[purekoryo]

I am currently contemplating the purchase of a 718 GTS and will seriously consider tuning. I currently own an RS3 with some mods and currently producing around 620hp and roughly 500 ft*lbs. of torque. Unfortunately, these cars do not have forged rods and are the weakest link (over 550 ft*lbs. is pretty much the limit) and many folks have already bent their rods and "windowed" their blocks.

I tried some quick googling and search on this forum and couldn't find the specs on the pistons, rods, and crank.

Obviously with this being a relatively new platform and tuning companies recently coming out with new products, we do not have empirical data on the limits of this engine; therefore, I would at least like to make a calculated guess on what the limits are based on the material and mechanical manufacturing spec of these engines. Anyone know if the rods and pistons are at least forged?

 

[don]

Interesting question and great thread. I believe Porsches are designed for abuse and constant track laps so the engines have to be strong and engineered to withstand extremes. For example, I was out with a buddy in a tuned Golf R the other day on some alpine style roads in cool weather and his oil temp was running at 277F before he had to back off. At that time mine was only 217F in the GTS while in sport+ which is remarkable given we were going at a similar pace. The 718s and particularly the GTS with extra center radiator has an additional cooling system which switches in during sport/sport+ modes such that the cars often run hotter in normal mode. Unless you are doing lap after lap on a track the engine temp never really rises.

If you do a search Suncoast has a tuned Cayman S that they run down in the heat and I don't believe they have had any engine or drive train problems, nor has anyone else. There are also a few running laps of the ring without issues. I've heard there have been some engine issues in the older 991 generation NA six cars but I haven't heard of any problems with the turbo 4.

I read that the turbo 4 is derived from the 991.2 3l turbo six with technology taken from the 911 turbo S, so it is reasonably well evolved. You can read a little more on it in the link below and perhaps search a bit more on the 991.2 3l engine. I'd be interested to hear what you find.

Tech Dive: In-Depth with the New Porsche 718 Boxster’s Turbocharged Flat-Fours

Where once there were glorious flat-sixes now sits a turbocharged flat four. Go inside Porsche's newest turbo engine at Car and Driver.

www.caranddriver.com

Also worth keeping in mind is that the drive train loss in the 718 is a lot less than your RS3 so the APR stage 1 tune in the GTS @ 440hp is like 500+hp in a rear wheel drive and even more in 4wd cars. You may have read stock quarter mile times for the GTS at 11.9 sec which for only 380hp is surprising. These cars are remarkably quick given their relatively lower power output in comparison with say stock RS3s and A45s.

 

[purekoryo]

Great points and also good to hear that the GTS has extra cooling! I wonder how much torque the stock clutch can hold as well. I think I would be very happy with a low 11 second manual 718 GTS with all the suspension mods galore.

I hope with porsche being under the VW umbrella, uses a completely separate material spec of the engine internal components.

Unfortunately, the RS3 has the exact same piston rod as the golf r. Having said that, as long as torque is limited via tuning, I am happy with the fact that stock motors can take over 700hp.

If the cayman does not have forged rods, I will look closely on how the tuning companies manages the torque curve. For example in the Audi world, unitronics has a great track record of having one of the safest tunes due to a slower ramp up of torque VS. say APR... But also having the quickest tune.

Interesting question and great thread. I believe Porsches are designed for abuse and constant track laps so the engines have to be strong and engineered to withstand extremes. For example, I was out with a buddy in a tuned Golf R the other day on some alpine style roads in cool weather and his oil temp was running at 277F before he had to back off. At that time mine was only 217F in the GTS while in sport+ which is remarkable given we were going at a similar pace. The 718s and particularly the GTS with extra center radiator has an additional cooling system which switches in during sport/sport+ modes such that the cars often run hotter in normal mode. Unless you are doing lap after lap on a track the engine temp never really rises.

If you do a search Suncoast has a tuned Cayman S that they run down in the heat and I don't believe they have had any engine or drive train problems, nor has anyone else. There are also a few running laps of the ring without issues. I've heard there have been some engine issues in the older 991 generation NA six cars but I haven't heard of any problems with the turbo 4.

I read that the turbo 4 is derived from the 991.2 3l turbo six with technology taken from the 911 turbo S, so it is reasonably well evolved. You can read a little more on it in the link below and perhaps search a bit more on the 991.2 3l engine. I'd be interested to hear what you find.

Tech Dive: In-Depth with the New Porsche 718 Boxster’s Turbocharged Flat-Fours

Where once there were glorious flat-sixes now sits a turbocharged flat four. Go inside Porsche's newest turbo engine at Car and Driver.

www.caranddriver.com

Also worth keeping in mind is that the drive train loss in the 718 is a lot less than your RS3 so the APR stage 1 tune in the GTS @ 440hp is like 500+hp in a rear wheel drive and even more in 4wd cars. You may have read stock quarter mile times for the GTS at 11.9 sec which for only 380hp is surprising. These cars are remarkably quick given their relatively lower power output in comparison with say stock RS3s and A45s.

 

[purekoryo]

Not of 991.2 Base rods but still a good read. This pertains to 991.1 Turbo and again NOT the 991.2 base.

Porsche 991 Turbo Connecting Rod - How Much Can it Handle?

Since releasing tuning support for Porsche’s most recent 911 Turbo/Turbo S, our Porsche Expert Group has been pushing the envelope of what the 991 911 Turbo motor is capable of. With our experience at Pikes Peak and helping many of our Protuners push the platform, we wanted to take a step back...

www.cobbtuning.com

 

[don]

In the manual 718s and 981s there is a weak third gear issue which you will probably read about in time so surprisingly the PDK appears to be the more robust system with no failures reported so probably more suited for tuned cars.

 

[purekoryo]

In the manual 718s and 981s there is a weak third gear issue which you will probably read about in time so surprisingly the PDK appears to be the more robust system with no failures reported so probably more suited for tuned cars.

How about the gts?

 

[don]

The PDK and manual gear box is the same in all 718 models. Both manual 981 GT4s and 718s have had third gear failures. I believe Porsche is covering both models with extended warranty due to manufacturing flaw. Presumably once it is repaired or newer model 718s the issue wont be as problematic. You can read about the third gear problem here:

Manual 718 Cayman S - 3rd Gear Gone

Strangest thing happened yesterday - lost 3rd gear on my manual 718 Cayman S - 3rd gear has the same effect as neutral - Dash says 3rd, but when the clutch is released no gear is engaged. I could roll to a stop, go to neutral, back to 3rd, release the clutch at 0 mph and the car will not stall...

www.718forum.com

GT4 3rd Gear Failure | Porsche Forum from Porsche Club GB

If you have any problem with Porsche being reluctant (which they have not been so far) to replace GT4 gearboxes, see this gem of a Service Bulletin.

www.porscheclubgb.com

Recall for GT4 3rd gear issue? - Page 1 - Boxster/Cayman - PistonHeads UK

 

[purekoryo]

Wow, that's a shame. Glad I joined this forum. Don't think they would cover under warranty once I tune it... Thanks for letting me know Don.

The PDK and manual gear box is the same in all 718 models. Both manual 981 GT4s and 718s have had third gear failures. I believe Porsche is covering both models with extended warranty due to manufacturing flaw. Presumably once it is repaired or newer model 718s the issue wont be as problematic. You can read about the third gear problem here:

Manual 718 Cayman S - 3rd Gear Gone

Strangest thing happened yesterday - lost 3rd gear on my manual 718 Cayman S - 3rd gear has the same effect as neutral - Dash says 3rd, but when the clutch is released no gear is engaged. I could roll to a stop, go to neutral, back to 3rd, release the clutch at 0 mph and the car will not stall...

www.718forum.com

GT4 3rd Gear Failure | Porsche Forum from Porsche Club GB

If you have any problem with Porsche being reluctant (which they have not been so far) to replace GT4 gearboxes, see this gem of a Service Bulletin.

www.porscheclubgb.com

Recall for GT4 3rd gear issue? - Page 1 - Boxster/Cayman - PistonHeads UK

 

[CupraLeon]

Wow, that's a shame. Glad I joined this forum. Don't think they would cover under warranty once I tune it... Thanks for letting me know Don.

Gearbox has had a revision so after 2017 this should no longer be the case. Tuning/ altering something on your car ALWAYS leads to loss of waranty from the manufacturer.

 

[chester7]

Reading purekoryo's approach to tuning, makes me think getting the APR stage 1 for 93 AKI will not hurt my 6 MT. I am tame compared to him! I am waiting until spring, because honestly I lose traction in my 718 GTS quite easily in Texas in winter.

 

[purekoryo]

Reading purekoryo's approach to tuning, makes me think getting the APR stage 1 for 93 AKI will not hurt my 6 MT. I am tame compared to him! I am waiting until spring, because honestly I lose traction in my 718 GTS quite easily in Texas in winter.

Sound like you're in North Texas? Im in the dfw area...

 

[chester7]

Sound like you're in North Texas? Im in the dfw area...

Austin in Hill Country

 

[purekoryo]

Austin in Hill Country

Ahh, was just there with my family. Awesome area! Just the right sized city and as you said, actually has hills!

 

[nineball]

If you do a search Suncoast has a tuned Cayman S that they run down in the heat and I don't believe they have had any engine or drive train problems, nor has anyone else. There are also a few running laps of the ring without issues. I've heard there have been some engine issues in the older 991 generation NA six cars but I haven't heard of any problems with the turbo 4.

that's not entirely true. i recently ran into heat soak problems on a track and called suncoast and spoke to them about their 718s track toy. they have modified quite a few things to avoid the same heat soak, which they have already encountered. if memory serves they added the 3rd radiator, removed some foam in a duct leading up to the intake, changed the panel under the car to one from a bgts for the redesigned air entries and something else which i can't recall right now. unfortunately they could not pinpoint one item that solved the heat soak problem but rather guessed it was a combination of the things they had done.

i track my 17 S more than most (last year was 9 events totaling almost 30 days) and had never had any real problems until this past decemeber on my 3rd trip to daytona. after 3-5 laps my oil was around 255 and i experienced a real loss of power. the same thing happened every single session. ambient temps never got over 80 so it wasn't as warm as previous years by a long shot.

removed the panel under the car, no help. talked to a porsche tech who was there and they suggested turning on the air full blast as it turns on every fan (including the cooling fans in the engine) but that didn't do anything either. spoke with the owner of bgb racing and he suggested a pdk fluid change. on their dedicated track cars they change the fluid every 6-7 weekends, on de cars once a year. mine has never been changed. swapped it out (and a new filter) when i got home.

both the tech i met and the guys from bgb said they had experienced the heat soak problem multiple times on 718 caymans and boxsters but have never really found an off the shelf solution. the 3rd rad helps to a degree but on their dedicated cars they have installed extra oil and trans cooling to combat the heat soak, both of which would void my warranty.

already ordered the 3rd rad kit from suncoast and will install that in the next month or two and see how things go next year. sucks i have to order the extra grille now too

 

[don]

Yes, what you say is true about the heat soak but it is very hot down in Florida and Suncoast had already installed a third radiator and were still having heat issues before adding the other cooling mods but they were also running a stage 1 tune. Although with that said I haven't heard of a GTS with any heat soak problems so I wonder if there is more to meets the eye that just the third radiator or if it is just the higher tune.

Anyway, what I meant by engine and drive train problems were engine or PDK failures not heat soak. There is now an extended warranty on 991.1 GT3 engines due to potential engine failure and as noted above the 3rd gear issue. Other Porsche 991 engines have also had problems, but I think the turbo engines on the whole have been very good.

Heat is one of those things that is always a challenge with turbo cars but the CPU will protect the engine by running in limp mode as Suncoast found.

 

[FazedChicken]

that's not entirely true. i recently ran into heat soak problems on a track and called suncoast and spoke to them about their 718s track toy. they have modified quite a few things to avoid the same heat soak, which they have already encountered. if memory serves they added the 3rd radiator, removed some foam in a duct leading up to the intake, changed the panel under the car to one from a bgts for the redesigned air entries and something else which i can't recall right now. unfortunately they could not pinpoint one item that solved the heat soak problem but rather guessed it was a combination of the things they had done.

i track my 17 S more than most (last year was 9 events totaling almost 30 days) and had never had any real problems until this past decemeber on my 3rd trip to daytona. after 3-5 laps my oil was around 255 and i experienced a real loss of power. the same thing happened every single session. ambient temps never got over 80 so it wasn't as warm as previous years by a long shot.

removed the panel under the car, no help. talked to a porsche tech who was there and they suggested turning on the air full blast as it turns on every fan (including the cooling fans in the engine) but that didn't do anything either. spoke with the owner of bgb racing and he suggested a pdk fluid change. on their dedicated track cars they change the fluid every 6-7 weekends, on de cars once a year. mine has never been changed. swapped it out (and a new filter) when i got home.

both the tech i met and the guys from bgb said they had experienced the heat soak problem multiple times on 718 caymans and boxsters but have never really found an off the shelf solution. the 3rd rad helps to a degree but on their dedicated cars they have installed extra oil and trans cooling to combat the heat soak, both of which would void my warranty.

already ordered the 3rd rad kit from suncoast and will install that in the next month or two and see how things go next year. sucks i have to order the extra grille now too

Thanks for the info about your experience. I also have a 718 S and have been following the Suncoast build.

I did around 15 track days last year but looking to do more this year. So far I haven't done any cooling upgrades to the car but I'm considering it before the 2020 track season starts.

That's concerning that you went into limp mode on a cooler day after you've already done many track days in warmer weather. I wonder what caused it to start triggering limp mode. I was going to do the speedster front underbody panel + GT2 RS underbody spoilers (like the Suncoast car). Those 2 seem like they would be the best value spent right now. That rear GTS engine cover they have is not cheap. I'm still on the fence about doing the 3rd radiator right now but I might as well just bite the bullet and get it done sooner than later.

I want to do a bunch of cooling mods before I get the APR tune on my car. I wish there were bolt on cooling upgrades like intercoolers/radiators but I can't seem to find anything. The oil/trans coolers that BGB mentioned, are those for the 718 platform? I know they were popular on the 981 but I haven't heard anything about doing that on the 982. I would definitely be interested in bolt on cooling kits for our cars like that.

 

[nineball]

swapped out the pdk fluid and it didn't look too bad. it was definitely a little different, but i would liken it to comparing coffee w/ cream vs coffee w/ more cream - there, but slight. changed the filter and it certainly didn't look new but again it didn't look terrible.

i can't tell you anything about what they used for external coolers unfortunately. as soon as they said it would void the warranty i stopped, noting it may be something we talk about next year when my warranty is about to end. one of the main concerns i was told was that something simple like a fitting could go bad and drain the system causing catastrophic damage. if it's not a factory part then it's not covered nor the resulting damage.

i would go for the 3rd rad before anything else if cooling is the goal. that will have the biggest impact and they are factory parts, so as long as you have a reputable shop install them (or a dealer) it should not cause you any problems. honestly if i were in your shoes i would just run the car as-is until something compels you not to. i ran my S on a host of tracks across the country for 3 years and never had this problem before, nor any real issues at all. ironically both track-related issues i have had have been at daytona, but there is no way i won't be going back for year #4 in december

 

[FazedChicken]

I think you might be right about just running it. I usually like to be overly cautious and would rather upgrade/replace stuff early if I can. A few small cooling upgrades wouldn't hurt ? Hopefully it was just a fluke for you. Seems like you really beat on the car and it holds up well - that's great! Are you planning a tune or any other mods to your car for this years track season?

 

[jns211]

I am currently contemplating the purchase of a 718 GTS and will seriously consider tuning. I currently own an RS3 with some mods and currently producing around 620hp and roughly 500 ft*lbs. of torque. Unfortunately, these cars do not have forged rods and are the weakest link (over 550 ft*lbs. is pretty much the limit) and many folks have already bent their rods and "windowed" their blocks.

I tried some quick googling and search on this forum and couldn't find the specs on the pistons, rods, and crank.

Obviously with this being a relatively new platform and tuning companies recently coming out with new products, we do not have empirical data on the limits of this engine; therefore, I would at least like to make a calculated guess on what the limits are based on the material and mechanical manufacturing spec of these engines. Anyone know if the rods and pistons are at least forged?

Have you read the attached document yet?

It might have some information that could answer your questions.

 

[purekoryo]

Have you read the attached document yet?

It might have some information that could answer your questions.

Nice! Thanks! Found exactly what I wanted to know. These motors are built "Porsche Tough"!