Outer Limits 4x4 Board

Hi all,
I (like many others it seems) am thinking of going down the turbo LPG gas route - I currently have a duel fuel setup which is gutless and frustrating when faced with a hill/head wind or slight load. I recently did a trip to Tenterfield and back with a 12x6 trailer on the back fully loaded weighing what I guess to be about 2+ ton! I averaged about 180km's per 80 litres of gas which is pretty frightening, however I managed to get gas on all occasions bar one where a short run on petrol was required - so as a result I'm no longer that worried about range with gas as I managed to keep it running even with such a short range and on the relatively deserted New England highway…..it was flaming slow going though I tell ya - average speed would have been about 60kmph I'd say!

So my plans and questions are:

1) I plan on just going to straight gas, first running a Gas Research system without the turbo - does anyone have pictures and comments on this setup?? I've learnt over the years to do one mod/change at a time before proceeding with the next….

2) I want to run a second gas tank in place of the current long range fuel tank which is under the drivers side rear passenger seat - what sized tank can I fit, will I need a custom one made or will I simply need to use a couple of scuba tanks - unlike the present fuel tank I don't want it to stick down below the chassis rails at all! I would like to be able to have no less than 150ltrs of gas for a worse case range of approx 600kms….

3) Just running the Gas research system at first should I expect much better running and economy considering the carby will be completely out of the equation?

4) Now onto the turbo - I presently have a WRX TD04 turbo that I was hoping to get away with using as I know it's in perfect condition. In my WRX (I really miss the Rex) it used to come on boost at about 3000rpm, so can I make the assumption that as the TB42 is basically twice the size, it'll pump out twice the volume of air potentially allowing the turbo to come on boost at about 1500rpm?? I am quite happy for it to run out of puff at about 3-3500rpm as I never go much further than that anyway - also 110km cruise where the car suffers the most is about 2400rpm and therefore right in the boostable range in theory?? Comments, am I way off here??

5) Now onto the manifold - my preferred option is probably to just get a turbo diesel manifold, or the factory petrol one with an adaptor plate welded on, which is the best/cheapest option in peoples opinion - I'm not after optimal performance here just enough to make driving a pleasure with out constant gear changing….

6) If I choose to go the WRX turbo route, will I be able to get away with the standard in-built waste gate? I may need to use a helper spring to keep it closed a bit longer possibly, used this before on another turbo car as a cheap way of gaining a bit more boost pressure….

7) Using a Gas Research system and turbo setup - blow through I believe (turbo pushing the air through the GR throttle body) can I run a blow off valve? Also I have a series five RX7 intercooler that I'm keen to use - is this possible?

The big question is - am I living in fairy land with all of this???

Overall I'm hoping to be able to run approx 6 - 8 psi of boost and have enough power to hold 5th gear up a hill with an incline of greater than 1 degree and even some wind involved

Apologies for the amount of questions - but it's keeping me up at night going over it in my head!

Firstly if you getting 180km from 80l of gas (thats 44.4l/100km) i would getting your current set up tuned!!!!!!!

1) I'm not a big fan of gas research but thats only my opinion. For the cost (gas research seems pretty expensive) i would get an EFI manifold (unless already efi) and then just get a cheap impco system with a 225 mixer. These are able to handle boost when u use a balance pipe and a few guys on here have done it succesfully and on the cheap. You can pick these up for nothing on ebay and they are a sinch to tune.

2) I think u can only run scuba tanks there.

3) Getting it tuned will give better economy. I average around 23l/100km around town and about 21l/100km on freeway. Doesnt seem to change whether i tae off fast or slow.

4) U could probably use the turbo but it will prob run out of puff a bit early. U will never really know 100% untill u do it.

5) I was going to go diesel manifold but i have seem in some cases that it puts the turbo too close to the firewall....but people still use them so dont count it out. I got a custom extractor manifold made up for $800 which is only a little more than some crappy cast diesel ones.

6)Just use a boost controller. Got mine for $30 or something. They bleed the pressure from the turbo to the wastegate actuator.

7) Yes u can run a blow off valve. Not sure about cooler. but i wouldnt bother with 6psi!!!

Jimmy


PS do a search there is a fair bit of info

Hey jimbo,

Thanks for the info mate!

It has been tuned on a dyno and in normal day to day running I get about 360km's from 90ltrs which from what I can ascertain is pretty much the norm - I used to get 420 on 31's, I now run 33 after getting rid of my 35's due the lack of power

Mine is currently a carbie setup so the EFi route is out of the question as I think it'll be too expensive and a lot more complicate - I love simple set ups!

How much would the impco system with a 225 mixer cost roughly - the gas research stuff looks as though it'll be about $1100 all up...also I assume i'd need to adapt some type of throttle body setup to make this option work - XF falcon maybe?

I'd really like to try and use the WRX turbo as I have one which means it's one less expense - my budget for this whole thing is hopefully gonna be no more than $2500...

As for the manifold I was even thinking of using a stock TB42 manifold cut and shut to suit - I currently have extractors...

Cool about the boost controller - I have a few of those kicking around - I knew all the performace car stuff I've hung onto over the years would come in handy (full fixed bucket seats, turbo, intercooler, boost controllers, guages etc )

You're right - I probably won't bother about the cooler - but it's there if I need it....

Is anyone running a Flashlube system by chance - several mechanics have told me to definately run one of these if I'm gonna be on straight gas??

Cheers Phil

Firstly i didnt mean go efi i mean just get the EFI intake manifold that way you dont need to make some sort of adaptor or use an xf one.......plus they flow better than the carby inlet manifold!!!!!

Not sure how much they cost but it is a lot cheaper than the gas research stuff. I'm not saying Gas research is crap but its a lot more expnsive and harder to tune (u did say budget setup).

I did ask around about getting extractors moded for teh turbo but they all said they are too weak....remember it has to support the heavy turbo over all kinds of bumps and stuff.

Look up raptorthumpers setup in his 4.5 GU. I know yours isnt efi but with teh efi manifold it will look exactly the same.


I'm also looking at getting mine setup for under $2500

Jimmy

i have a tb42 straight gas turbo, which runs a gas research throttle body and mixer, before the turbo setup it was just petrol.
I had gas research install a whole system and tune for $2800 which i thought was quite reasonable, best bit was i got $2000 back from the goverment.
I am running a turbo diesle manifold bought brand new $400
Front mount cooler which dose help as these setups on the tb42 produce huge amounts of heat.
The thing that i found made all the differance was a good ignition system, to start with i was runing after market parahnar ignition the car went but needed to be tuned rich in order to stop pinging(running rich = more heat) occassionaly it would backfire splutter and just play up due to lack of spark.
I had performance ignitions build me a high energy scorcher distributer with boost retard $850, made it a hole new car to drive have not had a problem since. it was expensive but worth every cent.
good luck with your set up

I don't suppose you have some pictures you can post up do you - or even email me if it's easier?

Was the $2800 including the turbo setup, or did you put that all together and just deliver the car with everything ready to go bar the Gas Research system fit-up and tune? What type of turbo are you running with the TD manifold and when does it start to come on boost? As for the cooler I'm certainly keen on using what I have, I was also planning on cutting some serious venting into the bonnet to allow the heat to get away - I'm also a huge fan of exhaust rap and those types of products so will be using these aswell. My extractors are currently rapped and it made a huge difference to the under bonnet temperature as it is...

As for ignition - I'm having troubles of that nature now I think (lumpy idle, hard to start and the odd back fire - considering it was dyno tuned 5000kms ago and was perfect… ) - I'm gonna throw a new set of points in it for now to see if it fixes the problem temporarily - if it does I was gonna get a Pertronix for it - I already run a MSD 5 and Blaster coil so that side of things is good.

Just out of interest do you run an airbox with filter

Cheers Phil

the $2800 was just the gas system and tune i did the hole turbo set up myself.
My turbo is a T03 turbine and T04 compressor with internal waste gate.
boost comes on at around 1600 to 2000rpm which is probably a bit late depending how you drive, although now boosted the motor will rev quite easly to 5500rpm.
i run a modified air Vl commodore air box with 4" inlet and outlets which flows really well but is not quite good enough filter. ordered a donaldson today.
keep in mind i had a hole sgas system installed from scratch. think the gas research throttle was about six hundred on it own.

Thanks for the info mcgill,

Do you run one or two gas tanks?

If the T03 your running comes on at those revs then i'd imagine my WRX turbo will probably come on even earlier - I can only try I guess....

Where about's do have you located your airbox - do you run custom snorkel to match?

Just finally what sort of k's are you getting out of how much gas?

Cheers