Car's been running A1 and nothing to report. Its been a great daily driver through the 4C and 6C of winter we've had so far, as long as you watch your throttle input at times.
In 2014 (I think, I can't quite remember) I bought the JHP "300kw GTS MAF Pipe kit" from JHP online. This was supposedly the best MAF pipe kit available online, it was engineered to be strong, less restrictive, etc... So being new to the car, I bought it. I think it was about $100 or $160 online and came with a rubber coupler at the MAF end.
(You can probably find the JHP MAF pipe if you google image search it)
Fast forward to 2016 and the car began to run slightly rough one day a few weeks ago. I checked everything and got a code for unmetered intake airflow (lean). A quick visual inspection revealed the JHP MAF pipe had developed cracks through it and the rubber coupler it had come with was deteriorated and perishing as well.
Now the JHP MAF pipe is only made out of about 2mm (possibly thinner) plastic and over time its just not beefy enough to hold up to the vibration and rigors of the shaking engine and it cracks which gives an unmetered air leak past the MAF.
I patched the cracks and am generally pretty unhappy with the JHP MAF pipe because it only lasted 2 years in service before falling apart, whereas even the factory corrugated MAF pipe lasted 13 years with no issues.
I have found a better MAF pipe. And a weirder MAF pipe.
Behold the CMS (Conrod MotorSport) "Adrenalin" MAF pipe. Thats a mouthful right there.
This strange looking thing was hand fabricated out of carbon fibre for the LS engines, back in the early 2000s. It was one of the first aftermarket MAF pipes available in Australia around the time of the VX and VY. So its actually fairly old. They are no longer available for sale anymore. I found this one second hand with big gouge scratches across it, as it it had skated across a concrete floor. I couldn't get the scratches out so I painted the pipe with some bronze wheel paint.
This thing is beefy- its about 3mm thick carbon fibre so its not going to crack any time soon. I've ordered some proper silicone couplers for each end of it as well.
It has two ports underneath it- one for PCV air intake, and one for intake air temp sensor for various models of LSI. Having the intake air temp sensor in the airbox, and having the PCV in the throttlebody, I blanked both these holes with rubber grommets.
I haven't put it on the car yet, as I'm waiting for the right silicone couplers to get here. But its a lot stronger and better made than the JHP pipe.
It's designed properly for a start and has provisions for an air sensor and PCV connection. Every pipe I have seen doesn't have PCV which I need on the VZ. I mean yeah you could drill a hole but that's a bit shonky in my opinion.
^And I suspect I could skateboard this carbon fibre pipe down a flight of stairs and it would stay structurally intact, whereas the el cheapo thin plastic JHP pipe crumbles with engine vibration within 2 years of use.
The standard OEM corrugated MAF pipe is sturdy as well, but it looks pretty awful in an upgraded engine bay. And the corrugations don't flow very well. A smooth bore MAF pipe is good for a very, very ever so slight increase in performance.
I spoke too soon. One fuel injector (cylinder number 5 on the passengers side) decided to start leaking yesterday. So its off the road until a replacement injector arrives.
Debating a set of aftermarket billet fuel rails as the factory one doesn't seem the best at sealing, even with new O-rings on the injectors. Not sure at the moment. Seems as though the one issue thats common to LS engines the world over, is poor sealing of the injectors. Many forum topics, many people asking how to fix it, and many people saying they see more leaking than not leaking. I'll see what I can do..