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From YourSITE.com Technical Features As we sat down and put together the original plan for our TT project series, one of the first items on the list was to get a baseline dyno graph of the car so that we could evaluate the effectiveness of all future modifications that we were planning based against this baseline. Of course, not everything goes as planned. In fact, it was our intent to run our baseline dyno results as our second segment for Project TT back in June 2005.
Getting With The Program Since the 1.8T has been around quite some time, there are numerous options out there when it comes to ECU enhancements. With such tuners as GIAC, APR, MTM, O.CT., Neuspeed, Revo, Dahlback offering programs for the TT’s 225-hp 1.8T engine, finding the right program to fit suit our car wasn’t easy. With so many choices available to us, we had to look more closely at our specific needs. While specific output increases can be important, other factors such as local support and the ability to have multiple programs available were just as important in our case, if not more so. We also liked the fact that several tuners offered the “flash” method of upgrade so that ECU does not need to be removed and a new chip physically soldered in place. As with all later model Audis, the TT’s ECU is protected by a metal bar and tamper resistant bolts to prevent it from being opened, often referred to lovingly as a “chastity belt”. While these can be removed, we preferred to not have to do this. These requirements placed the GIAC, APR and Revo offerings at the top of the list, as all three offered the ability to flash the ECU through the car’s OBD port. Of these three, GIAC and APR both offered multiple programs as part of the flash including various different octane settings, 91, 93 and 100 octane, valet mode and also a security or anti-theft mode. Although Revo doesn’t offer the ability to directly switch between different programs, they do offer the ability to fine tune the programming by purchasing a separate SPS 3 device, which allows the owner to tune boost and timing settings to accommodate different octane gas or other modifications. They also offer a security program as well.
Since all three also made similar claims in terms of horsepower and torque increases, our choice was not an easy one. When all was said and done though, we chose to go with GIAC. We’ve had a lot of positive experiences with APR’s products having run them on a variety of different project cars. With the advent of the Flashloader program, and having a local tuner who is a GIAC supplier with an in-house dyno, not to mention being impressed with what GIAC has done over the years, we decided to try something different this time. Install and Dyno – Our TT Has Issues For the software upgrade, we teamed up with Torque Factory owner Jeff Moss and Dick Chiang of Dyno Spot Racing (DSR) a local tuner who is well known in the VW and Audi circles. We arranged to have all available programs loaded including the 91 octane, 100 octane, valet and kill programs. With a date set, we headed down to DSR in San Jose, CA to get a baseline dyno and then get the software loaded and run another dyno in 91 octane mode. Arriving at DSR, the car was left to cool down for a couple hours before putting it on the Dynojet dyno. Although the TT is all-wheel drive, and DSR’s dyno is for front-wheel drive, this isn’t much of a problem for Haldex-equipped quattro models. To convert to front-wheel drive, one simply needs to disconnect the Haldex controller and strap the car down. Three dyno runs were performed and we all felt a little bewildered by the results. Project TT put down 177 whp and 192 ft. lbs. of torque. Having dyno’d several R32’s and other 1.8T VW’s on this dyno but no other TT 225, Dick indicated that he felt the numbers were low but not quite sure how low.
We then flashloaded the car and put it back on the dyno for another couple runs. The best run netted us 186 whp and 195 ft. lbs of torque. We also noticed a high pitched screeching sound over 5,000 rpms, which was pretty pronounced after the ECU had been modified. At this point we knew there was something wrong with the car. After talking to both Jeff and Dick, we decided to turn to our trusty VAG-COM to log boost, Mass Air Flow sensor (MAF) flow, N75 duty cycle and a host of other items in order to try and figure out what was wrong. Prior to the initial dyno runs, the only changes we had made to the car was installing Forge Race diverter valve with standard green spring and a green top coolant sensor, as the stock black top sensors are known to be problematic. First we ran a full diagnostic scan to see if any codes popped up. Nothing. We checked all the vacuum lines and headed out to a deserted county road to run some logs. Blocks 003, 115, and 118 were logged. Block 003 provided info on MAF flow in gallons per second, throttle position and ignition timing. Block 115 provided info on requested and actual boost and Block 118 on N75 duty cycle. When we got back we analyzed the findings and only one thing stood out immediately - the actual and requested boost readings were off slightly and the amount of actual boost in chipped mode was lower than it should have been, especially at higher rpms. This did correlate to the lower horsepower figures as shown on the dyno chart which leveled off at 5,000 rpm. We then forwarded the logs to Jeff and Dick as well as Steve Schwing of Modshack Tuning to see if they could provide any additional insight on the readings. We all concluded that nothing looked really out of the ordinary. While the MAF readings appeared to be ok, they were a tad low so we opted to put in a new remanufactured MAF. We also decided to try an N75 “J” valve just to see it’s effect on the car and boost levels, since the N75 valve controls the frequency of the turbo’s wastegate which, in turn, controls boost. Additionally, we switched over to the slightly stiffer yellow spring in the Forge diverter valve to see if that would help as well.
After driving around a while with these changes, the car felt stronger, so we went back to DSR to see what the dyno had to say. Since the conditions of the day were similar to the last time we were there, we were hoping to get positive results. As it turns out, at the end of the day, we were no further along in solving our problem than we were prior to dynoing the car. The dyno figures for the car that day were 188whp and 215ft.lbs. of torque. However, the higher torque figure was the result of a big spike at around 3,800 rpms, which then dropped off significantly. So it was apparent that the N75 “J” valve was providing that extra torque, which is what our butt dyno was feeling. However, the car was still not putting down the numbers it should. The next day we decided to run the same logs as we did previously to compare the two to see if that provided any insight to our ongoing lack of power problem. The logs revealed what we had expected. The N75 “J” valve was providing a very short increase in boost at 3,800 rpms with corresponding jumps in MAF flow which produced the jump in torque. Other than that, we were still boosting too low in the higher rpms and actual and requested boost were still off by about 3 psi. We had also wound up throwing some N249 codes, which indicated a DV malfunction. We decided at this time to try a Forge 007 diverter valve with the standard green spring and cleared the codes. They never reappeared. We also put the stock N75 “F” valve back in the car. Later that evening we received an email from Dick Chiang with an attachment of a dyno plot of another stock TT 225 which he had dyno’d earlier that day. The results on this TT were 197whp and 194 ft. lbs of torque. He had overlaid the results of that dyno with my original stock dyno of Project TT. What was immediately apparent was that my car was simply dropping power at 5,000 rpms, right where the other TT’s power started to climb. At this point it was pretty obvious that something was leaking boost at high rpms, but we had no idea what that could be. After several months of testing, at least we did narrow it down somewhat to some sort of high pressure boost leak. Hoping to find the leak we contacted 2Bennett Audimotive in Davis, CA and scheduled a leak down test of the car, though we found no problem.
We then headed to Tomas Sport Tuning and had Tim check the wastegate and look for other possible leaks or problems with the turbo. Although the wastegate seemed to be functioning correctly in terms of actuation under pressure, it wasn’t functioning that smoothly according to Tim. Could it be a sticking wastegate? At around the same time, our Bentley Repair Manual for the TT showed up in the mail. We immediately went to the section on troubleshooting the wastegate and turbo. After comparing the results of our logs to the Bentley test, it appeared that the wastegate was most likely the root of our problem. Armed with our logs, the page of the Bentley manual and our dyno comparison, we headed off to our local Audi dealer, convinced that the car had a malfunctioning wastegate which was causing a boost leak at high rpms. We went over the data and information with our service advisor, left the keys and headed home in our rental car. We received a call later that day to find that the dealership had not found any codes and therefore didn’t believe there was a problem. Of course, we were not pleased. After a long, heated discussion with the dealership, they agreed to at least test the wastegate and see if there was a problem. The next day we received a call directly from the technician working on the car that they had confirmed that there appeared to be some type of turbo or wastegate malfunction, as they had noticed that high pitched screeching sound as well. He also wanted to know if the car had been chipped. We told him that it was in fact chipped, but that the problem had occurred and was documented prior to us modifying the ECU. He said that it would have no affect on the warranty but wanted to know if the problem was more pronounced when it was running in chipped mode. We told him it was and he then agreed that the turbo should be replaced under warranty. After a couple days, the technician called again to inform us that the car would have to stay at the dealer a couple more days because they had to order some additional parts. One of these was the EGT sensor for the turbo and a new coolant line. As it turns out, the existing EGT sensor had been cross threaded into the turbo and couldn’t be removed. The technician indicated that this was the source of our boost leak, not the wastegate. So Audi replaced the turbo and associated parts under warranty and we had the car back in our hands within about 10 days total.
Fixed at Last We immediately noticed how much harder the car was pulling in the higher rpms. The difference was like night and day. Of course, we would hope that a 20 whp gain after 5,000 rpms would be noticeable. Even better, this was in stock mode. Getting the car home, we switched over the chipped mode and after the car had an opportunity to adapt, the gains were significant; at least that’s what the butt dyno said. Knowing full well that you can never trust that part of your anatomy, we were anxious to schedule a new dyno session to see if the results were real. Although we would have liked to have been able to dyno the car at DSR again, for the sake of consistency, we were unable to arrange for any future dyno’s at DSR. At this point we needed to find a new location to dyno Project TT. Having had the pleasure of dealing with the guys at Streetwerke in Palo Alto, CA on several previous occasions, we placed a call to Jason and informed him of our intentions. With their new Mustang Dyno in place, they have become a premier location for AWD dyno’s in the Bay Area. With their experience of having put their Haldex equipped Turbo R32 on this dyno, we were confident this was the best place to dyno Project TT. We have to admit, we were pretty nervous on the drive down to Streetwerke, hoping for the best but trying to prepare for the worst. After letting the car cool down for a couple hours, Darren and Jeff drove Project TT onto the Mustang dyno and hooked her up. Originally we would have like to run the car in both stock and chipped modes, but GIAC indicates that unless the car is directly flashed you can’t simply switch modes and then dyno, as it takes time for the ECU to completely purge the old maps and load the new maps in. Unfortunately, we simply didn’t have the time to be able to do this. In addition, while the GIAC stock program is similar to the factory programming, it isn’t the exact program so our results would not have been the same as if the car was bone stock. So much for establishing a stock baseline. However, based upon other dyno charts from stock TT’s done on a Mustang Dyno, as well as the info on GIAC’s website, we figured the car would have put down between 165 and 170 whp in stock mode. The dyno chart on GIAC’s website shows a 24whp and 46 ft. lbs of torque increase on a Mustang Dyno. We also knew that Streetwerke’s R32 put down around 185whp on this dyno stock.
We did five different runs, with the best hp reading coming in at 197whp and the highest torque figure coming in at 222 ft. lbs. Average for the day was 195whp and 219 ft.lbs of torque. This was right in line with the numbers published on GIAC’s website. Needless to say we were very happy with the results. We’re also happy to have put all the initial problems behind us. However, to quote an often overused saying, every dark cloud has a silver lining. For us, the knowledge gained in troubleshooting the turbo problem was just that. It’s made us more aware of how Project TT’s engine works and what to look for in the future should any other issues arise. We look forward to continuing the modification process and having the opportunity to work with Streetwerke again in assessing the results of our futures mods. Next time we hit the dyno, we’ll be seeing what effect a cat-back exhaust and intake have on the car. Of course, you’ll just have to wait until that segment to find out what exhaust and intake we’ll be using.
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