Rennlist - Porsche Discussion Forums - [4.5L GT4 review] Best sports car ever made?

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Engine/drivetrain:
Deman 4.5L conversion with X51 heads
718 Clubsport Intake Manifold with GT3 TB
Deman Motorsport race headers
2.5” Valved Soul Performance catback
K&N air filters
Shortened Guards gears 1-4th
Upgraded clutch and lightened flywheel
Numeric short shifter
Cobb Accessport tuned

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(had to grab a 3rd gear datalog for Rick :evilgrin:)

Power - As AP said 500hp is more than enough for a naturally aspirated Porsche. 4.5L gives you more than that :) you have an instant wall of torque on tap. Pair that with sonorous tone of a large displacement engine, it’s pure ambrosia. We can all agree all turbo Porsches sound like vacuum cleaners. Give me that naturally aspirated flat 6 howl ANY DAY along with smooth, linear power delivery.

I'm currently running a 2.5" valved Soul Performance catback and below 4000 rpms the car is pretty quiet with no drone (girflriend/wife/HOA approved). There is so much low end torque that the car is even fun below 4000rpms cruising around town and through school zones like the angelic, low abiding citizen you are. In my opinion GT3s never sound good below 6000rpms (nonsensical clattering at idle) unlike the 4.5L which sounds wonderful at idle and at low rpms. Once you take it up to 6000 rpms up to redline, the valves open up and the sound is like a horde of stampeding elephants behind your head, an utterly primal and visceral rumble that you feel at your core. It does have the 9000rpm menacing chainsaw-like buzz like the GT3 but it sounds way deeper. I would go as far as to say the sound at 6000rpms to redline in a 4.5L is better than a GT3 at 9000 rpms AND the 4.5L makes more power with LESS rpm than a GT3 ever could at 9000rpms.

Weight - 981 GT4 only weighs barely above 3000. GT4RS is 3200lbs and GT3 3120lbs. Sure Ariel atoms are lighter but I would like to feel safe in a crash and I (ESPECIALLY the significant other) like the bare necessities of a full interior with A/C.

Balance - Low center of gravity inherent to a boxer motor in a mid engine setup is the best balanced configuration I can think of. Furthermore having the weight over the rear wheels greatly improves traction and you'll need plenty of it with the torque the 4.5L cranks out. Think of all the front engine RWD M3's, mustangs, Hellcats, just lighting up their rear wheels and not going anywhere. You can also have the option of converting to multi link rear if you're hardcore at tracking. The cayman utilizes space in a very purposeful way which makes for an intimate experience between man and machine. There are no backseats to rip out and have a bunch of useless space behind your head.

Transmission - 6 speed manual is a must. When you buy an automatic car, you are buying 50% of the car. You don’t appreciate how light the flywheel is when you blip throttle, you don’t appreciate how light/heavy the clutch pedal is, you don’t appreciate where the engagement point, you don’t appreciate the precarious balance between stalling and moving from a stop. You don’t appreciate the shortness of the gear throws, you don’t appreciate the precision of the shifter and the tactility of rowing gears. You don’t appreciate the pucker you feel taking one hand off the steering wheel when you shift at 110mph with the car screaming at redline, hoping the car keeps going straight. Heel toe downshifts require usage of all 4 limbs in a highly coordinated fashion whereas in an automatic even your grandma can just flick a paddle. The manual transmission gives each car I own a distinct idiosyncratic feel. I have 3 vastly different presets in my brain depending on which car I decide to drive.

Automatics? Just put car in drive. I will never own an automatic sports car. I’ll take that to my grave. You can talk up how awesome a sport car is but when I see two pedals, I get completely soft. I rather drive a manual Corolla than an automatic Ferrari.

I have a Numeric short shifter, light flywheel, and massively shortened Guards gears with 2nd topping out at 68mph. It is the best feeling manual set up I ever felt. I can enjoy the car while staying at legal speeds. If I get a manual 991/992 GT3, 2nd would top out at 82mph.

I mostly drive this car to work and Whole Foods. I am truly blessed to have a hobby that I can enjoy everyday and don’t have to go out of the way to do so (as opposed to golf, hunting, boating, etc). I don’t have to go to a track to enjoy my GT4. 9000rpm bursts in a GT3 on the public road will land you in jail. Short gears and tons of low end torque from 4.5L makes mundane trips on local roads so eventful and fun. Driving is mental decompression for me which has allowed me to excel both in my family and stressful, high-stakes professional life. In regards to my mental well-being, I never regret any money I spend on my cars because psychiatrists and institutionalization is way more expensive :icon107:

Bang for the buck - Expect to pay 200-300k for a GT4RS or GT3 accounting for ADM and the rabid used car market. Buying a GT4 + 4.5L conversion + shorter gears is much better bang for the buck. Plus you make 100 more torque than a GT3 engine. Sure a modded GT3 can hope to close the gap to a 4.5L but cost of replacing a GT3 engine if something goes wrong due to modding makes me queasy.

Long term - thinking about replacing the engine out of warranty when you hit 200k. GT4 case halves cost $6000, 4.5L conversion costs $31k. Cost of replacing a GT3 engine outside of warranty?

The only thing better than a 4.5L GT4 is a manual swapped, 4.5L 718 GT4RS. We didn’t make it to this point of our lives to afford Porsches by settling for less right? :evilgrin: always striving towards goals makes life worth living