LPG Chimaera (Follow My Conversion)

[SILICONEKIDOBHP]

So what you are saying is one of the three maps needs to be swopped on closed loop all the way up and a bespoke fuel map for lpg .How can you map the ECU closer so its more friendly for the piggyback ? ,i thought the lambda feed back would not be able to cope with that ,at a certain point it needs to go on to open loop .

Do you use around 15% more fuel on lpg ?

Edited by SILICONEKIDOBHP on Tuesday 8th July 21:18

[ChimpOnGas]

SILICONEKIDOBHP said:

So what you are saying is one of the three maps needs to be swopped on closed loop all the way up and a bespoke fuel map for lpg.

Closed loop & or fuel temp correction is the answer to making LPG work correctly.

SILICONEKIDOBHP said:

How can you map the ECU closer so its more friendly for the piggyback ? ,i thought the lambda feed back would not be able to cope with that.

Even when you run closed loop the system still reverts to open loop under certain conditions, so you need to start with a good open loop map in the first place.

SILICONEKIDOBHP said:

Do you use around 15% more fuel on lpg ?

Yes this is chemically unavoidable, LPG has a lower calorific value than petrol.

The bottom line is you can't beat the science, but LPG is so cheap to buy the savings are still excellent.

However, using more gas means you'll need to carry more of it to travel the same distance, that along with the steel tanks means more weight.

Carry some reserve petrol and the weight goes up still further, and remember you're also losing boot space.

Packaging of the LPG tanks, the reserve petrol tank, and the efficiency of your system starts to become very important indeed if your conversion is going to be a success.

There's lots to think about, which is why I invested a lot of time in the planning stage.

Even after my conversion was completed I found myself wanting a bit more gas which invariable meant a bit less petrol, I'm confident I've got the perfect balance between fuels now and the folding Surrey top made a roof down run to Le Mans much easier.

If I were you Daz, I'd just copy my fuel packaging and save yourself all the guess work.

[Quinny]

ChimpOnGas said:

We also pulled a genuine sat nav confirmed 142 on gas spanking yet another Porsche 911, he arrived at the next fuel station 10 minutes after us with the boys in blue on tow.

The fekin Porker weasel started pointing at us gassing up with LPG, I think he was saying "that TVR was going much faster than me".

Bet he also couldn't get his head around the whole TVR filling with gas thing, I get a lot of that

Police probably clocked you and thought "poor devil" won't be able to afford the fine, and we don't want to impound a crappy old TVR

Ahh a Porsche.... Now he'll be able to stump up the readys

[ChimpOnGas]

Quinny said:

Police probably clocked you and thought "poor devil" won't be able to afford the fine, and we don't want to impound a crappy old TVR

Ahh a Porsche.... Now he'll be able to stump up the readys

Well Porker weasel didn't look happy Quinny

[SILICONEKIDOBHP]

So why is it 99.99% of people just have there piggy back wired up to there ECU ? Most of the modern ECU`s do not have the capability to build a closer map .

When you talk about having it on closed loop ,thats going to be impossible because the lambda feed back is not fast enough. Can you tell me at KPA can you stay on closed loop ?

I`m aware close loop will not come in to play until a certain set engine temperature .

How many litres do you have in the torpedo tanks ?

[ChimpOnGas]

SILICONEKIDOBHP said:

So why is it 99.99% of people just have there piggy back wired up to there ECU ? Most of the modern ECU`s do not have the capability to build a closer map.

You've just answered your own question

If your Emerald offers you the facility to get things closer to where they should be for gas why wouldn't you map it accordingly? At the end of the day the less processing work your piggyback needs to do the better.

However, even if you could get your Emerald map spot on for gas you'll still need the piggyback as it has the peak & hold injector drivers inside it, these are essential to fire the LPG peak & hold type injectors.

You can not run peak & hold LPG injectors off petrol type saturated injector drivers!

Many LPG piggy backs also have a fuel temp input and the ability within the software to allow for temperature correction, this is a useful feature to help nail your AFRs as when the LPG warms & cools the fuel goes through significant volume fluctuations which in turn will dramatically affect you AFRs.

To get LPG working correctly, nailing your AFRs is everything so you must have some means of correcting the effects of fuel volume fluctuations. This could be closed loop or temp correction, or both.

SILICONEKIDOBHP said:

When you talk about having it on closed loop ,thats going to be impossible because the lambda feed back is not fast enough. Can you tell me at KPA can you stay on closed loop?

Ok Daz, you know best, funny how it works perfectly on my car though. Your Emerald is more than capable of processing lambda feedback and correcting the AFR in closed loop mode many times a second, in practice what you end up seeing is a perfect match to your AFR targets and a wonderfully smooth drive no matter what temperature/volume the LPG is.

If you insist on running LPG on a purely open loop basis all I can do is wish you the best of luck, but I have to warn you that you'll never get a nice drive under all conditions that way...FACT!

SILICONEKIDOBHP said:

I`m aware close loop will not come in to play until a certain set engine temperature.

And your point is

SILICONEKIDOBHP said:

How many litres do you have in the torpedo tanks?

It's a car not a submarine, there are no torpedoes just two cylinder tanks.

The top one is 30 litre single hole tank supplying the four hole 42 litre bottom one, the vaporiser is fed with liquified fuel under pressure from the bottom tank only, the injectors are fed with gas from the vaporiser.

The tanks hold a maximum wet capacity of 72 litres however I have adjusted the fill valve so it shuts off the forecourt pump at 65 litres, this is to allow 10% free space for expansion on a hot day when the car has just been filled.

That gives me 14.25 usable Imperial gallons of LPG and a 312 mile range, basically I'm carrying two more gallons of gas than the standard petrol car caries petrol to compensate for the slightly higher LPG fuel consumption.

[SILICONEKIDOBHP]

Dave Why do we have closed and open loop if you are saying it works better on closed loop . .


I thought the reason for this is because the lambda can not process the signal fast enough after a certain KPA ,thats why it goes on to open loop .

[ChimpOnGas]

15.7:1 AFR on light load cruise.




And how that looks at the plugs when running super clean burning LPG.




Engine oil remains golden brown for over 5,000 miles, no bore wash... this & the low carbon clean burn equals extended engine life.

Not to mention the cost equivalent of 45mpg and more horsepower on the cheap clean stuff

[Sardonicus]

Impressive stuff Dave but............... seeing as that style of plug has such a long service life you may want to consider some anti-seize on those plug threads you naughty boy I have had to Time-Sert/Re-thread more No3 cylinder spark plug (hottest running cylinder) threads on eighties Honda's than I care to remember because of this (back in the dealership days) and many since on various other cars and its not caused by cross threading SORT IT

[ChimpOnGas]

Sardonicus said:

Impressive stuff Dave but............... seeing as that style of plug has such a long service life you may want to consider some anti-seize on those plug threads you naughty boy I have had to Time-Sert/Re-thread more No3 cylinder spark plug (hottest running cylinder) threads on eighties Honda's than I care to remember because of this (back in the dealership days) and many since on various other cars and its not caused by cross threading SORT IT

Will do Simon, it's a good point.

TBH when I fitted the NGK LPG plugs 8,000 miles ago there was quite a residual of copperslip in the plug holes from the last set so I chose not apply more at that point, but you're right looking at the photo it definitely needs re-doing now mate

The real point I'm making is after an equal amount of miles the original shrouded electrode NGK B7ECS on the 14CUX burning petrol always looked like this:



Whereas the Iridium LPG LaserLines burning gas (all wind out easily with no galling) look like this:

[Sardonicus]

Never quite under stood why TVR used a race style plug in the RV8 its just not able to throw enough at it, even the so called early 500 with supposedly too much CR could not over whelm stock style 6 heat range protruding electrode NGK plugs never mind 7's Rover V8! NGK would plugs st it all in their stride although Denso are another good plug in fact if the truth be known in a stock 400 you could probably get away with 5's (dont try it though people) its low output per CC and nearer 8.5/9.0 true CR wont break them into a sweat

Edited by Sardonicus on Friday 1st August 12:26

[macdeb]

Sardonicus said:

Never quite under stood why TVR used a race style plug in the RV8 its just not able to throw enough at it, even the so called early 500 with supposedly too much CR could not over whelm stock style 6 heat range protruding electrode NGK plugs never mind 7's Rover V8! NGK would plugs st it all in their stride although Denso are another good plug in fact if the truth be known in a stock 400 you could probably get away with 5's (dont try it though people) its low output per CC and nearer 8.5/9.0 true CR wont break them into a sweat

Edited by Sardonicus on Friday 1st August 12:26

6's for me.

[ChimpOnGas]

Sardonicus said:

Never quite under stood why TVR used a race style plug in the RV8 its just not able to throw enough at it, even the so called early 500 with supposedly too much CR could not over whelm stock style 6 heat range protruding electrode NGK plugs never mind 7's Rover V8! NGK would plugs st it all in their stride although Denso are another good plug in fact if the truth be known in a stock 400 you could probably get away with 5's (dont try it though people) its low output per CC and nearer 8.5/9.0 true CR wont break them into a sweat

Edited by Sardonicus on Friday 1st August 12:26

I'll second that

[SILICONEKID345HP]

I`m going to change mine ,they are very sooty yet my afr`s run up to 15.5 ,i currently run the standard RV8 BPR7ES .

What should i try ? 6`s

[carsy]

BPR6ES is what you want Daz.

Dont buy off Ebay, theres plenty of fake NGK out there. Last time i bought of Ebay i was suddenly running on 6 cylinders. Go to a proper motor factors.


ETA Dave that plug looks great. Those pistons of yours should be super clean.

Edited by carsy on Friday 1st August 19:09

[SILICONEKID345HP]

macdeb said:

6's for me.

Just fitted NGK BPR6ES ,smooth idle and goes like a train

[macdeb]

SILICONEKID345HP said:

macdeb said:

6's for me.

Just fitted NGK BPR6ES ,smooth idle and goes like a train

Yup, I was told that 6's would tidy up my 'fluffy' tickover, couldn't believe the difference.

[SILICONEKID345HP]

macdeb said:

Yup, I was told that 6's would tidy up my 'fluffy' tickover, couldn't believe the difference.

Yes but it does advance the engine a little .

[ChimpOnGas]

Here's what the engine oil looks like on gas after yet another 3,500 miles (when I changed it last).



Soooo clean

[Chuffmeister]

That is incredible!