[RKDinOKC]

Yeah, the mech that worked on 928s at their shop retired about the time I picked up the GTS. But Bob was still there for a short time.

The local tuner guy is not doing it as a business. Did it as a favor, the 928 group is really a bunch of nice guys. He currently has 4 928s, and has had 6. He got a Sharktuner for the supercharged 90GT he picked up. Then got more PEMs to be able to tune the rest of his cars as well.

The Sharktuner consists of PEMs or programmable chips you replace the factory chips with and a box that interfaces between the chips and software you run on your computer using the ODB port. You add a wideband o2 sensor for AFR. Then you plug in the laptop to the ODB and wideband and it records everything, and/or allows you to upload and download the maps to the ECU chips. Pretty cool for a vehicle that does not have ODBII.

To make changes you download the maps. There is a graphics program that you can display the maps overlayed with recorded data so you can visually see what is going on. You make the changes to the data file, then upload it to the chips. The program can analyze the recorded data and automatically update the maps. but I don't know of anyone that uses that feature. There are sevaral maps for both fuel and timing for different loads etc. There is even a plug under the dash that lets you change to different mapsets on for different octanes. Some of the guys use that to create a vallet mode that limits rpm.

One of the problems I've had is with the o2 sensor. When you install the wideband it has a simulated narrowband output you can wire to the ECU instead of the stock narrowband. All of the 928 tuners say to NOT use the widebands simulate narrowband, to leave the stock o2 in and ADD the wideband for tuning. Say if you don't you end up having problems tuning because there is a lag in the widebands simulated narrowband output.

The guy got my GTS running well quickly by disableing the chips trying to read the narrowband. Said it was also set for the wrong size of injectors. Since it is not reading an o2 sensor is not really optimal, but works okay and will not hurt the car. Am going to have to have another o2 port added to the x-pipe and install a factory narrowband to feed the ECU. Using the wideband o2 just for tuning.

Also it still has the factory fuel injectors, 18lb. Tuning for the hotter cams, headers, and x-pipe maxes them out when under load, full throttle, and higher rpms. They said it is okay, but really needs to go to 24lb to be safe and have the injectors last. The guy that sells the Sharktuner is selling me some Ford injectors cheap he is having rebuilt by Witchunter. They are a newer injector design, plug right in with no modifications, and have a better spray pattern.

When I very first got the Sharktuner was when I put an x-pipe on. Mike had a horrible time tuning it. He kept blaming the sharktuner. I kept telling him it needs a narrowband o2 for the ecu and bigger injectors. That is what all the good 928 mechs were telling me. Mike never did either.