We put Scrat, the 2026 Ultimate Callout Challenge champion, on the dyno to answer a question every big power Cummins guy argues about: which turbo combo actually makes the most horsepower? Seven different compound turbo combinations, all fuel only, all on the same truck. And at the end, we bolt on a 122mm G57 to see if this Cummins can crack 2,000 horsepower without nitrous.
The testing covers three things. First, 11 blade compressor wheels versus 7+7 splitter blade wheels. Second, our new Power Driven G57 110mm and G55 turbos. Third, turbine housing sizes, running a 1.0, a 1.25, and a 1.41 A/R to see how much housing size really changes spool and top end power. We also show how our modular housings work, using one casting machined for different turbine wheels so you can swap turbo sizes on a compound setup like Lego.
The G57 results surprised us. The big 1.41 housing made 1,845 hp and laid a dyno graph almost right on top of the tighter housing. The data log tells the real story, with boost, drive pressure, and interstage boost all shifting while the two turbos balanced each other out.
Then we drop to the G55 Aggressor 98 with an S480 on the manifold. The 7 blade version only made 1,521 hp, so we swapped to the classic 11 blade and picked up over 70 horsepower. More interstage boost, cooler EGTs, and a way quieter turbo in the cab. On the G57, the 7 blade won by about 30 hp, so blade count really depends on the turbo.
Will Terry also throws on his "Elvis turbo," the GT55 with a 115mm billet compressor he's run on his Junker drag truck for years. It made an impressive 1,782 hp, but the overlay against the G57 shows exactly where it falls short.
Swapping the G55 to a 1.0 housing made 1,611 hp, spooled faster, and ran nearly 50 degrees cooler on EGT before the pull. If you're building a street truck or tow rig, the data shows why the tighter housing is the one to pick.
Finally, the 122mm G57 goes on and Scrat breaks 2,000 horsepower fuel only on a true compound setup, then picks up another 18 hp on a more aggressive tune for 2,028 hp.
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Shop everything mentioned in this video at PowerDriven.com. Links below.
Shop Power Driven Diesel: https://www.powerdriven.com
Power Driven Aggressor Turbos: https://powerdriven.com/collections/aggressor-turbos
Power Driven Aggressor 98 (11 Blade): https://powerdriven.com/products/power-driven-aggressor-98
0:00 Intro
0:19 11 Blade vs 7 Blade and Housing Test Plan
1:17 How the Modular Turbine Housings Work
2:05 G57 with the 1.41 Housing on the Dyno
2:57 G57 Housing Results and Data Logs
5:50 Aggressor 98 7 Blade Results
6:29 Swapping to the 11 Blade Aggressor 98
8:00 11 Blade vs 7 Blade Results
10:04 Will Terry's Elvis Turbo
11:23 Elvis Turbo vs G57 Results
12:57 Testing the 1.0 Housing on the G55
13:53 1.0 vs 1.25 Housing Results
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