Supra Forums banner

1 - 8 of 8 Posts

·
Registered
Joined
·
52 Posts
Discussion Starter · #1 ·
Hello everyone,
I have a 93 tt jdm supra that came with a greddy profec b spec 2. What would be the recommended hi and low settings to get the maximum amount of psi without damaging the engine. Mainly for high way pulls. Let me know what your settings are if you have this boost Controller setup.
 

·
Registered
Joined
·
212 Posts
I had one of those. I had it set to 18 psi on pump 93 octane, but it wasn't doing much more than a manual BC, so I took it out and went with a manual BC set to release at 18psi. Note that my mods are only BPU, no engine, fuel system, or timing work.
 

·
Registered
Joined
·
315 Posts
Need more info (specs) about the car. Can you list everything that has been changed from the OEM set up to get the car where it is today.
 

·
Registered
Joined
·
52 Posts
Discussion Starter · #4 ·
I recently bought the supra and to my knowledge there is a bov and boost Controller. Everything else is stock. Stock twins setup with a bigger intercooler.
 

·
Registered
Joined
·
315 Posts
To raise boost beyond the stock level the catalytic converters need to be removed to allow the turbos to spin faster and produce more boost pressure.

With both cats removed the j-spec turbos will overspin and you will see boost over 1.6bar (23.2psi). At these pressures the ceramic blades usually become detached from the shaft and cause catastrophic failure of the turbo.

A restrictor ring is fitted between the midpipe and exhaust and if properly sized a restrictor should bring the maximum boost pressure down to 1.2 bar or less.

You need the following.

- De-cat pipe, midpipe (2nd decat pipe) and a good exhaust.

- Restrictor ring.

- Larger fuel pump.

- Colder plugs.

- A speed delimiter aka Speed Limit Defender aka SLD. J-specs are limited to 112mph.

Nice but not essential would be an AFR and/or EGT gauge to go alongside your boost gauge.

Check the intercooler piping and all rubber joiners. Make sure they are in good condition. Check two accordion looking pipes on the turbo intake side, they tend to collapse internally.

Make sure your brakes are in good condition. If possible fit new OEM pads and discs, change all fluids, oil and fuel filter too. The V8 Toyota engine filter is a nice one to use over the Supra one as it’s slightly larger. New OEM air filter or the TRD panel filter in the stock airbox will be fine.

Drain all the fluid in your autobox, flush it through, fit a cooler with an inline thermostat, fit a new filter then top it up. Take it for a drive and check the fluid level again. Top up if necessary. You can fit a deeper pan to the autobox which helps keep temps down on WOT. A temp gauge with a sensor fitted into the pan wouldn’t be a bad idea either.

Also check where your diff mounts to the subframe, look underneath the car from the exhaust end towards the engine. J-specs didn’t always come with both diff mounts fitted from the factory. If you are missing one, get the other ordered and fit that too or fit two new OEM ones if you are feeling flush.

For the setting work around 10-15% gain. Set warning to 1.3 bar and set the limiter to 20%. See what boost that gives you then you either reduce or increase depending on how far off from your boost target you are. IIRC if the GAIN value is set too high you will get boost spikes.

The only thing left after those settings would be your set value. This changes from car to car and is dependent on what weather conditions you will mostly face.
 
1 - 8 of 8 Posts
Top