[8833]

Has any tuner identified where Porsche is limiting the power of the 2.5 turbo to 350/365 HP and ~309 torque?

Is it a restrictive downpipe? I guess time will tell as tuners crack the puzzle.

 

[Soul Performance Products]

Has any tuner identified where Porsche is limiting the power of the 2.5 turbo to 350/365 HP and ~309 torque?

Is it a restrictive downpipe? I guess time will tell as tuners crack the puzzle.

You'd be surprised at the difference an aftermarket downpipe makes on the 718. You can feel an increase in responsiveness from bolting one on without a tune. We're curious to see how far modders can push the stock engine before you reach the limit of the internals.

-Mike

 

[autobahn]

There is contention. Cobb says it's cooling, others say that's not the case.

 

[8833]

There is contention. Cobb says it's cooling, others say that's not the case.

Wow! So a tuner thinks there is not adequate cooling. Surely, that would be for a large power increase, not a modest 10-15% increase, especially since a street tune would not be WOT that much.

 

[ZuffenHouseRules]

tuner thinks there is not adequate cooling

But is that referring to engine cooling (what Porsche on the 718 calls High-Temp Cooling System) or charge-air cooling (Low-Temp Cooling System). Each has its own dedicated radiators, ducting and plumbing, sharing only the coolant reservoir. On 911 turbos with air-to-air intercooling, LTCS does not exist (nor on naturally-aspirated cars).

I look at what Ehresmann Automotive GmbH has done with only a tune and downpipe on the S with its 64mm compressor wheel -- 450 hp. That tells me something impacted by the downpipe is the initial constraint (apart from the tune itself programming all the proper ECU functions -- not a given all tuners are equal in this regard).

VTG turbo with ECU-actuated variable vanes and integrated wastegate on the hot/exhaust side would have critical interaction with exhaust-system back-pressure I think. That sure seems like something a downpipe would impact.

 

[Gtipirelli]

My Cayman S sounds and feels the least stressed engine I have ever driven. Most road cars sound like they really need to change up a gear when they get close to the red line but the 2.5 litre doesn’t

350 bhp is more than adequate for the road though in my opinion

 

[aeronca65tl]

There is contention. Cobb says it's cooling, others say that's not the case.

I have no facts on this but I have noticed one interesting point about my 2.0 Cayman. It obviously has a 195F thermostat. Which is cooler than the thermostat in most cars these days. My van runs at 212F and I'm pretty sure our Honda runs slightly above boiling point.

I was wondering if maybe the lower temp thermostat was in place to allow some cushion in higher temp areas?....which might imply the cooling system doesn't have a lot of extra capacity.

It hasn't been any issue in my (stock) car but the coolant temp seems low by modern standards.

Most manufacturers like to run right at 212F or so. I think this is helpful with managing emissions.

 

[8833]

My Cayman S sounds and feels the least stressed engine I have ever driven. Most road cars sound like they really need to change up a gear when they get close to the red line but the 2.5 litre doesn’t

This is exactly why I am trying to determine where Porsche hobbled the engine to keep the 911 on top.

 

[johan]

I think the 450Hp Ehresmann and others have as a upper limit, is the limit without a extensive rebuild.
Jens him self says that 500Hp could be done but it will cost a lot of $


Before we all get crasy and start say that we belive that this or that could be done, take a look at the 919.
Thats a fullblown race car with all thats comes with it and it produces (WEC fuel limit) ~ 500Hp.
So a new exahust, gearbox, cooling and some internal engine parts you good to go!


Back to Jens, he recomendes 430Hp if you will track, if your only will track once or twice and shorter runs then 450 would be ok.
One more thing to consider is that launch control and +400Hp does not work very well due to wheel spin so how will TC/PSM react under driving/track conditions?
Then we have PTV, PDK and the cooling of the turbo.......


Stage One with down pipes, that could be a good combo, have not seen that yet.


My 5 cents

 

[LittleBlueGT]

Tracking a car in 100 degree temps and tracking a car in 80 degree temps are two entirely different things. Cobb saying cooling is the limited factor tells me they are trying to make their tunes bulletproof with guys tracking in 100 degree temps.

That being said, I see no reason why a street only driven vehicle would be limited via cooling. Assuming the car is not relentlessly beat on in 110+ temps.

 

[Happy Days]

The size of your wallet?

 

[nn7man]

The constraint on the 365 hp engine is a brand one i.e. the 370 HP 991 Carrera.

 

[peaedvard]

I am currently running a stage 1 flash on my GTS ,and i planning to add some catless downpipes in the spring.
But it would have been nice to add 30% E85 in the fuel, it did wonders on my BMW.
Has anyone find out what the fuelsystem can handle?, it could be expensive letting the motor go lean, something i found out the hard way before

 

[8833]

The constraint on the 365 hp engine is a brand one i.e. the 370 HP 991 Carrera.

That is exactly why I think modest, but meaningful power increases can be had for reasonable money.

 

[ZuffenHouseRules]

This is exactly why I am trying to determine where Porsche hobbled the engine to keep the 911 on top.

If I understand the question, the answer is: through programming of the ECU.

Consider: so-called Stage 0 or 'flash only" tunes increase power in turbo engines without any hardware upgrades, solely by altering code or maps (table of numeric values) in the ECU. If they can increase boost and power that way, then Porsche can limit boost and power in the factory programming. So factory-rated peak power does not represent the full thermodynamic potential of the engine with all systems (fueling, boost, ignition, cooling) running wide-open, but an arbitrary limit imposed by how the ECU marshals it all.

Actually I have this vague idea that the factory-programmed "limit" is not just a particular number for max. boost, but a more complex set of maps which basically describe a predefined power curve. So on a dyno the engine is just drawing the power curve with which it has been mapped (or the one which best fits the exact current conditions of fuel octane, internal temps, ambient air pressure and temps, etc.). The automotive version of ascendancy of computers (software) over hardware. Could this also help explain why dyno results and factory bench-test ratings don't seem to align with real-world performance for these cars....is the computer actually recognizing when it is being tested and selecting a soft (sandbag) mapping?*

I think tuners in the past mainly increased boost by manipulating Wastegate Dump Cycle WGDC code. With VTG, the same actuator which controls vane position also controls the integrated wastegate. So tuners may be encountering a learning curve in this area with the 9A2/VTG engines (2.5 and 3.8 911 Turbo/S/GT2).

*I think this forum has still not answered "how is this even possible": that a nominally 350hp 718 accelerates to a range of speeds/distances at exactly the same rate as a 400hp 991.1 Carrera S with the same PDK and weight? (per C&D track sheets, quarter-mile and all splits below 120mph)

 

[Olympic Blue]

Do you think there would be any gains by adding the GTS intakes (which seem to look like they would flow better) and a catted down pipe, and exhaust. without any ECU tuning?

What changes could be made without affecting the warranty.

 

[8833]

Do you think there would be any gains by adding the GTS intakes (which seem to look like they would flow better) and a catted down pipe, and exhaust. without any ECU tuning?

What changes could be made without affecting the warranty.

Your 914 is awesome. I grew up in Pittsburgh. I am thinking an ECU map (Zuffenhouse premise) is an efficient way to do it. I had an Audi 1.8T with an APR tune that was improved every few years (for free). I suspect someone will tame the variable vane turbo some day- and I'll be waiting.

 

[ZuffenHouseRules]

Do you think there would be any gains by adding the GTS intakes (which seem to look like they would flow better) and a catted down pipe, and exhaust. without any ECU tuning?

What changes could be made without affecting the warranty.

You mean an after-market free-flowing cat (not bypass 'test pipe') which could still pass emissions testing for street-legal use? I've seen those, but have to question how much improvement over the factory cats...

In any case I suspect whatever the bolt-on upgrade, without corresponding ECU changes it will not be fully exploited or optimized. Porsche does have a history and current example of factory-authorized 'Power Kits', like the X51 for 991.2 Carrera S upgrade to GTS power, which includes both hardware (larger turbo) and upgraded ECU program to exploit it. But that example suggests they won't in any case increase power beyond the existing top-of-line model -- and only after you've paid as much as you would have originally for higher model -- thus preserving/protecting the investment of those owners.

eta: I've always kept my Ferrari/Porsche cars factory-original and will continue to do so (apart from rims), it's just me. This tuning topic fascinates simply for what it tells us (or causes us to ask) in understanding the stock 9A2 engine architecture -- esp. the complex interaction of ECU and new turbo technology.

 

[don]

Correct me if I'm wrong but it looks to me like the 718 only has a one main cat and no pre-cat so removing it would mean you have no cat which would certainly help with flow but result in a strong exhaust odor.

I think the only thing you can do is install a higher flowing cat which isn't going to make a massive difference to the OEM cat unlike many other turbo engines which have a pre-cat in the down pipe which is commonly removed (e.g., BMW N54/55) but still leaving the main cat and/or a high flow cat leading to more significant gains but still passing emissions.

 

[Little German]

I have a 2.0L 718 Cayman. I installed a FabSpeed 200 CEL Cat turboback exhaust and a BMC F1 air filter to allow more free flow at both ends. No affect on warranty and my dealership service manger and the service techs think it's an awesome upgrade. I can definitely feel a difference in power and responsiveness. FabSpeed estimated an increase of 10 whp with the exhaust and another 5 whp with adding the free flowing air filter (+15 whp), and 13 ft-lbs of torque for the exhaust and 5-7 ft-lbs with air filter (+ 20 ft-lbs of torque). This set-up has all but eliminated any turbo lag and the sound is awesome. The upgraded exhaust also leaves the car weighing 35 lbs less.



When the warranty is up, I can add an ECU tune to further optimize the performance and expect an additional 60 hp and 80 ft-lbs of torque. Even if I don't go with the ECU tune, it's a great performance upgrade and I'm very happy with the power and responsiveness.