Monday, November 24, 2014

DIY Fix: How to Install a Greddy Boost Cut Controller (BCC) on a 2JZ-GTE with VVT-i (Lexus GS300/Toyota Aristo)

A Greddy Boost Cut Controller (BCC) will allow you raise the boost pressure without hitting the factory boost cut.
Our project Lexus GS300 (Toyota Aristo) has been running great, and we love the flexibility of the VVT-i 2JZ-GTE engine around town.  Boost comes online at 1500 rpm in sequential operation to provide adequate torque, and the 2nd turbo comes on at about 4200 rpm to provide additional power up top when needed.  We switched the car to a parallel setup aka True Twin Conversion (TTC mode), which has a bit more lag with the turbos providing boost starting at about 2800 rpm, but there is no dip in power between 3800-4200 rpm when the 2nd turbo would spool up in sequential mode.  This gives the car a more linear feeling powerband with more midrange punch, albeit at the expense of low end torque. 

We recently installed a bleed valve style manual boost controller to increase the boost from the factory setting of 12 psi.  One thing we noticed with the installation of the boost controller was the immediate increase in low end torque.  Noticeable boost (~5 psi) would come in at about 2200-2400 rpm depending on the gear we were in, which made our GS300 much easier to drive around town at low speeds.  We wanted to set our boost to 16 psi, however we were running into boost cut at 14.7 psi (1 Bar) of boost.  Boost cut is a safety feature where the computer cuts the ignition to the motor if the manifold pressure exceeds a certain threshold (1 Bar in our case with the 2JZ-GTE engine) for more than a second or two. 

To bypass the factory boost cut, we went with Greddy's Boost Cut Controller (BCC).  This device caps the voltage signal coming from the manifold pressure sensor, so the car's computer will not invoke boost cut.  Since Greddy does not make a 2JZ-GTE specific BCC, you will need to source one for a 2nd generation MR2 (SW20 chassis).  Follow along as we show you how to install the BCC on a Lexus GS300/Toyota Aristo 2JZ-GTE VVT-i engine. 

Thursday, November 20, 2014

DIY Fix: Increasing trunk tension on a Lexus GS300 or Toyota Aristo (preventing decapitation!)

The Lexus GS300 (Toyota Aristo for our overseas readers) is a great luxury sport sedan, and it has been our ongoing project car for the past 18 months.  There are a lot of things we love about the car, and a few things we don't like.  One annoyance is the fact that the trunk closes way too easy, and it comes down with enough force to leave a bruise on your back or head, such as when were installing the rear strut tower bar on the car. 

On a recent trip to get groceries, a small incline was enough to keep our trunk from staying open.  Juggling groceries, packing a stroller, getting rained on, and caring for a toddler don't make for a great mix.  We decided enough was enough, and took a look to see if we could do something to keep the trunk from being so easy to close.  Thankfully, there is a remedy to increase the tension on the trunk, and it literally took a few minutes to do.