The Big Single TO4Z Turbo on a forged RB26

In the early 2000’s modifying Japanese import cars was the thing. Forums like Nissan Silvia and Skylines Australia were awash with budding Japanese car owners and your status on the forum was based on the ride you had. More importantly, how powerful your ride was. It was a funny time. I however kept the modifications to my car totally secret, I wouldn’t open my bonnet at all for people to see. In fact, I offended a lot of people by blatantly refusing to discuss or show my car off.

For the small group of people that saw what was under my bonnet it was evident that the one item took centre stage under my bonnet. That was my Garrett TO4Z! 

Background of the T04Z turbo

The TO4Z in the early 2000’s was the weapon of choice for GT-R owners. The single turbo on most forged bottom end RB26’s behaved very similar to the HKS 2530 low mount turbos. TO4Z saw full boost at around the 4500rmp with an amazing mid range and top end. These turbos were easily getting GT-R’s in the 400KW mark with the highest result I heard of being around the 480KW’s. These power figures meant that GT-R running the Garrett TO4Z were all in the 10 second quarter mile bracket.

The TO4Z’s were released by Garrett and HKS. The difference with the HKS version was the trim on the wheels of the turbo and the anti surge holes on the comp cover of the turbo. The HKS T04Z in the early 2000 was priced close to $4,000 with a full HKS TO4Z kit costing close to $8,000 (turbo, manifold and external gate). The Garrett equivalent T04Z was around the $1600 to $2000 range which made it a far better alternative at the time than the HKS version.

My TO4Z setup

When I finally made the decision to go with a big single from my original Blitz twin high mount turbo set up. I first purchased the stainless steel high mount manifold from JMS. HKS manifolds were retailing upwards of $3000 and so were the other major Japanese performance brands. Instead I opted to buy the JMS manifold which retailed at $1800. I initially was expecting a lower quality manifold to the HKS branded manifold but when it arrived I was pleasantly surprised. The JMS manifold was actually better than the HKS manifold I was comparing it to. So much for paying 3K for a lesser quality manifold to the cheaper JMS version. 

Soon after taking delivery of the manifold I made the purchase of the Garrett TO4Z turbo. I went with the .82 exhaust housing which matched the power curve of the HKS 2530 turbos. I wanted a whole load of mid range with a decent top end hence why I didn’t select the larger 1.06 housing.

My next purchase was of the Turbosmart 50mm pro gate which was purchased at Autobarn. At the time the gates were daily expensive, priced at around the $800 mark. The Turbosmart gates are a thing of beauty and I recommend anyone going with a Turbo that requires an external gate go with the Turbosmart range of gates.

I chose to go with a huge air filter and custom ordered one of the larger filters from K&N. For the screamer pipe and the elbow join from air filter to turbo I used a series of stainless steel bends which costed a pretty penny. Not to mention the amount of silicone and hose clamps I had to buy which wasn’t cheap. All up I think I would have spent around $5,000 for the full kit including oil and water lines which is a saving of about $3,000 on the HKS kit.

What it was like to drive with this turbo kit

To be honest it was laggy! But I think that was due to the massive cams I was running. I chose to go with the HKS Step 2 10.8 lift 280 degrees input and exhaust cams. Very lumpy which made the car come alive in the top end; gutless on the bottom end. 

To drive the car on the power band was amazing! At one point the 4WD wasn’t working on my GT-R and so it was stuck in rear wheel drive. The car with the T04Z set up used to step out easy. Even when going through the gears in a straight line I was fighting to keep the car in check.

The sound of the external was something that I can’t put down in words. The look on peoples face, especially pedestrians when they hear the car was entertaining to say the least. One of my brothers friends was driving on the same highway as me unbeknown to me. I gave my GT-R a small squirt and he called my brother and I quote “I just saw your brother in his GT-R. He gave it a bit. It sounded like the world was coming to an end”. I still laugh to this day at what he said.

Another time where I gave it a small squirt was after playing some street basketball with my friends. I opened the car up after a short rolling start. When I got back my MSN messenger was full of chat windows open all talking to me about my car and how mental it sounded. One of my friends Ramy commented “You’ve inspired me to buy a GT-R”. Oh fun times when the car was on the road.

My final thoughts

I do miss having my 32 GT-R with a T04Z turbo kit or a single turbo set up for that matter. With todays turbo technology my 32 GT-R with a single would go like a bullet. It really is a shame that it is illegal in the state of Victoria to have external gates, even if it is plumbed into the exhaust. But what would you rather? A GT-R that you can drive without problems from the cops or a monster GT-R with a massive single turbo hanging off the engine? I’d like to hear your opinion. Please use the comment section below to join the discussion.