LPG Forum


All times are UTC



Post new topic Reply to topic  [ 37 posts ]  Go to page Previous  1, 2
Author Message
PostPosted: Sun Nov 20, 2016 6:26 pm 
Junior Member

Joined: Tue Aug 26, 2014 1:48 pm
Posts: 202
Location: South end of North Yorkshire
Just as an update, I was looking in the workshop manual for something else and found a nice picture of the Gen IV Legacy 2.0 turbo inlet manifold and components. That engine does indeed have tumble generator flaps, with the petrol injectors mounted in the body of these, below the flaps. So any spuds fitted in the inlet manifold would be above the flaps.

_________________
-
2004 Subaru Outback 3.0Rn auto (LPG)
1991 Mitsubishi Pajero 2.5 LWB (WVO)
2008 Volkswagen Caravelle (Diesel)


Top
 Profile  
Reply with quote  
PostPosted: Mon Nov 21, 2016 2:17 pm 
Installer

Joined: Wed Sep 29, 2010 5:01 pm
Posts: 2871
Location: Yorkshire
That might tell a bit of a story Rich! Though on the other thread it's been suggested the flaps are only shifted to aid driveability with a cold engine... A point I'd look further into because flaps low down near the valves could aid with throttle response, particularly on a turbo engine, during other driving conditions too. Throttle valves are near valves on some BMW M engines specifically to make for better throttle response. And even if such flaps don't move the presence could potentially cause problem for gas/air mixture with spuds fitted above them.

Still haven't been given the license file implementation by BRC. I believe the car is now with BRCGB supplier (BRC Ben/Peter) rather than with one of their installers as although the installer managed to considerably improve matters they didn't manage to sort it completely. Could be that BRCGB intend on sorting it before allowing me the software even if that means putting a different (not Seq32) BRC system on it. I'm just standing by in case even then they can't sort it, but I'm pretty sure they will, especially with all the insights given on this thread, Subaru forum thread and in my chats with the owner. 2 Months after original install when I would have converted it job done first attempt, or could have had this install sorted quickly if allowed the software ;-) Would rate my own chances of sorting it above any supplier or manufacturer too. :lol:

Simon

_________________
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240


Last edited by LPGC on Tue Nov 22, 2016 11:56 am, edited 1 time in total.

Top
 Profile  
Reply with quote  
PostPosted: Tue Nov 22, 2016 8:56 am 
Junior Member

Joined: Tue Aug 26, 2014 1:48 pm
Posts: 202
Location: South end of North Yorkshire
Looks like the flaps might only be on post 2006 2.0 turbo models (despite them being shown in my 2004 manual) anyway...

Yes, it seems that they are making some progress with the car now.

_________________
-
2004 Subaru Outback 3.0Rn auto (LPG)
1991 Mitsubishi Pajero 2.5 LWB (WVO)
2008 Volkswagen Caravelle (Diesel)


Top
 Profile  
Reply with quote  
PostPosted: Thu Jan 05, 2017 6:28 pm 
Installer

Joined: Wed Sep 29, 2010 5:01 pm
Posts: 2871
Location: Yorkshire
Got a Subaru Forester 2.5 turbo to convert week after next, which will run perfectly on LPG by the time the owner picks it up, which will be 3 days after he dropped it off ;-)

Simon

_________________
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240


Top
 Profile  
Reply with quote  
PostPosted: Thu Jan 05, 2017 8:41 pm 
Junior Member

Joined: Tue Aug 26, 2014 1:48 pm
Posts: 202
Location: South end of North Yorkshire
I probably ought to bring my Outback back to you for a check over and service at some point! Maybe when the weather's nicer. Quite busy now I've started a new job in Leeds.

_________________
-
2004 Subaru Outback 3.0Rn auto (LPG)
1991 Mitsubishi Pajero 2.5 LWB (WVO)
2008 Volkswagen Caravelle (Diesel)


Top
 Profile  
Reply with quote  
PostPosted: Thu Jan 05, 2017 11:57 pm 
Installer

Joined: Wed Sep 29, 2010 5:01 pm
Posts: 2871
Location: Yorkshire
No probs Rich, have you heard anything else about the Subaru with the issues?
Simon

_________________
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240


Top
 Profile  
Reply with quote  
PostPosted: Sat Jan 07, 2017 11:55 am 
Junior Member

Joined: Tue Aug 26, 2014 1:48 pm
Posts: 202
Location: South end of North Yorkshire
Other than your recent post the thread seems to have dried up on the UKLegacy forums.

_________________
-
2004 Subaru Outback 3.0Rn auto (LPG)
1991 Mitsubishi Pajero 2.5 LWB (WVO)
2008 Volkswagen Caravelle (Diesel)


Top
 Profile  
Reply with quote  
PostPosted: Sat Jan 07, 2017 2:52 pm 
Installer

Joined: Wed Sep 29, 2010 5:01 pm
Posts: 2871
Location: Yorkshire
There has been a more recent flurry of activity on the thread on UKLegacy forum, it looks like things are going from bad to worse.

_________________
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240


Top
 Profile  
Reply with quote  
PostPosted: Sun Jan 08, 2017 6:15 pm 
Installer

Joined: Wed Sep 29, 2010 5:01 pm
Posts: 2871
Location: Yorkshire
But things may be looking up...
TinleyTech wrote:
BRC GB (the uk importer) were recently liquidated but we are now taking care of BRC distribution in th UK.

_________________
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240


Top
 Profile  
Reply with quote  
PostPosted: Mon Jan 09, 2017 12:30 pm 
Installer

Joined: Wed Sep 29, 2010 5:01 pm
Posts: 2871
Location: Yorkshire
This will be the first day of business that TinleyTech have been official distributors of BRC equipment (taking over from BRCGB), but I emailed them about the software an hour ago and they have already sent me a license file that works. So now I have the software! That's another 100 Brownie points to Tinleytech in my book. :-) Will have to withdraw negative stuff about BRCGB, besides any none work issues I was told key members of staff had to deal with it's now also obvious they will have had a lot of work stuff to deal with too.. and they were good with me in the past.

Cheers again Tinleytech.

Simon

_________________
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240


Top
 Profile  
Reply with quote  
PostPosted: Fri Jan 13, 2017 4:24 pm 
Installer

Joined: Fri Oct 21, 2005 7:56 pm
Posts: 2574
Location: North Wales
Good to hear brc are now in good hands.

_________________
http://www.classicswede.com/
http://www.classicswede.co.uk/LPG/cat17 ... 10800.aspx

LPG installer Anglesey North Wales

DIY LPG Kits

07824887160


Top
 Profile  
Reply with quote  
PostPosted: Sat Jan 14, 2017 8:52 pm 
Installer

Joined: Wed Sep 29, 2010 5:01 pm
Posts: 2871
Location: Yorkshire
classicswede wrote:
Good to hear brc are now in good hands.
Sorry to hear of BRCGB going and I wish everyone there all the best, they were good with me but their policies didn't seem to make much sense in recent times. Now that I've said that and got it out of the way, I couldn't agree with you more mate.

But in a weird way I will almost miss the cloak and dagger, closed shop supply, 3 tier dealer network, don't tell anyone we're giving you special treatment type stuff. It will seem strange for a while buying BRC stuff from the official UK supplier without any of that kind of thing.

Prins next please Tinleytech :wink: Then the BS will just about be cleared completely.

Simon

_________________
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240


Top
 Profile  
Reply with quote  
PostPosted: Wed Mar 29, 2017 3:03 pm 
Installer

Joined: Wed Sep 29, 2010 5:01 pm
Posts: 2871
Location: Yorkshire
Below I pasted a post I just did on this subject on Legacy forum. Can't see the pics due to copying and pasting and the way the other forum works with pics but I'll sort the pics out later. Meanwhile the post on Legacy forum can be seen here http://www.uklegacy.com/forums/index.php/topic/143724-jdm-spec-b-lpg-help/page-6

Haven't had much time to do a write-up since I had Jamie's car, due to having all my usual work to do plus messing with the gearbox on my own car (seems the autobox pump has gone or there's some major internal leak), plus helping my son change the front struts and hubs on his Mondeo and having to repeat because the CV joints pulled apart during the work.

I had Jamie's car for a few days, didn't manage to fix the problem but did identify the underlying issues and am confident I could fix it if we were to change the LPG ECU, possibly also injectors.

There was also a shortfall with the physical install that I did put right - The installer had fitted 'spuds' (gas entry points on the inlet manifold) in too high a position, at least a couple of inches above the petrol injector position. For accurate fuelling and good throttle response, particularly at low rpm, it is necessary to fit spuds as near as possible to the petrol injectors and to have short pipe runs between LPG injectors and spuds. I blanked the existing spud positions and fitted a different type of spud a couple of inches lower down on each manifold port runner right beside each petrol injector and doing so also allowed some of the pipes between LPG injectors and spuds to be shortened, one pipe in-particular to be shortened drastically. Most spuds are just a hollow fitting that screws into a drilled/tapped hole in the manifold, the different type of spuds are similar but the very end of the spud where the gas would usually exit is blanked off, gas instead comes out of the side of the end of the spud and this allows gas to be aimed towards the engine's inlet valves. I regard the shortfall with spud location as a very basic underlying issue, spuds should have been fitted much lower at the time of installation... But failing that, any issue such as hesitation during acceleration at low RPM that Jamie described should have prompted installers to move the position of the spuds to the lower position because such issues are classic symptoms of installing spuds too far from petrol injectors.

However, the main problem with Jamie's setup is that the engine momentarily goes too rich on sudden acceleration at low rpm. It seems the last person to adjust settings on Jamie's car realised this and attempted to compensate/lean fuelling under these conditions by adjusting 'tip-in' settings in the software to a largely negative value. Tip-in is a BRC software handle for compensating fuelling during acceleration, at all times the LPG ECU refers to it's basic calibration 'map' (the map itself can be adjusted by the installer) so tip-in is a fiddle factor that sees the LPG ECU combine the basic map and tip in settings to arrive at pulse time for the LPG injector during quickly increasing engine load... This implies that tip-in can be used as a fudge factor to momentarily correct mixture during acceleration even if the basic underlying map is incorrect... Emphasis here on that last point, because it does seems to me that the basic underlying map is incorrect, I found I could improve that hesitation during acceleration at low rpm by leaning the underlying map, however Jamie's ECU does not allow good control over the underlying map, the control you do have is just a few sliders that can be adjusted and these sliders have global effect on the map. There is a slider for idle mixture control which effects low load/rpm mixture and there is a slider that effects mixture under none low load/low rpm conditions. Some of the various problems with this, particularly in Jamie's case, are that the issues occur at the transition point from one slider to the other, so for starters you've got to adjust both main mixture sliders to overcome the hesitation during acceleration at low rpm issue. Then, considering the sliders have global effect on mixture, if you adjust the sliders in attempt to correct the hesitation you cannot avoid effecting mixture during other driving conditions that you wouldn't want to effect (because during other conditions mixture appears to be correct).. at best this would result in fuel trims being inconsistent (if they were consistent before) and at worst you can end up with MIL light issues due to fuel trims out of range, too lean a mixture during WOT conditions not good for the engine.

Observations and reading between the lines - 1. Like some other BRC systems this system is calibrated using a manifold pressure sensor that is only attached during the calibration stage, during which time it learns to anticipate what manifold pressure will be during all the varying driving conditions (after the map sensor is removed). Like most LPG systems it needs to know what manifold pressure is in order to know the difference between gas pressure and manifold pressure (like other BRC systems this system calls difference between gas pressure and manifold pressure delta pressure). Gas pressure on all vapour type sequential LPG systems (including this system) is directly measured, most systems directly measure manifold pressure too (above I described how this system doesn't directly measure it but anticipates it). Most LPG systems, including this system, need to know delta pressure because for any given LPG injector pulse length that injector will flow more gas if delta pressure is higher, so systems need to compensate LPG injector pulse length for delta pressure, even for slight/momentary fluctuations to delta pressure. The potential problem here is that if the system does not correctly anticipate manifold pressure it cannot properly compensate LPG injector pulse length for delta pressure. Now suppose a system that has learned to anticipate manifold pressure seems to have generally done a good job of learning, this is verifiable because if we trust the reducer to keep manifold pressure constant above manifold pressure we can check this by just watching delta pressure, if delta pressure behaves like we expect during various driving conditions (i.e. remains the same) then it is likely that manifold pressure has been learned properly... However, this may still leave question marks about accuracy of anticipation of manifold pressure during quickly changing manifold pressure and in fact monitoring pressures (directly read, ECU anticipated and calculated delta) in the scope facility built into the LPG software does seem to reveal some pressures that I wouldn't expect during quickly changing pressure situations. 2. The system seems to be designed to be very plug n play but it doesn't seem to offer the type of control over fuelling that is possible using other systems (particularly some systems). Seems to learn the underlying map during it's 'autocal' stage and then present the installer with only the few slider handles to effect control over the underlying map that I mentioned in the paragraph above. Any system that relies on autocal to get the basic shape of an underlying map correct will struggle on certain vehicles, most particularly on vehicles that have very short petrol injector pulse lengths, mostly because LPG injectors take far longer to open and close than petrol injectors.. Most engines idle with pinj (petrol injector pulse length) of around 3ms (milliseconds) at idle with a warmed engine, if an LPG injector takes 1ms longer to open and flow fuel than a petrol injector then if the LPG injector (at it's provided delta pressure) flows the same as the petrol injector while open then for same flow as the 3ms pinj, ginj would need to be 4ms, so the underlying map at the 3ms pinj point would need to multiply the 3 by 4/3 = 1.33. For this same average engine with same spec injectors and same delta pressure, for 10ms pinj, ginj would only need to be 11ms which would mean a multiplier at the 10ms point of only 1.1... From this we can imagine a graph of the necessary multiplier going all the way from say 2ms (engine very light load on over-run) to around 16ms (engine torque peak). The graph would be curved, it would start at a low multiplier figure for very low pinj's (because the LPG injectors, once starting to open, also take time to close), would peak somewhere maybe at around 3.5ms, then would fall off at a diminishing rate, so we end up with a multiplier graph that looks a bit like a stretched out sine wave. This multiplier graph is what I am terming in this post as the shape of the underlying LPG map.. Installers normally have direct control over the shape of this map but do not have the same control over the shape of this map on this system, instead we just have the sliders which in simple terms lower or raise entire sections of the map. So suppose Jamie's engine idles at 1.8ms pinj, so if we use the same 1ms slower LPG injector spec that we used in the example for normal engine above, we might expect Jamie's ginj to need to be 2.8ms and multiplier of 2.8/1.8 = 1.56 but the multiplier would still need to be 11/10 = 1.1 at the 10ms pinj point of the map and 17/16 = 1.06 at torque peak. On overrun Jamie's engine might go down to pinj of 1.4ms and due to open/close time of LPG injectors at 1.4ms multiplier may need to be 2 or may need to be less than 1, regardless of which the shape of the map will be very different to what it would be on a normal engine. It may be that the autocal would get the basic shape of the map just about right on a normal engine but get it very wrong on Jamie's engine. Without getting too technical, the point to draw/conclude from this is that engines which use very short pinj's are much more demanding in terms of LPG components spec, much more demanding to calibrate properly (sliders to control fuelling not enough control, especially if autocal anticipated incorrect shape of the underlying map), some injectors (those that are not quick enough to open and close) would have little chance of doing a decent job at all because they would make it necessary to compromise drive-ability on LPG at low loads at one extreme against ability to run at high engine loads on LPG at the other extreme (consider what shape of map would have to be if LPG injectors took 3ms to open/close and couldn't accurately meter fuel below 3ms pulse time.. 4.4/1.4 at idle = multiplier of 3.14, 19/16 at full load = 1.19 but this would restrict ability to provide rich enough mixture at high rpm flat out because 19ms is longer that it takes the engine to complete a 4 stroke cycle at high rpm, so for high rpm full load we would have to increase pressure, but increasing pressure would mean that at idle LPG injectors would need to pulse below the minimum duration at which they could accurately meter fuel - a problem here would be the type of LPG injectors regardless of ECU). BRC injectors aren't bad in any of these respects but are not what I would have selected for this install, one of their drawbacks is that they are on rails of 2 so even if the rail could be sited between the 2 port runners on one side of the engine pipes between injectors and spuds will be longer than would be possible using single injectors that are not on rails but could be mounted almost directly onto the spud. I reckon that limitations with the ECU is the aspect that is preventing all the issues being cured.

Few pics

Original arrangement on driver side with inlet air ducting and water header removed.


20170322_115506_zpsot1p0urk.jpg

new nozzle position and pipe length cut down

20170322_130009_zpsfazw2ryr.jpg

original type spud

20170322_130456_zpsyhv0bxx2.jpg

spud type I fitted lower down

20170322_121441_zpsxdsnlzv1.jpg


passenger side

20170322_124922_zpsr3ty2cpg.jpg


I think I took a screen shot showing pressure response, if I find it I may post it here



SImon

_________________
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240


Top
 Profile  
Reply with quote  
PostPosted: Thu Mar 30, 2017 6:46 pm 
Junior Member

Joined: Tue Aug 26, 2014 1:48 pm
Posts: 202
Location: South end of North Yorkshire
I read it on UKLegacy and it does seem in part to confirm what we suspected early on - that the spuds are too high and that the specific BRC ECU isn't best suited to the Subaru twinscroll (or maybe any) turbo engine. Similarly with SteveGT's over on that forum too.

_________________
-
2004 Subaru Outback 3.0Rn auto (LPG)
1991 Mitsubishi Pajero 2.5 LWB (WVO)
2008 Volkswagen Caravelle (Diesel)


Top
 Profile  
Reply with quote  
PostPosted: Fri Mar 31, 2017 10:33 am 
Installer

Joined: Wed Sep 29, 2010 5:01 pm
Posts: 2871
Location: Yorkshire
Pretty much it, Rich.

Just to clarify, I did fit spuds lower.

Won't be so much directly related to the twin-scroll that is preventing it working properly, but indirectly / by implication, because the twin scroll idles at only 1.8ms.. A lot of 4 cylinder Subaru's have pinj at near 2.5ms at idle, what we'd usually expect for a turbo engine or a high revving engine, regardless of whether the Subaru model is turbo'd or normally aspirated, but the twin scroll idles at that lower still 1.8ms... There is no reason why it had to be like that due to it being twin scroll, but it is! Probably to allow for big power increases via chip tuning etc without having to raise petrol pressure of fit bigger injectors. There probably isn't an LPG system autocal facility made that would anywhere nearly anticipate correct shape of the map for an engine that idles at 1.8ms, but any related issue here may be compounded by the manifold pressure anticipation with this system too. Not even good enough enhancing manifold pressure anticipation by reading airflow meter readings either (which this system is capable of), especially on a turbo, because airflow on input side of turbo can raise much more quickly than manifold pressure due to longer total inlet tract length and the turbo sat in the middle complicating matters. I've said before on this forum on threads about other LPG system ECUs that if you need to start using features such as acceleration enrichment/leaning (tip-in) it is probably because you got some other aspect of the install wrong, such as manifold pressure sensor pickup location wrong or the shape of the map wrong... this system doesn't have a manifold pressure sensor and won't let you manually change the map in a specific area without also effecting the map pretty much as a whole.

Simon

_________________
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240


Top
 Profile  
Reply with quote  
PostPosted: Fri Mar 31, 2017 8:24 pm 
Junior Member

Joined: Tue Aug 26, 2014 1:48 pm
Posts: 202
Location: South end of North Yorkshire
I guess what I was getting at is that the Gen IV Legacy engines were when Subaru started to make some effort to improve fuel economy and reduce emissions, so the introduction of the twinscroll turbo (rather than the sequential twin turbo on the Gen II and III), swirl flaps, variable valve timing (and lift on some engines such as the six cylinder 3.0), secondary air injection on the 2.0 and so on. So I wonder perhaps that as electronics and petrol injectors got faster, then the opportunity to have very short injector pulse durations was one way of achieving those reductions in petrol use and emission. And Subaru have always had a fondness for high flow, short duration injectors :)

_________________
-
2004 Subaru Outback 3.0Rn auto (LPG)
1991 Mitsubishi Pajero 2.5 LWB (WVO)
2008 Volkswagen Caravelle (Diesel)


Top
 Profile  
Reply with quote  
PostPosted: Mon Apr 03, 2017 11:21 am 
Installer

Joined: Wed Sep 29, 2010 5:01 pm
Posts: 2871
Location: Yorkshire
You'll know more about evolution of Subaru vehicles than me, Rich!

Can only offer a few thoughts that touch on some of the basics.. I think from an emissions standpoint, fuel droplet size is important to most manufacturers because the smaller the droplet size the better the fuel atomisation. Small droplet size depends on fuel pressure and injector nozzle size, the higher the pressure and smaller the nozzle the better the atomisation, usually good for HC emissions. Points to consider would be combination of pressure and nozzles great enough to allow rich enough fuelling at full engine load while allowing enough time for injectors to completely close before being opened again for the next induction cycle (duty cycle), the idle pinj just corresponding to the fraction of the full load pinj that correct mixture for idle dictates. If these are the only points to consider then if pinj duty cycle would give room for the injectors to be pulsed for longer when the engine is at full load, then injector nozzle size could be decreased to allow for better fuel atomisation (rather than lowering fuel pressure - higher pressure through small nozzle gives smaller droplets than lower pressure through bigger nozzle) .. this will be why most engines with red line at around 6000/6500rpm idle at 3ms and go to 16ms and why most moderately boosted engines idle at maybe 2.5ms and go to 16ms. If peak RPM remains the same, peak pinj can remain the same, if peak rpm increases then peak pinj has to decrease to avoid overshooting pinj duty cycle window, if peak rpm stays the same but boost pressure increases idle pinj is usually lower because (again) idle pinj is just the necessary fraction of peak pinj. Fuel pressure is usually around 3 or 4 bar because this is what manufacturers can make work reliably, not too high to cause problems with leaks or with petrol injector reliability, not too low to allow vapour locks to form during heat soak. Other factors can effect idle pinj such as atmosphere rather than manifold pressure referenced petrol pressure but if a manufacturer chooses petrol injectors and fuel pressure that don't approach 100% dc when the engine is at full load it may be because they have another agenda... such as allowing headroom for future performance upgrades, fitting engines that make different amounts of power with the same injection system (so standardisation), maybe they don't want fully atomised petrol for some reason, maybe the engine benefits from shorter pinj if it features VVT. On that pressure / nozzle size / atomisation point again, if we had twice the pressure and half the nozzle size it might seem atomisation could be better... but if these even smaller droplets are fired into a port where the air isn't moving because the inlet valve is closed and engine is at low rpm the fuel may just hit the port wall opposite the petrol injector so not end up being so well atomised as with injector firing for a different length of time, therefore turning out to be a negative for atomisation.. brings us back to the take advantage of as near 100% pinj dc while the engine is at full load point again. So I dunno why idle is 1.8ms on this spec engine, other than what I've said above would probably need to ask a Subaru engineer. Nearly forgot to mention one last thing, petrol injectors are generally very quick to open and close, can pulse them for 0.5ms and they seem to work pretty accurately so I dunno if some modern development has allowed them to use idle pinj of 1.8ms.

Simon

_________________
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 37 posts ]  Go to page Previous  1, 2

All times are UTC


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group