Outer Limits 4x4 Board

I have a Mav carby 4.2.

My aim is to turbo it utilising second hand parts.

I have purchased an EFI manifold with throttle body which is minus the fuel rail injectors and some ancillilary parts which I will blank off. When turbo'd it will be straight gas.

I was asked on the weekend whether I would go injected LPG at any stage but that requires an existing EFI setup with computer and the injected gas computer would have to piggy back the original.

Questions.

Could the original GQ processor/computer be installed and effectively run without the petrol fuel injectors, and all the other bits and pieces. ie would the computer get confused without the oxygen sensor, anti knock, etc...

I think it would also require the EFI dizzy and loom.

Lots of probs I think but????

http://www.outerlimits4x4.com/phpBB2/vi ... sc&start=0

Im no nissan ECU expert, more familir with the E Series Ford ECU's.

However i would have to say that without the appropriate inputs from sensors like the O2, MAP, Temperature, Throttle position and the like, the effectiveness of the ECU would be almost useless.

You only have to look at the way an EFI car runs when any one of the ECU attactched sensors is faulty to know that it will cause you problems.

The other option would be to have the OEM ECU re mapped for use without them, if thats possible.

TJ,

thanks for the input. I think you are on track.

I had planned to go straight gas just utilising the throttle body as I don't have an ECU in my model. Injected gas was an afterthought but in the end it would turn my 'on the cheap' into an expensive fitup.

cheers

RN

Hotrod the manifold to accept the GRA mixer in place of the throttle body. Very common.

BowTieGQ wrote:Hotrod the manifold to accept the GRA mixer in place of the throttle body. Very common.

And a lot more effective, than a BBQ ring or Impco 425 in the line in front of the throttle body.
I have helped built lots of XF Turbo's using that setup. Most of them were EFI originally, but all are now straight gas.

Thanks for the update. What does hotrod mean...is that modify and adapt to the manifold??

Also how does the throttle work without a TB? Does the GRA mixer do both.

Are they dear???

Any pictures of a finished conversion?

RoadNazi wrote:Thanks for the update. What does hotrod mean...is that modify and adapt to the manifold??

Also how does the throttle work without a TB? Does the GRA mixer do both.

Are they dear???

Any pictures of a finished conversion?

Yeah, hotrod means modify/fab up.
The GRA is the new throttlebody, the cable hooks up to it. Mulisha is running the kit my Brother supplies, and has pics posted up in his thread.

GRA is the go for all round tunability can change jet sizes etc like a carby, mixer and TB in one. neater etc etc etc

but if your a mega tightass...

b2 mixer, impco 225 mixer, and biggest TB from the wreckers (performance gas shops will chuck em at ya as they remove em to fit the Gas research stuff)

but search through mulisha's thread's, if you cant suss it out from the info given to him, then you wont be doing it on the cheap

GRA's mixers retail at only $440+ GST anyway. Converters are less than $200. It probably is the best LPG setup just not the only option. But I'd say do it for sure. Have a really good GRA fitter tune it though. It is different to setup and must be right to be worthwhile otherwise worthless. Unsure where you are RN, let alone which state, but if in Melb metro do try Crushu's brother. Knows his shizle.

If your heart is set on injection then have you considered the megasquirt ecu ? ( do a web search on "MegaSquirt" ). Can be purchased as a kit or ready built.

Its very low cost, completely tuneable and not really that complex, if you have some knowledge of EFI basics and are prepared to read the infomation available. Can run spark and fuel - including lambda sensor which is a cool way to ensure your getting optimal mileage.

But if your looking for a bolt on, ready to run solution then its not the way to go. It also requires you to have/develop some tuning knowledge - which is good if you interested in that sort of thing.

Have a read anyway - can't do any harm at the worst you will feel more confident in whatever decision you make.

BowTieGQ wrote:GRA's mixers retail at only $440+ GST anyway. Converters are less than $200. It probably is the best LPG setup just not the only option. But I'd say do it for sure. Have a really good GRA fitter tune it though. It is different to setup and must be right to be worthwhile otherwise worthless. Unsure where you are RN, let alone which state, but if in Melb metro do try Crushu's brother. Knows his shizle.

I am located in Frankston and Chrushu's brother is in SE suburbs so it is only a few gear changes away...

Thanks for the info. I have the GQ EFI manifold for $ 150.00 and I czn get the turbo for $200.00 so I think in time the budget would stretch to get the right mixer.

cheers

RN

RoadNazi wrote:Chrushu's brother is in SE suburbs think in time the budget would stretch to get the right mixer.

cheers

RN

Carrum Downs

I understand that a GRA setup is the way to go but what is the disadvantage of using an impco 225 mixer like "raptortumper's" setup? I only ask because i'm turboing my gq and already have the 225 mixer?

Cheers

James

I called in and visited Gas Research people in Dandenong today. Nice blokes. GRA mixer sounds right , $480 retail including tax, Convertor $225 then a hi flow cut off.

That sound like the most expensive part.

Still I am not after a lot of grunt just more torque down low from 1500 to 3000 rpm range as I rarely go over that.


Anyway thinking of projects stops me from getting ...........uh.....

.....dementia.

Still I am not after a lot of grunt just more torque down low from 1500 to 3000 rpm range as I rarely go over that.

In that case, buy a Volvo.
No really, it's not that expensive, but it is the most. But worth it in my opinion. Injected Liquid LPG will be the next big thing. Until then, GRA.

We played with liquid injection, as have a lot of people here and overseas, 10 years ago when I was with Gasresearch Australia, but there were a lot of issues with the injectors freezing due to the atomization of liqiud at the nozzel and agressive wear and so on, thats the main reason we are seeing medium pressure vapour injection, easier to control. Lpg expands 270 times as it changes state from liquid to gas and the injectors struggle for fine enough control. Liquiphase had a crack at it years ago and gave up, I remenber pulling a Liquiphase system off and putting Gasresearch on years ago as it was unreliable.

The Gasresearch is still a great product but unfortunatly the company that bought it out (St Francis Mining) have done no product development since they took over in about 2000. Thats partly why I got out of it.

Joel

Joel,

after speaking to Peter at GRA place in Dandenong, I think he said that the convertor they supply is modified to keep the amount of gas up to the engine whilst on boost. Any idea what convertor they would be supplying?

B2 converted?

Some one also in the industry advised having two B2 convertors?

Early days yet but trying to get my old head around what I will be up for.

RN