Toyota Supra 2.5l Twin Turbo (JZA70) Blitz SBC iD II
Boost Controller with Power Meter II

Introduction

Although the 1JZ-GTE engine is a strong one and can take large amounts of boost pressure as stock, the same cannot be said for the turbos. If you want to go anything above 14psi you really need to think about fitting better turbos.

I'm still running stock turbos on my supra, so I'm not able to take full advantage of the boost controller (yet!) but it does fit nicely into the hole left in the dash, and I can monitor what boost I am pushing more accurately than the stock meter, and also lets me do 0-50 and 1/4 mile times. Also when I get the optional engine ECU harness for it I will be able to monitor things like intake temperature and other techie things.

Fitting

Fitting the boost controller was tricky in parts, not so much through complication, but mainly fiddly access. It can be split up into 3 main stages.

Stage 1 - Under the bonnet

One of the trickiest parts of the installation was locating a suitable place for the solenoid to be mounted. I was able to mount mine between the air filter box and the right side suspension strut. I needed to move my alarm out of the way slightly, but If you have nothing extra mounted there you should be fine. The instructions say it should be mounted as close to the turbos as you can get it.

Plumbing the solenoid into the turbos was also tricky, but this was due to the limited access. The picture below shows a view of the twin turbo setup on the 1JZ-GTE engine

On either end of the setup you can see a pipe which goes from the turbo outlet housing to the actuators. On the front end (left of the diagram) you can easily get to the top of the hose, but not the bottom. And on the rear, you can just get round to access the bottom of the hose but not the top.

This is ok because you can remove the top part of the hose on the front turbo and the bottom part of the hose on the rear turbo and just extend the stock pipe leaving it attached to the parts of the turbos you cannot reach.

The SBC iD II did not come with enough connectors and piping to be able to plumb in the solenoid with 2 turbos. It only came with one T piece and 2 straight through pipe connectors. RS came up trumps here and the below connectors are ideal and are sold in packs of 10. It worked out at about £10.00 for a pack of straight through connectors and a pack of T piece connectors. (795-348 for straight through, 795-405 for T piece).

While I was ordering from RS, i also got some extra hose, as I couldn't see there being enough to make 2 runs all the way round to the rear turbo from the front. Although pricey at £35.00 for 5 meters (754-482), it did the job well and fits the connectors beautifully without the need for jubilee clips.

To plum the turbos I connected a piece of tubing to the front turbo outlet union (top) and ran it round to a T piece in front of the solenoid.

I then ran another piece of hose from the T piece round to the back turbo and used a straight through connector to connect this hose to the existing hose which goes to the slightly inaccessible turbo outlet union on the rear turbo. I needed to use jubilee clips to secure the existing hose to the straight through connector for the rear turbo and also to secure the hose to the outlet union of the front turbo. I then ran a piece of hose from the T piece up to the solenoid and fitted it to the solenoid at the connector marked "IN". This also required a jubilee clip.

I then did the same for the actuator connectors, using the existing hose on the front turbo and just managing to attach the hose to the actuator on the rear turbo. This should be plumbed up to the "OUT" connector on the solenoid.

On the left of the engine bay there is a Turbo Pressure Sensor unit with a hose which goes to the intake manifold. I tee'd off this hose using the supplied T piece and attached the small rigid black pressure pipe which comes with the SBC iD. This connects to the controller and is used to measure the intake pressure.

This just leaves the wiring harness for the solenoid and the rigid pressure pipe to be routed round the engine bay and through a hole in the bulkhead into the cabin. For this I disconnected the engine wiring loom from the various ECU's behind the glove box and pulled the engine harness through into the engine bay. With a slight modification the new wiring and pipe can be fed through the existing grommet with the ECU loom. Once this was all pushed through and the grommet back in place, the work under the bonnet was done. I left the engine wiring loom disconnected from the ECU for now as I would need to do some wiring into the connectors for Stage 3.

Stage 2 - Mounting the displays

As I had removed the stock Toyota double DIN radio and fitted a single DIN unit, I already had a single DIN sized hole in my dashboard for the units to go into. I searched high and low for a suitable blanking plate that I could mount the displays onto, but couldn't find a suitable one anywhere, and the ones I could find were gash.

I eventually went to halfrauds and purchased a Celica Supra stereo mounting kit which was quite a substantial bit of kit (I should hope so for £30). It contained plastic replacements for the metal side brackets which hold the stereo in, and all manner of connectors, and even a mounting kit to mount a graphical equaliser beneath the stereo.

I didn't particularly want to rip the metal brackets out and replace them with plastic ones as the metal ones give added security for your stereo, so I went about modifying the graphical equaliser mount. What I ended up with was a piece of plastic that looks like the below drawing (apologies!)

This was ideal as it sat on the metal brackets nicely and if I shaved it down to be the correct depth it would be held in place when the plastic dash/console surround was refitted. It also had a hole already in the centre for the cables to go through.

The cables were fed through and the 2 displays stuck side by side with double sided sticky tape (works quite well). The cables needed to go out the back and into the passenger foot well, where they will be later fed up into the glove box area.

I held the units in place and refitted the plastic surround and it held them in place superbly. They feel steady as a rock and are pretty much inline with my stereo.

Stage 3 - Electrical wiring.

This was quite an easy task, as there aren't many wires to connect.

The SBC iD II display connects directly into the SBC controller module, as does the wiring harness for the solenoid which came through from the engine bay earlier. The small rigid boost pressure sensor pipe from the engine bay also connects to the controller using the supplied joint. The solenoid wiring harness also has a red and black wire which give the unit its power. I left these hanging for now.

The SBC Power meter display connects to the loom provided and has 3 wires on it. A red and black wire which are for power, and an orange wire which connects to the engine ECU for a speed sensor signal. Again I left these wires dangling for now.

I removed the engine ECU unit and stuck the controller unit to the top of it and neatly tied up all the excess wiring that was left from the solenoid loom and the 2 display units. There was just enough room above the Engine ECU for all this so it was nicely out of sight when refitted.

I connected the two black earth wires together and earthed them onto the Engine ECU mounting bracket (Use a multimeter or bulb test to check that this is earthed, it was on mine)

This just left the 3 wires left which can be spliced into the engine ECU wiring loom just before the connectors (2 power and speed signal) 

Result

Everything worked as it should. The displays functioned correctly and on first blast the boost went up to a maximum of 11.1psi.

I tweaked the boost up slightly to a maximum of 12.5psi which is where it will stay until I get some new turbos.

Price

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