of parts proved to work on VR-4s.

I have always attributed the lean idle after sitting for ~30 minutes to heat-soak of the inlet air temperature sensor within the MAF - at idle, there is not sufficient airflow to cool the sensor down, but revving slightly, or driving away, soon clears the idle.

You should be able to, with Kenneth's 2.0 ROM, have selectable maps which take the LPG-on signal from the LPG signal - these can have different fuel/timing/boost tables associated with LPG and petrol running.

[Davezj]

I have tracked my lean idle to the short term fuel trim not kicking in correctly.
You can monitor the stft and see the change in the O2 sensor output.
If I just leave the car idling it will be lean but if I blip the throttle, the stft will kick in there and the AFR will move to 14.7 but the stft will max out and when it does it will shut down and the AFR will drift lean again.
But that could be to do with my ECU setup as I tuned it myself.

Sent from my MI 5s using Tapatalk

[Piers1989]

That sounds promising then relating to my lean idle, hopefully not an issue

Confused, are you going to be doing a build thread etc?

I'm running Kenneth's 1.03 at the moment, I think I first looked at 2.0 and wasn't too sure how to set it up as maybe my definitions were wrong? I have more experience now so may take a look into this. Reading through the threads I thought it should be possible to do the automatic map change with fuel change, would be a really cool implementation!

[Confused]

Yes I'll post up the details in My Long-Term Legnum Project thread

I only have a 7201 in my Legnum, so no fancy tricks with that, but I do also have a MAP-ECU fitted (albeit only in learn mode, currently) but I may look at utilising the 2 switchable maps in this for amending timing when on different fuel types

[Piers1989]

In relation to the switchable maps, I'm looking at the Definitive EFI ECU Pinout and am a little uncertain of something.

My ECU is from a manual car, but my car was Auto before conversion to manual.
I've not done anything to change the ECU / ROM from being Auto or Manual, I don't see this anywhere in the ROM.
When the ECU was put in my car, everything fully worked as intended. No issues with the Autobox, TCL or ASC.
The Definitive EFI pinout shows that ALL the switchable inputs are ONLY available on manual, but if the EFI ECU is interchangeable how does that work - or am I misunderstanding?

How do I know if my ECU is capable of using these as switchable inputs if I don't know if the ROM is auto or manual?
Obviously to get the car to understand whether it is running on LPG I will need to use an input!

Also looking further into it - could it be possible to use the EFI ECU on one of the maps with different injector scaling to actually directly control the LPG injectors?
This would remove the need for the piggyback ECU for the system if it would work? I know LPG normally turns on after a certain coolant temp, but we could also have an activation lookup on coolant temp.
Would need some kind of output (maybe just to a relay?) to switch between LPG injectors and petrol - is their functionality for this, I haven't seen much on outputting!

[fassi1]

Dave is absolutely right with lean idle.
Rescaling petrol injectors helps to bring stft back closer to 0%

Regarding LPG, it's the way it's installed and tuned is the most important.
These days most of the components are very god quality as long as they are correct efficiency.
There is no need to spend extra money on expensive kits like BRC or Prinse.
People still think they are the best, but that was 20 years ago. Since than LPG market has changed massively.
No flash lube is needed. As long as AFR is correct, there is no risk of damaging your engine.
Few years back I done EGT test on petrol and LPG and there was no difference at all.
The results are here somwhere on the forum.
Having experiance converting few Legnums, they need to have ignition system in very good condition.
If not, you may experiance misfire at low rpm. Unfortunately all the VR4s are slightly aged so things like ignition leads and coil packs may not be performing at their best.

[Piers1989]

Dave is absolutely right with lean idle.
Rescaling petrol injectors helps to bring stft back closer to 0%

Does that mean that if I deliberately under scale the injectors, the car will inject more fuel (thus not running so lean on idle) - and then the trim system will handle the differences from what's expected?
What would this mean under open loop? I guess on KSmod 2.0 I could make a map that's only applicable at idle and when engine isn't fully up to temp that scales the injectors down, then puts them back to normal under driving conditions?

Regarding LPG, it's the way it's installed and tuned is the most important.
These days most of the components are very god quality as long as they are correct efficiency.
There is no need to spend extra money on expensive kits like BRC or Prinse.
People still think they are the best, but that was 20 years ago. Since than LPG market has changed massively.
No flash lube is needed. As long as AFR is correct, there is no risk of damaging your engine.
Few years back I done EGT test on petrol and LPG and there was no difference at all.
The results are here somwhere on the forum.
Having experiance converting few Legnums, they need to have ignition system in very good condition.
If not, you may experiance misfire at low rpm. Unfortunately all the VR4s are slightly aged so things like ignition leads and coil packs may not be performing at their best.

The reason I was interested in BRC more than the other brands, is that 2 of the LPG cars I've had didn't run great on LPG. I had to buy the cable and remap both of them, and one of them still liked to run lean. I believe it was a Romano system and there wasn't much to change.
Also this system was not capable of providing enough LPG at WOT in my old 540i sport, so I had to enable the feature to allow some Petrol to flow too.

Is it possible for my coils to be tested? Within reason I'm happy to replace all these semi-consumables to increase the cars' longevity so long as the cost isn't astronomical.

[adaxo]

Any LPG system is as good as installer, very common here is installers 'specialise' (read have good connection or deal) in one of LPG brand/shop and fit the same bits to 1.2 fiesta and V8 Range, see them personally come out from installer close to me which also selling LPG hence I have nosy always what's hes up to while he filling my car, @fassi1 can you imagine BRC genius fitted to V8 RR on 6mm supply pipe? probably everything above 3000 RPM is still running on petrol without driver knowing this

I don't like BRC for they pricing, not very good output vaps and awkward (massive) injectors rails, which will work on Legnum BUT other brands components can be better installed and be more suitable for Legnum.

I did convert about 12 Legnums on proven and tested combination of LPGtech ecu, KME TwinTur vap and HANA blue injectors, All of them running fine to date unless being written off or scrapped

To answer your main questions

1. Been running various cars on LPG since 2002 on various brands (BRC incl) yes have various issues hence I take things in to my hands and install them myself to avoid issues with poor installations of lowest quality components used at not necessary lowest price. Remember rule No1 is: save money AFTER installation NEVER before (on actual kit/installer)
My Legnum running great on LPG in ANY conditions.
2. No don't have one and would never fit one as IMO its just marketing blurb
3. Yes you can utilise switchable maps, I didn't go to that stage as im always run on LPG and have ignition tweak so hard it will knock its tits off on petrol (0 knock on LPG) so if im really desperate to run on petrol then I just drive carefully to nearest LPG filing station.
4. It will probably do the same on LPG, as long as you and installer are aware of this issue prior to installation IMO is ok-ish.

[Piers1989]

Any LPG system is as good as installer, very common here is installers 'specialise' (read have good connection or deal) in one of LPG brand/shop and fit the same bits to 1.2 fiesta and V8 Range, see them personally come out from installer close to me which also selling LPG hence I have nosy always what's hes up to while he filling my car, @fassi1 can you imagine BRC genius fitted to V8 RR on 6mm supply pipe? probably everything above 3000 RPM is still running on petrol without driver knowing this

I don't like BRC for they pricing, not very good output vaps and awkward (massive) injectors rails, which will work on Legnum BUT other brands components can be better installed and be more suitable for Legnum.

I did convert about 12 Legnums on proven and tested combination of LPGtech ecu, KME TwinTur vap and HANA blue injectors, All of them running fine to date unless being written off or scrapped

To answer your main questions

1. Been running various cars on LPG since 2002 on various brands (BRC incl) yes have various issues hence I take things in to my hands and install them myself to avoid issues with poor installations of lowest quality components used at not necessary lowest price. Remember rule No1 is: save money AFTER installation NEVER before (on actual kit/installer)
My Legnum running great on LPG in ANY conditions.
2. No don't have one and would never fit one as IMO its just marketing blurb
3. Yes you can utilise switchable maps, I didn't go to that stage as im always run on LPG and have ignition tweak so hard it will knock its tits off on petrol (0 knock on LPG) so if im really desperate to run on petrol then I just drive carefully to nearest LPG filing station.
4. It will probably do the same on LPG, as long as you and installer are aware of this issue prior to installation IMO is ok-ish.

Thanks for the input Adaxo
Do you still do these conversions yourself? If so can you get the car put on the lpg register things insurers like?

What have you done in those Legnums for the Tank? I'd like a lot of capacity as my other LPG cars have always been thirsty beasts - I think I had 70l fuel tanks but it doesn't last long with thirsty engines and a heavy right foot! Is it possible to fit a tank in the spare wheel well as well as one in the boot? Possibility of using a valve of some kind to make the boot one actually removable?

[fassi1]

Does that mean that if I deliberately under scale the injectors, the car will inject more fuel (thus not running so lean on idle) - and then the trim system will handle the differences from what's expected?
What would this mean under open loop? I guess on KSmod 2.0 I could make a map that's only applicable at idle and when engine isn't fully up to temp that scales the injectors down, then puts them back to normal under driving conditions?




The reason I was interested in BRC more than the other brands, is that 2 of the LPG cars I've had didn't run great on LPG. I had to buy the cable and remap both of them, and one of them still liked to run lean. I believe it was a Romano system and there wasn't much to change.
Also this system was not capable of providing enough LPG at WOT in my old 540i sport, so I had to enable the feature to allow some Petrol to flow too.

Is it possible for my coils to be tested? Within reason I'm happy to replace all these semi-consumables to increase the cars' longevity so long as the cost isn't astronomical.

To start with it's good to know what open loop and closed loop is.
Under closed loop ECU cntroles lambda with target 1. As far as I know, on VR4 it can only adjust fueling by +-15%.
As long as trims are within the limit, lambda is 1 which means your AFR is 14.7
As soon as fuel trims exceed the limit, ECU goes in to open loop (limp mode) and stops adjusting the fueling with fixed fuel trim around 3% on VR4s as far as I remember, and for that reason your AFR starts decreasing and you experiance lean idle.
If you rescale the injectors to smaller capacity, ECU will start with greater duty cycle and for that reason, fuel trims will decrease and should stay within +-15% range af adjustment. Mid load and idle is controled by fuel trims (closed loop) so your lambda will always be 1 (AFR 14.7).
Under high load ECU goes in to open loop and runs richer to achieve max power.
Standard VR4s are normally overfueled, so rescaling injectors will help to bring AFR to more reasonable.
I would strongly recommend to do a proper test after reascaling injectors to make sure that correct fuel trims and AFR are achieved.
That's how it works on standard VR4 ECU.

[Piers1989]

To start with it's good to know what open loop and closed loop is.
Under closed loop ECU cntroles lambda with target 1. As far as I know, on VR4 it can only adjust fueling by +-15%.
As long as trims are within the limit, lambda is 1 which means your AFR is 14.7
As soon as fuel trims exceed the limit, ECU goes in to open loop (limp mode) and stops adjusting the fueling with fixed fuel trim around 3% on VR4s as far as I remember, and for that reason your AFR starts decreasing and you experiance lean idle.
If you rescale the injectors to smaller capacity, ECU will start with greater duty cycle and for that reason, fuel trims will decrease and should stay within +-15% range af adjustment. Mid load and idle is controled by fuel trims (closed loop) so your lambda will always be 1 (AFR 14.7).
Under high load ECU goes in to open loop and runs richer to achieve max power.
Standard VR4s are normally overfueled, so rescaling injectors will help to bring AFR to more reasonable.
I would strongly recommend to do a proper test after reascaling injectors to make sure that correct fuel trims and AFR are achieved.
That's how it works on standard VR4 ECU.

I just flashed KS 2.0 and set up 4 configs using 3 maps.
1. "fun" mode, high boost, AFR and timing tweaked for about 2 hours to not cause knock (need to spend more time to tweak more), over 6kph and over 60% TPS
2. "cruise" mode, when under normal throttle, use standard map (also needs tweaking), over 6kph
3. "Launch control / ALS", retard timing, add fuel, limit RPM - under 6kph over 60% TPS.
4. "setting off", in none of the above situations, use the standard maps to set off.

I also reduced the injector size by 2% on every configuration, the AFR still looks fine under normal use. Haven't tried a warm start yet.
I had my injectors cleaned and tested a few months ago and they are capable of flowing 400cc/min under static conditions so I know they are good.
Will see if there is any difference next time it gets a warm start

Is it worth me setting only my "setting off" map to have downscaled injectors and actually setting the others to the 400cc they are?

[giblet]

Adam converted my old Galant VR4 and my only complaint is I should have had it done a lot lot sooner! My weekly fuel costs plummeted and I made back the cost of installation in savings from the first 12 months of running LPG. I still regret selling that VR4. I've got a fairly quick Evo X at the moment and it drinks V Power like a mother******.

[fassi1]

I also reduced the injector size by 2% on every configuration, the AFR still looks fine under normal use. Haven't tried a warm start yet.
I had my injectors cleaned and tested a few months ago and they are capable of flowing 400cc/min under static conditions so I know they are good.
Will see if there is any difference next time it gets a warm start

Is it worth me setting only my "setting off" map to have downscaled injectors and actually setting the others to the 400cc they are?

Personally, I would keep downscaling the injectors to the figure, untill I would be satisfied with the fuel trims and AFR under high load, regardles they are in perfect condition.
Injectors perform basing on calculated duty cycle, which depends on many variant factors, condition of the engine and condition of the all the sensors that readings are taken in to account. Injectors may be perfect when tested on the bench, but story may be slightly different when fitted to the engine.
As long as engines compression is fine, there is no air and exhaust leaks and engine runs smooth I would just rescale the injectors to achieve correct fuel trims.

[fassi1]

Adam converted my old Galant VR4 and my only complaint is I should have had it done a lot lot sooner! My weekly fuel costs plummeted and I made back the cost of installation in savings from the first 12 months of running LPG. I still regret selling that VR4. I've got a fairly quick Evo X at the moment and it drinks V Power like a mother******.

It must be time to convert EVO then

[adaxo]

Thanks for the input Adaxo
Do you still do these conversions yourself? If so can you get the car put on the lpg register things insurers like?

What have you done in those Legnums for the Tank? I'd like a lot of capacity as my other LPG cars have always been thirsty beasts - I think I had 70l fuel tanks but it doesn't last long with thirsty engines and a heavy right foot! Is it possible to fit a tank in the spare wheel well as well as one in the boot? Possibility of using a valve of some kind to make the boot one actually removable?

In Legnum perfect fit is 650x270 usable capacity will be about 60ltr which will give you 180-220 miles, not stupidly long range but IMO is enough. If you consider to fitting more than one tank then yes it is possibile to fit one in spare well and other in the boot but you have to bare in mind each full tank would weight about 60kg. Not sure I would likek to carrying 120 kg in my Legnum boot all the time.

Yes I still occasionally do convert cars for family/friends as side thing to my main job, and yes still can put car on to LPG register but its bollox anyway, its still very grey area which they (UKLPGA) trying to put hands on in but most insurers do not recognize they 'register database' anyway

[Piers1989]

In Legnum perfect fit is 650x270 usable capacity will be about 60ltr which will give you 180-220 miles, not stupidly long range but IMO is enough. If you consider to fitting more than one tank then yes it is possibile to fit one in spare well and other in the boot but you have to bare in mind each full tank would weight about 60kg. Not sure I would likek to carrying 120 kg in my Legnum boot all the time.

That's a valid point about the weight.
My concern is that I drive between Newcastle and South Cumbria on a regular basis (there and back a couple of hours later) which is around 130 miles each way. There's limited places to get LPG where I go in Cumbria (Morrison's which is closed in the evenings - I usually go on Sunday) and a Texaco with an ancient LPG machine that tends to be out of order. Also as I live 10 miles from Newcastle, the nearest filling station is there too.
I also semi regularly drive down south to see friends and stuff. I can see 60 ltr being enough for day to day use for work, but can imagine it being a real faf to keep it topped up with my longer drives.

Also bare in mind by not keeping a full tank of petrol there is some weight to be saved there.

Combining http://www.lpgshop.co.uk/450-865-120...cal-tank-gzwm/ with http://www.lpgshop.co.uk/650-270-76l...m-with-valves/ should give a usable capacity around 157 litres, right?
I measured the rear load space in the legnum, and I'm aware at 450mm I would have to lose the load cover if I want the tank tucked behind the seats, but otherwise that tank at 865mm width should fit with about 1cm to spare from my measurements?
For my use, I think I would be willing to sacrifice the extra weight to get that much extra capacity.

Do you do these conversions commercially or just as a favour to board members now?

[adaxo]

That's more than 150kg combined tanks with gas. Its a fair bit IMO.

Not sure what mobile system you use but if android then get yourself FillLPG app its a must have for any LPG user, it will navigate you to LPG fill points and give you pricing ect, great app save ma a lot money and time while travel all across country on LPG as my job require me to do.
Screenshot_2017-02-19-12-31-58.jpg

I close my LPG business last year, and as a full time worker and family man with two kids, one 3 months old its hard to justify to spend more time in garage converting cars, so no I don't do it commercially any more but willing to help others to run on this magnificent fuel.

[fassi1]

Other option is to go for slightly taller tank 650x300 and keeping boot space and full length wit rear seats down.
Second cylinder tank will permanently take that space away, which is very usefull.

[Piers1989]

That's more than 150kg combined tanks with gas. Its a fair bit IMO.

Not sure what mobile system you use but if android then get yourself FillLPG app its a must have for any LPG user, it will navigate you to LPG fill points and give you pricing ect, great app save ma a lot money and time while travel all across country on LPG as my job require me to do.
Screenshot_2017-02-19-12-31-58.jpg

I close my LPG business last year, and as a full time worker and family man with two kids, one 3 months old its hard to justify to spend more time in garage converting cars, so no I don't do it commercially any more but willing to help others to run on this magnificent fuel.

Ahh I understand, I'm super busy myself too, but don't have all the family business on top!
There's a website I found when I used to have LPG, but that FillLPG does look better, couple in this area I didn't realise had LPG, but still 5 miles or so out of the way - none in south Cumbria other than that Morrisons in Barrow and Texaco in Ulverston!
I guess I feel for the extra weight, having the capacity to do that much may be worth, need to weigh up my options (pardon the pun!)

Other option is to go for slightly taller tank 650x300 and keeping boot space and full length wit rear seats down.
Second cylinder tank will permanently take that space away, which is very usefull.

How much more capacity is that size? I can't find one of those dimensions.
Indeed I'd rather not loose the rear load space, but at the end of the day the only times I need to fill the car with stuff I am not using the rear seats, so folding them down for more space wouldn't be the end of the world.

For reference I just did the trip back to Barrow today, and met a friend and spent a few hours of "spirited driving" there. This is a regular occurrence.
I brimmed my tank with Super Unleaded on the way there, was at just above 1/4 upon arrival, then we topped up again with Tesco Momentum 99 (£45 ish), then we did fun driving....., and as I left the area I had about 1/2 tank and filled up again with another £30, now I'm home I have a little over 1/4 tank left.
All in all I've probably used about £120 in super unleaded, around 95 litres.

I'd like to at least be able to do that without having to refill, as after I leave this area it becomes impossible to refill at night (I know that sounds a stupid reason, but I always go driving at night and none of the 24 hour garages in south Cumbria do LPG).