LPG in a Nissan 300zx

[7ERO]

Hi, I've been reading the forum for quite a while now and spoke to a few fitters too but I haven't been able to draw any definitive conclusions so I was hoping I could get some help.

I want to fit LPG to a Nissan 300zx. From what I can tell the Prins kit seems to be the best option and whilst most places seem happy to have a go I did speak to a fitter the other day who said it would not be able to run enough fuel for the car's power. It's at just about 390bhp atm. Is this right? and does anyone have any general advice as to what I need to be looking at for this kind of car (I don't want to skimp and overlook anything)

Ideally I would like to install a liquid LPG kit but I really can't seem to find much info on it. The only kits of any real merit I seem to have found have been the Vialle and Prins kits, but one isn't released yet and I can't find a fitter for the other (aside from Millbrook who I don't believe do private work). Is there any other liquid kits I could consider and who could fit them?

Thank you in advance for any help!!

[Tubbs]

Liquid injection systems are very vehicle specific atm. You would need to look into it a bit more. Your concerns about a vapour injection system are right, but a good quality vapour injection system should be able to cope i would say. Ive topped 260 bhp on a 4 cylinder system without any problems. So if you do the maths thats 65hp a cylinder and you are talking about the same on a V6.
It certainly didn't run out of legs and was clean as a whistle right up to the line. Holding a steady pressure and pulse duration. The system i fit is classed as a 'mid range' system. But more than happily coped with that kind of output on a single reducer. I would be concerned if a system like prins, which is seen as the market leader would not be able to cope with such an engine. I would quite happily take it on without any major concerns. But maybe thats just me....brave (some say stupid !)

[dannyf]

I run 320bhp on a 4 pot engine and thats fine on LPG

[7ERO]

Hi thanks for the input. That eases my concerns a little. I'm going to try and allow as much headroom in the system as possible so I'm going to be fitting the brown injectors as they seem to be a good upgrade. Would I need to look at twin vaporisers too on the prins?

Also what sort of theoretical power should a well fitted prins system be able to handle for if i decide to try and squeeze a few more ponies under the bonnet at a later date?

I've seen a lot of mention of flashlube too for jap motors. What would be the best system? Prins Valvecare or something else?

[Gilbertd]

Have a look here http://www.lpgforum.co.uk/viewtopic.php?f=32&t=10413 at a system installed by an installer on his own car. Makes your power output look positively feeble.......

[Tubbs]

If you are going down the prins route, dependent on where you are in the uk. Chap on here called woody in Southend. Rossko in Chippenham. Billy Saul at Hilton autogas in Wolverhampton. Neil mugglestone in Boston, Lincolnshire. All top lads and very good installers. That's got to be most of the country covered for you !

[7ERO]

I'll see about giving Neil a call then as he's probably closest to me. I'd ring Billy but he's the chap who told me it wasn't possible. I also chatted to AutoTech in Derby who sempt very confident and knowledgeable but I can't find many reviews on them. Are they a good outfit?

[Tubbs]

K mugglestone and co, anton's gowt, boston, lincs 01205 280317.
I cant really comment on autotech, ive not come across them.
I'm surprised that billy isnt prepared to have a go. I would say it should be more than possible.

[billynoband]

While people on here know that Prins or BRC with Keihin injectors would run this car it would be nice to see for a change a sucessfull conversion on a very powerful engine using a AEB kit. It's been ages since Badger fitted the OMVL piro to his Hemi in 2006.
Bigas claim 380 hp is possible for their 4 cylinder twin reducer kit

[Tubbs]

The EMER Palladio reducer is very capable. 1.4 bar but can be set up at 2.5 bar if needed.
Buit it's the customers decision at the end of the day. I wouldn't have any qualms. I just had a repeat order from one of my customers today. They used to be engine remappers. They have skoda vrs octavia's running in the region of 250bhp. 4 cylinder's. I did the dads one before chrismas and his son booked in today for his. And it's still got bags of headroom. No significant pressure drop at 1.4 bar, no injector duration's over 17 ms. I've also used the EMER system on an amg merc without any issues. As I said earlier v6's and v8's are no where near as demanding as the 4 cylinder high output engines.

[LPGC]

Hi,

I wouldn't fit Prins on a turbo'd engine that can run high boost pressures - Prins reducers work at a set pressure that does not rise accordingly with manifold pressure. Thus, if the Prins reducer supplies a typical (for Prins) 2.1 bar LPG vapour pressure, and the manifold pressure rises to only 1.6 bar boost pressure, then the actual working pressure of the LPG vapour under engine boost conditions will be only 0.5 bar and this will not be enough pressure to allow the very good Keihin injectors to put enough LPG into the engine.

Prins don't make a reducer that will flow enough LPG for the bhp levels you're talking about. Prins is expensive, and although I do rate the Keihin injectors I do not rate the rest of the Prins components - and all Prins components are very bulky and heavy when compared with similarly performing components. The Prins system really relies on the excellent performance of the very linear and quick Keihin injectors to get away with an ECU which lacks in terms of calibrational abilities. The Prins system has facility for a map sensor to be fitted as part of the system, but in practice I don't see map sensors fitted on hardly any Prins systems I repair. Without a map sensor, the Prins systems rely on the pressure from the reducer never drifting or else the whole calibration is wrong (I repair a lot for drifted pressure). I don't find Prins reducers particularly reliable and the dealers / fitters still seem to think it is 2003 and they can charge £2500 to install a system on a V8 because the customer could claim half that money back in a grant..

Prins don't recommend LPG converting low compresssion engines to LPG - so that rules out turbo'd vehicles?

Several people have left comments about certain reducer models. I would fit two reducers, each reducer capable of 350bhp, so my system would flow enough LPG for 700bhp. You wouldn't be able to fit two of any other reducer in the fairly tight engine bay of the 300ZX, so would fit two times MagicJet reducers - I've fitted a great many and they seem to be reliable and god performers with good pressure stability, and the pressure from these reducers will rise with manifold pressure so the full LPG pressure will still be there under boost conditions.
Injectors? Keihin are very good but bulky and are 16ohms impedance so not compatible with many LPG ECUs except Prins and a few other ECUs that usually don't offer great calibrational abilities. BRC injectors look like they've poorly copied the Keihin design and usually leak in time where the plastic part of bonded onto the metal part, and they are expensive for their performance and reliability. Matrix flow good and have a good response, so a possibility but can be unreliable so would rather not. OMVL Superlights quite good flow and very reliable and linear but don't flow as good as the older OMVL Fast injectors. Bigas similar to old OMVL performance but perform poor at low temps. I could go on about injectors but would likely go for MagicJet injectors as these flow extremely well and have a very quick and linear response, even if they don't look well made and I have had a couple of solenoid failures in the past.
ECU? If the reducers and injectors flow enough LPG then a none Italian ECU would be best as these work fully sequentially whereas Italian ECUs only measure injection time for the first cylinder on each bank of cylinders. If the boost kicks in very fiercely such as with an aftermarket turbo, then the LPG pressure could possibly drop low enough momentarily to allow the injectors not to be able to deliver enough LPG, so in this case an AEB ECU would be best - and AEB Italian ECUs have good A/D convertors and mapping for both load and rpm that actually works.

I have converted a great many of the Hemi engines that somebody mentioned and regard these as a fairly easy conversion with even the standard components that come in many Italian systems. I have converted a great many vehicles that people usually think cannot be converted due to high power levels and have no doubt I could do a great conversion on your 300ZX (having converted several highly tuned Skyline Turbos with no problem). I am currently repairing a supercharged V8 Jeep which has never run properly on LPG due to the installer's poor understanding of how LPG systems actually work - They had done what looks like a neat and thorough job, but their lack of understanding has caused them to install the system in such a way that it could never work properly. Regarding your 300ZX, I can supply a DIY kit or do a full conversion that will outperform any other LPG system at a price that is much less than you might pay elsewhere.

I have no bias towards for or against any LPG system or component, because I can and do fit all makes of components, so it's not like I'm biased to advise what I fit because I fit and repair everything LPG.. In contrast, many installers are stuck in their ways installing the same old same old and need to get over what might have been the best in the past because there are better performers that are just as reliable but are much cheaper these days.

I recently advise Car Mechanic magazine on much of their technical info for their recent 'Spotlight on LPG' supplement and can assure you I know my stuff!

If you need any help getting your 300ZX running on LPG, give me a shout - I'm not really big headed but unless I put the word out, no-one will know my skills eh?

Regards,

Simon
LPGC - search Google?
Yorkshire WF9