Update 2003.02.04
[After about 2 weeks of use, my "HKS" wastegate failed on me. As it turns out, it appears that there is (or was) a company making knockoff HKS products. I managed to get one of these gates. To avoid this happening to you, here are some comparison pictures:
Fake Gate:
Fake gate 01 - HKS gates don't have the allen head bolts in the bottom flange
Fake gate 02 - HKS gates do not have countersunk bolts on the diaphragm cap.
Fake gate 03
Fake gate 04 - this is *completely* different
HKS Gate:
HKS Gate 01
HKS Gate 02
HKS Gate 03
HKS Gate 04
HKS Gate 05
A comparion: (HKS on the right)
Comparison - not flange sizing differences.
A few images of the dead gate:
fork it 1
fork it 2
fork it 3
fork it 4
fork it 5
fork it 6
]
This is my second attempt at an O2 housing. The first time I bolted on a stainles 2.5" housing for an internal gate, dumped to atmo. This time, I did what I've wanted to do from the beginning, which was to order a 2.5" O2 housing for an external wastegate, plumbed back into the O2 housing.
There are a few reasons for the change. First, the external gate means that boost control will never be a worry again. external gates can control boost much better than the stock flapper, which will get blown open at high boost, not flow enough air, ad nauseum. The internal plumbing is because I didn't like the noise and mess of the external dump. (yes, I smell something too)
Plus, it is necessary to be legal for SCCA Solo II Street Modified, which is the main focus for my car. Lastly, I chose to go with an O2 mounted setup since it seems to be what folks prefer these days. the idea of venting all cylinders equally rather than just #1 makes sense to me, and they say it sounds cooler ;-). So be it.
Installation Notes
For most of us out there, moving to an external wastegate setup will mean converting your turbo from an internal gate to external. This means you have to remove the old flapper door and wastegate actuator, port out the hole leftover, and slap the new O2 housing on.
I'll assume you know how to, and have already gotten your turbo off the car. If you don't know how, I provide some quick instructions in this VFAQ, or you can find more complete ones at VFAQ.com.
The first step to this is removing the wastegate actuator. This is two 12mm bolts, and undoing the little cotter key holding the small end on the lever arm of the flapper door. (fig. 1)
Next, remove the turbine housing from the turbo. For more specific instructions on how to do this, see my turbo clocking VFAQ. Once the housing is off, (fig.2, fig3) you can begin your modifications.
Removing the flapper is a 2-part process, or at least, it was for me. First, I took a skilsaw with a metal cutting blade and cut the lever arm off of the flapper. After it is off, you can see that the flapper door rides inside a metal bushing pressed into the turbine housing. (fig.4)
Next, I took a die-grinder and ground off the small peg that holds the flapper door on the arm. Once the flapper is removed, you can pull the arm out. (fig.5) You will need to take the housing to an exhaust shop, or similar, to have the hole formerly occupied by the lever welded shut.
Now it's time to hog the heck out of the hole where the flapper used to be. Give this as much volume as you dare, so you can avoid boost creep later on. See the figures for my porting (please, be gentle), and for a friend's FP Green that I got a look at. The only thing that I particularly noticed is that FP's portwork seemed to really direct the airflow to the wastegate portion - gave it a nice straight path to take, rather than a sharp corner to turn. If you haven't done much porting, or don't have somebody that knows their stuff to help you out, it might be worthwhile to send your t-housing off to FP or somebody and have it ported.
Now that all that silliness is taken care of, go ahead and bolt the turbine housing back on the turbo and reinstall the turbo in your car. Once you have the new O2 housing in hand (be sure to allow quite a while for this - they all seem to be pretty slow), slide it on the turbine housing and torque down the four 14mm bolts that hold it on.
If you haven't done it recently, I'd highly recommend running a tap (M10x1.25, I believe) through the threads on the turbo (and a die through your bolts) to clean them up to make sure that the O2 comes off easily next time. Most of the O2 mounted gates require that you have to bend the oil dipstick a bit out of the way, or perhaps grind a bit of off the P/s support bracket. As well, you will likely need to have either a slim fan on the driver's side (or none at all) to make sure the gate will clear.
When installing your new O2 housing, more than likely you'll have to molest the dipstick a bit to get it out of the way, since the new housing will likely have a wastegate right where the dipstick used to run. As well, the O2 sensor will probably be relocated a touch as well. Andy put it on the underside of the housing curve, which makes it a piece of cake to get on and off, which is a welcome change from the factory location.
As one final note, be sure to use a quality TiAL or HKS wastegate - new Deltagates seem to have horrible longevity reputations. I went with HKS since Andy said it was a bit easier to plumb back to the exhaust.
Impressions
I got my housing from Andy Beachly at 122 Performance, with an HKS wastegate installed on it. Several very fast DSM's are using O2's built by him, so I figured I'd give it a shot. Andy makes the O2's out of mild steel, rather than Stainless, which some others do. He does coat them with some sort of high-temp black paint, which looks nice.
Installation was quite easy. Andy listened to all my concerns about fitment - I have dual slimline fans, and wanted to keep them for cooling purposes. As you can see, (figs 16+) fitment on the p/s pump is quite tight, but fit just fine. I was even able to install the O2 with the turbo on the car.
The result? I absolutely could not be happier. Boost response and top-end are hugely improved. With that last bit of porting I did and this new O2 and wastegate, boost response above 4000 is instantaneous. I have full boost by the time my foot hits the floor. There is absolutely zero boost creep, and maximum 0.5 psi spike with my Hallman controller. I just have a line run to the side nipple, and the top is open to atmosphere, which is standard for a non-EBC setup. Since the wastegate is plumbed back in, I couldn't hear any difference in the sound of the gate opening. I chose a standard 14psi spring to go with my wastegate, which looks like it will work fine.
With as well as everything, fit, looks, and performs, I'd install this again in an instant, and recommend Andy B at 122 Performance highly.
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fig.1
fig.2
fig.3
fig.4
fig.5
FP Green Porting 1
FP Green Porting 2
FP Green Porting 3
FP Green Porting 4
FP Green Porting 5
my porting 1.
my porting 2.
my porting 3.
my porting 4.
my porting 5.
fig 16.
fig 17.
fig 18.
fig 19.
fig 20.
fig 21.
fig 22.
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