[moswald80]

I just got StreetTuner a few weeks ago and I haven't really started tuning with it yet but I have been logging and learning as much as I can. This site is the best StreetTuner resource I have found.

Anyway, my goal for boost is to hit about 18 - 18.5 psi around 3000 rpm and hold it until around 4500 - 5000 rpm. Then taper to about 14 - 14.5 psi at redline. First, does this sound reasonable for the stock turbo and factory boost control solenoid? For you guys running super high boost (i.e. TurboQueef) or hitting peak boost super early (i.e. WolfPlayer) with the stock turbo, did you adjust the turbo dynamics maps or just the Wastegate Duty Cycles (besides the Boost Targets, of course)?

Oh, my engine mods are:
Cobb Catted Downpipe (Stock Catback)
Intake Silencer Removed and K&N Panel Filter
LC-1 Wideband O2

Also, I live in Arizona so I run pretty crappy 91 octane. I have heard it is the same as California gas.

[crystal_Imprezav]

Sure that is a very feasible goal. I run 18.5-19psi at 3000ish with a nice smooth taper to 14.5-15.2 (weather depending) at redline. I didn't have too much help when I first started tuning my boost so here is a quick lesson to help you out. IMO the WGDC (low) is a more important table than the high. The low table is where the ecu looks to start the WGDC to hit the target boost specified and will go up to the high tables amount max to reach that target. With that being said, start with your target boost table. Set your values at your desired levels. Make sure that the table is smooth though or else your car may feel jerky trying to hit different boost levels at different rpms. When you are happy there, move on to your WGDC high table. Go back and look at your datalogs in 4th gear. Make an excel table that lists the rpm, boost, WGDC, and turbo dynamics. Basically the turbo dynamics is a value that tells you how far off your WGDC tables are and what the ecu is doing to make up for it to hit target boost. There is no need to really touch that table is your target boost and WGDC tables are set right. Ok back to the logs, look at the rpm values in ST and find those values on you excel files. I set mine in bold to make them easier on the eyes. What I do it I look at say 3200rpm and see if I hit target boost. If so wonderful, look at the WGDC for that boost/rpm and I usually add about 2% more just to be safe in really hot weather that I will hit my target boost. Set that value in the WGDC high table. Now look at your turbo dynamics. +means your tables are too low and - means you are overboosting. This will show you how off the OTS map was and how the ecu was hunting for boost. In the end you would like to see those values at around +/- 10 which means your have a very good WGDC/Boost map. Ok, now that you have all your WGDC high values set move on to the WGDC low map. You will see that the values are way lower than your high table and they are all over the place. What I do at this point is copy and paste your high table values into excel with the corresponding rpm. In the next column subtract 5-8% from them (this is what I found to work the best with my car causing the best turbo dynamics). I use -8% down low to make up for any creep during colder weather and -5% around 6k+ b/c to even make 15psi at redline is not easy under some conditions, with 100% WGDC during really hot weather I have seen only high 14's (this was with racegas so I was being careful). Now paste all the rpm's from the low table since there are more of them and smooth them out with the values you already have set from subtracting from the high table. Ideally, you will want to go back to your log and look at the WGDC for those rpm's to get an idea of where in the tables they using WGDC high and subtract from those. To get an even smoother table interpolate the missing values with your set values instead of going back into the logs. Ok, so now your done tuning for WOT, but what about other throttle positions? I am happy with my partial throttle boost/loads so I left the lower positions alone however for the upper throttle positions, I interpolated the values with my new WOT values so I have a nice transion from say highway closed loop to WOT open loop. Another thing that I highly suggest is Wolfplayers TDC changes. They will add a whole new world of comfort to the way your ride turns into a smooth machine under closed loop and the switch into open loop. Go out and log your new boost/WGDC setup and look at your turbo dynamics. If they are +/-10 great your done. If not (which is likely since many conditions affect the way your turbo works) make slight changes to the low table until you are happy (unless you are overshooting the high map to make target boost then go raise both tables). You will notice that the car makes boost faster since now it knows where to start its WGDC and is not going from an extremely lower value all the way up to make its target. Now you can go on to tuning fuel and oh timing which is a whole new world of fun and headaches

BTW the stock boost control solinoid is more than powerful enough to handle any levels of boost that the VF-39 can efficiently produce. Switching out the solinoid and trying to produce unreasonable levels of boost for the vf-39 will end with disasterous results. 15 psi of cooler air will make more power than 16psi of hot air. Also when you are inputing your target boost values, there is no need to input say 20psi at redline when you are only trying to hit 15. This will throw your dynamics off, so set your values to achievable/reasonable values. This way you will know how close your WGDC tables are to being correct. In most cases I hit peak boost of about 18.8-19 around 3800-4100 rpms and am hitting 18psi by around 3300rpms. I can hold 19 until about 4500 and hold 18psi after that until about 5000rpms in which point I am at around 17 until 5650ish then 16 til 6200 and then a smooth transition from 16-15 at redline.

p.s. the reason I am writing like a book right now is b/c I am extremely bored at work and solitare isn't cutting it anymore The recent rain/flooding here in No. VA have put a huge damper on construction (since I am a project manager for a general contractor) not to mention it is almost the end of the week followed with a long weekend b/c of the holiday