1989 BMW E32 730i help needed

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Mouse
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1989 BMW E32 730i help needed

#1 Post by Mouse » Wed Oct 30, 2019 10:01 pm

Hi there. I'm new to the board, but not to lpg.

My father used to convert cars to lpg back in the 70's and 80's. My first few cars, as a result, were running on lpg. I trained as a mechanic, and the premises directly beside was, and still is, a lpg installer, but on houses, rather than cars. Although most of the workers cars ran on lpg.

Recently I was offered a 1989 E32 BMW 730i, and as an avid classic car fan, I was interested. If I was to buy it, it would be with the iintention of converting it to lpg, as I would use it every day. However, my problem is that technology has changed so much since I, or my father, were in the habit of converting to lpg.

So can anyone point me in the correct direction? I've done some research on the conversion, and have some ideas that would work, but some things I don't fully understand. Like, what is my best option in regards to a full kit? I've read about the Zavoli multi point conversion, and it sounds like that is what would suit. Or is there better options?

Thanks in advance.

Gilbertd
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Re: 1989 BMW E32 730i help needed

#2 Post by Gilbertd » Thu Oct 31, 2019 3:41 pm

You could just keep it simple and stick with technology that matches the age of the car (and your experience) and fit a single point system. Much cheaper than a multipoint, far simpler and will work just as well.
96 Saab 900XS, AEB Leo, sold
93 Range Rover 4.2LSE, Lovato LovEco, sold
97 Range Rover 4.0SE, multipoint, sold
98 Ex-Police Range Rover 4.0, AEB Leo, daily motor
96 Range Rover 4.6HSE Ascot, AEB Leo, my spare


Proud member of the YCHJCYA2PDTHFH club.

Mouse
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Re: 1989 BMW E32 730i help needed

#3 Post by Mouse » Thu Oct 31, 2019 9:00 pm

Thanks. I was assuming that the more modern system is better, as regards, more improved fuel economy, and power, and easier to use. I don't mind learning new tricks with the multipoint system.

Does the single point system use an ecu?

Gilbertd
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Re: 1989 BMW E32 730i help needed

#4 Post by Gilbertd » Thu Oct 31, 2019 9:21 pm

Yes, it takes an input from the existing lambda sensor and adjusts the gas flow from that. So it is a mixer system that you will be familiar with but instead of the manual power valve between the vaporiser and mixer, it uses a stepper motor valve controlled by the ECU. Unless you intend running it down a drag strip, you won't notice any difference in performance between running on LPG or petrol. The multipoint system slaves off the existing petrol injection system so depending on what system is fitted now, may mean you can't fit a multipoint anyway. What injection system does it have fitted?
96 Saab 900XS, AEB Leo, sold
93 Range Rover 4.2LSE, Lovato LovEco, sold
97 Range Rover 4.0SE, multipoint, sold
98 Ex-Police Range Rover 4.0, AEB Leo, daily motor
96 Range Rover 4.6HSE Ascot, AEB Leo, my spare


Proud member of the YCHJCYA2PDTHFH club.

Mouse
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Posts: 7
Joined: Wed Oct 30, 2019 9:32 pm

Re: 1989 BMW E32 730i help needed

#5 Post by Mouse » Thu Oct 31, 2019 9:53 pm

I haven't the car yet, but I'm think it's Bosch Motronic. It being a 1989, I doubt it has a cat, so I can't say it would have a lambda sensor or not.

I won't be doing the drag strip thing, more like a driving Miss Daisy, handy go slow, kind of driving

Gilbertd
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Location: Peterborough

Re: 1989 BMW E32 730i help needed

#6 Post by Gilbertd » Thu Oct 31, 2019 11:05 pm

If it's running Motronic, I would have expected it to have a lambda sensor although according to http://www.ecolambda.co.uk/main/bmw.htm it doesn't until 04/92. Maybe it isn't Motronic or maybe an early version that didn't use one. Not really a problem to add one though, it just needs a boss welding into an exhaust downpipe. My Range Rover runs 5-0V Titania lambda sensors instead of the more common 0-1V Zirconia sensors. The 5-0V ones stop giving an output at idle which confuses the LPG system so I've got an additional boss in one downpipe for a 0-1V sensor purely to drive the singlepoint LPG system.
96 Saab 900XS, AEB Leo, sold
93 Range Rover 4.2LSE, Lovato LovEco, sold
97 Range Rover 4.0SE, multipoint, sold
98 Ex-Police Range Rover 4.0, AEB Leo, daily motor
96 Range Rover 4.6HSE Ascot, AEB Leo, my spare


Proud member of the YCHJCYA2PDTHFH club.

Mouse
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Posts: 7
Joined: Wed Oct 30, 2019 9:32 pm

Re: 1989 BMW E32 730i help needed

#7 Post by Mouse » Thu Oct 31, 2019 11:20 pm

Yeah. I stand to be corrected on this, but I think new EU reglations on emissions didn't come into effect until Aug 1992. Prior to that cats weren't needed. Us cars, depending on the state, meant it did need a cat well before that. And Japan too, and probably other countries as well.

Either way, as you say, it's not the end of the world to retro fit a new sensor.

So which system make am I best looking at? Zavoil, or Lavato or whoever? No point in fitting a cheapo system that's just going to be constant trouble, although I'd like to think a single point system would have less to go wrong with it.

Mouse
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Re: 1989 BMW E32 730i help needed

#8 Post by Mouse » Thu Oct 31, 2019 11:59 pm

In part of my looking across the interwebs, I found this thread in bimmerforums. https://www.bimmerforums.com/forum/show ... 0i-big-six . On the third post he posts pictures on the install. No need to go any further as regards the install of lpg. As you can see he has a multipoint system fitted. Zavoli. I know I'm asking questions on a specific vehicle, and I'll need to do more research, but from those pics, do you think I'd need to go multipoint, or is it a case bt case basis?

Gilbertd
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Location: Peterborough

Re: 1989 BMW E32 730i help needed

#9 Post by Gilbertd » Fri Nov 01, 2019 9:19 am

Best wait until you get the car and see exactly what petrol system it has. In Italy, where many of the LPG systems come from, all components must come from the same manufacturer. Rather than each one going their own way and designing everything there's a lot of badge engineering. AEB manufacture the ECUs for Bigas, Zavoli, King, OMVL, Emer and probably a few others for instance. They are all the same ECU just with different firmware (and label stuck on the outside). Simon on here (LPGC) will be able to advise on the best reducer and injectors for your engine. There's pros and cons for both single and multipoint. With the dedicated lambda sensor on my Range Rover, I have two totally independent fuel systems the original petrol system and the singlepoint LPG system, so if one develops a fault, I've still got the other. It will also run on LPG from stone cold so the petrol in the tank is treated the same as the spare wheel, something to be used only in case of emergency. Downsides are that the fuel metering, while good, isn't optimum and the mixer in the intake will restrict airflow at full throttle. With a multipoint, there's a lot more work involved in the install (drilling the inlet manifold, lots and lots of wiring) and once installed it needs to be calibrated. It can't run on LPG from cold it needs to warm up on petrol first before it switches over, so if you do lots of short journeys you'll still use a fair bit of petrol. It slaves off the petrol injection system so if that develops a fault, then the same fault affects the LPG system too. However, the fuel metering will be more accurate so the economy will be better (although even if accurately calibrated, maybe only by 1 or 2 mpg) and the power output from the engine will be only fractionally down from petrol. In fact, if you can advance the ignition timing, you can get more power due to LPG having an Octane rating of 105 allowing you to run more advance.

While it isn't state of the art, I bought my car with the singlepoint on it almost 10 years ago and was intending changing it for a multipoint. I never have as the simplicity of the singlepoint and the fact that it is a stand alone system means I've got belt and braces when I set off on one of my 3,000 mile round trips around Europe (which I do regularly). In the time I've owned it, it's needed 2 replacement lambda sensors (because the first one I bought was a cheapo Chinese generic that lasted less than a year) and a vaporiser as the original one was getting very tired after 150,000 miles.
96 Saab 900XS, AEB Leo, sold
93 Range Rover 4.2LSE, Lovato LovEco, sold
97 Range Rover 4.0SE, multipoint, sold
98 Ex-Police Range Rover 4.0, AEB Leo, daily motor
96 Range Rover 4.6HSE Ascot, AEB Leo, my spare


Proud member of the YCHJCYA2PDTHFH club.

Mouse
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Posts: 7
Joined: Wed Oct 30, 2019 9:32 pm

Re: 1989 BMW E32 730i help needed

#10 Post by Mouse » Fri Nov 01, 2019 8:21 pm

Thanks a lot for that info. From what you're saying the singlepoint will suit me best. More simple all 'round. I'll wait until I get the car, if I get it, before I'll settle on what system to use. It'll need some work anyway, so I'd be in no rush to make a decision.

Mouse
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Posts: 7
Joined: Wed Oct 30, 2019 9:32 pm

Re: 1989 BMW E32 730i help needed

#11 Post by Mouse » Fri Nov 08, 2019 10:58 pm

Just as an update to this.

I viewed the car this week. Turns out that despite I being told it was in storage for a few years, it was "in storage" under a tree for 13 years. If you wanted a proper project car, it would have been ok, but for me I was not interested. However, it got me well interested in old Skool BMW's, so I think I'll keep an eye out for one.

So, so far, thanks for everyone who answered my questions.

As governer Schwarzenegger would say, I'll be back.

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