Mk4 Supra - BlownByTwins

Tuning VVT-i Properly: From Chasing Errors to an Oil-Temperature-Compensated PID

How oil temperature changes what the 2JZ-GTE's VVT-i controller needs, and the path from fixed feed-forward to an oil-temperature-compensated PID on the Emtron KV12.

Engine Management Mk4 Supra Tuning

What the Logs Changed in My Supra Traction Control

The previous version of the traction control worked. That was the problem. It worked well enough to make a 1,114 whp Supra feel calm, so the remaining faults were hidden…

Engine Management Mk4 Supra Tuning

Erratic Shifts and Idle Overfuelling on the 2JZ: Finding a DBW Feed-Forward Fault

Inconsistent torque, delivery and shifts, with nothing obvious in the log. Working outwards from the symptom into the DBW loop, and the arithmetic that showed the integrator was spending its whole authority cancelling a feed-forward error.

Chart of permitted wheel slip against lateral G for three traction control settings, each forming a dome that peaks in a straight line and tapers as cornering load builds

Engine Management Mk4 Supra Tuning

Traction Control on 1,114 whp: Feedforward, PID, and Why It Never Cuts

1,114 whp, 880 lb ft, and a 295 section road tyre on the back. Traction control on this car is not a driver aid. It is the thing that makes…

Chart of injector flow against rail pressure showing a square root relationship, so an injector rated 1,000 cc at 3 bar flows 1,155 cc at 4 bar rather than 1,333

Engine Management Mk4 Supra Tuning

Twelve Small Injectors Instead of Six Big Ones

Every big power build hits the same wall. You need enough injector to feed the engine at full noise, and the injector that does that is too big to idle…

Bar chart comparing raw wheel speed channels reading 2.8 percent apart against a corrected Drive Slip channel reading zero at steady cruise

Engine Management Mk4 Supra Tuning

Staggered Tyres and Traction Control: What the ECU Corrects, and What It Can’t

If you run staggered tyres and a standalone ECU with traction control, there is a field in your configuration that almost certainly matters more than you think it does. It…

Chart of ignition advance gained on E85 over 99 RON pump fuel, showing identical timing below 100 kPa and four to five degrees more advance above it

Engine Management Mk4 Supra Tuning

What E85 Actually Buys: Boost, Timing, and Where the Advantage Vanishes

Ask what E85 is worth on a big turbo engine and you get one of two answers. Either it is magic, or it is 30% more fuel for 30% more…

Schematic showing engine speed continuing to rise while measured output torque falls away, the signature of clutch slip inside a ZF 8HP70 during a dyno pull

Engine Management Mk4 Supra Tuning

Where the Stock ZF 8HP70 Gives Up: 901 lb ft, Measured

The ZF 8HP is the default answer for anyone putting an automatic behind a big power engine, and the question that follows it everywhere is the same: how much will…

Chart comparing the true geometric open area of an 82 mm butterfly throttle against a linear table, showing the real curve sitting far below the straight line across the lower range

Engine Management Mk4 Supra Tuning

Throttle Body Effective Flow Area: Building a Correct Area vs Position Table

Open any modern standalone ECU that runs a throttle-based air model and you'll find a table mapping throttle position to flow area. Open a dozen real calibrations and a good…

Mk4 Supra

Mk4 Supra Zestek Steering Wheel Adapter Failure: Downshift Paddle Not Working

The Zestek steering wheel adapter on my Mk4 Supra has suffered another downshift paddle failure. This is now the third failure in 15 months on a £1,400 + VAT product.…