XGTRX

Bright pink keeps the fuel cooler too

It's called respect. Don't see much of this anymore. Sign of the times mate.

Stock. Use 5-10W40 Build. depending on tolerances 5-10w40 to 50

What's the dump and exhaust size

found it http://www.autospeed.com/cms/article.html?&title=Pure-Pipe-Perfection-Part-1&A=0877 important sections of the article: Going from 2 1/4 to 3 inch. Hungry for an Improvement?Before running out and whacking a new system onto my Commodore VL turbo (which is already equipped with a high-flow air intake), I first wanted to see how badly the car needed a big exhaust. Was investing a large bundle of cash in a new system gonna be beneficial, or was I just squirting it up against a wall? The only way to tell is by measuring the engine's displeasure, in the form of exhaust back-pressure. Back-pressure can be measured with any accurate boost pressure gauge connected through the wall of your exhaust pipe. Under high engine load, pressure builds in the exhaust and you'll soon see how choked up the engine gets. In my VL turbo's case, I decided to take measurements at two different points in the factory system - one at the first bend in the exhaust pipe, and another right up behind the turbocharger (in the cast elbow). My aim here was to identify how bad the factory dump pipe/elbow was. The pressure fitting in the exhaust pipe was easy to tap (I had a short length of metal brake line welded flush into the side of the pipe), but the one behind the turbo needed a little more ingenuity. I opted to make up a fitting to screw into the location of the factory EGO sensor. This was constructed from a threaded bolt with a hole drilled through the middle and a short length of pipe welded onto the end. Rubber hose was used to connect each fitting to the in-cabin pressure gauge. Now, I had already suspected that the standard (2½ inch) Holden AC cat converter was collapsing - and this was confirmed when I saw how far the needle on the pressure gauge swung around. On the road - at full power - there was an 80 kPa (11.6 psi) build-up in the exhaust bend and a full 90 kPa (13.2 psi) at the back of the turbo. Ouch - that's a helluva lot! Note that the closer to the engine you take your measurement, the higher the cumulative back-pressure reading will be. Naturally. Curious to see how much of that monumental amount of back-pressure was caused by the obviously clogged cat, I dropped the sucker from the car and took to its inners with nothing less subtle than a crow bar. After a couple of minutes of battering, the entire inside of the cat converter was removed and its hollow shell then re-fitted to the car. Back on the road (with the boost pressure gauge fitted to the first exhaust bend) the exhaust back-pressure was still through the roof. Try 70 kpa (10.3 psi) at full noise... Indeed, a noticeable improvement in response and torque was felt with the collapsed cat guts removed - but, regardless, this level of back-pressure was still way too high for any high performance application. AND AFTER THE EXHAUST INSTALL After choosing the right vital indigents, the VL's new exhaust has made it a different car - and for a grand total of only $630 (including the $220 cat). Throttle response is vastly improved, boost builds much quicker and top-end urge is markedly up. (accidental wheel spin off the line is now very common!) And peak exhaust back-pressure? Well, our initial reading at the front of the system (just behind the turbo) has fallen from a huge 90 kPa to a mere 20 kPa - a stonking 82% reduction in back-pressure! And restriction across the factory cast dump pipe was not even measurable! Of course, this reduction in back-pressure has also yielded a significant increase in 0-100 km/h performance, with times falling from 7.6 to 7.1 seconds (measured during 30-odd degree C ambient temperatures).

That doesnt tell the full story though. There was a good article on autospeed i read ages ago. I will try to find it for you.

Same, picked up so much midrange doing the same thing. Chalk and cheese really

It will be a totally different car. The previous exhaust setup was a nugget. Just be careful until you get used to the newfound midrange torque explosion.

Slow mo it so it goes for 20 ha ha

Post the video on youtube and link it. Come on I have gone through a tonne of popcorn waiting for this.

Fark that's a health figure for lowish boost. Nice a safe AFRs at that level I bet. Whats spring pressures are you using in your wastegates?

Dyno vids? Want to hear the whistling

Awesome results fatz . Do you have a comparo with the to4z. Would be interesting to see it graphed against your current set up. Look forward to seeing those times drop too. That midrange should make a huge difference.... Assuming traction holds up. It would be like getting comfortable with a new car all over again. Looking forward to the first track outing shakedown.

Is this why you get more transient response in between gear changes, in that the larger wheel has more momentum? I remember vaguely a discussion that implied that even though a turbo with a larger exhaust wheel is laggier to build up boost is less prone to falling off boost on gear changes.

Not good enough. Can't wait until next week or I will have to get counselling

Anyone got any experience Pro-boost stuff. I am considering the GT35 orTo4z T4 bush bearing kit, manifold and wastegate. The rotary guys don't mind them. Any fair and truthful info would be great.

Pete, i bet your car will be a different beast mate. Beware of the traction or lack there of when she comes on boost. And get them to film it on the dyno and post it up here. Best of luck

Your incorrect proclamation not mine. If anyone with - 5s has issues with rexxys, you are shit drivers probably the same people that need - 9 or 7 to launch off the line properly and make up for your lack of skill.

Go 5s, don't listen to the - 7 fan boys. Best daily/fun set up by far.

This

Gearbox rebuild: Competition gearboxes 97201187. Have a chat to Simon, nice bloke. Look them up. Garrett 2860-5 turbos

But somehow 'gtr and kids' go well together, so wins all around.

'Gtr and marriage' somehow they don't go well together