More power out of a dedicated gas AU2

soulink · 25-05-2010, 05:47 PM

Hey guys,
Just wondering ive got pacemaker 4499 headers, 100CPSI cat, and 2.1/2 catback exhaust. ive also got the BA XR6T snorkel with a K&N panel filter.
jsut wondering would there be anything else i can do to it that would give it more power without shoving a cam and stuff into it?

Thanks
soulink

Auturbo6 · 25-05-2010, 06:02 PM

Not really..... However if ure looking for a cam get in contact.

Bushbasher · 25-05-2010, 07:32 PM

It all comes down to more air in - more air out. Right now, your biggest restriction to that end is the mixer ring, Camming it up won't help you much above 3000rpm as the mixer won't flow any more than it already does. your stock petrol TB is about 60mm or so but with a mixer tacked on the front of it that size suddenly goes down to not much over 40mm, The cheapest mod you can do if you can find one, is to get rid of the mixer ring and replace it with an Airod variable mixer. Look in on the LPG forum and do a search for more info, then join the list of people standing in line looking for one, lol. I was lucky enough to grab one and I can tell you that it has made a difference to the performance of my missus' wagon, and that's basically stock. With a decent exhaust system I reacon it'd get up and go quite well.

Bushbasher

Mr Hardware · 26-05-2010, 09:02 AM

Quote:

jsut wondering would there be anything else i can do to it that would give it more power without shoving a cam and stuff into it?

nope.

**Mechan1k** · 27-05-2010, 06:18 AM

I found the LPG cam I had in mine really brought it to life ... yeah it was still a bit strangled up top ... but at least it was still making power at the top of the rev range and not dying off.

My mechanic actually used my ute as a guinea pig ... and it worked a treat ... no tune either (probably would have made more with an EDIT too).

Another way to bring these alive is to change the diff ratio too ... to make it easier to get the things off the line. I had a rebuilt trans in mine as well (that was built to manually shift ... and had been setup for a supercharged XR6) ... boy it was a nice auto to drive after i had that put in.

soulink · 27-05-2010, 11:15 AM

well maybe it was good timing for my diff to ****** itself then

, haha

T3man · 27-05-2010, 12:14 PM

Yep, I use a 3.73 diff and it helps.

However, on the mixer ring thing? Why would you have one? If it's an EFI engine surely you have a complex convertor??? No mixer ring on mine and it goes just as hard on gas as petrol, in fact better down low with the more advanced timing. I have standard factory exhaust (well almost), and intake.

The only other way to make it go harder would be to lighten it a bit - try deleting all your speakers and amps.

Just kidding.

GK · 27-05-2010, 05:55 PM

Quote:

Originally Posted by T3man

However, on the mixer ring thing? Why would you have one? If it's an EFI engine surely you have a complex convertor??? No mixer ring on mine and it goes just as hard on gas as petrol

Please explain your comment about no mixer ring!

GK

T3man · 27-05-2010, 06:35 PM

I have two cars (AU 4.0L and ZL 4.1L) that don't have a mixer ring - the gas is drawn through a simple venturi with an adjustable "jet" (for want of a better term). It is thus drawn directly into the inlet tract upstream from the throttle. A third, Capri V6 has a simple dual inlet venturi sitting atop a throttle body off an XF 4.1L (68mm I think) adapted to the OE manifold - so it is like a donut but not restrictive as it doesn't sit inside the throat. I have one other that does use a donut mixer but it is a 2.0L Escort with a 65mm (I think) throttle body off an EF 4.0L motor adapted to the OE manifold - so the air flow restriction caused by the ring is certainly not an issue.

**Mechan1k** · 27-05-2010, 08:04 PM

Dedicated LPG AU's run a mixer ring (integrated into the throttle body) ... different to some aftermarket setups.

If you can get your hands onto an Airod variable mixer (rare as rocking horse dung) ... and change your throttle body over to a petrol version ... you will get better results from it as the intake is less restrictive.

As for diffs ... I was looking at 3:73 also for my previous work ute. If my current ute needs a diff change I'll be definitely be looking into getting a shorter gearset.

T3man · 27-05-2010, 08:18 PM

My bad - I didn't realise the dedicated factory gas systems were so archaic. Explains why my Fairmont wagon eats them all day every day on the hills. LOL.

**Mechan1k** · 27-05-2010, 09:16 PM

Yeah it sucks a bit. I really should have picked up a variable mixer when i could (have seem them at work in an Fairmont V8 wagon ... and man it ran better on gas than petrol.

Mind you though ... I found with the cam that low down torque was brought in much earlier ... and the torque curve was fatter and meatier than the factory cam. This made for a massive increase in drivability more than anything. I found there was less need for the auto to downchange as there was more torque on-board at lower revs.

And the good thing as well ... I didn't need an EDIT either ... although ... it would have benefited a bit more from one. Drivability was good straight out of the box.