Running a 450HP LS3 on LPG

[skiergeorge]

Looking for advice. Been running OMVL Dream twin regs and think they call them superlight injectors. Upgrading our boats from 350 to 450 HP with the LS3 and doubt this kit will cope. Already running quite how map around the 200's . I am fitting the kit in boats so need quality kit with good response times as our ECMS put the power down fast. Tempted by Prins but cost seems very high. Have tried BRC but had issues on the overrun.

[classicswede]

I have done a lot of ski boats over the years and the AEB electronics do work well. Getting the water feed sorted is a big key part.

If you have the old OMVL HP regs then they are not great in all honesty. 5 years ago yes they were one of the best but there are now better reducers out there. The OMVL injectors are ok but at those power levels will be getting near the limit of flow.

Are you changing the ECU from group injection to sequential to go with the engine change?

[skiergeorge]

Thanks for that information. I ended up with OMVL Regs because we could keep the gas temp up with EMME Gas. OMLV injectors I am sure won't cope as we are nearly flat out on our 350 Vortecs. Latest Idea is a King ECM with Hanna injectors. Heard they are like Kehin.

[skiergeorge]

By the way we use the sequential injection as all out boats are individually injected now. No Group Injecting since 2005. We are also using pre and post lambda sensors. Often having an issue with trimming at idle where one bank goes lean and other rich. Dip Tubes help that issue.

[classicswede]

Most of the boat engine even with 8 injectors operate a full group injection stratergy.

The hana injectors are good and will flow well

[skiergeorge]

Thanks again, I have been thinking maybe a King ECU with Hanah injectors, just not found out if King have the latest AEB software available. Other option is BRC.

[rossko]

just not found out if King have the latest AEB software available.

Why, what do you think it does that, say, last year's doesn't?

[classicswede]

Temp corrections? I've not needed them on any of the boats I have converted.

[LPGC]

The vast majority of sequential ECU's have built in gas temp correction, even if it is none adjustable, there are only a few sequential ECUs that don't.

All AEB ECUs including King have both gas and water temp correction but with some software / firmware / lack of dongle combinations you cannot adjust them. The latest King 6.1.03 software does allow access to adjust both temp corrections, but as has been said, you shouldn't really need to do that.

OMVL SL's will flow enough gas for the 57bhp per cylinder if you remove the brass nozzles from the outlets and use an appropriate feed pressure. By appropriate, 1.5 bar should be enough and a wide range of reducers will stretch to this pressure. They would give good results but there are better injectors for higher power levels.

You do have high map figures, but remove the brass nozzles from the injector outlet and recalibrate the system then tell us what the map numbers are! I bet those 200s will come down to around 140s. What pressure are you running at?

Does the boat have cats then? You said it has post cat probes? What kind of bank trim problems are you having? What are the bank trims like on petrol?

Simon
Lpgc

[classicswede]

The vapourisers should be running around 1.8 bar, one is enough for the power but getting the heat with a boat is the problems and two vaps is the best way. You can take them upto 2.5 bar, omvl made a spacer for the high pressure spring to do this.

What temp readings are you getting on the vapourisers under sustained full load?

[skiergeorge]

Thanks for all the good information. Did not realise you could space to 2,5 bar, back to the good old impco days. Can the OMVL injectors take 2.5 Bar ? I also suffer pressure drop on the OMVL regs down to a bar at full throttle. I already take the brass nozzles out for anything above 350HP. When I take the nozzles out I do suffer on idle trimming I guess due to the lower nozzle pressure. I never really pay too much attention to post cat sensors only the pre cat. Sounds like I may be able to stick with OMVL although Hanah injectors do tempt me. By the way I really do need 2 regs to keep the gas temp up, circulation is terrible at low revs. I am injecting alot of gas as well. One issue I do have is by the time I include dip tubes and the supply piep I am 15 inches from injector nozzle. The boat ecm we use does have adaptive learning by the way as well.

[classicswede]

They will work at over 2.5 bar no problems.

What is you petrol injection times on tickover?

[skiergeorge]

Hello .

Injector times for petrol are around 3 which gets adjusted to 5.5 to 6 ms when on LPG.

[classicswede]

Is that 3ms on petrol and 6ms LPG? Or does the petrol time climb to 6ms?

Are you using the full group setting or sequential?

[skiergeorge]

The petrol injection at idle is around 3 ms and this converts to 5 or 6 on LPG. Alwaysuse sequential not full group. Petrol map is pretty solid with learning never varying by more than 1 or 2 %. On lpg I can sometimes end up 16 to 20 % adjusted off petrol map. I have factory level connection to petrol ecu.

[classicswede]

I would say you are not getting enough flow there. With a petrol time of 3ms I would expect as LPG time of around 3.5 to 4.5 ms on LPG if you gas pressure and injectors are sized correctly.