john - BlownByTwins

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

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…

Graphic of a catalytic converter honeycomb substrate, intact on the left and dissolving into empty space on the right, illustrating the difference between catalyst replacement and catalyst removal

General

The DfT in-use emissions consultation, what it actually proposes

The Department for Transport wants vehicles to meet their build emissions standard for life. Here is what the proposal actually says, which vehicles it covers, and the one line in it that treats catalyst replacement the same as catalyst deletion. Closes 6 September 2026.

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.…

Events and Meets Mk4 Supra

Mk4 Supra | Isle of Man 2026

In May 2026, a select few of use went off to the Isle of Man for a few days higher speed fun. A break from Scotland this year. And to…

Mk4 Supra

Mk4 Supra: The 3.4 Stroker Build

If you've been following this build from the start, you'll know the plan was always to go 3.4 stroker. The 3.0 on the G40-900 was never the finished article. It…

Events and Meets Mk4 Supra

Scotland with slap! Adventures

The annual pilgrimage to Scotland with slap! Adventures took place in May, back it is usual time after the 2024 May trip to Monaco. As usual, I had the car…

Mk4 Supra

Mk4 Supra – Big Brake Kit (BBK!)

Back in November, I realised I was going to need a brake upgrade on the Supra, given the performace increase I was going to having, both now and scheduled for…

Mk4 Supra

Mk4 Supra – Rival Worx TRD Style spoiler

For Black Friday, 2024, I ordered the Rival Worx TRD Style rear spoiler for the Supra. On the website, it says 3-4 weeks for delivery. Perfect. Get it for Christmas,…