Omega Owners Forum

Chat Area => General Car Chat => Topic started by: Lazydocker on 01 March 2010, 16:45:26

Title: LPG Flat Spot seems to have been cured
Post by: Lazydocker on 01 March 2010, 16:45:26
At per the title... After quite a long chat with Teilo last week I've lowered the Vaporiser pressure to about 1.1 BAR at idle and re-mapped it... Moved the switchover back to petrol to 6500 RPM, floored it and was a pretty smooth change 1st to 2nd. Tried it several times and it seems to have cured it :y :y :y

Also seems to have improved the drive considerably :y :y :y

Chris, had a quick chat about your issues and he suggested trying to drop the pressure as I have, although the issue could well be the multi-valve not flowing enough gas... He may be able to do something but very fiddly!
Title: Re: LPG Flat Spot seems to have been cured
Post by: Kevin Wood on 01 March 2010, 17:08:29
Hmm. Interesting. Will have to try that. :y

Kevin
Title: Re: LPG Flat Spot seems to have been cured
Post by: Lazydocker on 01 March 2010, 17:15:25
Quote
Hmm. Interesting. Will have to try that. :y

Kevin

As you know, I have tried quite a few different pressure settings and this seems to be the best so far :y :y

Teilo is also trialing some new injectors... I may get a set through the post to try for him ::) ::)

There is also a good deal to be had for anyone thinking of converting... He has had his own kit made, ECU etc, and is after people to fit it and test it for him. It's been successfully installed on some 1000 vehicles so far and is offering a substantial discount to anyone who wishes to fit it and try it out for him, on the condition he gets the feedback, good, bad or ugly! :y
Title: Re: LPG Flat Spot seems to have been cured
Post by: feeutfo on 01 March 2010, 18:54:25
thanks for posting LD. Will let the lappy chat to it and give it a go. See what happens.

I think i mentioned in a previous pm that i found the pressure to be running at 1.1 when i was expecting 1.2 . Was not calibrated at 1.1 though so obviusly need to try as you suggest.

Thanks again. :y
Title: Re: LPG Flat Spot seems to have been cured
Post by: hotel21 on 01 March 2010, 18:57:27
Quote
Quote
Hmm. Interesting. Will have to try that. :y

Kevin

As you know, I have tried quite a few different pressure settings and this seems to be the best so far :y :y

Teilo is also trialing some new injectors... I may get a set through the post to try for him ::) ::)

There is also a good deal to be had for anyone thinking of converting... He has had his own kit made, ECU etc, and is after people to fit it and test it for him. It's been successfully installed on some 1000 vehicles so far and is offering a substantial discount to anyone who wishes to fit it and try it out for him, on the condition he gets the feedback, good, bad or ugly! :y

As a tight Jock, might be interested.

What ballpark figure for a V6 3.2 ??
Title: Re: LPG Flat Spot seems to have been cured
Post by: TheBoy on 01 March 2010, 19:18:04
Quote
Quote
Hmm. Interesting. Will have to try that. :y

Kevin

As you know, I have tried quite a few different pressure settings and this seems to be the best so far :y :y

Teilo is also trialing some new injectors... I may get a set through the post to try for him ::) ::)

There is also a good deal to be had for anyone thinking of converting... He has had his own kit made, ECU etc, and is after people to fit it and test it for him. It's been successfully installed on some 1000 vehicles so far and is offering a substantial discount to anyone who wishes to fit it and try it out for him, on the condition he gets the feedback, good, bad or ugly! :y
I have the new 'non drill' type injector adapters.  They dont fit on a V6 intake (fortunatley he provided the traditional type as well).  Mine are still Valtek injectors though.


Good nes about the pressure, that may help.
Title: Re: LPG Flat Spot seems to have been cured
Post by: TheBoy on 01 March 2010, 19:18:42
Quote
Quote
Quote
Hmm. Interesting. Will have to try that. :y

Kevin

As you know, I have tried quite a few different pressure settings and this seems to be the best so far :y :y

Teilo is also trialing some new injectors... I may get a set through the post to try for him ::) ::)

There is also a good deal to be had for anyone thinking of converting... He has had his own kit made, ECU etc, and is after people to fit it and test it for him. It's been successfully installed on some 1000 vehicles so far and is offering a substantial discount to anyone who wishes to fit it and try it out for him, on the condition he gets the feedback, good, bad or ugly! :y

As a tight Jock, might be interested.

What ballpark figure for a V6 3.2 ??
You will need to decide on tanks first, as that can make a huge difference
Title: Re: LPG Flat Spot seems to have been cured
Post by: feeutfo on 01 March 2010, 19:22:32
Quote
Quote
Quote
Hmm. Interesting. Will have to try that. :y

Kevin

As you know, I have tried quite a few different pressure settings and this seems to be the best so far :y :y

Teilo is also trialing some new injectors... I may get a set through the post to try for him ::) ::)

There is also a good deal to be had for anyone thinking of converting... He has had his own kit made, ECU etc, and is after people to fit it and test it for him. It's been successfully installed on some 1000 vehicles so far and is offering a substantial discount to anyone who wishes to fit it and try it out for him, on the condition he gets the feedback, good, bad or ugly! :y

As a tight Jock, might be interested.

What ballpark figure for a V6 3.2 ??
assumimg you want a donut in spare wheel well in your estate? range could be an issue in remote parts, how close is your nearest lpg station?
Title: Re: LPG Flat Spot seems to have been cured
Post by: Lazydocker on 01 March 2010, 19:24:08
Quote
Quote
Quote
Hmm. Interesting. Will have to try that. :y

Kevin

As you know, I have tried quite a few different pressure settings and this seems to be the best so far :y :y

Teilo is also trialing some new injectors... I may get a set through the post to try for him ::) ::)

There is also a good deal to be had for anyone thinking of converting... He has had his own kit made, ECU etc, and is after people to fit it and test it for him. It's been successfully installed on some 1000 vehicles so far and is offering a substantial discount to anyone who wishes to fit it and try it out for him, on the condition he gets the feedback, good, bad or ugly! :y

As a tight Jock, might be interested.

What ballpark figure for a V6 3.2 ??

Thought you may be ::) ::)

Don't know yet but I've been looking for my replacement estate (if I get it)... Actually, I'll PM you my best guess as it's not fair to post publicly ;) ;)

Tank size is your biggest issue... I've looked at lots of options but can't seem to find anything bigger than 60L to fit in the wheel well, and that includes raising the boot floor by about an inch (bit of 1" ply cut to fit floor with wheel well cut out ;)) which is a range of about 200 miles, less if towing :( :(

Considered all sorts, including cutting out the bottom of the wheel well :o :o but can't see anything bigger fitting without going down the custom petrol tank route :-/ :-/

Title: Re: LPG Flat Spot seems to have been cured
Post by: Ken T on 01 March 2010, 23:53:22
Could I add a slight word of caution. The manpower required to design/test/ production engineer/write software/ source all parts for an ECU is quite large, you would need quite a large team to do it properly/well/reliably. And if you look at the price they are being sold for, ( a Stag front end kit for £140 ish ) there isn't much profit in there, not enough to fund all that R & D. It might be reliable, but if its fitted like the OMVL N stuff, it mimicks the Petrol ECU and controls the petrol injectors, so if it dies, so will the car. We're talking safety critical here.

The Stag stuff must be bad/ not enough profit  for him to change supplier.

Ken
Title: Re: LPG Flat Spot seems to have been cured
Post by: Lazydocker on 02 March 2010, 08:21:12
Quote
Could I add a slight word of caution. The manpower required to design/test/ production engineer/write software/ source all parts for an ECU is quite large, you would need quite a large team to do it properly/well/reliably. And if you look at the price they are being sold for, ( a Stag front end kit for £140 ish ) there isn't much profit in there, not enough to fund all that R & D. It might be reliable, but if its fitted like the OMVL N stuff, it mimicks the Petrol ECU and controls the petrol injectors, so if it dies, so will the car. We're talking safety critical here.

The Stag stuff must be bad/ not enough profit  for him to change supplier.

Ken

Nope... But he has had his own kit made and released... It's all about name and profit I agree, but he has taken the best parts of several kits (by the sound of it) and combined them into one :y :y

Oh... And nearly all LPG ECUs "Piggy back" on the petrol ECU... It's the norm otherwise they would have to be vehicle specific ;) ;) If it dies (as mine did a few weeks back) it doesn't stop the car working, the petrol injectors are directly connected and the LPG ECU only cuts the signal when live :y
Title: Re: LPG Flat Spot seems to have been cured
Post by: Marks DTM Calib on 02 March 2010, 09:05:28
Quote
Could I add a slight word of caution. The manpower required to design/test/ production engineer/write software/ source all parts for an ECU is quite large, you would need quite a large team to do it properly/well/reliably. And if you look at the price they are being sold for, ( a Stag front end kit for £140 ish ) there isn't much profit in there, not enough to fund all that R & D. It might be reliable, but if its fitted like the OMVL N stuff, it mimicks the Petrol ECU and controls the petrol injectors, so if it dies, so will the car. We're talking safety critical here.

The Stag stuff must be bad/ not enough profit  for him to change supplier.

Ken

I disagree.

Complex its not, and its only a basic microcontroller which many serious hobbiests can handle. Add some testing in etc and its the sort of thing a single compitent engineer could do in sub 12 months without to much of a challenge.

Then chuck it at an outsource company (such as Flextronics, Sanmena, Solectron, Jabil etc.....) and they will source all parts, build and test in return for some VA markup.

I would guess, in 1-10K quantities, that it would come in at around 70-80 quid.....and if you got into the millions at sub 30!
Title: Re: LPG Flat Spot seems to have been cured
Post by: feeutfo on 02 March 2010, 12:53:20
ok, set to 1.1 and recalibrated, certainly massively improved. Tick over seems smoother, and on a full tank of gas the gear changes seem fine on a 5 minute blast. Sudden lift off from full throttle is far better but not quite as smooth as on petrol, acceptable though.

Will see how it goes as the tank empties.

Still switching back though, no change on that score.

Thanks LD
Title: Re: LPG Flat Spot seems to have been cured
Post by: Lazydocker on 02 March 2010, 12:59:26
Quote
ok, set to 1.1 and recalibrated, certainly massively improved. Tick over seems smoother, and on a full tank of gas the gear changes seem fine on a 5 minute blast. Sudden lift off from full throttle is far better but not quite as smooth as on petrol, acceptable though.

Will see how it goes as the tank empties.

Still switching back though, no change on that score.

Thanks LD

Under hard acceleration? If so it sounds like the limits of the multivalve have been found :( :(

You may only have a 6mm pick up pipe which can be changed to 8mm, which would raise the limits of flow a little but is very fiddly. Is it still only doing it once you have used some of the fuel from the tank and OK when first filled? If so it does all point towards the flow rate from the multivalve :(
Title: Re: LPG Flat Spot seems to have been cured
Post by: feeutfo on 02 March 2010, 14:30:34
Quote
Quote
ok, set to 1.1 and recalibrated, certainly massively improved. Tick over seems smoother, and on a full tank of gas the gear changes seem fine on a 5 minute blast. Sudden lift off from full throttle is far better but not quite as smooth as on petrol, acceptable though.

Will see how it goes as the tank empties.

Still switching back though, no change on that score.

Thanks LD

Under hard acceleration? If so it sounds like the limits of the multivalve have been found :( :(

You may only have a 6mm pick up pipe which can be changed to 8mm, which would raise the limits of flow a little but is very fiddly. Is it still only doing it once you have used some of the fuel from the tank and OK when first filled? If so it does all point towards the flow rate from the multivalve :(
sounds likely from what your saying, its far less likely to  switch back with a full tank, and gets peogressivly worse until empty...?
Title: Re: LPG Flat Spot seems to have been cured
Post by: Lazydocker on 02 March 2010, 14:51:57
Quote
Quote
Quote
ok, set to 1.1 and recalibrated, certainly massively improved. Tick over seems smoother, and on a full tank of gas the gear changes seem fine on a 5 minute blast. Sudden lift off from full throttle is far better but not quite as smooth as on petrol, acceptable though.

Will see how it goes as the tank empties.

Still switching back though, no change on that score.

Thanks LD

Under hard acceleration? If so it sounds like the limits of the multivalve have been found :( :(

You may only have a 6mm pick up pipe which can be changed to 8mm, which would raise the limits of flow a little but is very fiddly. Is it still only doing it once you have used some of the fuel from the tank and OK when first filled? If so it does all point towards the flow rate from the multivalve :(
sounds likely from what your saying, its far less likely to  switch back with a full tank, and gets peogressivly worse until empty...?

Yep... ISTRC that this was what you described recently :-/ :-/
Title: Re: LPG Flat Spot seems to have been cured
Post by: TheBoy on 02 March 2010, 21:11:25
Teilo has a supplier for a higher flow multivalve, but their is no stock anywhere.

It may be something I will consider in a few months if I find its constantly switching to petrol at high revs.
Title: Re: LPG Flat Spot seems to have been cured
Post by: Ken T on 02 March 2010, 21:35:28
Quote
Quote
Could I add a slight word of caution. The manpower required to design/test/ production engineer/write software/ source all parts for an ECU is quite large, you would need quite a large team to do it properly/well/reliably. And if you look at the price they are being sold for, ( a Stag front end kit for £140 ish ) there isn't much profit in there, not enough to fund all that R & D. It might be reliable, but if its fitted like the OMVL N stuff, it mimicks the Petrol ECU and controls the petrol injectors, so if it dies, so will the car. We're talking safety critical here.

The Stag stuff must be bad/ not enough profit  for him to change supplier.

Ken

I disagree.

Complex its not, and its only a basic microcontroller which many serious hobbiests can handle. Add some testing in etc and its the sort of thing a single compitent engineer could do in sub 12 months without to much of a challenge.

Then chuck it at an outsource company (such as Flextronics, Sanmena, Solectron, Jabil etc.....) and they will source all parts, build and test in return for some VA markup.

I would guess, in 1-10K quantities, that it would come in at around 70-80 quid.....and if you got into the millions at sub 30!

Yes, and design and produce a mould for a zinc diecasting. I'm not saying it can't be done, I'm just saying he will need to shift a lot of units to repay development.

Re the LPG ECU, well its in series with the petrol injector lead, and any element in series can fail. It would be interesting to see how they arrange to "fail safe ".  Subcontract manufacturing, well the place I am currently at, use a subcontractor to source parts and build stuff. Problems I had the other day were an IC the wrong way round (16Pin DIL), tombstone resistor and the soldering is way up the DIL ic legs. Oh and they are IPC certified.  :-X

Interestingly enough, remember the Lexus that stuck on full throttle, and the Toyota sticking throttle recall  ?. Well a recent article on the EMC website 'suggests' that the Lexus problem might have been caused by the ECU deciding to go on full throttle, and there's basically nothing you can do about it. Car brakes can't absorb several hundred HP, and with electronic controls there is no way of cutting power to the ECU, so no way of stopping. And the Toyota pedal manufacture said that there was no evidence of their assemblies sticking. I wonder if Toyota ECU's occasionally stop monitoring the pedal. Not a nice thought.

And you would let some single engineer write code to control your engine ?. The amount of testing GM etc must do to ensure fail safe code must cost millions.

Ken
Title: Re: LPG Flat Spot seems to have been cured
Post by: TheBoy on 02 March 2010, 21:38:03
Thought in Toyotas case, it was pedal physically stick in the mat?  LOL, used to happen on your crappy vans at work ;D
Title: Re: LPG Flat Spot seems to have been cured
Post by: Kevin Wood on 02 March 2010, 22:00:57
Quote
Interestingly enough, remember the Lexus that stuck on full throttle, and the Toyota sticking throttle recall  ?. Well a recent article on the EMC website 'suggests' that the Lexus problem might have been caused by the ECU deciding to go on full throttle, and there's basically nothing you can do about it. Car brakes can't absorb several hundred HP, and with electronic controls there is no way of cutting power to the ECU, so no way of stopping. And the Toyota pedal manufacture said that there was no evidence of their assemblies sticking. I wonder if Toyota ECU's occasionally stop monitoring the pedal. Not a nice thought.

If these rumours are true then the Toyota ECU is a truly sh1te design. There are plenty of watchdogs, in hardware and software then could monitor the operation of the system and prevent such a scenario. Safety critical firmware / hardware systems are everywhere. (airbag ECU, anyone?) How often does this type of mishap occur?
Quote
And you would let some single engineer write code to control your engine ?. The amount of testing GM etc must do to ensure fail safe code must cost millions.

But an LPG ECU doesn't control the throttle, and without opening the throttle there is nothing you can do to a petrol engine to make it fail unsafe.

I have been involved in an open source project to build an engine ECU for years  http://www.megasquirt.info/. The core code in that box is very small. About 2500 lines of 8 bit assembler. Most of that code is to allow the ECU map to be edited, and not used to actually run the engine.

I think the worst "bug" I have experienced in running round on beta firmware was a problem where the engine would only start when cold. It did cause a bit of embarrassment when I stalled it but no safety issue at all.

Sadly, it doesn't yet incorporate a stability control system compatible with driving on icy puddles. Recent experience shows where the real point of failure is inmost car designs - the wheel-to-seat interface!

I, for one, would not hesitate in trying Teilo's ECU. In fact if, in the light of the above, he thinks my input would be useful I'd be happy to do so.

Kevin
Title: Re: LPG Flat Spot seems to have been cured
Post by: Ken T on 02 March 2010, 22:13:08
http://www.compliance-club.com/

Ken
Title: Re: LPG Flat Spot seems to have been cured
Post by: Kevin Wood on 02 March 2010, 22:18:14
Quote
http://www.compliance-club.com/

Ken

Ahh, yes. Good guys. Have come across them as they share my loathing of power line networking adaptors. I've got that journal on my desk at work. Will have a good read of that. :y

Kevin
Title: Re: LPG Flat Spot seems to have been cured
Post by: feeutfo on 03 March 2010, 01:33:31
been to work and back up the m4, still happy with the gear changes, full throtle lift off is not quite as improved as first appeared this morning, weird, still needs work but better, defo.
 :y
Title: Re: LPG Flat Spot seems to have been cured
Post by: Marks DTM Calib on 03 March 2010, 16:05:27
Quote
Yes, and design and produce a mould for a zinc diecasting. I'm not saying it can't be done, I'm just saying he will need to shift a lot of units to repay development.

Or use an off the shelf item....there are plenty about!

Quote
Re the LPG ECU, well its in series with the petrol injector lead, and any element in series can fail. It would be interesting to see how they arrange to "fail safe ".

Easy enough, relays, OC outputs, watchdogs etc will see this sorted easily. 

Quote
Subcontract manufacturing, well the place I am currently at, use a subcontractor to source parts and build stuff. Problems I had the other day were an IC the wrong way round (16Pin DIL), tombstone resistor and the soldering is way up the DIL ic legs. Oh and they are IPC certified.  :-X

The build is only as good as the design....and there is more to the design than just the circuit and pcb.....

I have been using outsourced manufacture for uber complex buils for 8 years plus now.....and no major problems at all.


Quote
And you would let some single engineer write code to control your engine ?. The amount of testing GM etc must do to ensure fail safe code must cost millions.

Ken

Yes, a compitent engineer yes....it happens all the time already today......
Title: Re: LPG Flat Spot seems to have been cured
Post by: Lazydocker on 04 March 2010, 22:43:30
I had a good play today and it's still not perfect on mine either, but much better.

I can sense another small pressure adjustment and re-map coming on ::) ::)
Title: Re: LPG Flat Spot seems to have been cured
Post by: feeutfo on 04 March 2010, 23:48:24
Quote
I had a good play today and it's still not perfect on mine either, but much better.

I can sense another small pressure adjustment and re-map coming on ::) ::)
was wondering in the car on the way home tonight, is it worth going to 1.00 bar?

What are we compromising between with this setting? if you see what i mean? we know what happens when going too high, lag/flat spots. What happens with too little pressure? Not sure i understand it fully, i'm thinking it does the same as the fuel pressure regulater on petrol i suppose?
 :-/
Title: Re: LPG Flat Spot seems to have been cured
Post by: Kevin Wood on 04 March 2010, 23:56:35
Quote
was wondering in the car on the way home tonight, is it worth going to 1.00 bar?

What are we compromising between with this setting? if you see what i mean? we know what happens when going too high, lag/flat spots. What happens with too little pressure? Not sure i understand it fully, i'm thinking it does the same as the fuel pressure regulater on petrol i suppose?
 :-/

Insufficient fuel at wide open throttle and running lean. Always check that, on a full throttle acceleration run, the Lambda sensor outputs stay rich right up to the red line. Do this whenever you've adjusted anything. :y

Kevin
Title: Re: LPG Flat Spot seems to have been cured
Post by: feeutfo on 05 March 2010, 02:01:52
Quote
Quote
was wondering in the car on the way home tonight, is it worth going to 1.00 bar?

What are we compromising between with this setting? if you see what i mean? we know what happens when going too high, lag/flat spots. What happens with too little pressure? Not sure i understand it fully, i'm thinking it does the same as the fuel pressure regulater on petrol i suppose?
 :-/

Insufficient fuel at wide open throttle and running lean. Always check that, on a full throttle acceleration run, the Lambda sensor outputs stay rich right up to the red line. Do this whenever you've adjusted anything. :y

Kevin
oh yeah, that. Will do. :y
Title: Re: LPG Flat Spot seems to have been cured
Post by: TheBoy on 05 March 2010, 08:28:29
Quote
Quote
was wondering in the car on the way home tonight, is it worth going to 1.00 bar?

What are we compromising between with this setting? if you see what i mean? we know what happens when going too high, lag/flat spots. What happens with too little pressure? Not sure i understand it fully, i'm thinking it does the same as the fuel pressure regulater on petrol i suppose?
 :-/

Insufficient fuel at wide open throttle and running lean. Always check that, on a full throttle acceleration run, the Lambda sensor outputs stay rich right up to the red line. Do this whenever you've adjusted anything. :y

Kevin
Won't it detect lean running, an pop back to petrol?

Drill the injectors out more if it does?
Title: Re: LPG Flat Spot seems to have been cured
Post by: Kevin Wood on 05 March 2010, 09:26:55
Quote
Won't it detect lean running, an pop back to petrol?
No - it only monitors the vapour pressure so if that pressure is not able to deliver enough fuel through the injectors...
Quote
Drill the injectors out more if it does?
I think we're at the max. at 3mm. Then again, according to the documentation that's supposed to be good for more than 200 BHP @ 1 BAR.  :-/

Kevin
Title: Re: LPG Flat Spot seems to have been cured
Post by: TheBoy on 05 March 2010, 09:30:13
Quote
Quote
Won't it detect lean running, an pop back to petrol?
No - it only monitors the vapour pressure so if that pressure is not able to deliver enough fuel through the injectors...
Quote
Drill the injectors out more if it does?
I think we're at the max. at 3mm. Then again, according to the documentation that's supposed to be good for more than 200 BHP @ 1 BAR.  :-/

Kevin
Can the injectors take more - ie, just a case of new brass bits (presumably both ends - injector and manifold), or new injectors?

Or is the whole thing some kind of flaw with the vapouriser?
Title: Re: LPG Flat Spot seems to have been cured
Post by: Lazydocker on 05 March 2010, 09:49:43
Quote
Quote
Quote
Won't it detect lean running, an pop back to petrol?
No - it only monitors the vapour pressure so if that pressure is not able to deliver enough fuel through the injectors...
Quote
Drill the injectors out more if it does?
I think we're at the max. at 3mm. Then again, according to the documentation that's supposed to be good for more than 200 BHP @ 1 BAR.  :-/

Kevin
Can the injectors take more - ie, just a case of new brass bits (presumably both ends - injector and manifold), or new injectors?

Or is the whole thing some kind of flaw with the vapouriser?

I've offered to try out a new type of injector for him, which is supposed to be more responsive. At present I'm getting "Injectors Fully Open at WOT" but it's staying rich (high voltage) :y Teilo Did say that he feels the software is a little anal about it ;) ;)

The trouble with the injectors is that they are effectively an electronically operated valve, which opens against the flow of the LPG, hence increasing the pressure wasn't the answer :y :y

As it stands at the moment I've got settings I am much happier with and I'm going to see how it behaves over the next couple of tank fulls before fettling again :y :y
Title: Re: LPG Flat Spot seems to have been cured
Post by: Kevin Wood on 05 March 2010, 10:00:31
The injectors are actually specced to 4.5 BAR so, I must admit, I'm wondering why there's so much trouble with them at 1.25 BAR.

Kevin
Title: Re: LPG Flat Spot seems to have been cured
Post by: Lazydocker on 05 March 2010, 10:10:32
Quote
The injectors are actually specced to 4.5 BAR so, I must admit, I'm wondering why there's so much trouble with them at 1.25 BAR.

Kevin

He said that although they are specced higher (I asked the same question!) it's really a Max pressure and they seem to work better at lower pressure and they're also very noisy at high pressure.

It certainly seems to run a lkot more sweetly now at a lower pressure and, although I did manage to get some lag yesterday, I was giving really "giving it large" ::) ::)

He's talking about trialling some Matrix style injectors, which are a metal flap instead of a "Valve" (or something like that) which are more responsive :y :y
Title: Re: LPG Flat Spot seems to have been cured
Post by: Kevin Wood on 05 March 2010, 10:17:34
Quote
Quote
The injectors are actually specced to 4.5 BAR so, I must admit, I'm wondering why there's so much trouble with them at 1.25 BAR.

Kevin

He said that although they are specced higher (I asked the same question!) it's really a Max pressure and they seem to work better at lower pressure and they're also very noisy at high pressure.

It certainly seems to run a lkot more sweetly now at a lower pressure and, although I did manage to get some lag yesterday, I was giving really "giving it large" ::) ::)

He's talking about trialling some Matrix style injectors, which are a metal flap instead of a "Valve" (or something like that) which are more responsive :y :y

Will be interesting to see how they fair. Open/close time on those Valkek injectors is a bit lazy. With 3.3ms opening time and 2.2 ms closing time they aren't well suited to 6K rpm use, TBH. (you have 20ms between power strokes at 6000 RPM)

It also doesn't say at what pressure the open / close times are specified.

Maybe the best way is just to set the pressure so they end up "fully open" from about 5.5k RPM onwards. Then it's not an issue, as long as the engine doesn't go lean.

Kevin
Title: Re: LPG Flat Spot seems to have been cured
Post by: Lazydocker on 05 March 2010, 11:05:02
Quote
Maybe the best way is just to set the pressure so they end up "fully open" from about 5.5k RPM onwards. Then it's not an issue, as long as the engine doesn't go lean.

Kevin

Exactly how mine is currently set. Like I said, he did comment that the software is a little anal about it ::)
Title: Re: LPG Flat Spot seems to have been cured
Post by: Marks DTM Calib on 05 March 2010, 15:34:50
Kin ell, those injectors are a bit naff......I must admit, they always did look like they had been recovered from used washing machines....
Title: Re: LPG Flat Spot seems to have been cured
Post by: Lazydocker on 05 March 2010, 15:36:46
Quote
Kin ell, those injectors are a bit naff......I must admit, they always did look like they had been recovered from used washing machines....

Yep... Still don't think LPG systems have been perfected and Dual Fuel is always going to be a compromise as the timing needs to be so different for LPG compared to Petrol
Title: Re: LPG Flat Spot seems to have been cured
Post by: Kevin Wood on 05 March 2010, 16:30:05
For comparison, a petrol injector, driven properly, will have sub-1ms open/close times.

Kevin
Title: Re: LPG Flat Spot seems to have been cured
Post by: Martin_1962 on 06 March 2010, 09:35:58
The Romano injectors are plastic and use a flap so are supposed to be quicker and quieter.

They are also OK to use without a filter.

But they do not like going over 2 bar