The stock EFII 6 cylinder motor has had a couple of mods done - headers, removed the cat, K & N air filter, an XR6 air intacke snorkel The results of these minimal mods have been a slight but noticeable improvement.
The next steps to more power will be a much bigger job.
To do the job I bought from a wrecker an EFII XR6 cyl head complete with injectors. Latter, I bought an ECU from an XR6, AU injectors, a new AU head gasket. A $320 investment all up so far. I'll get the head crack tested & skimmed, but the project is at a point where I am wondering if the XR6 head swap is the best way to go, or if a cam and some work on the existing cyl head is better?

Regards
Bruce

Last edited by citylimits on Mon Dec 21, 2015 12:37 pm, edited 1 time in total.

Did you get the XR cam with the head?

injectors in the XR head are exactly the same as the GLi injectors.

Since you already have the head, might as well use the XR6 head.

As SWC mentioned, did you get the XR6 cam with it?

Personally I'd use the EFII XR6 head, grab an aftermarket upgrade cam such as a Wade cam (or their equivalence of today), such as a 1636 profile, which will give you a much more noticeable improvement and is automatic friendly. Wade 1674 will have a rougher idle and was not recommended for automatic transmissions. If memory serves me right, there was an cam profile that was between 1636 and 1674 profiles that was automatic friendly. While the head is off, you could send it off to get mild port/polish while you still drive the car around.

AU injectors are a good upgrade over the E-series as the spray pattern is better, however it is best to get a higher fuel pressure regulator to go with it. I'm not sure if AU fuel regulators are higher than the standard E-series, I do know though that the E-series XRs came with a higher fuel pressure regulator.

To get the most of all the mods I'd suggest getting a better exhaust system to go with the bigger camshaft.

When you got the AU MLS headgasket, did you get new head bolts as well? You can't reuse...or should I say recommended, to reuse the head bolts as they are torque to yield (TTY). Once off use as they stretch once they have been torqued up.

While you're at it, to get the most out of an upgraded cam, get a variable camshaft gear...that way you can adjust and dial the cam in properly to cam spec.

Thank you both very much for your suggestions.
The XR6 head was complete and included the cam when I bought it..
New head bolts were included with the AU head casket as a kit that I bought on e-Bay 2 or 3 years ago around the time I bought the XR6 cyl head. I thought about changing to ARP studs but something - I can't remember what now - meant I abandoned the idea, Probably the cost - it's usually something like that.
Using the XR6 head I have here it looks like from what you have said is that further gains can be made the choice of a better and auto trans friendly cam. I didn't know about cerain cam profiles being more suitable to use with an auto trans than others so you have given me some valuable intel.
Along with the crack testing & skimming I will ask the machine shop to also do some mild head work undertaken to improve flow as well.

As soon as I can in the new year I will make take the XR6 head to a specialist machine shop and,
get this project underway.

Thanks again for your help, its been great.

Regards
Bruce

No worries
Just FYI, if you get a regrind camshaft, you will need extra shims in the rocker arms to make up the amount shaved off the cam.

EDIT: just noticed I put my post in your quote.

Last edited by phongus on Wed Dec 23, 2015 9:05 am, edited 1 time in total.

Faced with a possible dilemma if this is true I have been told that apparently its important to know if the XR6 cylinder head, computer and LSD Diff Head 3.45:1 I have were originally from cars with either manual or auto shifts.
I don't have this information and know of no way now to find out being that all these parts were gathered together over time and from several different cars.
Is the transmission type relative to these parts matter to any extent?

Thanks a lot.
Bruce.

Last edited by citylimits on Sun Nov 06, 2016 1:17 pm, edited 1 time in total.

Only the ECU is Manual or Auto.

The other parts were used on both auto and manual.

Hey mate - How the hell are you?

Still rocking on I see, bloody good to see this too!

You have auto and a wagon - the parts you mention - XR6 head with original cam and valves etc) will go straight on with your AU gasket set. The head itself had no signs of leaks when I saw it on the original block - it is is the one I am thinking of)...

Kerry Lindsay is the man for getting the head milled flat to make sure... There is another place at bottom of Wainui hill that I can recommend, but Kerry did mine for under a hundred bucks, and I had reshaped things myself - maybe this gave him a smile on the inside rather than cringing like most do...

These guys have worked on these engines for years on stock cars around Wellington.


You can leave all the parts on the head if you want... He'll sort it all...

Other things you *may* want to do is to put in the XR6 fuel regulator (300 rather than 270) and a set of AU injectors (which don't work well all that well at 270... AU XR6's were 350 - standard AU 300 basically)....

The coomputer you have standard will run all this fine.

You have EF, not EL right? If you have EL I even have an EL XR6 computer here that I have been trying to sell for ages and is currently $40 on TradeMe, give or take.

This will help with some shift changes etc etc to suit that diff and also give you a bit more bang for buck out the head without J3 reprogramming....


Anyway matey patatee... Don't check my email on this site, virtually ever, but reply here.... Will say hello again sometime....

Also happy to give you a hand if you need it... I have no garage ATM, in a state house out Avalon way. Sad to say the perfect little twenty year old I was with was far too perfect, so ended up homeless, broke and back in Wellington area... To be expected really, but some of us do punch outside our weight after all.........



Any hooooooooooo...

Have torque wrench and wouldn't be the first head to have been changed in a driveway.... Even remembered to put all the bolts back in the cam last time I changed one, so things are improving!

STD AU 6cyl are 270kpa, XR are 300kpa and VCT are 350kpa

Holy shamolie, Tony, hell, I thought you were dead! The last time we spoke was taking a flight of stairs at Wellington hospital and that must have been getting help with my weight loss programme also know as chemotherapy.
Great to see that your absence was due to some tap dancing with a tight twenty year old - well done, young fella - well done indeed. Now after all of that you are at your Avalon retreat - thats you and Futurelane - right?
Yes, that's right mine is an EFII wagon. Nursing a nasty scar at the right rear quarter where I used the side of the garage door opening to remove the rear bumper. Life was nearing too perfect anyway so an adjustment was long overdue. This time of the year all the panel shops are streesed with work until after the New Years break - well the decent ones are anyway and with no show dates for the old tart to keep I am happy to wait.
The XR6 conversion has been in the planning stages for a while now - ever since, I bought the XR6 head from you. That must be a while back now but in the mean time I've been building up additional parts to make the plan work. Kerry Lindsay - Porirua or Petone?
Any way lots to talk about give me a txt if you can - 0220428942 - the Milky Bars are on me.

You will also need an AU/B series Fuel Rail to use the AU Fuel Regs. They won't fit an EF/EL Rail.

Rather than adding AU parts to an EF head would installing an AU XR6 head be a way of achieving the same outcome?

No, fitting an AU/B series Fuel Rail is no big issue, easier and cheaper than buying a AU Head.