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From YourSITE.com Technical Features Over the past year and a half, we’ve subjected Project TT to numerous modifications and a few runs on the dyno. The intent was to document as best we could, changes in power as a result of the modifications installed. In a perfect world, we would have dynoed the car stock, then again when we added a chip, again when we added an exhaust and so on. Unfortunately, this isn’t a perfect world. We’ve encountered several setbacks along the way and circumstances beyond our control have precluded us from being able to achieve this. Before we move on to the modifications covered in this installment, let’s recap some of our previous installments to illustrate our point.
This brings us to this installment of Project TT. Another set of modifications, another dyno session and yet another set of extenuating circumstances. In this installment, we go back to the dyno after installing a new GIAC BETA ECU upgrade, a Forge front mount intercooler and MCPi Inc. DV relocation kit. It would have been nice to have been able to dyno the Forge front mount and MCPi Inc. DV relocation kit before and after the new software, unfortunately time constraints and scheduling worked against us again. As we put together our plan for Project TT, we had a good idea of what modifications were available, and what had worked for others in the past. The GIAC ECU modification was one of them. The Forge Motorsports front mount intercooler was another. GIAC is known for their ability to provide some of the biggest gains in the industry while still maintaining good driveability. While we were happy with our initial dyno numbers, after finding out about the correction factor errors during our initial dyno and looking at the uncorrected numbers during our second dyno run, we placed a call to Jeff Moss at Torque Factory. We also did some VAG-COM logging and sent the numbers to Jeff so he could discuss the matter with GIAC. Jeff also noted to us that at the time, another GIAC customer who had recently purchased a 2005 TT and had installed the GIAC software had commented that he didn’t feel it was as strong as his previous 2001 TT which also had GIAC software.
After investigating the situation, we determined that the ECU tuning for the BEA engine (2003 and on) program had never been revisited and the boost numbers were quite conservative – actually not much higher than stock. While the GIAC program for the AMU engine (2001 and 2002) had seen several iterations and changes over time, the BEA engine software was the original programming. Jeff indicated that GIAC would provide us with a BETA program to test that should provide better numbers. The worst part about this was waiting for the new program to be developed. As we waited patiently, well impatiently, for the new program to be developed we encountered yet another problem with Project TT. While driving home one day, the car simply just lost power on the freeway. We managed to pull off to the side of the road and popped the hood. One quick look in the engine bay and we noticed that the hose coming off the charge pipe on the passenger side of the engine compartment had blown off. A seemingly easy fix, we popped it back on and tightened it down with the handy screwdriver from the Audi tool kit. Upon further inspection when we got home, we noticed that the hose had already slipped down and was ready to come off again. That’s when we noted the hose was completely frayed at the bottom and needed to be replaced. Since we had anticipated installing the Forge front mount intercooler from the onset of the project, we had ordered one from the guys at TTStuff.com about a year ago and were waiting until after we intake and exhaust dyno before installing it. The Forge front mount intercooler kit is made specifically for the TT’s 225 hp engine, and replaces the dual side mount intercoolers without modification to the front of the car. It also includes all the necessary Samco hoses, which connect to the factory fittings. The hoses come in several colors, but in keeping with our OEM plus look, we opted for black. We also picked up a set of Hose Techniques stainless steel T-bolt clamps for the install. Unfortunately, we ordered a couple of the clamps in the wrong size, so the kit was installed with the high quality screw clamps that came with it. We’ll replace these with T-bolts the next time we take the front end off the car. Audi's original dual side mount intercoolers have a claimed efficiency of just over 80% in reducing intake temperatures. Testing on the Forge Front Mount Intercooler by Steve at the Modshack has indicated that the Forge is 93% efficient in reducing intake temperatures.
During this time, MCPi Inc. had put together a group buy on some SFS Hoses with an integrated DV hose that relocated the DV from the turbo intake pre-intercooler to the post intercooler hose connecting to the intake manifold, in the front of the engine compartment. Included in the kit were the two hoses, clamps, a Greddy RS DV with custom CNC machined adaptors, a CNC machined aluminum plug for the hose connection from the charge pipe and a new hose and fitting to connect the DV to the original location on the turbo intake. All CNC parts also incorporated the TTs signature dimples as well. The purpose of relocating the DV to this location on the "cool" side of the intercooler is to provide cool air into the intake when the engine is under vacuum conditions and the valve is open. In the stock location, air coming right out of the turbo before the intercooler is put back into the intake track. Additionally, it places the DV in a cooler location away from the turbo, as well as in a location that is easier to service, if you have an adjustable DV or one that has a piston that requires regreasing. With these two kits sitting in boxes in our garage, we opted to go ahead and install them rather than purchase an expensive factory replacement hose that would eventually be removed anyway. We pondered installing just the one hose from the MCPi Inc. kit, but in order to do so, we still would have had to remove the front end of the car, so we figured while it was off; it made more sense to install everything at this time.
The install of both the front mount intercooler and DV relocation kit is extremely straightforward. In fact, even taking off the front end of the TT was pretty simple. Since the both kits rely on replacing factory parts, nothing required any real modification. The only thing that needed relocating for the front mount install were the horns, which were moved to their respective sides. After completing the install in an afternoon, we needed to adjust the spring tension in the Greddy RS DV. The Greddy RS is a diaphragm based DV, with reported lightning-quick action. It has two springs inside to regulate spring tension on the diaphragm. Most people who have installed the valve have removed the smaller inner spring and used just the larger spring set at 4 turns from full soft. Unfortunately, this setting didn’t work for us and after trying a number of different settings; we reinstalled the second spring and set it one-half turn from full soft. The key is balancing spring tension so that it holds boost, but is also soft enough to stay open during vacuum. We’re admittedly not sure we have it right, but it seems to be working correctly now, with no fluttering or resonance. With the front mount and DV relocation kit installed, we would have preferred to dyno this setup but again, due to timing constraints, we opted to wait to dyno after we had the new GIAC BETA software installed. Fortunately for us, the program was completed by GIAC right before Dubfest in September 2006 in Southern California and Jeff Moss was available to download the program the Friday before the show. So we packed up Project TT and headed south to hook up with Jeff. When we arrived, we headed out to do some preliminary VAG-COM logs to see if there were any issues that needed to be addressed before installing the new software. After testing showed no problems, we downloaded the new file into Project TT and drove around for little bit to allow it to adapt and then did some new logs. Of course, the butt dyno and a quick glance at the boost gauge confirmed that the new file was considerably stronger than the old file.
In fact, it proved to be too strong after looking at the logs. The logs of the existing software done that day showed that we were boosting to 18psi then holding about 17 psi and tapering to 15 psi towards redline. The new GIAC BETA “A” file was hitting the ceiling of the VAG-COM at 22 psi + and holding then tapering down to 17 psi by redline. If the boost gauge is relatively accurate, it was showing that it was holding around 24psi. After looking at all the logs though, the car wasn’t pulling any timing at all on 91 octane, and EGT temps were well within acceptable limits. However, sustaining 24 psi from 2800 to 4800 rpms could prove to be problem over time for the factory turbo, which was confirmed by a quick call to Garrett Lim of GIAC. Since Project TT is our daily driver, we were concerned about reducing turbo life and we all decided that GIAC would tone the program down a bit. After enjoying the Southern California sunshine for about 4 hours, Jeff and I received the call that the new software had been completed. So back to Project TT to download GIAC BETA file “B”. After downloading the program, we did several more VAG-COM logs and noted that boost had definitely been reduced. Although we still were hitting that VAG-COM ceiling of 22+ psi, it was just a spike at 3200 rpms that dropped to 19 psi and held till about 5300 rpms then tapered off to around 15 psi at redline. Since it was now about 8 pm in the evening, we decided to call it a night. So what does all this mean? It means that it’s time to throw the car back on the dyno at Streetweke and see what all this PSI is about. Of course with the addition of the front mount intercooler and relocated DV, we were not unable to compare our new GIAC numbers with our previous run, nor could we determine if the FMIC or relocated DV were contributing to any changes to the numbers. It should also be noted that, due to the misfire on the previous dyno and that the car was nearing it’s 60k service, I had changed to new factory NGK plugs gapped at .030 prior to the new dyno run. It’s probably a good time to post the uncorrected dyno numbers from our previous dyno runs for comparison purposes. Since we don’t have any true uncorrected numbers from our first dyno run, for comparison purposes, we have reduced our first dyno numbers by the correction factor used for the second dyno. The first dyno yielded 197.2 hp and 216.5 ft. lbs. at the wheels. By reducing the number based upon the correction factor, our result is 158 hp and 174 ft. lbs. at the wheels. Next are the uncorrected numbers from the intake and exhaust dyno run, where the misfire occurred. These were 166.6 hp and 192 ft. lbs. at the wheels. So if you compare the increases, there was an 8 hp and 18 ft. lb increase at the wheels. This is the amount of increase we reported in the original installment. So while the overall numbers are lower, the amount of net increase was the same.
So why go through all this to show the same increase occurred from the first dyno to the second dyno? It will all make sense when you see the results of the most recent dyno. This will also allow us to more accurately gauge any improvements from future modifications. Since we were aware of the correction factor problem from the previous dyno session, we decided to do a couple of corrected and uncorrected runs. The corrected numbers were too good to be true. We posted a best run of the day of 236.4 hp and 277 ft. lbs. to the wheels! Unfortunately, we all knew that those numbers were too good to be true. That would have been an increase of about 30hp and 30 ft. lbs at the wheels on Streetwerkes Mustang dyno. While we would have like to believe this was possible, we know that a few psi of boost does not translate into 30whp. The next uncorrected runs yielded results that were more in-line with our expectations. The best run of the day was 181.7 hp and 214 ft. lbs. at the wheels. This was a net increase of 15 hp and 22 ft. lbs. at the wheels over the previous run. After examining the dyno chart, the power improvements were consistent with the VAG-COM log runs we had performed previously. The torque spike was apparent as was the increase in power throughout the rpm range. In fact, there was a big increase in torque and horsepower after about 5700 rpm. The curves were also smoother overall, and the big dip attributed to the misfire during our second dyno was now gone. We should also note that subsequent runs yielded results all within 1-2hp showing that the front mount intercooler and DV relocation kit were doing their job.
Some would say that our numbers are disappointing based upon other dyno runs from other cars with similar modifications. We’re not. If you take into consideration that the first GIAC flash was pretty conservative and not much stronger than stock, the first set of numbers should have been pretty low. We also knew that the intake and exhaust wasn’t going to net us a big increase in hp or torque. The dyno results showed decent gains for a simple intake and cat-back exhaust. If the car didn’t misfire, those increases might have been greater, but we’ll never know for sure. The latest dyno, combined with a review of the before and after VAG-COM logs indicate that it was really the changes to the GIAC software that yielded the increases in power. In fact, if you compare dyno runs on GIAC’s Mustang Dyno of a 2002 TT with the AMU engine, which had similar modifications performed, our numbers are right in line with those numbers. We are happy that Project TT no longer misfires and is putting down numbers that are in line with the level of modifications that have been installed to date. While the GIAC file is still a BETA test file and needs further tweaking to eliminate the spike and solve some minor throttle related drivability issues, it’s clear that it’s making close to the level of power it should have from the start… or at least in comparison to GIAC’s other TT offerings. Of course, we’re going to continue to work with Jeff Moss at Torque-Factory and GIAC to squeeze as much power out of the TT as we can and not compromise reliability. We are disappointed that things didn’t go so smoothly from the start. In retrospect, it would have been nice to not have a boost leak from the factory, or have the wrong correction factors during the first dyno, or have a turbo hose disintegrate and have to be replaced. There really is no perfect world, but the grin on our face after driving the TT helps us have hope. So we continue to move on, and subsequent to this dyno session, we brought Project TT into Stasis Engineering to have them do the 60k maintenance service, change the timing belt and water pump as well as a Haldex fluid and filter change. Also due to a few more misfires (all cylinder one), we also decided to change all four coils. Which makes us wonder what the results would have been if we had changed the coils before the last dyno. But I digress. Even with all these issues and unfortunate circumstances, we’ll visit our friends down at Streetwerke yet again for the next installment, where we’ll see what gains we’ve made with the installation of the new 3” downpipe made by the good folks at 42 Draft Designs. Stay tuned!
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