Lpg Stagea Rs4 Series 2

[RS4StagMan]

Many have asked about my LPG conversion over the last few months.

Here are some details and photos.

Car: Stagea Series 2 (R34 RB25DET Engine)

Installed Date: July 2007

Fuel: Dedicated Auto LPG 100+ RON (Mixture of Propane & Butane) [No petrol]

Alternative Fuel: Sometimes run "Premium LPG" 100% Propane, 105-110+ RON available straight from browser in VIC. www.supagas.com.au

LPG System: Dedicated LPG

Gas Research throttle body and Gas Research converter (www.gasresearch.com.au) with mechanical injection based on engine demand and boost, own ECU to control LPG system with throttle position, oxygen sensor etc connections

Initial Tuning: On road and in cabin data download of info based on real world conditions

Cold Start: Gas Research Primer thermostat controls fuel delivery under cold conditions (starts first click even when outside ambient temperatures approach freezing point). Bypasses factory cold start circuit

LPG Tank: 59 Litre useable capacity manifiold tank (APA TANKS AUSTRALIA) placed under car in place of original petrol tank, retains original tank connection points. Torana style SLR 5000 drop tank to cover LPG tank

Wagon Space: Not affected

Fuel Economy: City 17.8 litres/100 (330 km range). Highway 14.8 litres/100 (400 km range)

Cost per tankful $36.50 based on current $62c/litre in VIC

Calculated Payback: Calculated at 9 months before conversion in July 2007. Payback is after $2000 federal governmant rebate

Actual Payback: Only 6 months due to bigger difference in price of LPG and petrol. Payback is after $2000 federal governmant rebate

Filler Location: Factory location

Fuel Gauge: Factory gauge reused

ECU: Factory Nissan ECU

Ignition Timing: 25 degrees advance static timing adjusted on Crank Angle Sensor (CAS). Factory setting is 15 degrees for petrol.

Ignition Timing Curve Remap: Piggyback Timing Computer allows up to 15 degrees advance in addition to above static timing setting of 25 degrees (Up to 40 degrees initial advance!).

Retains factory ECU retard of timing on auto gear changes.

Coilpacks: Spitfire

Boost: Turbotech boost controller

Petrol Infrastructure: Tank and pump removed, lines, injectors etc kept in place for any future reinstatement

Exhaust: JJR front pipe and CATCO hiflow catalytic converter. Factory catback system

Modifications: Nil apart from above

Future Work: Dynotune and ignition timing setup (we think the car can take more than 40 degrees initial advance without any knocking!)

Future Endevours: When the technology is proven in Australia for high performance forced induction applications, skip the (SGI) LPG sequential gas vapour injection technology altogether and go to LPG Liquid Injection technology!

[EvoMitchy]

looks like a good idea mate- do you have any dyno graphs for torque? I will be towing with my stag so dont want LPG reducing the torque

also how will modifications affect fuel delivery? ie will raising boost require the lpg ecu to be retuned?

Cheers

Mitch

[RS4StagMan]

Torque and HP curves will be available once put on dyno (see above- dyno yet to be done).

Low and mid range torque, HP and boost response has been improved already just with the front pipe mod. Ignition advance available at 40 degrees + should see an improvement in HP and torque.

The guys from VL Commodore land with LPG RB30DET's report that just by tuning and increasing static timing and boost slightly has dyno proven increases in HP and torque over most of the rev range over petrol.

Already running around 11.5 psi boost and it was tuned this way.

The initial tune on LPG has been set up slightly rich leaving a bit of headroom for future boost increases if required.

[D3RV]

In terms of future modding; are there mods which simply cannot be done due to the fact that the car has been converted to gas?

Also do you mind filling us in on how much the whole process costs, and how the government rebate works.

Thanks man.

[chef_stagea]

what did it cost you after gov rebate? and how long did it take them to get you your car back? im asuming all is normal apart from more $ in your pocket eventualy!...ive seen falcons etc that run on both gas and petrol... would this be possable?? daily on gas and once every so often or track days switch to petrol???

[RS4StagMan]

what did it cost you after gov rebate? and how long did it take them to get you your car back? im asuming all is normal apart from more $ in your pocket eventualy!...ive seen falcons etc that run on both gas and petrol... would this be possable?? daily on gas and once every so often or track days switch to petrol???

The overall cost of the system was $3750.

The following is a copy of what I posted in the "The Gas Thread" on 11th Jan, 2008.

http://www.skylinesaustralia.com/forums/Ga...&hl=economy

For my particular situation, the payback after the $2000 Federal Government grant (WA gets an additional $1000 state grant) is 9 months, based on;

Monthly Savings $189

Payback Period 9 months

Annual Savings $2268

Weekly Savings $44

Based on: Annual Km:25000

Petrol Consumption 15L/100km

Cost of petrol/Litre:$1.45

Cost of LPG/Litre:$0.65

Conversion Cost $1750

These potential savings are indicative only

based on a range of fuel consumption.

Calculations include the benefits of Federal (and State) Government grants (rebate).

Using this calculator here

http://www.lpgautogas.com.au/index.cfm?action=MyCar

I got better than the 9 month payback, in fact repaid cost of system is only 6 months due to increase in difference of petrol cost from $1.45/litre to about $1.65 /litre.

Conversion took about a week to do.

Dual fuel has been done may times before with sequential gas injection (SGI) technology [there are a few other threads about this in the "Stagea" section and also the "Forced induction" section of the forum] and with older mixer systems.

I prefer to tune to one fuel only, in this case being LPG therefore having no compromises in tune between the two fuels. I think there are people looking at having two completely different setups in ECU's for dual fuel....but until that is sorted and proven, I like to run either on petrol or LPG- but not dual fuel.

[RS4StagMan]

For those who have asked the LPG tank that was used is the 3 manifold tank package.

Dimensions are (3x203 OD x 840 length). 59 litre useable LPG.

APA TANKS- MODEL G84.

http://www.apamfg.com.au/main_pages/product_downloads.html

[RS4StagMan]

In terms of future modding; are there mods which simply cannot be done due to the fact that the car has been converted to gas?

Also do you mind filling us in on how much the whole process costs, and how the government rebate works.

Thanks man.

Well, limitations on mods that I can think of;

a) the tank does sit about 200mm off the ground at the back so maybe some limited scope for lowering at the back, should be able to lower the front no probs.

The 'SK' lowering Bilstein suspension kit (group buy) might be fine given that you can adjust the ride height or you could have adjustable coilovers?

Always a good idea to check before you commit.

My car isn't lowered at all.

b) Tow bar- the "Max" special (Canberra?) or similar made up tow bar may be problem to fit after doing the conversion with the tank where it is, but anything can be made to work. Possibly measure up before you contemplate the conversion to verify that it will fit with the LPG tank

I don't have a towbar on mine.

c) Anything to do with fuel control.....such as piggy back SAFC as you no longer have petrol

In terms of the rebate process look here....

http://www.ausindustry.gov.au/content/leve...07A2EFBDB3D4AF7

Relatively painless process except that you need to pay upfront and get your $2K back ($3K back in WA) via Centrelink or Medicare offices. Mine took about 2-3 weeks to get the rebate back.

[thedriver]

Many have asked about my LPG conversion over the last few months.

Awesome thread RS4StagMan. Nice details.

I live in Canberra and have been trying on and off for the last three years to find a suitable dedicated, injected system for my Stagea. Unfortunately, because of environmental factors in Canberra's winter (-10*C) and the snowy mountains (-20*C), cold starts on a vapour injected system aren't an option.

The GTi Stealth Injection System and LPG Liquid Inject system are both looking very promising, I just wish they'd come to market.

Can you tell me what sort of temperatures you experience in winter and how your cold starts are in the middle of winter?

Good to finally see a conversion. Congrats!

[RS4StagMan]

Awesome thread RS4StagMan. Nice details.

I live in Canberra and have been trying on and off for the last three years to find a suitable dedicated, injected system for my Stagea. Unfortunately, because of environmental factors in Canberra's winter (-10*C) and the snowy mountains (-20*C), cold starts on a vapour injected system aren't an option.

The GTi Stealth Injection System and LPG Liquid Inject system are both looking very promising, I just wish they'd come to market.

Can you tell me what sort of temperatures you experience in winter and how your cold starts are in the middle of winter?

Good to finally see a conversion. Congrats!

I'm in Melbourne and we rarely see anything below 0 degrees. With the Gas Research system and the primer device, I have so far managed to start the engine down to 0 degrees ambient temperature without a problem.

You should probably have a chat to the guys at gas reasearch (www.gasresearch.com.au) in Q'land [talk to their technical guys] and some of their approved fitters about cold start as they may have a better product available or can adapt the above primer arrangement to suit your needs. Failing that, dual fuel may be the option for you.

Cold starts should be less of an issue with liquid LPG injection.

As you say both the Liquid Injection LPG systems you have quoted should be good however I understand are still not available to the market.

The only LPG Liquid Injection system that I know is going to be made available in the next few months is from....

http://www.australianlpgwarehouse.com.au/

JTG Italian LPG Liquid Injection system...supplier claims only 5% loss in fuel consumption compared with petrol and increased efficiency "Like turning a 4.0 litre engine into a 4.5 litre engine".

Not sure how long it would be until available for performance and forced induction applications but maybe worth contacting them....

[FelixTRX]

I believe there is a mob in SA playing with the JTG on a BA XR6T and getting very good results with the gas injection system.

Think I read something about it in Street Machine or Zoom or something.

We are seriously looking at it for down here in Tassie but it's the cold start issue which is holding us back (and waiting for tax returns too!)

Cheers, Greg.

[inmate]

A primer switch would eliminate any cold starting probs you may encounter.

Simply turn the ignition on, hold the button for a few seconds to fill the vapour hose with gas, release button & kick it in the guts. No Problemo!

I have used a primer switch on a car with approx 4ft of vapour hose. This thing would have been extremely hard to start had it not had the primer installed, but once primed & the hose filled the gas nowhere to go except into the engine...

[RS4StagMan]

A primer switch would eliminate any cold starting probs you may encounter.

Simply turn the ignition on, hold the button for a few seconds to fill the vapour hose with gas, release button & kick it in the guts. No Problemo!

I have used a primer switch on a car with approx 4ft of vapour hose. This thing would have been extremely hard to start had it not had the primer installed, but once primed & the hose filled the gas nowhere to go except into the engine...

This would be a 'manual' priming switch arrangement that you have descibed above that should work fine.

What I have on mine is a 'automatic' arrangement that starts to flow LPG from the converter into the motor (via the throttle body) as soon as the key is turned over and the engine starts to crank- no switch to press. The result is, as you say, No Problemo.

Another way would be to 'manually' prime (press the button on the LPG converter) a few times before you start it- but who wants to pop the hood every morning and do it this way? Much better to have control in the cabin, or better yet an all 'automatic' arrangement.

[webng]

If this was available in Adelaide I'd definitely be on it considering I would be more than halving my fuel cost. Thanks for the info.

EDIT: Might even be worth the trek over your way in xmas to get it done. How long did it take to do?

Edited July 18, 2008 by webng

[MRO]

If this was available in Adelaide I'd definitely be on it considering I would be more than halving my fuel cost. Thanks for the info.

EDIT: Might even be worth the trek over your way in xmas to get it done. How long did it take to do?

i am sure you will be able to find a gas conversion place in adelaide. plenty of places should be able to give you the same set up. all the gear is from the same warehouse, it is only the tuner that differs.

[DARKMAZE]

I was just wondering if this was a carbie supplied setup, or an EGI setup.

Only confused, as I can't seem to find the info anywhere on the Gas Research website, and you mention Mechanical "injection" and an ECU, which I wouldn't have though would be required for a carbie system?

Cheers.

[RS4StagMan]

I was just wondering if this was a carbie supplied setup, or an EGI setup.

Only confused, as I can't seem to find the info anywhere on the Gas Research website, and you mention Mechanical "injection" and an ECU, which I wouldn't have though would be required for a carbie system?

Cheers.

Yes, it is a throttle body (carburetor system), as stated above in original post, not a sequential gas injection (SGI) system into the engine manifoild. But with a difference.

The injection part of it is, as i understand, a single injection point into the throttle body from the converter. There is a solenoid inline between the two that controls LPG flow based on inputs that the 'CTI Processor' gathers from the engine. The solenoid is controlled by 'CTI Processor' according to engine demand/acceleration.

I say 'mechanical' injection because it only controls the LPG fuel by opening and closing the solenoid (mechanical device) and doesn't control the actual injector itself 'electronically', although it sends the pulse signal to the solenoid 'electronically'.

Go to www.gasresearch.com.au, look under "downloads", then "CTI Closed Loop Instructions"- It is all there.

The factory throttle body was replaced with the GRA (Gas Research Australia) type using all the factory intake pipework. It has seperate and multiple stages of control from idle/cruise and WOT (wide open throttle).

Not very easy system to tune by the average LPG installer, so you need to get a specialist tuner, but can have nice performance potential when set up correctly- and is not limited to about 200 RWKW like some 'SGI' LPG systems.

[MRO]

I am going SGI - l am scared of the carby style set up. Without a good installer (you obviously have one) it can be real trouble. I dont plan to crack 200kw in this car.

[DARKMAZE]

Yes, it is a throttle body (carburetor system), as stated above in original post, not a sequential gas injection (SGI) system into the engine manifoild. But with a difference.

The injection part of it is, as i understand, a single injection point into the throttle body from the converter.

Oh.. ok.. So, it is a throttle body injection system (similar to say an early Camira EFI setup) with a single injector located in the throttle body.

I had a conversation with a friend tonight who was talking about the original Bosh (I think it was Bosh) mechanical injection setup where the mechanism was designed to be run mechanically off of say a cam. Sounds like a similar setup, but with a Solenoid powering the setup instead. Makes sense now. Thanks.

[inmate]

Any chance of seeing more pics of the rear end and tank set-up?

I went in to see my installer today but he is worried about the tank clearance.