CBender
07-30-2003, 12:40 AM
Having dragged many in the S2000 community through my turbo woes over the past 15 months, I thought I would post a thread to let you know that the story seems to finally have a happy ending. This has been written with input from Giles (GilbertG), as he shared much of the journey with me, and we took the same route to its completion.
First, however, we want to thank a few people -- including (in alphabetical order) CJB80, ChrisD, HeCash, RT, Schwett, TwoHoos, Ultimate Lurker, Wesmaster, and Yellow Streak -- without whose help we would not have made it. Both Giles and I were seriously ready on more than one occasion to throw in the towel and sell our cars. We are also deeply grateful to Sean McElderry from TorqueFreaks, a most excellent EMS tuning shop (more on Sean and TorqueFreaks later).
Second, none of our troubles reflect negatively on either Speedcraft (the source of my turbo kit) or Stage 6 Motorsports (the source of Gile’s kit). Todd and Tracy at Speedcraft and Dwight at Stage 6 sell quality kits, with top-of-the-line components, and both shops did a terrific job installing them. Moreover, they have consistently stood behind their products, and we have nothing but good things to say about them.
To the contrary, our complaints revolved around the problem of partial throttle tuning -- at wide open throttle the basic setup was pretty good – as well as our concerns surrounding the longevity of these kits when mated to the stock ECU’s fuel and timing maps. We never quite figured out the cause of the problems, but for me they were most apparent when feathering in throttle when exiting corners in VTEC in boost on the track. The power was often uneven, which shifted weight around the car in a way that unsettled it enormously and made it scary to drive at, or near, the limit.
Possible explanations for these partial throttle tuning complaints include (i) underlying variability within the ECU (witness the fact that the VTEC engagement shifts upward under light throttle), (ii) limited tune-ability on the part of the A’PEXi VAFC, (iii) slow response times from the rising rate Vortech FMU and the problems inherent in running very high fuel pressures, (iv) the VTEC mismatch (although RT offered up a solution for that one), or (v) some combination of these. It remains a mystery.
In any case, we finally decided to ditch the original setup -- stock ECU and injectors, A'PEXi VAFC, Vortech FMU, and Profec B (boost controller), -- and upgrade to the AEM EMS, 550 RC Engineering injectors, wideband O2 sensors, and AEM adjustable fuel pressure regulators. There have been several excellent posts on this conversion already by ChrisD and CJB80 -- see, especially http://www.s2ki.com/forums/showthread.php?threadid=124653 -- so we won’t repeat the information here.
We did the hardware installation ourselves -- it's really not very hard provided you’re careful -- but after printing 400 pages of EMS technical manuals, we threw in the towel and called in TorqueFreaks. The power of the EMS lies in its ability to control virtually everything. Therein, however, lies the problem. It must be taught to control anything, and while the base maps are better than they used to be, the only thing that’s “plug-and-play” about the EMS is its installation. Beyond that, you need a tuner.
For tuning, we called on TorqueFreaks. TorqueFreaks is located in Portland, Oregon (some of you may recognize why I, in particular, like this solution). Check out their website -- www.torquefreaks.com -- for more information. After talking to four of their customers -- all of whom had nothing but great things to say about them – we flew Sean (the owner but only one of several qualified tuners) out this past weekend to tune our cars.
Bottom line? The cars start, idle, and run like stock, with a lot more power of course -- we're guessing 300-305 hp to the wheels at 7 psi of boost. Idle, boost control, partial throttle tuning, on/off throttle transitions, etc., are all much improved and the EMS has definitely resolved our complaints with the VAFC. With O2 feedback enabled and the wideband installed, our air-fuel ratios are unbelievably rock solid across all sorts of conditions (boost, throttle position, engine speed, etc.). We take comfort in knowing that Sean was very conservative when tuning our cars. We suspect that there was more power available -- on pump gas at 7psi there wasn’t even the slightest evidence of knock -- but longevity is far more important to us than the extra horsepower. On the track, I was happy with the 285 whp I got from the old setup at 6 psi of boost.
The biggest lesson from this weekend is that unless you retard the timing and run a MUCH richer mixture, there is serious risk of serious knock under boost. We could see that pretty easily when we measured the wave forms under race and pump gas. We worry that anyone running 6-7psi of boost -- whether by supercharger or turbo -- could be at risk, particularly if their air-fuel ratios are in the commonly perceived "safe zone" of 13.5-13.7. To eliminate all knock, we had to run air-fuel ratios under 13.0 at moderate boost and under 12.0 at full boost, which is a lot richer than what I once ran with the VAFC (although the car feels great, even with the extra fuel in the maps).
TorqueFreaks isn’t the cheapest route for getting an EMS tuned, particularly once you consider the cost of the airfare, lodging, hay and water, but it was worth every penny. We have nothing but good things to say about them, and the fact that we now seem poised to start enjoying our cars again after months of despair really is the ultimate proof that all’s well that ends well.
If you’ve got any questions, pls. feel free to ask us. For those of you new to this issue, however, pls. do your homework first. There’s a lot of great information already posted about wideband O2 sensors, the EMS, and so forth. Thanks.
Best,
Cbender and GilbertG
First, however, we want to thank a few people -- including (in alphabetical order) CJB80, ChrisD, HeCash, RT, Schwett, TwoHoos, Ultimate Lurker, Wesmaster, and Yellow Streak -- without whose help we would not have made it. Both Giles and I were seriously ready on more than one occasion to throw in the towel and sell our cars. We are also deeply grateful to Sean McElderry from TorqueFreaks, a most excellent EMS tuning shop (more on Sean and TorqueFreaks later).
Second, none of our troubles reflect negatively on either Speedcraft (the source of my turbo kit) or Stage 6 Motorsports (the source of Gile’s kit). Todd and Tracy at Speedcraft and Dwight at Stage 6 sell quality kits, with top-of-the-line components, and both shops did a terrific job installing them. Moreover, they have consistently stood behind their products, and we have nothing but good things to say about them.
To the contrary, our complaints revolved around the problem of partial throttle tuning -- at wide open throttle the basic setup was pretty good – as well as our concerns surrounding the longevity of these kits when mated to the stock ECU’s fuel and timing maps. We never quite figured out the cause of the problems, but for me they were most apparent when feathering in throttle when exiting corners in VTEC in boost on the track. The power was often uneven, which shifted weight around the car in a way that unsettled it enormously and made it scary to drive at, or near, the limit.
Possible explanations for these partial throttle tuning complaints include (i) underlying variability within the ECU (witness the fact that the VTEC engagement shifts upward under light throttle), (ii) limited tune-ability on the part of the A’PEXi VAFC, (iii) slow response times from the rising rate Vortech FMU and the problems inherent in running very high fuel pressures, (iv) the VTEC mismatch (although RT offered up a solution for that one), or (v) some combination of these. It remains a mystery.
In any case, we finally decided to ditch the original setup -- stock ECU and injectors, A'PEXi VAFC, Vortech FMU, and Profec B (boost controller), -- and upgrade to the AEM EMS, 550 RC Engineering injectors, wideband O2 sensors, and AEM adjustable fuel pressure regulators. There have been several excellent posts on this conversion already by ChrisD and CJB80 -- see, especially http://www.s2ki.com/forums/showthread.php?threadid=124653 -- so we won’t repeat the information here.
We did the hardware installation ourselves -- it's really not very hard provided you’re careful -- but after printing 400 pages of EMS technical manuals, we threw in the towel and called in TorqueFreaks. The power of the EMS lies in its ability to control virtually everything. Therein, however, lies the problem. It must be taught to control anything, and while the base maps are better than they used to be, the only thing that’s “plug-and-play” about the EMS is its installation. Beyond that, you need a tuner.
For tuning, we called on TorqueFreaks. TorqueFreaks is located in Portland, Oregon (some of you may recognize why I, in particular, like this solution). Check out their website -- www.torquefreaks.com -- for more information. After talking to four of their customers -- all of whom had nothing but great things to say about them – we flew Sean (the owner but only one of several qualified tuners) out this past weekend to tune our cars.
Bottom line? The cars start, idle, and run like stock, with a lot more power of course -- we're guessing 300-305 hp to the wheels at 7 psi of boost. Idle, boost control, partial throttle tuning, on/off throttle transitions, etc., are all much improved and the EMS has definitely resolved our complaints with the VAFC. With O2 feedback enabled and the wideband installed, our air-fuel ratios are unbelievably rock solid across all sorts of conditions (boost, throttle position, engine speed, etc.). We take comfort in knowing that Sean was very conservative when tuning our cars. We suspect that there was more power available -- on pump gas at 7psi there wasn’t even the slightest evidence of knock -- but longevity is far more important to us than the extra horsepower. On the track, I was happy with the 285 whp I got from the old setup at 6 psi of boost.
The biggest lesson from this weekend is that unless you retard the timing and run a MUCH richer mixture, there is serious risk of serious knock under boost. We could see that pretty easily when we measured the wave forms under race and pump gas. We worry that anyone running 6-7psi of boost -- whether by supercharger or turbo -- could be at risk, particularly if their air-fuel ratios are in the commonly perceived "safe zone" of 13.5-13.7. To eliminate all knock, we had to run air-fuel ratios under 13.0 at moderate boost and under 12.0 at full boost, which is a lot richer than what I once ran with the VAFC (although the car feels great, even with the extra fuel in the maps).
TorqueFreaks isn’t the cheapest route for getting an EMS tuned, particularly once you consider the cost of the airfare, lodging, hay and water, but it was worth every penny. We have nothing but good things to say about them, and the fact that we now seem poised to start enjoying our cars again after months of despair really is the ultimate proof that all’s well that ends well.
If you’ve got any questions, pls. feel free to ask us. For those of you new to this issue, however, pls. do your homework first. There’s a lot of great information already posted about wideband O2 sensors, the EMS, and so forth. Thanks.
Best,
Cbender and GilbertG