Hey guys,
Just wanted to share with you my experience with the APR Stage1/2 tunes and supercharger pulley thus far.
Let me first give you a background of my previous modification experiences so you can establish a baseline of my expectations. I have owned 3 Subaru's prior to the S4, a Wrx and 2 STi's. My last STi had a stock ported turbo but had headers, exhaust, custom tune and ran full time on 50/50 water/alcohol injection (with safety devices installed of course). It dyno'd at 330 whp and 400wtq @3000rpm. What was impressive about the STI was the power change after 2500 rpm when the turbo spooled up instantly to 21psi and the car felt like a real monster with 400wtq in less than a second. Of course it died past 5500rpm because of the small turbo. So this is what I was used to for about 5 years.
Now enter the S4. No brainer upgrade, the much improved luxury was welcome, but the car was too smooth and it also lost breathe up top. I was missing that torque down low that I could get from any gear in the Subaru and I was hoping the tune and pulley would fill in some of those gaps.
Stage 1...Mild improvement with the butt dyno down low, but it definitely felt much stronger up top. It did feel more powerful after a few more days driving it, but it was still lacking in a large part of the lower powerband. The pulley was already on order and I got to drive the car this way for about 2-3 weeks. If Stage 1 was the only available option, I personally would not repeat this purchase because the improvement just wasn't par with what I was looking for. It would definitely help with your quarter mile time, but the car was not any more fun to drive in the city.
Pulley install...APR sends an excellent set of instructions with their pulley removal kit (which is a necessity) and there is also a great youtube video detailing the install from ECS tuning. I have taken the bumper off before, so this was a breeze. The long bolts supplied with the pulley removal kit came in real handy to slide the support frame forward and expose the pulley more. Removing it was also easy with the kit. During all of this, we had the pulley in a toaster oven at 350F (confirmed with a heat gun) and it was probably in there for about 80 minutes before we were ready for it. Our first try to slide it on the shaft failed miserably and it would not slide beyond the tip of the opening. Well, I have read about this before and did what was recommended, turn it up to 400F. Tested with the heat gun at 395F and tried again...it got stuck half way down the shaft. We tried to lightly tap it with a hammer and this only bought us another few millimeters. Ok well, lets go to 450F and tested it at 440F with the heat gun after 45 minutes. Of course the finish was destroyed on the areas I grabbed it from, but it slid on very easily and bottomed out instantly. Finally! Tip: don't turn on the car with all the plugs disconnected. It will throw 20 error codes with a parking brake malfunction and airbag light. This is easy to reset if you have VCDS without any issues.
Stage 2...Much more like it. The extra power down low is definitely noticeable and the overall motor response also seems improved. This is definitely worth the extra $500 over stage 1. Its only been a couple of days so I am sure it is still learning and will likely improve even more from this point. This is still not the night and day difference like some folks have described but again, we all have different expectations shaped by our previous experiences. I am very pleased with the outcome and understand that it just won't be the torque monster that the STi once felt like. But I guess I have to try the 100 octane map to make it a more even comparison since I had alcohol injection on the STi.
Hope this helps someone.
Huss
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Originally Posted by Lennl
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