Tag Archives: mk4
MKiV Twin Turbo Sequential System
One of the unique new features of the MKiV Supra was the Twin Turbo Sequential operation. Only a handful of cars touted this Sequential System. The system was designed to provide greater power levels at lower RPMs by diverting all the exhaust energies to the front #1 turbo. Since these turbo’s are rather small, running on one turbo provided a high spool characteristic. At or around 4000 rpms, the rear #2 turbo would kick in to provide for the peak potential power.
With this unique system comes complications. There are a lot of components that go into this system. If any of them malfunction, the entire system goes down. The “orchestration” of Actuators, Vacuum Switching Valves (VSVs), and vacuum lines via the ECU is a
real feat. As our beloved MKiV Supra ages, so does the Sequential System. Vacuum lines become brittle, actuators lose there ability to hold pressure, VSVs start to break down, Pressure tank loses it’s ability to store pressurized air. All of which is needed to have the system work.
Understanding this system can be somewhat complicated and difficult to diagnose. Several years ago I wrote a diagnostic manual to help people try to understand how it works and help find issues. http://97supraturbo.com/public_html/Seq%20FAQ/Seq%20FAQ.doc This doesn’t cover 100% of all possible issues, but it covers the most common. If anyone is serious to understanding and diagnosing the Sequential System, I highly recommend to purchase a MityVac hand pump. Like the MV8510 series. http://www.lincolnindustrial.com/asp/distributors/access/distributors/4_MV8510%20PIS.pdf. You will be able to test all the components with this. Find leaks, and actuator healthiness. As well as testing the pressure tank.
This all should aid you into figuring out issues. Your going to find that there is not many dealers/repair places out there that can understand and repair effectively, so the only person that can really get to it and fix things is YOU! Good Luck.
Stu Hagen
Introduction: Road Racing Supra’s
Hi, I am Dave Hanna and the proud owner of both a Mk3 (1992) and Mk4 (1997) Supra. Unlike the majority of Supra owners I find the best way to enjoy the cars is not the quarter mile but rather on race tracks and auto-x venues which involve braking, turning AND acceleration.
I purchased my first Supra, the mk3, in 2008 while I was in college. I bought the car with 82k miles on it and took it from its completely stock state to a mildly upgraded, 342 rwhp car, including a full motor re-build. For suspension It still uses the stock TEM’s shocks and springs with upgraded Whiteline adjustable sway bars front and rear. Wheels and tires are stock Mk4 wheels, wrapped in any of the Extreme Performance street tires popular in the Auto-x world (Dunlop Z1 Star Specs and Hankook RS-3’s for example) I did my first track day in 2009 and I was hooked. Ever since I have done many Auto-x events and the pace the car is quite good at the local events I attend.
In 2009 I graduated from College and began the search for my MK4. I have wanted to buy a mk4 for
at least ten years at the time, but took mine time to search for the perfect car at a price I could stomach. I ended up finding that car in June of 2011 and picked the car up in Albequerque New Mexico the day before I was to attend the Pikes Peak Hill Climb in Colorodo. It worked out perfectly. The car was a Stock Paint, all VIN tags present, Southern car all its life. It already had a few upgrades, including a Boostlogic T61 Single turbo conversion, HKS intercooler, Apexi GT-spec exhaust, Tein Type Flex Coilovers, Volk GT-N wheels, and maybe my favorite modification 13.5″ AP Racing Rotors and corresponding 6 piston Calipers up front. The car is now corner balanced and I have gone through and upgraded things for track time longevity since my purchase which I will elaborate on in a future post.
I will elaborate on the track day fun and experiences in both cars but can tell you without a doubt that if you try your Supra out at an HPDE style event you will likely be hooked!
Here is a link to my Youtube channel, there is plenty of on track Supra Content.
http://www.youtube.com/user/supradma71?feature=mhee
-Dave