mikec Posted October 21, 2012 Share Posted October 21, 2012 Hi I'm just looking into megasquirt as a possible future option. If I fitted it, it'd be onto a 4.6, now the thing that bothers me is the lpg side of it. Say I fit megasquirt onto the car, then feed the gas with a mixer in the intake, the way I see it is I'm no better off in regards to power and the restriction a mixer causes, than my other option of running megajolt along with a webber carb and sprintgas mixer? Am I right on this? Just wondering how everyone else is doing it? The ideal option I'd think would be lpg injection but from what I can gather ms1 can only handle 2 channels of 6 injectors?? So that'd leave ms2/3 to go that route?? Cheers in advance mike Quote Link to comment Share on other sites More sharing options...
zoltan Posted October 22, 2012 Share Posted October 22, 2012 I have a 3.5 EFi V8, MS1 with Edis and a Blos Propane carb. I can't detect any drop in power between LPG and petrol. I use switch maps in the ECU so I have two different maps for ignition for each fuel. I have had this setup for about four years with no issues Here is a picture of the setup, for some reason I can't do anything other than post a link Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted October 22, 2012 Share Posted October 22, 2012 I've megajolted and BLOS carbed a ex-RPI 3.9V8, it goes like stink, no noticeable difference in power between the two fuels, and yes I use switchable maps between the fuels. On a very heavily (and heavy! 2x LPG tanks) modified 90 running 34" mud tyres, autobox, cage etc it gets 11MPG, and the driver has a lead foot EDIS in the engine bay, MJ on the passenger dash, simple to wire up and plumb in. If going LPG, I would do the same again, Hotwire EFI, with a plenum of your choosing, MJ+EDIS, switchable maps and a BLOS carburettor. If you off-road a lot, LPG injection systems that are out there do not have the same waterproofing as a good MS install... Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 22, 2012 Share Posted October 22, 2012 If you run the LPG through a mixer then yes that restriction remains, but you do get some gain on petrol from fuel injection vs carbs, and presumably would see similar gains on the LPG side too if you went LPG-injection. Quote Link to comment Share on other sites More sharing options...
mickeyw Posted October 22, 2012 Share Posted October 22, 2012 Colin, are you running open or closed loop? Just looking for a stepper motor mixture control in your photo. That's a nice tidy engine bay. Pretty sure Quagmire runs MS & LPG, maybe he'll be along soon. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted October 22, 2012 Share Posted October 22, 2012 If you run the LPG through a mixer then yes that restriction remains, but you do get some gain on petrol from fuel injection vs carbs, and presumably would see similar gains on the LPG side too if you went LPG-injection. Yup, also the BLOS stated above has an equivalent of something like a 45mm choke size, much much larger than the more traditional mixer systems(biggest I have seen is 38mm), I really do recommend them: http://www.ebay.co.uk/itm/BLOS-Propane-Carb-LPG-Mixer-Replacement-Performance-and-Economy-LOOK-/320995833421?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item4abcd7b64d It's variable venturi, so much more like a carb, than just a bucket, like regular mixers. Get a blowback valve as well and mount before the BLOS, the one he sells fits straight to the RV8 plenum. Quote Link to comment Share on other sites More sharing options...
mikec Posted October 22, 2012 Author Share Posted October 22, 2012 I have a 3.5 EFi V8, MS1 with Edis and a Blos Propane carb. I can't detect any drop in power between LPG and petrol. I use switch maps in the ECU so I have two different maps for ignition for each fuel. I have had this setup for about four years with no issues Here is a picture of the setup, for some reason I can't do anything other than post a link Nice setup, same colour as my 90. Quote Link to comment Share on other sites More sharing options...
mikec Posted October 22, 2012 Author Share Posted October 22, 2012 Yup, also the BLOS stated above has an equivalent of something like a 45mm choke size, much much larger than the more traditional mixer systems(biggest I have seen is 38mm), I really do recommend them: http://www.ebay.co.uk/itm/BLOS-Propane-Carb-LPG-Mixer-Replacement-Performance-and-Economy-LOOK-/320995833421?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item4abcd7b64d It's variable venturi, so much more like a carb, than just a bucket, like regular mixers. Get a blowback valve as well and mount before the BLOS, the one he sells fits straight to the RV8 plenum. I'd seen the blos "carbs" they look ok but still reduce the width of the intake by a third, obviously this is only really going to be a problem if the engine needs the full width of the intake anyway. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted October 22, 2012 Share Posted October 22, 2012 Agreed, it is far less than a normal mixer though Failing that, get an SD1/twin plenum and you can fit two, good for 400+BHP then Quote Link to comment Share on other sites More sharing options...
Quagmire Posted October 22, 2012 Share Posted October 22, 2012 Right, I run LPG on my daily driver which is a 3.5 (9.35:1) powered 90. My findings have been thus over the past 3-4 years: First configuration was twin SU's with mixer plates running open loop. - Ran ok, smooth and seemed quick (although I did change from a 2.25 so anything seemed quick then). Ignition was advanced on the dizzy as far as possible so that it would just ping/pink on heavy load on petrol. Then I fitted Megajolt which gave me the option of map switching and allowed me to run more advance on gas whilst retaining proper timing on liquid gold. Things got better- it wasn't rough before, but somehow it seemed smoother and pulled much better (on both fuels). Starting became much better too and it got a bit more economical. Then I fitted closed loop to the LPG, basically a lambda sensor that drove a stepper motor on the gas side (via a box of tricks)- constantly aiming for 14.7:1. This improved consumption and I was hitting heady highs of 17mpg on long runs. Then I fitted a wideband, and started to realise how off my fuelling was, particularly under load. The closed loop control box died and I went back to open loop, tuned with the wideband as best as I could. Then I fitted Megasquirt in place of the Megajolt. No change (obviously) as still running carbs. Fitting it ignition only did give me a chance to get all my wiring up and running and sensors reading correctly- including the wideband. Couple of months ago I fitted a flapper top end and went efi on petrol. This is running lpg through a mixer ring on the plenum throat. Looking at the restriction I was worried it would be strangled compared to the carbs, however I need not have worried! It now goes MUCH better on both fuels - especially petrol. Revs more freely and is generally much more fun to drive. Result! Next step is to fit a later hotwire manifold (just so I have more choice of injectors) and I am planning to pre-drill this for lpg injection nozzles prior to fitting which I will blank off for now. When time and funds allow, hopefully in next month or two I will see if I can get gas injection going. *edit- using the mixer ring (as recommended by Tinley tech) I am getting a WOT reading of around 93kPa, so you can see it does cause a restriction Quote Link to comment Share on other sites More sharing options...
mikec Posted October 22, 2012 Author Share Posted October 22, 2012 Cheers for the info, that's what I'm running now su's and mixer plates. So how are you looking at running the lpg injection? I made the mistake of flogging my lpg injection kit on the motor I bought oops! It puts my mind at rest a little but I still think its a little step backwards, ms and lpg injection is defo the way forward. In fact thinking about it, is there any reason a "normal" lpg injection system fitted to a ms powered car wouldn't work and just use ms to power the ignition? Along with the emulators etc? As the complexity seems to come from ms1 controlling lpg injectors as well? Quote Link to comment Share on other sites More sharing options...
mikec Posted October 22, 2012 Author Share Posted October 22, 2012 I have a 3.5 EFi V8, MS1 with Edis and a Blos Propane carb. I can't detect any drop in power between LPG and petrol. I use switch maps in the ECU so I have two different maps for ignition for each fuel. I have had this setup for about four years with no issues Here is a picture of the setup, for some reason I can't do anything other than post a link What's the Lucas box bolted to the heater? Quote Link to comment Share on other sites More sharing options...
zoltan Posted October 22, 2012 Share Posted October 22, 2012 Colin, are you running open or closed loop? Just looking for a stepper motor mixture control in your photo. That's a nice tidy engine bay. Pretty sure Quagmire runs MS & LPG, maybe he'll be along soon. My nice clean engine bay didn't last long. A day in fact Mine is running open loop. It stays around Lambda 1 throughout the rev range so I didn't feel the need to complicate it any further Quote Link to comment Share on other sites More sharing options...
zoltan Posted October 22, 2012 Share Posted October 22, 2012 What's the Lucas box bolted to the heater? Resistors for the injectors. I lifted the engine and loom from an '83 RR 3.5 EFi and patched the Megasquirt ECU loom into that. The wiring is a bit of a mess in hindsight but it hasn't given me any grief so I have left it well alone. Quote Link to comment Share on other sites More sharing options...
Quagmire Posted October 22, 2012 Share Posted October 22, 2012 Mike - do you mean splicing in the LPG injection kit as you would on a "normal" car? i.e. the LPG ecu taking direction from the MS ECU with the MS blissfully unaware that it is infact running LPG? That should work I guess. I am going to try MS driving both sets of injectors natively as it were. Am yet to figure out the best way. Biggest problem as far as I can see is how to drive16 injectors (I was going to cut the +12v supply across with a relay) and that pressure differences on the LPG supply can make big differences to the fuelling, and not sure how to get around that. Some LPG injector rails have pressure sensors, so thought perhaps I could add an extra input to the MS and do something that way... All just a brain fart at the moment though. Quote Link to comment Share on other sites More sharing options...
Quagmire Posted October 22, 2012 Share Posted October 22, 2012 What's the Lucas box bolted to the heater? Thats a resistor pack for flapper type (low-z aka low impedance) injectors. Quote Link to comment Share on other sites More sharing options...
mikec Posted October 22, 2012 Author Share Posted October 22, 2012 Resistors for the injectors. I lifted the engine and loom from an '83 RR 3.5 EFi and patched the Megasquirt ECU loom into that. The wiring is a bit of a mess in hindsight but it hasn't given me any grief so I have left it well alone. Ah ok cheers Mike - do you mean splicing in the LPG injection kit as you would on a "normal" car? i.e. the LPG ecu taking direction from the MS ECU with the MS blissfully unaware that it is infact running LPG? That should work I guess. Yeah that's what I was thinking. Again I don't k ow enough/anything about ms to know if it'd work or not. It sounds good to me though, leaves a good ignition setup, maybe not ideal LPG fuelling but surely better than a mixer? I am going to try MS driving both sets of injectors natively as it were. Am yet to figure out the best way. Biggest problem as far as I can see is how to drive16 injectors (I was going to cut the +12v supply across with a relay) and that pressure differences on the LPG supply can make big differences to the fuelling, and not sure how to get around that. That would be ideal, but as I see it ms1 won't do so many injectors so it's have to be ms2/3?? With regards to the pressure of the LPG varying I'm sure I read somewhere that is why they have special vapourisers for LPG injection, where I read it though could be anywhere I've googled that much lately! Cheers again guys Quote Link to comment Share on other sites More sharing options...
task Posted October 22, 2012 Share Posted October 22, 2012 See, I've been giving this some thought lately. I have a tuned 4.6 with a SGI injected LPG kit (no lambda control) that's running along side my re-mapped hotwire system. I've been thinking about megasquirt or at least megajolt for a while, seems like a nice winter project. I will most likely just go Megajolt though. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 23, 2012 Share Posted October 23, 2012 That would be ideal, but as I see it ms1 won't do so many injectors so it's have to be ms2/3?? MS2 is just an MS1 with a different CPU. If you switch the injector supplies with a relay the MS will drive 8+8 (8 at any one time) no problem. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted October 23, 2012 Share Posted October 23, 2012 I just had a though as to how to get LPG,which requires no cold start enrichment working on MS, just stick a relay on the coolant temp sender which either gives the true engine temp, or a fixed engine temp (is it 800 Ohms?) equivalent to ~90C, which means you get no fuel enrichment. That would work, wouldn't it? LPG pressure is set by the reducer, which should remain constant for a given demand level, don't fiddle with this during tuning and I expect it should be fine, just tune to the LPG pressure supplied. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.