Semi-Trucks & Busses Application

Spiral Turbo Specialties has developed an exhaust baffle system for the semi-truck, bus, and heavy duty vehicle industry. This system not only significantly reduces noise levels, increase horse-power and torque, BUT also improves fuel economy by 3%-8% (depending on driver, geographic area, and all the other varialbles concerned with obtaining better fuel economy).

Main Improvements:

  • dB levels are within 1-2 dB’s of stock OEM mufflers (80-82 dB’s)
  • Horsepower and torque increases, but vary for different models.
  • Pyrometer temperatures have dropped 50-100°. COOLER TEMPERATURES MEANS BETTER MILEAGE.
  • Turbo chargers spool up quicker. Quicker spooling also means better EFFICIENCY.
  • STRAIGHT STACK LOOK…without the noise or the tickets! The STS Baffles fit “INSIDE” the stacks.
  • Mileage up 3%-8% on average.
  • ALL Steel construction, 14 gauge Aluminized.
  • LESS RESTRICTION means everything runs better.
  • Idles better.

Your test results may vary according to conditions, engine set-ups, geographical area, etc. Many state patrol agencies across the USA are familiar with the STS Baffles, and how they control dB levels. Jake Brake levels remain the same or slightly higher though. 6.0″ STS Baffles have a general dB level of 81. These tests for dB levels were done with a loaded trailer, and the tractor was an N14 Cummins. The STS Baffles BOLT in so there is NO Rattling.

Available now is part no. STS6.022545A14 for the 6″ stacks.

Available Soon…STS 8.0″ incased baffle (5.0″ in and 5.0″ out) for above 15L and 400 HP motors (dual baffles only).

Total lenth for the 8.0″ will be a stock 51.0″ length. Adapters with the kit to make the install direct bolt on, and will work with your shield.
Call for 8.0″ availability.

For Information Call:

Chrome Depot, Inc.
9769 State Route 44
Mantua, Ohio 44255


Ask for Bill Puleo or Michelle


Engine Size (Litre)Engine Size (Cubic Inches)Horsepower RangeRecommended Minimum Size QP Part #
14.6L892UP TO 350STS62254514A
14.7L898UP TO 350STS62254514A
15L916UP TO 400STS62254514A
16L977UP TO 400STS72254514A

*A single STS can be used for these smaller engines. To determine litre size, take your cubic inch÷61.07=litre size (855ci÷61.07=14litre).

(5.0") STS52254514A*Call for pricing
(6.0") STS62254514ACall for pricing
(7.0") STS2254514ACall for pricing
(8.0") STS82.2536.512A*Call for pricing

*Available soon. Call for info.