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5.5L LT6 flat-plane V8 · E85 (factory baseline)

2023 Chevrolet Corvette C8 Z06

The LT6 goes soft near 5,500 rpm on the factory calibration. On E85 our calibration fills it — 91 more wheel horsepower right there, and 62.5 at the peak.

Across the whole pull

+91 whp at 5,500 rpm, right where the factory curve sags

Peak to peak: 584.1 hp stock, 605.0 on 91 octane, 646.6 on E85. The biggest difference on this car is not at the peak.

Factory calibrationfuel not stated
584.1
380.9 lb-ft
DEFI calibration91 octane
605.0
402.7 lb-ft
DEFI calibrationE85
646.6
444.3 lb-ft
1002003004005006007003,0004,0005,0006,0007,0008,000rpmwhp+91@ 5,500
  • Factory calibration · fuel not stated · 584.1 peak
  • DEFI calibration · 91 octane · 605.0 peak
  • DEFI calibration · E85 · 646.6 peak
Traced from the sheets on this page: each curve matches the peak printed on its own sheet to within 1.5 hp. These sheets print no rpm scale, so rpm is fixed from the peak rpm each sheet prints and is good to about ±4 rpm. The shaded band is the difference between the first and last runs. The sheets, not this chart, are the record.
Wheel horsepower and torque read off the traced curves.
rpmFactory calibration, fuel not statedDEFI calibration, 91 octaneDEFI calibration, E85E85 vs stock
4,000233 hp · 311 lb-ft249 hp · 333 lb-ft288 hp · 385 lb-ft+55 hp
4,500295 hp · 349 lb-ft331 hp · 390 lb-ft362 hp · 426 lb-ft+67 hp
5,000334 hp · 354 lb-ft371 hp · 394 lb-ft405 hp · 429 lb-ft+71 hp
5,500364 hp · 349 lb-ft417 hp · 401 lb-ft455 hp · 438 lb-ft+91 hp
6,000411 hp · 362 lb-ft425 hp · 374 lb-ft459 hp · 403 lb-ft+47 hp
6,500464 hp · 376 lb-ft484 hp · 392 lb-ft514 hp · 417 lb-ft+50 hp
7,000504 hp · 379 lb-ft520 hp · 392 lb-ft549 hp · 412 lb-ft+45 hp
7,500533 hp · 375 lb-ft551 hp · 386 lb-ft589 hp · 413 lb-ft+56 hp
8,000563 hp · 370 lb-ft579 hp · 380 lb-ft616 hp · 406 lb-ft+53 hp

What the dyno read

Baseline
584.1
380.9 lb-ft
After calibration
646.6
444.3 lb-ft
Gain
+62.5
+63.4 lb-ft · +10.7%

Measured at the hubs on a Mainline ProHub in Corona, California, on E85 (factory baseline). Baseline taken on the factory calibration.

Reading the result

A 2023 C8 Z06, measured at the hubs on the factory calibration, then on our 91-octane calibration, then on E85: 584.1 hp, 605.0, 646.6. The LT6 revs to 8,600 rpm, and all three peaks land within 150 rpm of each other near the top.

The more useful part of the result is lower down. On the factory calibration, torque sags from 354 lb-ft at 5,000 rpm to 349 at 5,500 before it climbs again, and power stalls with it. We are not going to claim to know every reason the factory calibration shapes that region the way it does. What the sheets show is that it can be filled.

Our 91-octane calibration is worth 54 hp at 5,500 rpm, and between 13 and 19 hp from 6,000 rpm to the top. The peak moves 20.9 hp.

On E85 the gain is 91 hp at 5,500 rpm and between 45 and 59 hp from 6,000 rpm to the top, with 62.5 hp at the peak. Peak torque rises 63.4 lb-ft.

What this cost

E85 costs fuel economy and is not at every pump, and its ethanol content moves with the season, which is why a flex-fuel sensor is worth having. More torque through the midrange is more load through the transmission every time it is used. And a modified calibration takes the car out of emissions compliance in California.

The sheets on this page are the dyno software exactly as captured. They do not show the correction standard or the ambient conditions for each pull, and we are not going to fill those in from memory — they are being taken from the run files and will be published here. Until then, read these runs against each other rather than against a number from somebody else's dyno, and read how we measure for why that distinction matters.

The sheets

Every run on this page, as the dyno showed it

Uncropped captures of the Mainline DynoLog window. Colour is the run being shown; white is the reference run loaded under it. Open any sheet at full size and check the figures above against it.

Dyno overlay of a DEFI E85 calibration, 646.6 hp and 444.3 lb-ft, against the factory calibration on a 2023 C8 Corvette Z06
DEFI E85 calibration (colour), 646.6 hp and 444.3 lb-ft, over the factory calibration (white).
Dyno overlay of a DEFI 91-octane calibration against the factory calibration on a 2023 C8 Corvette Z06
DEFI 91-octane calibration (colour), 605.0 hp, over the factory calibration (white).
Mainline ProHub dyno sheet for a 2023 C8 Corvette Z06 on the factory calibration: 584.1 hp at 8,390 rpm at the wheels
The factory calibration on its own: 584.1 hp at 8,390 rpm, 380.9 lb-ft at 7,130 rpm.
Mainline ProHub dyno sheet for the same 2023 C8 Corvette Z06 on a DEFI 91-octane calibration: 605.0 hp and 402.7 lb-ft at the wheels
The DEFI 91-octane calibration on its own: 605.0 hp at 8,536 rpm, 402.7 lb-ft at 5,336 rpm.

Questions this result answers

How much power does a tune add to a C8 Z06?

On this 2023 car, measured at the wheels: 20.9 hp at peak on 91 octane and 62.5 hp on E85. The larger gains are lower down — 54 hp on 91 and 91 hp on E85 at 5,500 rpm, where the factory curve sags.

More results