l320 reducer options?

[mgrover]

so it seems i have 2 brc mb1500 reducers that struggle under hard acceleration. would it be better to replace them with something like https://www.ebay.co.uk/itm/123489244925 and use the additional outlet? ive refurbed one of the reducers but since they are both rated at 188bhp doesn't that mean they'll never actually be able to satisfy the cars requirements(385bp)

[Themoog]

What a coincidence.. Our L320 supercharged has two reducers (see other thread) and I've noticed that if I hoof it the engine stutters and seems to be starved of fuel - not that I do it very often.
It would seem we have a similar problem.

[LPGC]

@mgrover In practice there isn't much difference in using 1 outlet or 2 outlets on the MJ reducers. The MJextra is rated at 450hp but real world will probably do 400bhp, still good because other reducers rated at over 400bhp will also only flow about 400bhp while the MJextra is more pressure stable under load and pressure can be adjusted over a wider range (1 bar to 1.7 bar) than most. There's also the tank valve and tank to engine bay piping limitation which particularly in cold weather (tank pressure low) can be as much of a limitation as reducer flow rate.

@Themoog Are you still having the same problems you had on this thread viewtopic.php?t=15399 ?

[Themoog]

Yep still having the problem. Some lpg specialist in Stevenage said they will take a look but I havnt had the time to sort it at the moment. If I drive it from cold I just stop and restart the engine after 5 min or so and its OK.

[mgrover]

@mgrover In practice there isn't much difference in using 1 outlet or 2 outlets on the MJ reducers. The MJextra is rated at 450hp but real world will probably do 400bhp, still good because other reducers rated at over 400bhp will also only flow about 400bhp while the MJextra is more pressure stable under load and pressure can be adjusted over a wider range (1 bar to 1.7 bar) than most. There's also the tank valve and tank to engine bay piping limitation which particularly in cold weather (tank pressure low) can be as much of a limitation as reducer flow rate.

@Themoog Are you still having the same problems you had on this thread viewtopic.php?t=15399 ?

perfect, I'll order a MJextra and hook the sucker up. I assume after that I'll have to recalibrate.

[LPGC]

Before removing check (in software) what the expected pressure is and what the actual pressure is when the engine's running on gas. Yes it's a good idea to re-calibrate.

[mgrover]

I ordered from tinley tech but they were out of stock. They suggested this instead https://tinleytech.co.uk/shop/lpg-parts ... e-reducer/ definitley seems like it'll hold up? is it worthwhile or what?

[LPGC]

Besides the flow capability of the reducer it also needs to be able to output the pressure that the BRC system (the combination of injector flow and pressure) expects in software settings.
The original BRC reducers on your car will have been factory set to either 1.2 or 1.5 bar but are capable of being set to higher pressure (and be fairly pressure stable and reliable at standard or higher pressure).
Check in software what pressure the system expects to be working at. Especially if that pressure is higher than 1.5 bar I'd advise the MJex over the KME.

[mgrover]

the systems kinda a frankenstein, from what I can tell tis BRC injectors, but the BRC ecu has been stripped out in favor of a AC Stag ECU. So my plan is to get a diagnostics wire and see whats going on in the software, but would the best thing to do is basically drive it like a loon and see what the requirements are?

[Gilbertd]

Once you've got a laptop connected, that's when you need to drive it like you stole it and you'll be able to see the problem.

[mgrover]

so when I drive it like I stole it either its low pressure, around 0.2-0.6, or its high pressure, 3 was the highest I saw it at. then obviously the system freaks out at low pressure. the kme one has arrived. not sure if itll be able to keep up with 3 bar given it was advertised at 1.7 bar. or will getting two of them sort me out?

I'll upload a video of the run and maybe you guys can understand more than me...who am I kidding ofc you will am a complete noob at this.

https://www.youtube.com/watch?v=xQjC2pmuutM

2:00 is the first run
another run at 5:15
i switched to petrol at 6:30 ish because it start to run rough after slowing down from a run

also the car seems to be turning on from cold on lpg, is that normal? the old ecu used to wait till it warmed up.

i might do an auto calibration to see what gains come out of it in terms of stability.

[LPGC]

Plenty to note from the vid, e.g....

At 6mins when you give the car some stick (1.5 bar manifold pressure reading so it's under boost conditions) the gas temp reading falls to 0 which is too cold.

Seems you have Stag Qbox electronics. Qbox has it's gas vapour temp sensor built into it's inline pressure sensor, so the 0deg gas temp reading is probably accurate (although having said accurate it's reading seems buffered by the ECU because I would expect actual temp change to be quicker than rate of change readings reflect... so probably accurate eventually but a bit slow to respond).

Reducer temp reading seems unusually stable for the range of engine loads and range of gas vapour temps, usually with falling gas temp the reducer itself will also get cooler even with really good hot water flow. Have you swapped in the KME reducer yet (and if so have you used the temp sensor on the reducer)? If not (and because the BRC reducers use a different spec temp sensor) it seems as though the installer has got around the incompatible (BRC) reducer temp sensor issue by plumbing in a water temp sensor somewhere else in the system... in which case the reducer temp readings you're seeing are not the reducer temp but the car's coolant temp, the reducer may be running cooler than readings suggest and this could be most of your problem (too cold reducer won't be able to turn enough liquid gas into vapour at high loads).

Poor running following booting it is probably a combination of a few problems but the worst problem is the high pressure. I expect the continued high pressure following booting it is due to the reducer being too cold (outputting partial liquid gas into the vapour lines where it will evaporate to form high pressure vapour) due to poor coolant flow through the reducer. The initial high pressures following booting it will be due to no 'pressure letting off' being set up in software (without checking probably under the advanced settings tab), if you find this option enable it and set it to 2.5bar.

If you can smell gas during or after booting it and have fitted the KME reducer it could be because some KME reducer designs feature a built in over pressure relief valve set to around 3 bar... So for example if the reducer is set to output 1.5 bar gas pressure above manifold pressure and manifold pressure itself reaches 1.5 bar under boost conditions the reducer will be outputting gas at 3bar absolute pressure during boost conditions sailing close to opening the over pressure relief valve. Some KME designs have a discrete prv on the reducer, (in which case it will open whenever pressure is 3 bar relative to atmosphere), some designs combine the prv with the vacuum port (in which case it will open whenever pressure is 3 bar relative to manifold pressure, thus also effecting engine mixture). You may have noted KME make 'turbo' spec reducers. Some reducers such as MJ don't feature a prv so won't vent gas to atmosphere or manifold in case of high pressure during and/or following booting a turbo engine.

To ensure good coolant flow through any reducers fitted on an L322 supercharged (and most other vehicles for that matter) it's necessary to fit the reducer(s) lower than the highest part of the cooling system and preferably below expansion tank water level. L322's also feature heater matrix water control solenoids in the rear nearside of the engine bay, these solenoids can restrict (even fully shut off) flow of water through the heater matrixes (2 heater matrixes on an L322) so the reducers have to be plumbed in such as way (parallel with the matrix's and on the engine side of the solenoids) to esnure they get a flow of hot water regardless of what the heater system is doing.

[mgrover]

Plenty to note from the vid, e.g....

At 6mins when you give the car some stick (1.5 bar manifold pressure reading so it's under boost conditions) the gas temp reading falls to 0 which is too cold.

Seems you have Stag Qbox electronics. Qbox has it's gas vapour temp sensor built into it's inline pressure sensor, so the 0deg gas temp reading is probably accurate (although having said accurate it's reading seems buffered by the ECU because I would expect actual temp change to be quicker than rate of change readings reflect... so probably accurate eventually but a bit slow to respond).

Reducer temp reading seems unusually stable for the range of engine loads and range of gas vapour temps, usually with falling gas temp the reducer itself will also get cooler even with really good hot water flow. Have you swapped in the KME reducer yet (and if so have you used the temp sensor on the reducer)? If not (and because the BRC reducers use a different spec temp sensor) it seems as though the installer has got around the incompatible (BRC) reducer temp sensor issue by plumbing in a water temp sensor somewhere else in the system... in which case the reducer temp readings you're seeing are not the reducer temp but the car's coolant temp, the reducer may be running cooler than readings suggest and this could be most of your problem (too cold reducer won't be able to turn enough liquid gas into vapour at high loads).

Poor running following booting it is probably a combination of a few problems but the worst problem is the high pressure. I expect the continued high pressure following booting it is due to the reducer being too cold (outputting partial liquid gas into the vapour lines where it will evaporate to form high pressure vapour) due to poor coolant flow through the reducer. The initial high pressures following booting it will be due to no 'pressure letting off' being set up in software (without checking probably under the advanced settings tab), if you find this option enable it and set it to 2.5bar.

If you can smell gas during or after booting it and have fitted the KME reducer it could be because some KME reducer designs feature a built in over pressure relief valve set to around 3 bar... So for example if the reducer is set to output 1.5 bar gas pressure above manifold pressure and manifold pressure itself reaches 1.5 bar under boost conditions the reducer will be outputting gas at 3bar absolute pressure during boost conditions sailing close to opening the over pressure relief valve. Some KME designs have a discrete prv on the reducer, (in which case it will open whenever pressure is 3 bar relative to atmosphere), some designs combine the prv with the vacuum port (in which case it will open whenever pressure is 3 bar relative to manifold pressure, thus also effecting engine mixture). You may have noted KME make 'turbo' spec reducers. Some reducers such as MJ don't feature a prv so won't vent gas to atmosphere or manifold in case of high pressure during and/or following booting a turbo engine.

there is what seems to be a temperature sensor next to the reducers but its been disconnected for some reason? It was part of the brc system so it could be the AC stag fitter.

a lot to read, but a quick reply is the KME extreme doesn't have a temp sensor. Is that going to be an issue?

I have refurbed one of the two BRC reducers, so the other one could have a pierced diaphragm.

I can't smell any gas when booting it.

I'll be fitting this reducer either tomorrow or Saturday so will keep ya updated.

[LPGC]

Seems I was right about your system taking temp readings from a reducer temp sensor that isn't actually mounted on the reducer then (instead having a discrete water temp sensor fitted in one of the heater water pipes) - In which case I bet I'm also right about the existing reducers not getting enough hot water - In which case the new reducer probably won't get enough hot water either unless you relocate it (and possible re-plumb it).

The KME reducer doesn't have a temp sensor fitted as standard but you can remove the screw that clamps the plate that clamps it's water elbows and fit a Stag/KME compatible temp sensor in place of that screw, so the temp sensor clamps the plate and water elbows instead of the screw. Then disconnect the reducer temp sensor wiring from the discrete sensor and wire in the new reducer temp sensor.

The BRC reducers you'll be removing are a decent bit of kit but any reducer will fail prematurely if it gets too cold in use. Instead of buying and fitting the new reducer you might have just fixed (if necessary) the original reducers and relocated them. As broad as it is long really and it may be easier to fit the single KME lower in the engine bay than the 2 BRC units.

[mgrover]

this is the current system. https://imgur.com/a/ujB07kD

btw the brc reducers each are rated up for 188bhp. will that be enough? i guess each reducer to a bank?

[LPGC]

Looks like there is a wiring connection to the reducer temp sensor (bottom pic in your link), though due to different spec temp sensors (BRC / KME) this doesn't mean the temp the ECU reads is correct for the reducer with the sensor and doesn't necessarily mean both reducers are at the same temperature.

Real world performance of LPG components often doesn't manufacturer's and on paper specs, the little BRC units are probably a little under-rated but they'd both at least need to be set up to output close to the same pressure to realise the full flow potential of the two combined units. On the other hand I reckon the full total flow potential of both units isn't realised when 2 reducers are fitted.

[mgrover]

the kme kit actually came with what looks like a temperature sensor so ill hook it all up and see whats what.

[LPGC]

The type with the pink and black/green wire? I've dumped hundreds of them and will still be sweeping up dozens of them next time I have time to sweep up

But if you have a different type sensor with too long a thread you, tip, you can cut the threaded section short because the thermistor is in the none threaded/hex section.

[mgrover]

so if the reducers have to get up to temperature to work effectively. how can the car start on lpg so quickly? do I need to turn on leaning on cold start for this?

also I did another run, this time with the system auto calibrated. it didnt go well since it switches back to petrol when i hammer it. so I went back to the maps that came from the fitter and that seems to be fine.

btw feeling the reducers by hand, they are very very hot. so not sure if that theory stacks up? like what temperature do they need to be at for them to be effective?

https://www.youtube.com/watch?v=yjBEjge ... e=youtu.be

also the cars idle is still not steady which could point to the 2nd reducers diaphragm being spannered.

but I do also have to change the petrol fuel pump and the supercharger coolant pump out since that seems knackered. so it can be messing with performance

[LPGC]

I expect the autocalibration map will be too rich at high loads (and wrong at most other loads too). Running too rich at high loads is to be expected on vehicles that idle with short petrol injector pulse duration that have been autocal'd, either the engine runs too rich or if the reducer(s) can't flow the extra gas (which makes mixture too rich) the pressure will fall and the system will interpret this as if you've run out of gas so switch back to petrol.

Don't change the leaning on cold start settings lol, those settings are not for this reason (they're usually implemented on VAG cars which tend to apply more cold start enrichment under load than most other brand cars, they give same cold start enrichment as others but on others enrichment tails off under load conditions). The setting to change to make the car switch to LPG at a warmer temperature will be under 'switch to gas' settings.

The reducer hand temp test should be done just after you've booted it... boot it then turn the engine off asap and check temp of them both by hand, particularly the one that doesn't have the temp sensor fitted.

How quickly does it switch to LPG from a cold start? On a cold morning what is the reducer temp reading?

Unsteady idle could be caused by a faulty reducer diaphragm but the shape of your map probably isn't right either. Realistically calibration of a system on a supercharged L322 isn't an easy job for an amateur.

What makes you think there's a fault with the petrol pump? What are petrol pressure readings in OBD live data and what fault codes are you getting? Does the LPG install have a petrol return fitted or is there any electronic petrol pressure emulation?