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Fine Tuning with Cobb AP Stage 1 + SF

6K views 17 replies 7 participants last post by  Donkey 
#1 ·
Hey guys, I recently installed the Cobb SF intake w/ box in my '12 WRX. I tuned with the AP using a Stage1 + SF 91 octane map. I use 92 because it is the only widely available high octane gas in Washington State. The map stated peak boost should be at 16.5 (+/-1psi). I drove it easy for 100 miles then recorded a few 3rd gear pulls. I noticed a consistence over-boost to 17.5psi (within the +1 psi stated by Cobb). I went out driving a few nights ago and noticed a max peak at 17.8 then later a 18.0!

I decided to try the LWG map and see if it would put me closer to nominal, but i'm still showing logs of 17.5psi

Should I try the super LWG map? Could this increased boost be a result of using 92 octane with the 91 map? (the map does say for 91 and 92 gas though).

Thoughts?
 
#3 ·
Very flat and straight road that is neither up-hill nor down-hill. upon further "investigation" I only hit up to 17.5 in a 4th gear pull with the LWG map. Should I be happy with this +1 psi only under that one condition or should I try to lower this max to a lower psi?
 
#8 ·
Okay, i've done quite a lot of logging over the past two weeks. I'm showing consistent boost near 16.5psi or under except for some 4th gear pulls still registering up to 17.4psi, but usually ~17.1psi

I feel a lot more comfortable now that the max boost is within the +/-1 psi that Cobb states, but should I still be worried about the over-boost even when its within Cobb's tolerance and only in occasional 4th gear pulls?
 
#9 ·
I'm no Donkey, but I believe it is normal for the boost to be higher in 4th gear than it is in third.
 
#11 ·
georgia-wrx said:
You only worry about 3rd gear pulls. Nothing else matters. Only STI with the 6 speed does a log in 4th. So your fine at hat boost and no knock.
Jeff
You aren't likely to downshift into third to pass someone on the highway, so I still like to see 4th logged. '07+ 6M/Ts are typically logged in 3rd gear, as well.
 
#12 ·
From Cobb site:

Data Log Recording
The first step to taking a good data log is collecting the proper information. If the data log is too short, there won't be enough to data to analyze, and if the data log is too long, there will be too much information to sort through. The best log is safely taken in 3rd gear for a 5-speed transmission and 4th gear for a 6-speed transmission. Start the data log at about 2500 RPM and drive to redline at full throttle. This kind of pull will have the most ideal load on the car in order to provide proper boost characteristics. Once the log is complete, transfer it to the computer using AP Manager and then open it using any spreadsheet program such as Microsoft Excel or OpenOffice Calc.
Jeff
 
#13 · (Edited)
georgia-wrx said:
From Cobb site:
I'm aware of what Cobb recommends.

The gear ratio changed in '07, and there is no equivalent like there was in '04-06 (4th on 6M/T was ~1.3, same as 3rd on the 5M/T). With the new 6M/T gearsets, ratio is ~1.5 for 3rd and ~1.1 for 4th. Since 4th puts the driver well above triple digits, I prefer to see full RPM datalogs on the '07+ in 3rd gear, and logs in 4th through peak torque, the same way I do for the WRX.

Additional information, especially with a situation you could find yourself in (like downshifting on the highway to make a pass), does matter, as far as I'm concerned. Putting the car into untuned load sites is not a good thing, and, as mentioned, can lead to catastrophic failure.
 
#14 · (Edited)
I see what your saying but in my past experience ain't 1:1 what we want for a true load test. All Dyno tunes are done in a 1:1 ratio to adjust and lock in a tune. I must admit I'm on a new learning curve since leaving the SVT Lightning realm. I'm with you 100% I want to know what my motor is doing in order to extend the life and longevity of my WRX. 4th is he correct gear for the STI and 3rd for the WRX. Forgive me if I'm wrong I do see what your saying.
Jeff
 
#15 ·
georgia-wrx said:
I see what your saying but in my past experience ain't 1:1 what we want for a true load test. All Dyno tunes are done in a 1:1 ratio to adjust and lock in a tune. I must admit I'm on a new learning curve since leaving the SVT Lightning realm. I'm with you 100% I want to know what my motor is doing in order to extend the life and longevity of my WRX. 4th is he correct gear for the STI and 3rd for the WRX. Forgive me if I'm wrong I do see what your saying.
Jeff
Dyno and street tuning are different. That's why every dyno tune should include a road tune to polish it off.
 
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