Proving Why The ZF 8 Speed Is The Way To Go.......
Having previously ran a GRT Powerglide in her S15, Naomi knew she could rely on a GRT built ZF 8HP to keep edging towards those goals.
At first Naomi was a little apprehensive to make the change from the 2-speed Powerglide that she loved to an 8HP. She admits it has been a unique experience. From learning how the car responds differently to learning to drive it again- Naomi admits the change has been an immense improvement from the 2 speed Powerglide.
When Naomi upgraded the turbo, it ended up lagging a bit with the Powerglide and was no longer suitable for street driving. When Naomi bought the S15 in 2014, she was aiming to build the car as a reliable all-rounder street and race car. We couldn't argue that the 8HP was the right step in that direction.
"The drive to Lakeside and in between the tracks and home was amazing with 8HP75." Naomi
When it comes to getting data, the more the better!! Testing this setup began last year at 2024 Brisbane Jamboree. Naomi hit the ground running and learnt that the new set up had brought out some new weak points in the car and unfortunately, breaking the pinion on the R34 GTR Diff.
The diff was replaced and next up was the 6 banger Nats. The S15 ran 5.9 @ 130 mph to the 1/8 mile with only 27 psi of boost. This mph was very close to the powerglide PB of 132 mph. But unfortunately, another R34 diff broke. After realising it was getting expensive, Naomi opted to upgrade to the Platinum Racing Products 8.8'' Billet Diff and axles upgrade.
"We are getting some good data and closer to the original PB done with the powerglide."Naomi
Naomi's original PB with the Powerglide was 8.42 sec @167 mph 1/4 mile. Which was done at Brisbane Jamboree in 2023.
Recently, Naomi took the S15 for the ultimate test, The Road Trip Drag Challenge. Starting at Lakeside, on Friday, the almost sorted road tune proved a bit too spicy for the no prep run when Naomi almost added some traffic cones for her collection.
On Saturday, Naomi proceeded to Warwick Dragway and managed to get the times down to 5.79 sec @ 131.31 mph to the 1/8 mile.
Sunday's racing ended up at Willowbank Raceway, where Naomi managed to clock a 5.75 sec @ 131.63 mph.
Handling 1200+ HP with 8HP75 seems to be no issue in the S15. With all the driving between race locations and racing, there was roughly 500 kms of driving for the weekend. The 8 Speed is proving to be the option to go when wanting to have the street-race car setup without having to choose one without the other. It can definitely be said that Naomi is enjoying the 8HP setup, and is not regretting dropping the powerglide.
What’s in the box?
Naomi currently has our 1200 hp rated 8HP75 build in the S15. Recently the 8HP made an appearance in the workshop for a health check and small upgrade with the Billet D clutch hub going into it. Her build currently consists of the following:
- New upgraded clutch pack including steels - increased clutch count
- Genuine ZF overhaul kit (new seals o’rings and gaskets)
- Billet 'A' clutch pressure plate
- New Upgraded pistons.
- Genuine ZF New pan and filter kit
- New Bushes, bearing and washers
- New Billet 'E' clutch hub
- New Billet 'D' Pressure plate
- Billet D Hub
- Modified planetary sets
As for the converter, when we spoke to Naomi about the transmission build, we opted to go to a Pure Drivetrain Solutions converter as the standard one, unfortunately was not up to the task.
Transbrake......
Not surprisingly, we get asked about this a lot. The best thing with the ZF 8 Speed transmissions is that the transbrake control is done through the TurboLamik TCU. Using the TurboLamik TCU, we are able to control the 8 Speed in almost any application.
Other set-up notes....
When choosing a shifter, Naomi chose to go the DCT style shifter over the traditional BMW. To make the 8HP75 fit, the transmission tunnel needed to be chopped. Naomi also chose to go with the billet pan over the factory style plastic pan.
Naomi's GRT - Transmission Specialists built 8HP75 doing a 5.75 sec @ 131.63 mph to the 1/8 mile at Willowbank Raceway
So what is the final verdict of the change to the 8HP setup??
"I am loving the 8HP so far." Naomi
Photo Credit: Goleby's Parts, Drag Photos and SL Images
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