CA 91 octane + E85
#31
08-26-2019, 02:28 PM
Join Date: Sep 2009
Location: Sacramento, CA
Posts: 59
Rep Power: 17 
Are all your mods in your sig? Are you sure that you don't have larger VTGs on the car? You are hitting 460 g/s on MAF flow at 18-19 psi and the waste gate duty cycle that is required to do that is very low: mid 30s usually. That took 22 psi and 45- 50%+ duty cycle on the waste gate on my 07 997TT with turbo inlet pipes and the Do88 big pack which made 660 whp on E85 on the factory turbos with 1000cc injectors. Might explain your significant boost overshoot on initial wind-up and why the car doesn't like the amount of timing the tune is trying to run as cylinder filling is more efficient and cylinder pressure is up over what is expected in this file. This is an off the shelf tune? I don't see any branding in the file name of the tune flashed to the car. You're obviously on the factory injectors or the car wouldn't run on this flash. Your injectors are getting close to tapped out with duty cycles of 85% even with the tame boost pressures.
I'm not sure I would drive the car in anger until you get more fueling and a pro-tune for the car. Good news is you may have bigger turbos already, and if you don't, you have an exceptionally well flowing setup
I'm not sure I would drive the car in anger until you get more fueling and a pro-tune for the car. Good news is you may have bigger turbos already, and if you don't, you have an exceptionally well flowing setup
My car has sport chrono, and per Cobb tuning notes (https://cobbtuning.atlassian.net/wik...urbo+Map+Notes) for this OTS tune, "Chrono Sport/Overboost mode - Is a Porsche option that increases boost for a short time period". Also, "Boost Targets: 17psi on normal mode, 20psi on Sport mode. (+/-1 PSI)", so the boost overshoot on wind-up to 22psi might not be too unusual considering I had sport mode on during datalogging?
#32
08-27-2019, 03:28 PM
Join Date: Sep 2009
Location: Sacramento, CA
Posts: 59
Rep Power: 17
So I grabbed a mirror and looked under the car, and saw 997 part number on the turbo housing, so I'm guessing it is a factory VTG, unless the inners have been changed on the stock housing.
#33
08-28-2019, 07:42 AM
The upgraded VTGs look identical to the stock part on the outside. They have larger compressor wheel and a clipped turbine wheel. You would have to take the turbo inlet off to look at the compressor to see for sure.
#35
08-30-2019, 10:08 AM
Yes- my understanding is that even bone stock 997.1tt's still pull timing when running 91 pump fuel. Adding 2 gallons of e85 will certainly help to eliminate that. Whether you feel any difference while actually driving is another question. I don't subjectively feel much difference when I add ethanol....but my data logs verify that my timing is not being pulled. These cars make a lot of power...and it's hard to subjectively feel the difference of 10 or 15 HP when the car makes 500 HP to begin with!
#38
09-02-2019, 02:50 PM
Join Date: Sep 2009
Location: Sacramento, CA
Posts: 59
Rep Power: 17
I spoke with Sharkwerks that worked on the original EVT600 install, as well as the previous owner, and the turbos are stock according to them.
So I guess I have a good flowing system.
So I guess I have a good flowing system.
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