Outer Limits 4x4 Board

Have been given the all clear on diesel gas after having my intercooler idea knocked back. I have narrowed it down to either diesel gas technologies or the d gas system. I am leaning towards the dgt because of the features the computer has but i am concerned about injecting the gas pre turbo, The dgas system is post turbo but i dont think it is as refined as the dgt. If anyt can shed some light on the subject it would be greatly appreciated, especially the bit about gas destroying the turbo. CHEERS

Why wouldn't you run an intercooler?

I'd go the system that introduces after the turbo, but I can't see why they can't all be post turbo with a balance line unless they haven't worked that out yet. If you imagine a boost leak it's safer to put the gas in as late in the system as possible, not to mention you get a better result as the turbo isn't having to compress an air/fuel mixture, just the air and then the fuel (lpg) is added under pressure to the compressed air steam, the pressure comes from the tank and is regulated by the converter.

Joel

got talked out of the cooler by 2 people for the same reason, they said for what it would cost the benefit would be f all, they both suggested either turbo upgrade or gas and i have been thinking about gas for a long time now. what you just said joel has gone straight over my head but i take it you would run a d gas system before a dgt system. do you think there is a problem with the gas playing havoc with the turbo?

Not so much a problem with the gas and the turbo but I do beleive you have been Ill advised about the cooler.

The intercooler cools the intake air which in turn lowers the EGT's which in turn allow you to add more fuel and boost. Granted some of the off the shelf systems are poor dollar value (and poor performers) but you can build one that will allow you to make excellent power with safe egts.

We recenty did a 3.0L hilux with an intercooler, BB turbo and chip that makes 109rwKw with EGT's within 10 degrees of stock, the standard already turboed vehicle made 55 rwkW.

With the TD42 if you fit an effective intercooler the limitation is the pump output.
With the right bits you can make an honest 110-120 rwKw from the GU td42 with heaps of midrange torque.

I'm assuming you don't have a 3.0L GU as I wouldn't gas that but a larger intercooler would lower EGT's and help keep the engine together. LPG tends to raise EGT's and the variable nozzel turbo isn't going to be keen on that, although Porshe do use variable nozzels on petrol cars.

Joel

4.2 turbo non intercooled. I'm not really looking for more power i just want to be able to drive a bit further without filling up and if i can get a bit more power at the same time thats great. Also i want a bit better pick up and i have been told that gas will help with that.

get an exhaust first i just cant see how gas in a diesel engine can be good.. why didnt you just buy a petrol in the first place n gas it..

get a 3" exhaust intercooler and up the boost a little.. give you some more power..

as for fuel economy well untill somone describes to me how this dgas works and makes it viable i dont no..

diesel burns slow.. gas burns fast..

diesel burns slow.. gas burns fast..

thats right gas increases fuel burn rate and efficancy ..... listen to what PGS4WD and if DLZTECH rights up follow what they are saying you will not regret it

Had a mate put d-gas in his 80 series. Had a custom turbo fitted afterwards. He says that the power gain with gas system only was minimal. He believes that the limitation was the lack of air with a naturally aspirated engine. You can jam as much fuel/gas in the engine as you like, but without enough air to make it burn, the benifits are minor.
However, after the turbo was fitted, the engine had as much air as it needs and ran like a thing posessed. His system injects the gas after the turbo so that (as PGS 4WD says) the gas injection doesn't effect the amount of air intake ie. you know that everything coming off the compressor wheel is air and you aren't sacrificing the air boost to make room for the gas.
Yes the gas makes the diesel burn cleaner and more completely so there is less smoke coming from the exhaust.
Having said all this, the vehicle runs a moderate boost (9lbs) plus gas injection into a 4.2lt motor turning 33" tyres, but he has found little change to the fuel economy. He used to get 550km per 90lt tank. Now add a 30lt gas tank refill per diesel tank refill and he gets around 690-700km per refill.
When looking at the milage, he would have been better spending his money on a long range diesel tank.

-BUT-

The engine burns cleaner, cooler and makes less soot so the oil stays cleaner for longer and so lubricates better for longer and a more efficient engine should last longer in the ahh...long... run.
These are the benefits of his system and as soon as the novilty of the extra power wears off and he takes his foot off the loud peddle, we may yet see a little better fuel economy.

Hope it all helps
Dave

So it looks like dgas might be the way to go as its post turbo. PGS4WD and DLZTECH, if you were doing the gas on your own vehicle which system would you prefere D-Gas or Diesel Gas Technologies and why. I will take your comments very seriously cause im having trouble getting unbiased opinions. Cheers. By the way i'm not ignoring what everyone else is saying, its all getting processed slowly

At this stage I don't know that I would, where to squeeze a tank and all that..

As I have the facilities to tune and can identify pinging or other potential issues I'd knock something up out of a simple mixer after the turbo and complex converter with a balance line. Cheap but effective.
Unfortunatly if I wanted it, and the the grant I'd have to pay someone to do it as the worshop doesn't have a gas liscence and I haven't paid my personal one for a few years. I don't think I'd be happy having a gas fitter work on my car having seen some of the crap I've seen.

Joel

a guy i work with has a 4.2 td intercooled. 12mm plunger and 3 inch exhaust running 18psi boost with dgas that he made himself. he makes 230hp at the rears and gets 10litres per 100km tested on 2 cape trips and one simpson trip.

he said that when the gas runs out in the middle of the trip if it does it just goes back to pre gas setting and runs fine but not as much power.

the gas gave him a huge improvement in economy and power, hes a diesel mechanic and has built several td42s before and loves his gu with gas so much.