VZ Alloytec 175 2 Hole mod

[Torquative]

Hey all,

Im sure this has been mentioned elsewhere BUT I thought I'd say I finally got round to doing the 2 hole mod.

I decided it was time to clean the air box as it had some oil build up across the bottom from the K & N filter being a tad over-oiled.

So while I was out I decided to do the "2 hole mod" which is so popular with V8's. Afterall, all it costs os $20 worth of materials and a few hours.

I followed the instructions here -
http://swingtan.customer.netspace.net.au/2hole.html

At the bottom of the howto he says

It’s much louder, if sound is anything to go by, it’s made a huge difference. But sound isn’t always a good test and I don’t have a dyno handy. The first time I really stuck the boot in though, there was a funny response. The car picked normally until it got to about 3500 RPM, then it was like the engine had VVT. It certainly picked up faster from 3500 to around 5000 and it wasn‘t just the feeling of being pressed back in the seat. I saw the tacho pick up faster from 3500

So I took the alloytec out for a spin. First thing I notice, a growl at light acceleration! Nothing too much but definately different

Onto the 50kph streets, yeh nothing too much.

Get onto the freeway where we go from 50kph to 110kph. Stick the boot in and my lordy, what he said above! Nothing special at low revs, as is typical with the alloytec, but once the RPMs picked up and the air started being funneled into the engine bay the thing pressed me back into my seat like a turbo had just kicked in, or VVT had just kicked, or something had done something.

On the freeway I tried overtaking. The 4 speed kicks back to 3rd, revs and takes off like theres no tomorrow!

Moral of the story, if you've got a few hours free DO THIS!! I did it in between certain parts of the Indy telecast. Cost me $20 for 1 meter of 90mm diameter plumbing pipe and some sandpaper from bunnings. Just gotta flare the ends of the 2 pieces of pipe and paint them matt black tomorrow for that factory look, but you will definately notice an increase of some sort.

[colk]

Nice tutorial!! Will have to do this soon

[VT Berlina 07]

haha, i did the same with mine (ecotec but) cant say theres any diff in power but the noise is louder

[GOTMYN]

Funny you say that, I just did my Eco... recently and This week had my usual 0-100 Race with a mate from work in his 190kw VZ SV6, it is normally me jumping him off the line, and then it evens out with me gaining a car length or two on him before we back off to get back to the 80kmh speed limit, but this week, even he pointed out, that when I shifted to second and started to gain speed, I shat all over him... Like 6 car lengths.... Thanks Home made CAI... so it seems!!

[Torquative]

Im definately impressed, as Ive said, and good to read so are others!

I never knew an Alloytec could create a growling noise at low revs and for so cheap. Still sounds awesome taking off from a set of lights

doy ou guys run K+N filters or just the standard paper ones? just curious

[=SKB=]

Im definately impressed, as Ive said, and good to read so are others!

I never knew an Alloytec could create a growling noise at low revs and for so cheap. Still sounds awesome taking off from a set of lights

doy ou guys run K+N filters or just the standard paper ones? just curious

Now you've had a week of daily driving how's the fuel economy? Any difference? The performance still there?

[AttaBoy]

Wouldn't it be sucking hot air??

[lacy18]

I did this mod a few months back and I definitely noticed a difference. Although its not much, for the cost its worth the effort! As for sucking in hot air, if you make the pipes as long as possible then the ends actually sit behind the headlight so it only sucks in cool air not all the air from the engine bay. Here's a couple of pics from when I did mine

[Troy711]

did mine the other day and it cost a big fat $0.00 cos i snaked the pipe off a job. it kinda feels a little smoother and it is alot louder but no louder then when you remove the snorkel.

dunno who asked the question RE filter... but mine is a normal paper type

[AttaBoy]

Can this be done on a VS?? Reason I asked because the air box is smaller. Not sure if this will make a big difference.

[Torquative]

the car went into the mechanics on Saturday for a service and the guys asked me "whats different about your car".

They told me they service many VZ's and they took mine for a spin round the block, put the foot into it to give it a good clean out and noticed an "awesome vaccum roar type sound while the car just took off from under me like Ive never experienced in a VZ V6". They then said "we had a good look when we got it back, its a stock exhaust and we can see theres no pod filter, whats different?" (coz I told them to leave the air filter alone as its a K and N so they had no reason to rip the lid off the air box)

With the radiator shroud back on you cant see the airbox mod so it does look stock which is good too!!

[VT Berlina 07]

lol i know, its sounds good. it makes people look. eg when in 2nd gear @ about 50ks and nail it theres that sound

[andrewmac]

do u have any pics of the mod ? i keep forgetting to have a look

[colk]

does anyone know if it effects holden warrenty? I am getting the dreaded vz knock in the diff and dont want to give em any reason to void warrenty? although then again modding the air intake cannot effect anything with the diff or trans so it shouldn't be an issue?

[=SKB=]

does anyone know if it effects holden warrenty? I am getting the dreaded vz knock in the diff and dont want to give em any reason to void warrenty? although then again modding the air intake cannot effect anything with the diff or trans so it shouldn't be an issue?

Maybe waiting until your diff gets sorted would be the better option.

[HoldenMan7]

Maybe waiting until your diff gets sorted would be the better option.

Yeah i have to agree, if it was me i wouldnt be doing it until, the warrenty is over, just incase

[-SV6-]

It is a cheap mod. Buy another airbox and do the mod to it and keep a spare for services or warranty.

[colk]

Good thinking, will do

It is a cheap mod. Buy another airbox and do the mod to it and keep a spare for services or warranty.

[Burnie]

Has anyone dynoed this mod? What might be nice is a series of runs from stock with stock airfliter, stock box with K&N, K&N with 1 ram tube, K&N with 2 ram tubes.

It does sound like nearly free HP though, and I never look a gift horse in the mouth!!!!

[Scottyo]

I did this mod a few months back and I definitely noticed a difference. Although its not much, for the cost its worth the effort! As for sucking in hot air, if you make the pipes as long as possible then the ends actually sit behind the headlight so it only sucks in cool air not all the air from the engine bay. Here's a couple of pics from when I did mine

Yes it will be sucking hot air you have to fit the shroud that comes standard on the VY After shroud then you will notice difference 2 fold....
Just took some pics off the phone camera, so they are a little grainy. As you can see the cut out is towards the upper part of the shroud, this shroud was part # 92096849 (only came with the single hole to suit VZ Monaro). but all that has to be done is trim away the section and it should fit in. It will take some squeezing to get it into place and fit snug behind the headlight. I had to get some extra foam tape to seal everything up nice and tight.

These photos will show you how to do the Monaro Cold Air Intake You have to cut 2nd hole in the shroud.







Hope this helps guys and happy modding

[CMA]

Hey guys!

Is there a way that the two hole mod can be done using flexible piping to capture cold air from the big voids in the lower front of an SV6??

Is there enough room at the side of the radiator to run the piping around, anyone know??

I guess what im saying is, is behind the headlight the only place that you can run the pipe to draw cold air??

[Troy711]

i have often thought about that, but never actually got off my arse to check it out properly

[Torquative]

dunno bout SV6 but when i looked at doing that with the 175 it would need some pretty heat resistant piping, because it will touch the radiator hose at some point, and that gets bloody hot!

I think it can be done, but as I said, needs to have fairly heat resistant hose

[Logan]

Hey CMA

- I did the Two hole mod the other weekend on my 2005 VZ ute using flexi-pipe.

3" Pipe cost $30 from Super-cheap and comes with a couple of tension clamps (not needed for Two hole mod)

I drilled into the SIDE of the air-box as opposed to the front (side furthest from engine), and then ran the flexi-pipe out and down under the head light.

The head light has to come out to get the pipe through, and then the pipe has to be squished a wee bit to get the light back in.

From there it is pinned up beside the horn to suck cold air from the small grill hole to the right of the number plate. (This grill is normally filled with a solid plastic facia, but I have ripped them out and put steel mesh in instead.

Will get a better line-up with the grill hole when I move the horn out of the way this weekend, but currently getting a dramatic improvement to pick-up around 3500 - 5000 rpm.

[bludeck]

Mod completed! soiunds abit deeper unnder acceleration didnt notice any power or economy gains tho :S