The above is with 29 PSI.

 

nice looking graph but doesn't the intake temp skyrocket after about 200km/hr? I had 23psi on my 68s and above 200km/hr the intake temps climbed quickly and you could definitely feel acceleration go down.

 

41 C @ over 300 km/h. This car has water meth injection, otherwise it wouldn't be possible or to be more correct: only one run quick and with full power and then power decreases from run to run as the engine starts knocking. With the current setup you can do run after run over 300 km/h and everthing is stable and repeatable.

 

This is where I think running the best possible intercoolers as well as E85 as a chemical intercooler and or alcohol injection would be very helpful

I think your biggest problem from what I can see is that you are trying to extract the maximum amount of power possible on the stock bottom end while using weak fuel - this obviously requires better / more efficient turbos to enhance the VE of the engine and create a more stable cylinder tio avoid detonation

 

Absolutely. My original plan was to keep the 68s and add the DO88 Big Pack system (which I now have on the car) with a new custom tune from Sam. Ended up with the Xonas and intake temps are way better for the 2 reasons - intercoolers and increased efficiency. When temps are in the 70s I'm seeing no knock sensor activity and even in the 90s there is minimal knock sensor activity. This is why I'm still inching forward with a little more tweaking to extract whatever I can safely get out of pumpgas.

 

Dont you have access to some race gas? 5 gallons of 100 octane unleaded in every tank would be cheap insurance agsinst a disaster. Pump gas is vety unreliable. While the factory ecu does have a lot of protection systems built in i would personally not push the envelope without the saftey margin of some race gas in the tank or a good alcohol injection system with a fail safe like aquamist

 

Definitely one of my favorite threads!

M3_Maestro...have you ever messed wit the F10 M5? I see a few coming off hard down to the $35k-$45k price range and was thinking about getting one. PM me so this doesn't turn into a thread jack.

 

Nope, no access to racegas. My tune currently has minimal knock sensor activity anywhere in the range so the car has lots of room to protect itself. I know what moderate knock feels like: when I was getting my 68s datalogged there was no mistaking the way the car feels with multiple 6's on the datalog! Haven't had a bad batch of gas locally in the years I've had the car and this current tune is smoooooth.

 

no access to race gas that is impossible.
I am sure you can souce some 5 gal containers of 100 octane just about anywhere.

Everyone has his / her own comfort level No way would i apporach 90% of the Rods bending capacity on staight pump gas. Over the years i have seen way too many engines fail from that scenario. There is a reason why they limit the stock cars to 480 crank hp. Because they have a warranty and a reputation to protect against poor fuel quality. The same system that protects you at 480 crank is not going to protect you at 850 crank and above if you pick up bad gas

 

Hey bud, no I haven't. I have only reviewed data on 1 of those for a tuner that wanted my opinion on how the turbos were doing. So other than looking at logs no hands on. The logs I saw it was making some power

 

Lets at least keep this topic about Porsche tuning and avoid the discussion of other Brands - (although I used to own a 91 M5 and it was just about the best car you could buy IMHO)

 

Thanks to Stef for doing such a great job modifying my stock tips to fit the giant 76mm tips on the EP2 system which I just installed

Here is a before and after of the outlet pipes of the 60mm stock tip size EP1 system which was making 750 whp and the

EP2 with 76 mm outlet pipes

And with the modified stock tips installed on the full 3" system

My new EP 2 system fit just as perfectly as the EP 1 system - simply put these systems are the best exhaust systems I have seen in 35 years of car modification

 

Awesome!!

 

I do not think it is about power as we are close to the limit of my power objective if not already over it at this point already
A lot of people who are tuning cars only keep in mind peak power levels without regard for what is going on in the system which I have repeated from my early learnings which in a turbo charged car is like a giant air pump. Obviously you have limitations at the weak links in the system

Upon getting more involved with VTG modified 997's it has become very clear to me that the number one problem / restriction in the system is the huge amount of back pressure before the turbine which can run upwards of 55 psi in some applications or a ratio of well over 2 times the boost level being compressed into the engine

As you start to get up over 600 whp a 2.38" tube per side is going to create additional back pressure - keep in mind the specifications from Europipe which measure the difference between the EP1 and EP2 are conducted on a stock vehicle

Obviously the EP1 is capable of producing a lot of power for a catted system as I have demonstrated

This change is less about turning up the power level - trying to make more power or boosting any of the tuning parameters

Rather, my objective is to simply lower the backpressure by a few psi on the discharge side and by doing so pick up VE on the engine set up by allowing more complete expulsion of exhaust gasses and create a more stable combustion event with less unspent exhaust charge left in the cylinder between cycles

Of course the trade off here for this is slightly more noise - yet to be determined

Will have more to report when I get the car on the road - it has been raining here and this car never goes in the rain

 

Picking up a little more power with the full 3" exhaust as we work to refine the tuning - I must admit that I do not drive the car very often so my tuning progress is going very slow - I will try to make it out to the track this season once it gets too cold for boating