Hi all
I wanted to post this review on a couple of UK forums as I personally found it really hard to find any real world views online from GT4 owners who have been down this road themselves.
The mods were done to my 2016 981 GT4.
My history of Porsches has seen my own various 911s, and a GT4 previously. In fact recently I went 981 GT4 to 991.2 GT3 and back to my current GT4. While this may seem odd, I love the GT4 platform so much and it feels just a better mix of value vs useable power and handling for our UK roads. Loved the GT3 but felt I was paying for so much I couldn’t use and wanted back into a GT4. I share this history as a hopefully explanation that I am not chasing power and torque unnecessarily, just wanting to get to the right level.
I have just got my low-miler GT4 back from nine-excellence having had the following mods completed:
- Gearbox rebuild to change gears 3, 4 and 5 to closer/shorter ratios
- Kline 200cel exhaust manifold
- 997 GT3 throttle body and associated IPD/Plenum upgrade
- 9e tune to wrap it all together.
There's lots online about this package of mods (see Sharkwerks in the US etc) but little written by actual UK owners that I could find.
As many will know/have read, the long gearing on the GT4 is a bug-bear for many. Not as big an issue as many like to make out, but an issue all the same and I personally find you spend too long out of the power band to get the best out of the car on the road. This is particularly true when changing from 2nd into 3rd unless doing licence-losing speeds.
The gearbox mod is naturally designed to tackle this. I wont bore you with why 2nd isn’t changed but it’s a seemingly much more expensive job that no-one seems to offer. The theory is that you bring 3rd closer to 2nd so there is little to be lost changing from 2nd to 3rd and lots to be gained. Likewise 4th and 5th are much more accessible in every day driving.
The rest of the mods just help to get the best out of the 3.8 DFI engine and take the power up to the right-side of 420bhp.
Its early days back with the car but I am so pleased with the results. Everything I read on US sites about the Sharkwerks package is correct, the car feels noticeably faster through the gears, with much more useable torque and a more rewarding manual driving experience all round. I have always thought 400bhp is the sweet spot for road driving in a car of this weight in the UK, and the mid-range performance characteristics of the engine are now a little closer to a turbocharged unit but with all the benefits of it still being naturally aspirated. There's further you could go with an unlimited budget (lightweight flywheel, LSD etc) but I didn’t feel the need, and it can bring some additional challenges.
The unexpected part for me is the impact on the noise. Wow. The already-great sounding car now sounds a lot more exotic with the Kline (using the standard PSE), without adding any drone when driving in 6th or taking it easy. This was a massively unexpected bonus for me as i thought the manifold would really just add power but not change too much else. (I suspect the newer 718 GT4 has exactly the right level of power and torque but I deliberately went back to the 981 as the sound is a huge part of the mix for me - im still pretty childish with it.)
I Was really impressed with Ken and his team at 9e who were excellent in advising me on the route to go and through the process generally. I felt very comfortable leaving a 2500 miler that was just stepping outside of its warranty comfort-blanket with them!
Hope this helps anyone else considering a similar project.