3.2mm nozzles and 1.8 bar... Would expect the combination to flow way too much gas.
Without re-reading the whole thread, can you see petrol rail pressure in OBD live data? If so: When running on petrol what is frp? / when running on gas what is frp? If there is a big difference in figures (e.g. frp rises by more than say 20%) then you will need to fit a fuel return if you haven't already done so (and before you'll get anything like good results).
I am currently converting a Merc C65AMG 6.5 litre V12 twin turbo, that has been tuned to maybe 800bhp with a wider stainless exhaust, increased boost, etc. But I don't expect to run as high flowing a combination of pressure and nozzles. This model has a return-less petrol system and does read frp, so while I was running Faro between the tanks and the reducers I also ran a petrol pipe from the engine bay back to the petrol tank.. Will see if I need to actually plumb it in but it seems very likely.
I just re-read and noticed you said spuds have only 3.1mm hole - Remove those spuds and fit spuds with bigger hole! As you know, the spuds are the restriction now, but this means your sequential system will become a continuous injection system at higher loads, which will really mess things up.
I expect the OMVL system has been wired incorrectly to petrol injector 1. Do the figures for inj 1 fluctuate as we'd expect (in fact do any/all of them fluctuate)? Do cyl 1 figures read properly when running on petrol? Does the car misfire on cyl 1 on petrol / on gas?
Run a pipeline from that pump over here!
My apologies for not replying before now. Trying to fit too much in as usual...
I've sort of thrown my toys out of the pram with the LPG - or more to the point, got fed up as to why I can't find this flatspot/stutter as it otherwise ran brilliantly on LPG. I'd been meaning to drop the pressure again as per your recommendation, but it really did run well on the configuration as set. I can't increase the 'spuds', as I am running on injector risers.
Actually, the toy throwing was more to the fact the one of the reducers failed at the Le Mans Classic a few weeks back, and it dumped 3.7 bar to the injectors. It took a little while to try and work out why pipes kept popping off. I drove the 700km back on petrol, parked the thing in the garage at work in Germany, and haven't touched it since. We are taking the old Dodge on holiday next week for 5 weeks, so I'll hopefully be motivated to get back on it when we return.
As for the petrol pressure, yes it rises when running on LPG, but may I ask why this causes a problem? Does the engine compensate somehow when the pressure rises?
Have you done a write-up anywhere on the S65 AMG? I would certainly love to read about that and see some pics...
Builder Brad wrote:
nice install on the AMG! I registered on this site so I could post this....
Ive done something similar in my BMW 550i, but wanted to increase the range per fill from what I had on petrol. Managed to get a 120 Litre 4 hole tank in the boot after quite a bit of faffing about.
I have a couple/3 of questions as I think that the only improvement over what I have may be with an AMG.lol. there are a lot of other alternatives that would be better for me, but not viable as the engines are direct injection. natural progression for me would be an M5 as I now have deacent knowlege around car.
is your car the M156 engine?
also, what range do you get on average per l of LPG?
what width and depth is availible in the boot for a large cylinder 4 hole tank? dont know how you put up with a donut tank, as your mpg has got to put you permanantly planning your next fuel stop.
Hi Brad, Yes, it's an M156 engine. It does about 7km per litre on gas when on a run, a heck of a lot less when driving spiritedly! I am running a tiny tank - 51 litre - it will take about 42 litres from empty. The reason for this is that the car has 7 seats, so the rear seats protrude quite significantly into the wheel well. It's a 650x200 tank if I remember correctly. Without the third row of seats, you could easily double the height.
Of course you could fit a huge cylinder tank, but then that would completely defeat the point in having an estate. I reckon it would be a good option in a saloon, as the boot space is really deep.
I fill up every 250km ish, but I don't begrudge that on the UK-Germany commute, as it is currently about 26 pence per litre in Belgium.