Yogi911

What boost are you seeing with and without sport mode on. Flooring it at 3k rpm.

Im curious to hear your boost in non-sport mode since in sport it probably stays >17

AudiOn19s

What's the difference in the updated tune vs. the old tune?

I have the flash loader with 4 tunes loaded, only ran the race gas tune once but on the 93 tune I only see 14-15psi and no more. Wondering now if that's a problem or just how the "old" tune was. Car also has champion intercoolers / hoses / etc.

Thanks,

Craig T.

I have a brand new three-program GIAC tune from GMG (3 months). I'm mixing in 3 gl of 104 octant unleaded Sunoco with the 91 octane pump gas with every tankful (=93.3). In the 93 "Pump" mode, I'm only seeing 14-15psi.

At Laguna Seca in July I filled an empty tank with 100 octane unleaded and ran in "race" mode. I could feel the seat of the pants difference, but still never saw more the 15psi.

A418t81

I can't believe this hasn't been mentioned yet, but it sounds like it could be detonation from what you've said. It's a metallic rattle, pop sound that is most prone to happening on our cars right when the engine hits full boost and max torque, particularly in the higher gears and higher load ranges.

In case you didn't know, it's bad if you are hearing audible detonation If you want to verify, and you have E85 at the pump, go pump in 3 gallons of E85 to a full tank of 93 octane. That should make it stop. The small amount of E85 will NOT hurt anything and does not require any changes to the car or software... it just increases your available octane a bit, and should bring the knock/detonation to a stop.

As said already, you should check your FPR line immediately. If it continues to detonate, there may be problem with the car. I would start with the MAF sensors if your FPR line is secure.

Kevin

As mentioned, you should really do some datalogging. The engine can pull 15 degrees of timing to save itself BUT with a aggressive TUNE and poor fuel you could easily exceed the 15 degrees safety factor. As the engine goes into distress it will pull boost and dump fuel.

The recommendation of getting E85 or race gas is a quick test. But datalogging your engine is the BEST measure.. Timing, injector duty cycle will be the required sensors along with EGT, and actual boost, and requested boost. With my datalogger, I can see each cylinder Knock Retard...

RugRunner

Ok, will try and datalog this weekend. I have a Durametric. To answer a previous question, in non-sport mode, going full throttle starting at approximately 2800 RPMs in 3rd gear, it goes right up to 15 psi, which is what a sport Chrono car should indicate as a max PSI when not in sport mode, I believe.

RugRunner

Seeing as the slight metallic noise evolved and went away entirely, now to only being more of a whipcrack sound, not metallic that I can tell, that occurs with far less frequency, is it possible that, seeing as the tune is brand-new, the car is now just effectively compensating for it? Both sets of runs to get the two different sounds occurred on the same tank of fuel with no top off in between.

Also, this weekend, I will be checking lines, etc.

ChristianR

i have owned a 997.1 turbo and 997.2 turbo, both with Todds tune, never seen 17psi, maxes as 15 and pulls like a freight train thru all gears.

RugRunner

Christian, if it's a non-sport Chrono vehicle, I don't believe you will ever see anything over 15 psi indicated. If it is a sport Chrono equipped vehicle, sport mode must be engaged in order to see anything above 15. I routinely saw 17 psi in sport mode, even before the tune.

dudley123

THIS! ^^^ First thing that came to mind in terms of the metallic sound!

RugRunner

Possibly caused by bad gas + new tune?
Could the car correct it away? It has changed in sound and frequency with just with two drives. Also, I assume if I did the 3 gals of E85 in the tank, that would affect Datalog results...

ChristianR

both had sport chrono.

A418t81

Here's the thing with the datalogging, you really need to see the per cylinder timing pull data to figure out how unhappy the car is. Unfortunately, the durametric cable last time I checked does NOT log this function. The only consumer facing product that does is the Cobb Access port.

The stage 2 GIAC software is aggressive, but safe, and runs well on cars that are functioning correctly. If you are indeed having detonation issues, there's an underlying issue. My FPR was unhooked and I had the GIAC software before moving on, and it wasn't until I got the AcessPort that I uncovered the FPR issue and fixed it. With this in mind though, my car never audibly detonated. It did feel noticeably smoother and a bit more powerful with a few gallons of E85 added.

So datalogging is best, but you're probably limited. Like I said, go pump in 3-4 gallons of E85 and drive the car around. You'll likely notice the noise is gone, and the car feels smoother and even a bit faster. If this is the case, check your FPR line. It's intact, I would start looking at the MAF sensors next. How old are your plugs? Worn plugs with deposits can lead to hot spots and detonation as well.

RugRunner

FPR & line appear in tact.
Just cleaned MAFs.
Boost lines at intercoolers look in tact.
Maybe 10k on plugs...
Will try adding E85 next

aa909

10K on plugs with aggressive tune, that may be your issue right there.