Jump to content
SAU Community

Recommended Posts

Hey guys

need some opinions. eventually in my R31 i want to run an RB20DET on straight gas, but i cant afford the new motor at the moment (as ive just spent 800 bucks gettin the head re-machined after a blown gasket - ouch). I am considering having the standard RB30 built for straight gas operation (ie pissing off the whole fuel system, gettin a bigger tank, removing the fuel tank and puttin the gas tank under the boot floor). Any ideas if this has been done yet, and if it is a good idea to do. I know i have to get brass valves and shit like that so it doesnt stuff up majorly, but im tryin to get rough pricing ideas cos no-one in adelaide wants to take me too seriously. i mean, they're more interested in poxy s13 silvias than a sleeper lookin 6 that could have a stomper of a motor underneath it (i apologise to any decent silvia owners).

Anyone who can help let me know

Matty T

If you're going to do it, it's worth doing a bit of research.

If it's done properly, you'll be very happy with the result, if it's done on the cheap, things will start to fall apart.

Check out gas research kits.

The most important thing in a gas only system is proper lubrication.

As far as octane goes, LPG is around 110 octane. Regular petrol 92(ish) octane and PULP 95(ish) octane

I had a VS V8 Commodore that towards the end was getting real heavy on petrol due to mods. I looked in to supercharging it as cams in the ol' 5ltr really do stuff all and use too much petrol.

I looked in to an EFI gas setup that used LPG Gas injectors. I also looked in to the gas research carbs which was cheaper but didn't yield as good results as the gas injectors.

The RB30 with a high comp 9.5:1, the twin cam head, a nice GT30 turbo would get it moving very very nicely on gas.

Cheers for the info so far guys...........Its good to know that i can get some people out there who take me seriously. Its almost the way to go now, my biggest thing will be is if i have to do anything to the ECU or not

  • 3 weeks later...

No you won't have to do anything to the ECU. Usually you have seperate gas computers and the switch that will switch from Gas to Petrol (or the other way around), but that's about all the electronics involved in a gas system. I've probably missed something out so someone correct me.

AFAIK a dedicated gas system is better that dual fuel, since there is a compromise on both fuels making less power etc.

Saw a RX3 or something in a mag that ran LPG, apparantly the exhaust ran really hot and it was always buring holes in it...or do rotors have a hotter exhaust temp anyway?

a lot of work, and for what gain?

There isn't too much work, i've helped do a LPG conversion and it isn't very hard at all just gotta get a mechanic or something to fit the tank and lines properly. Also gains would be cheaper gas prices!! also the EPA say that any car running straight gas is 100% under emissions, so there will be less trouble from them!

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • I haven’t pulled the injectors to watch them spray yet but they are clicking from the cas and all of the spark plugs are wet with fuel. I’ve thought the cylinders were being flooded from the beginning and was hoping fuel pressure would fix it. Tonight I am going to pull the rail and watch the injectors spray. Don’t know how to test/diagnose if the plugs are firing in correct sequence but that should be a timing thing and as far as timing goes my car still has the half moon for the cas can only install it 1 way. And my mechanical timing is 100% correct I posted photos above. Confirmed with the balancer on and off. 
    • I checked spark on all cylinders and they all visually have spark with the plug pulled and grounded, but plug 1 is the only one that fouled. This was a running swap that blew up and was rebuilt by a machine shop, put a new wiring specialties harness and did all gaskets, studs, and bolts while it was out.  compression is 135-150 across all cylinders. Aside from that from my understanding with the z32 ecu and maf the car should start regardless. The wiring for TPS and the dual 02 sensor/ dual knock sensor stuff shouldn’t actually stop the car from starting or even running well, (just slightly rich)  they just give fault codes. Car supposedly is supposed to start as long as you have z32 afm and ecu with the nistune base map and that’s info coming from a well known and trusted tuner who does a lot with SR/RB (Rsenthalpy). After more trouble shooting today where I’m at right now is that the cas is sending signal to the injectors they click while spinning the rotor, Fuel pressure is now set at 43psi, all cylinders have good compression and all of the plugs looked great (just wet with fuel) except for cylinder 1 which was very black (cylinder 1 has 150psi compression). all of the coils generate spark if pulled out and grounded out on the head. On the fuel pump car just pops into the exhaust. On starting fluid car will fire off. Hard to tell if all cylinders are firing off but definitley a couple. sounds like all of them but it’s only for 3-5 seconds hard to tell. 
    • Final update!!! Got the front bar fitted and sprayed and all sorted now. My cutouts worked great and the indicators aren’t just falling off. 😂  
    • Is this a brand new LSD? if so, have you followed any break/bed in procedure for it? Usually involves heaps of figure 8 patterns, a fluid flush.
    • It's TWO steering wheels actually. 😛 one for each hand They are wheels, and they steer!
×
×
  • Create New...