LPG on a Diesel engine

Simon B · 05 January 2009, 13:40

Anyone had an LPG kit fitted to their diesel? Am thinking of it when the 2.8 Isuzu lump goes into my Land Rover?

Looks sensible, the Australians seem to like it.

doggypaddle · 05 January 2009, 22:52

Theres a lot more things to do to the isuzu engine before LPG.
I hope its a 4jb1 your fitting and not a 3.1 or worse a 3.0

The fast warmup and EGR flaps can be removed from the inlet and exhaust manifold, and a less restrictive flange made to fit the turbo hose to the manifold. the exhaust size should be taken up to 3" immediately after turbo housing and a straight through system fitted. a front mounted intercooler of adequate size can be fitted,then the wastegate adjusted to take boost up from 10 to up to 20 psi and pump fueling adjusted accordingly.
when youve done all that then LPG may be worth considering for more power and maybe economy.
to be honest the 2.8 running an intercooler and well fuelled is all an LT77 5 speed gearbox can cope with you wont need LPG to bust it!
i ran a series 3 box(several actually) in mine for a year and it wasnt sucessfull i bust a layshaft and 2 mainshafts

i run an lt77 now but its borderline strong enough.
i will try gas as well one day......too many projects and not enough time

Nos4r2 · 05 January 2009, 22:57

Quote:

Originally Posted by doggypaddle

i will try gas as well one day......

Christ, don't ask me to get in your SII when you do that then

It was the bit where it kept accelerating harder and harder from 80mph upwards that got me

Simon B · 06 January 2009, 11:53

Cheers Chaps,

That's saved me £1000. It is the 2.8 came with a free gearbox in case I break this one. Exhaust is standard 110 at present and I was thinking SAAB or Volvo 850 for intercooler.

doggypaddle · 06 January 2009, 16:15

you cant have a cooler too big! its no point having cold air if the flow is reduced by restrictions.
i cant comment on saab or volvo ones but they probably arent big enough for max performance.
a landrover tdi one is too small, i have 2 grafted together in mine and 2.5 pipework, thats about OK.
If you intend keeping the LR try a jeremy fearn he does real nice ones .

doggypaddle · 06 January 2009, 16:18

Quote:

Originally Posted by Nos4r2

Christ, don't ask me to get in your SII when you do that then

It was the bit where it kept accelerating harder and harder from 80mph upwards that got me

Thets cos the intercooler is too small! it starts to work well by the time there is a 70mph wind through it

Simon B · 06 January 2009, 17:20

Quote:

Originally Posted by doggypaddle

i have 2 grafted together in mine and 2.5 pipework, thats about OK.
If you intend keeping the LR try a jeremy fearn he does real nice ones .

I was hoping to avoid Jeremy Fearn type prices, the volvo effort is about 21"x23" similar size with the SAAB but not anything like the bespoke jobs on offer at JF or Allisport.

Did you couple 2 together by running it through one then the other? sort like series are in parallel, would have thought this would not be wise as it'll go down path of least resistance.

Also wasnt sure if my old V8 air filter could be "dieselified"

doggypaddle · 06 January 2009, 17:54

Alisport is 1000 yards from my house! i would use JF though he has been helpful in the past, good advice free.
well just fit one and try it, and measure the boost lost across the cooler 1 psi is fine ! the air being cold makes up for the lost pressure.

re my intercooler, i just used TDI cores, my mate is shit hot with the old TIG.
made new header tanks. couldnt fit anything bigger in the series two cos of the headlamps in the way!
you are right two coolers in series would be rubbish, parallel would be OK but the pipework would need two Y pieces, it would look rubbish.
I did mine on the cheap, all the pipework is steel exhaust tube, way cheaper than ALI. the coolers were sodbury sortout £10 and the silicon hose came from scrap landrover TDIs and a reducing elbow from samco cos i was short!!
V8 air cleaner will be OK if you can find somewhere to fit it.
is your landrover a factory fitted v8 110? if so the santana lt85 box is well strong!

chewy · 07 January 2009, 10:17

Quote:

Originally Posted by Simon B

Cheers Chaps,

That's saved me £1000. It is the 2.8 came with a free gearbox in case I break this one. Exhaust is standard 110 at present and I was thinking SAAB or Volvo 850 for intercooler.

If your after an intercooler try Braydon Motor Compnay, they're Volvo breakers and are real helpful.
My T5 is running 280bhp through the normal intercooler and I believe its good for loads more!

doggypaddle · 07 January 2009, 11:02

should be big enough then, i never really looked at the larger car coolers when i did mine, as the 1960 series has the headlights in the middle leaving no room for a full width cooler, which is why i went down the route i did.
most coolers which would have fitted had plastic end tanks and or the pipes pointing the wrong way, ie into the radiator two tdi oned sise by side happend to be ideal when compined with Knobby and his TIG!

Simon B · 07 January 2009, 15:43

Yep factory fitted V8 1989, the volvo unit has the inlet oultet in wrong orientation, this could be changed!

I love tig, but have struggled a bit with ally welding. Twinning up a monster double sounds a neat idea what did your mate do make one large piece to fit to each end of the two cores held together?

doggypaddle · 07 January 2009, 16:59

we cut the old header tanks off and welded the two cores side by side, then made two new header tanks from 2mm ali plate. Wasnt easy to weld though,
it was difficult to get the ali clean enough. even wire brushing leaves a steel residue that affects the weld quality! its not he prettiest tigging in the world but its airtight!

Simon B · 07 January 2009, 19:38

Cheers Doggypaddle,

Might stick with shoe-horning in a SAAB one they are massive. Good info on flap removal will put that on my list of must do's. Along with pump tweaking not researched this yet but there must info out there.

I did get a free exhaust pipe, which could yield enough pipe to mackle up a replacement section for the middle silencer! Not 3" but a start.

Front mounting of the air filter appears an option, as did externally coupled to a snorkel - I had been drinking! Twin smoke stacks could happen next!

doggypaddle · 08 January 2009, 20:13

there will be plenty of room under the bonnet for the air cleaner, as its a V8 there may be room against the bulkhead.
plenty of info available on pump tweaking, its the same as a Bosch VE fitted to many other engines including perkins prima, cummins 5.9 b series, landrover tdi etc. trick is to get the spring under the compensator and the fuel screw set to get a similar amount of exhaust smoke throughout the rev range.
it took a week of driving with the mirror pointed at the tailpipe with mine.
tell you what though, with the wastegate tweaked up to 25psi and no regard for visibility behind, my series 2 would easily leave my mates 4.6 rangerover in a cloud of smoke!
turbo would soon melt like that though

Simon B · 14 January 2009, 11:50

Doggypaddle,

Interesting! maybe a touch extreme for me at this point. My interest in lpg had stemmed from the option to in part reduce the clouds of smoke (as well as getting more torque)

The idea is for this to be a daily drive vehicle that would last, I think the Isuzu should blow off at 13psi normally, I dont know what margin is safe to exceed this by, clearly 25psi has been obtained. 3" exhaust is starting to make sense...

doggypaddle · 14 January 2009, 15:52

I am not sure whats safe, its the exhaust gas temp you need to watch, may be worth getting a pyrometer if you want to start fiddling.
running high EGTs for long periods melts turbines and cracks wastegate housings as i found out with my perkins 2.0 Prima in the series one.
i ran that at 25psi boost and quite smokey at full chat, and melted the wastegate.
running at 20 psi boost at 5000rpm and the exhaust just whiffing a little smoke its lasted 10 years and over 100000 miles, the toltal milage on the engine is around 220000, but its an oil burner now

I dont have a wastegate on the isuzu. it does not need one, with the smoke at acceptable levels the fuel and small size of the turbo compressor means the boost gets to 20psi at 4200rpm.
the nice thing about the small turbo is that i get boost from a little over 1000rpm, i usually only need 5th gear once i am rolling

you need a big exhaust to get the heat away from the turbo ASAP, it makes a little improvement to the performance if nothing else changes, but then allows higher boost to be run at lower EGTs.

Simon B · 15 January 2009, 17:48

Thanks for all this diesel education Doggypaddle, I had theorised correctly about the exhaust, this is good! I believe lpg injection will raise EGT by 50-70 degrees, I assume centigrade. I'd seen forum posters using an EGT to monitor turbo meltdown and stuff.

For now I think I'll content myself with fitting correctly and getting all the old V8 stuff moved about, if convenient fit the intercooler at the same time then move on to more expensive and challeging mods later.

A chap who had run an Isuzu for a while remarked he'd cracked all 4 pistons but did not say how, sounds cooking related!

doggypaddle · 16 January 2009, 10:24

Quote:

Originally Posted by Simon B

.

A chap who had run an Isuzu for a while remarked he'd cracked all 4 pistons but did not say how, sounds cooking related!

too much boost and fuel without an intercooler or too small an intercooler.
or more likely the timing way too advanced, usually if overfuelled the turbo will go first. the isuzu ones are good though theyre watercooled.

get it in running standard first then start tweaking later!
standard fuel setting is a bit lame, theres lots of scope for improvement.

Simon B · 16 January 2009, 11:29

OK, I'll check back later when it's in, not sure if the pump has been adjusted or not so may have to get back to base settings if it has.

I'm quite looking forward to this, at the end of it I'll have an old chassis failure V8 Stromberg 110 to dump and a V8 engine on SUs. That'll clear up the partners drive way she'll be well happy but this will mean muggins will be laying paving afterwards.

doggypaddle · 16 January 2009, 17:50

getting back to base settings is a pump off and a trip to the diesel shop to lighten you a £100 quid or so. and to be honest a waste of time anyway.
once its in and running i can tell you how to get to the right fueling for your set up quite easily, if you run through it systematically.
theres only really 3 settings to adjust and they all affect each other. so you need to do it in the right order, or you will go around in circles!!

all you need is the mirror trained on the tailpipe so you can visibly check how much smoke you put out.
for everyday use its a case of getting the pump set so when you work it hard pedal to the floor there is a tiny bit of smoke at all boost levels and rpm.
PM me when its in or if you need any advice, ive done probably upwards of 20 conversions now, so have a bit of knowlege built up.