Jenner

I thought your heat related issues were determined to be a defective fabspeed exhaust that broke at the track?

ShakeNBake

Oh don't let me count the ways....fabspeed is helping take care of the fire. The limp mode stuff was cobb.

Jenner

Another dyno to add to the discussion and perfectly illustrates the tune makes a bigger impact to the dip than headers alone.
These are Cargraphic sport headers:


4800 and 6400 RPM show amazing gains of 30-35hp at each RPM and the entire power curve is substantially improved by the header/tune combo showing an average of 20-25hp gain across all RPM.

jslee225

I was on the fence about a tune like the post above, but your experience at COTA has made me realize that a tune may not be the best decision for track use. I can't imagine what it was like being at COTA with a car that you couldn't drive on such a glorious track. Well actually I do.................

Thanks for sharing your feedback with us!

Jimmy-D

But how many people have experienced issues at the track wit a tune??

And how many of those were using Cobb???

ShakeNBake

2 and both Cobb. Extreme conditions though, 95-100F track temps. And myBailey is the pretty much the fastest guy out there, so you have to be pushing hard. I don't want to have to drive my car with pink bunny shoes to make sure it can survive the weekend. What comes from the factory is very solid if that is what you care about. The other issue I had was that my car was slower with the tune somehow. I was getting pulled by other stock GT4s. A tune for a dyno-princess is different than a track car I guess.

CarAholic

Still a large torque dip though

Jenner

Where are you looking? 3500 RPM?

user1029

orthojoe is prescient - as he said better horsepower numbers with the tune but you have more heat generation due to more aggressive timing so you heat soak faster --> timing pulled

better upgrade radiators for more cooling if you are to track a tune

usctrojanGT3

Looks like I'll stick with my race headers that'll be ceramic coated.

Alan C.

Given the oil temperaure tends to run hotter on the GT4 as compared to the GT3, 255F vs. 235F in my case, are higher capacity radiators available?

Amazon just dropped my Mobil 1 5W-50 at the front door. I'm going to run it in place of my usual Motul 5W-40 for my next oil change.

trebien

Keep in mind, if they were stock tires as well, you've got significantly more rolling resistance... not that 30whp/tq shouldn't be able to overcome that. Maybe re-adjust the rear wing for lower attack angle and less drag. ;-)

Looks like we're starting to see the limits of the bigger engine stuffed into the mid-engine cave. Cooling in a mid-engine platform can be a bit of a challenge, and by the time we start creating more heat in the engine bay through aftermarket changes, we start creating more heat related issues popping up when driving 10/10ths on a hot day.

Hm... what to be done, what to be done...

Jenner

To the best of my knowledge there have been no reports of any GT4s having oil or coolant temperature issues so I'm not sure an upgraded radiator would make that much of a difference here.

A modified engine might be more prone to pulling timing and might see higher combustion temps but not higher coolant or oil temps. This can be prevented by running a few gallons of 100 octane mixed with 93 or a booster like Torco Accelerator to keep combustion temps lower and reduce chances of timing being pulled.

Mech33

No... we're seeing poor tuning choices for a car on a hot track day. As a general rule there are no gains to be had on a naturally aspirated car with software changes only (any gains you're getting are likely from margin put in there for such situations).

If you want to increase power, you need to burn more fuel to release more energy, which takes more oxidizer (air). To get more air through the naturally aspirated motor, you need to improve volumetric efficiency (X51 kit, some header mods, etc.).

trebien

We're not talking general rules, we're talking Porsche... so I respectfully disagree. It's quite easy to limit a car's power via ECU tables, especially if, as a manufacturer... you are prone to provide performance of your vehicles specifically in alignment with their pricepoints and market placement of your internal product matrix.

I'd say Porsche is quite adept at planning the ECU tables... about as adept as they are at planning their price/performance market placement tables.



The Cayman/Boxster platform has been "detuned" in OEM stock form since the 987.1 generation, with varying amounts of additional, safe power being available from ECU tuning alone. However, I will also state that Porsche has been adept at limiting power output by partnering the ECU planning with purposeful hardware limitations as well, such as restrictive intake- and exhaust-side components.