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From YourSITE.com Technical Features When we first visited Streetwerke’s dyno, our goal was to get a good baseline for future mods. Our first official day on the dyno was a good one and we were quite pleased with the results. However, after being around the venerable 1.8T engine for a number of years, we knew that a good exhaust system would net some additional gains. We also wanted to try one of Modshack Tuned’s VTDA – Velocity Tuned Dynamic Airbox intakes. Since both modifications separately would most likely net minimal gains – and the simple fact that most people will add an aftermarket intake and exhaust at some point - we felt it was better to add the combo together and then head back to the dyno at Streetwerke. We also took the opportunity with the exhaust off to fit an H&R 21mm adjustable rear sway bar that we picked up from North American Motorsports during a group buy. This particular bar fits both TT quattro models and the Volkswagen R32.
Some of the other top exhaust contenders are Milltek, Jetex, Neuspeed, Borla, Blueflame Performance, and Techtonics Tuning - as well as the Forge Motorsport exhaust. We chose the Forge Motorsport exhaust due to its quality fabrication from stainless steel, 70mm diameter, twin 100 mm rear slash style tips and because it wasn’t a particularly loud exhaust. It has a nice deep tone, with reportedly no in-cabin droning. As luck would have it, we picked up this particular exhaust from a fellow forum member for a very reasonable price. It had been put into service for only about three months and a sale of the car resulted in its removal. Unfortunately, Forge Motorsports no longer carries this particular exhaust. However, Blueflame Performance is the company that manufactured the exhaust for Forge, and produces a very similar exhaust which is now available directly from their website (www.blueflameperformanceusa.com) or sometimes it can also be found on eBay. The differences are the tip style and that one tip is adjustable to help with fitment. With the car raised, we took out our trusty impact gun to remove the two bolts on the exhaust sleeve that connect the rear exhaust to the catalytic converters. After slipping off the rubber exhaust hangers, the exhaust simply came down and off the car. Early model TT quattros had a middle exhaust hanger that was subsequently eliminated sometime around 2002.
Our new exhaust was not one piece like factory – the Forge is a two piece exhaust. As such, we went to the local dealer and purchased the metal brace and rubber hanger for the exhaust, since the Forge exhaust had a hanger welded onto it in the same location as the earlier TT quattro exhaust. We bolted up the extra hanger and inserted the first piece of the Forge exhaust into the sleeve. We added a little high temp anti-seize to the bolts on the sleeve as well. In order to properly connect the two pieces of the Forge exhaust, you have to modify the rear exhaust shield, which is pretty simple to do. We enlarged the area where the pipe connects to the rear muffler can for extra clearance. We cut some off with our Dremel, then notched the shield all around the opening and then bent the thin aluminum back to remove sharp edges along the opening and smoothed out the opening with our Dremel.
With the shield off the car, we unbolted the stock rear sway bar and bolted our new H&R 21mm adjustable bar - set on the softer of the two settings. We also took the opportunity while down there to drop the compression setting a half a turn on our KW VIII shocks, thanks to the added stiffness of the new rear bar. The H&R bar was selected for its adjustability and special Teflon-lined bushings which never need to be lubed. We have to admit though, that we liked how its dark grey color added to the stealth nature of the install. With the shield back in place, we were ready to bolt the rear muffler to the mid pipe. We also chose to use a gasket at the junction between the mid-pipe and the rear muffler, although some have reported that high temp silicone works as well. Again, we added some anti-seize to the stainless steel bolts, some lock washers and tightened them down lightly. At this point, we aligned the exhaust tips, and then started tightening down the muffler to the midpipe. Once that was done we checked the mid-pipe alignment, made a couple slight adjustments and then tightened it down securely at the sleeve. The exhaust fitment was excellent.
Next up was adding the Modshack Tuned VTDA. This is the most recent intake offering from Modshack - a one man operation in Greenville North Carolina run by Steve Schwing. The VTDA is constructed from Microseam Phenolic tubing. It is open ended, terminating in a 4" Velocity Stack style inlet. The tube is six inches in diameter and ten inches long. It is insulated with R14 rated Air Bubble/Foil lined for lightless. Steve offers a variety of finishes and will color match the intake to your car, or can powdercoat it any number of standard or custom colors or with a variety of finishes such as translucent, wrinkled or bead blasted, as well as wrap it in brushed or polished stainless steel or carbon fiber weave. In keeping with our theme, we chose the black wrinkled powder coated finish, which is an excellent match to the TT’s stock engine compartment covers. Installation was simple, just remove the old airbox, and replace it with the VTDA using the provided hardware. Also provided is a foam “sock” for the breather tube that attaches to the stock airbox. As an option, you can order a small K&N filter for this piece and that is what we did. One last option was to add dual hose feeds into the engine compartment from the front of the car. However, this can be done only if you are running a front-mounted intercooler or a 180hp TT with the single intercooler, as the stock drivers side intercooler is in the way on 225-hp models. We plan on adding the twin air feeds when we add a front-mounted intercooler at a later date. Now it was time to head back down to Streetwerke to see what gains would be realized with the new intake and exhaust. We actually had the modifications on the car for about two months prior to hitting the dyno, and we were anxious to see if there we any numbers to back up the increases we felt in the proverbial butt dyno. In that month since installing intake and exhaust, we’d thought the car was definitely pulling harder throughout the rpm range. The VTDA being an open intake added some nice intake and “blow off” noises to compliment the new exhaust tone, as well as provided sharpened throttle response. So a couple calls to Darren at Streetwerke and we were set. We arrived a little early in the morning and had an opportunity to talk shop and check out some of cars before putting the TT upon the Mustang Dyno. Streetwerke was in the process of readying several of their cars for the Dubwars show down in Southern California. We saw all three versions of their Turbo package for the R32 in various states of completion, as well as numerous other Audi’s and VW’s in the shop. The TT was finally strapped down and a couple low speed test runs were done to make sure that everything was setup correctly. After dialing in the dyno, we began the first of three runs for the day. It should be noted that conditions were almost identical to the first time we dyno’d Project TT, with the outside air temperature being only slightly warmer. As with most dyno’s, the first run usually yields the best numbers and ours was no exception, putting down just under 205 whp at 4,750 rpms and 238 ft. lbs of torque at 3,000 rpms. This was an increase of almost 8 whp and 22 ft. lbs. of torque over our previous best runs. The next two runs netted 201 whp and 231 ft. lbs. of torque, so some heat soak was apparent after the initial run. Horsepower and torque increases began at 2,400 rpms and continued until 5,200 rpms over our baseline chipped run. Another interesting tidbit was that max power occurred at 4,750 rpms on this dyno, compared to 5,750 rpms on our first dyno. One thing that we did note that was our AF ratios were on the lean side during the initial run, and that there was a slight hesitation at 4,800 rpms, with power dropping off noticeably at this point as indicated on the dyno chart. Jason also noted he felt this hiccup during the dyno run. It is clear from the dyno charts that something happened at that point and a subsequent check for codes revealed a random misfire and number 2 cylinder misfire, which most likely happened during the dyno run. AF ratios on the subsequent two runs were pretty normal, so we’re not quite sure what caused the blip during the initial run. It is pretty clear that we might have put down some better numbers if we didn’t have the misfire as both the hp and torque curve just drop off at 4,800 rpms. We will be doing some Vag-Com logging to see if this was just a random incident or if there might be some other issue with the car. We should also note that the car is running on some pretty old spark plugs at the time of the dyno, with near 30,000 miles on. We’ll be replacing those shortly during our 60k maintenance service. As for the H&R 21mm adjustable rear sway bar, it has been a great addition. The slight softening of the rear compression settings has improved ride quality fractionally, but the stiffer bar has moved the TT towards a much more neutral handling car. We haven’t had the chance to really test the bar at its limits, but it’s proving its worth every day. As we continue to modify the suspension, every addition has provided a noticeable improvement and accomplished what we had hoped for and we intend an ultimate test of this a the track later this fall. All in all we were pleased with the results of our most recent modifications, and feel that the incremental improvement was both noticeable on the street and proven on the dyno. Hopefully we’ll solve our A/F ratio/misfire issue (if there is in fact a real issue) soon and move forward with our additional planned modifications. After experiencing heatsoak on subsequent runs each time we’ve been on the dyno, we are going to implement some pretty common measures to try and reduce this. Look for Project TT to be sporting a new front mount intercooler, a phenolic intake manifold spacer, a new Greddy RS air bypass valve relocated to the intake track post intercooler and twin air feeds to the TTDA for our next dyno run. We will also be adding the last stage of the Modshack tuned series, which includes a larger custom billet MAF, “boost machine” manual boost controller and 4bar fuel pressure regulator. The next time we put the TT on the dyno, it should be sporting all of these modifications, which should again add up to some incremental improvements on the dyno.
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