What's new

Your goals and questions are answered at the top, then an at-a-glance table. A "What we checked" table covers fueling, fuel system, spark, idle, airflow, rev limits, cam/AFM, transmission, codes and anti-theft, with your number, how it compares to similar builds, the most likely cause and how to check it yourself.

Every report now gets an A-F grade for the tune with the reason. It is marked Preliminary when there is no log or too few similar builds to compare.

See at a glance whether a setting is lower, in line with, or higher than similar builds, and by how much.

Start a free Tune Report and send the file later, or order a fresh Start-up File built from a stock file for your computer.

Parts we can't confirm for your car are labeled Unconfirmed and never count as must-buys, and 144 more parts now link to their exact product page. C10 fixes from a real builder's feedback: Corvette accessories, Speed Engineering headers and engine-side mounts.

A clearer "check your email" step, with resend and reminders, so your free report doesn't stall.

Drive-by-wire builds now list the pedals swappers use (Corvette, CTS, Camaro, truck, Holley and Lokar), matched to your computer, with the bolt-in brackets for some classic trucks and cars.

Parts are now filtered by 2WD/4WD, transmission type, generation (RX-7 and more) and model years, and the factory computer vs Holley are shown as either/or. Thanks to r/LSSwapTheWorld for the reports.

The C10 guide now lists the accessory drive, headers and oil pan owners ran in their swaps, plus a bolt-in EFI tank with an in-tank pump.

Our Tune Report and tune files read HP Tuners (.hpt) files for now, with PCM Hammer and Holley next. Holley owners can send us a datalog for a free review.

We rebuilt the engine pages with engine-specific swap notes and donor details. Where we have enough matching Gen III/IV tunes, we show their real-tune ranges.

The E85 injector answer now has the formula, a worked example and a sizing table. The 4L60E answer explains what changed by year and what to match.

Our new report cards lead with a short verdict and fold the details underneath, so a report is easy to read on a phone.

A short side-by-side on the Tune Report page: what you get from us, what a shop does, and why every tune still finishes on a dyno.

If your cam isn't in our list, type in the specs from your cam card in the turn-on builder or the cam finder.

Table and channel names in the HP Tuners walkthrough now copy with one tap, and the checklist boxes tick. Visitors from our ads see the Tune Report and Get it running buttons first on the home page.

Tapping Plan without a vehicle now opens a quick vehicle picker instead of an empty planner.

A small group of mechanics who all tune, based in Phoenix. It also explains how every report gets signed off and how to tell us about a mistake.

Your tune file is usually on your laptop, so the Tune Report page can now email you a link to finish there.