S300 Single Turbo for 12V Cummins 1989–1998 | 1st Gen & 2nd Gen Dodge Ram
The Diesel Power Source® S300 single turbo for 1989–1998 Dodge Ram trucks with the 5.9L 12-valve Cummins engine is a direct bolt-on performance upgrade for both 1st gen (1989–1993) and 2nd gen (1994–1998) trucks. Choose from 10 stage configurations spanning 420 to 775 HP, with journal bearing and dual ceramic ball bearing options at every size. Every DPS S300 turbo includes a 360° thrust bearing, forged machined compressor wheel, high-flow dual valve wastegate, and a new intercooler hose.
Because the 12V Cummins uses mechanical fuel injection (VE pump or P7100), no ECM, no computer, and no programmer are required. The mechanical injection system responds directly to the improved airflow. Bolt the turbo on, and the engine responds immediately. This is one of the biggest advantages of the 12V platform for turbo upgrades.
4" Downpipe Required. All 1989–1998 12V trucks require a 4" HX40/S300 style exhaust downpipe when running an aftermarket turbo. The downpipe is sold separately. See our 4" Downpipe for 12V Cummins.
Stage Selection Guide
| Stage | Turbo | Compressor | Turbine | Max HP | Best For |
|---|---|---|---|---|---|
| 1.5 | S362/68/.70 | 62mm | 68mm / .70 A/R | 450 HP | Towing, daily driving, stock-to-moderate builds |
| 2.5 | S362/68/.70 BB | 62mm | 68mm / .70 A/R | 420 HP | Same as 1.5 with faster spool (ball bearing) |
| 3 | S363/68/.70 | 63mm | 68mm / .70 A/R | 500 HP | Moderate builds, towing with modified fueling |
| 3.5 | S363/68/.70 BB | 63mm | 68mm / .70 A/R | 500 HP | Same as 3 with faster spool (ball bearing) |
| 4 | S363/73/.80 | 63mm | 73mm / .80 A/R | 530 HP | Higher HP builds, larger turbine for top-end flow |
| 4.5 | S363/73/.80 BB | 63mm | 73mm / .80 A/R | 530 HP | Same as 4 with faster spool (ball bearing) |
| 7 | S366/73/.80 | 66mm | 73mm / .80 A/R | 650 HP | Performance builds, sled pulling, competition |
| 7.5 | S366/73/.80 BB | 66mm | 73mm / .80 A/R | 650 HP | Same as 7 with faster spool (ball bearing) |
| 9 | S369/73/.80 | 69mm | 73mm / .80 A/R | 775 HP | High HP builds, max single-turbo airflow |
| 9.5 | S369/73/.80 BB | 69mm | 73mm / .80 A/R | 775 HP | Same as 9 with faster spool (ball bearing) |
BB = Dual Ceramic Ball Bearing. Ball bearing stages spool 150–200 RPM faster than the journal bearing equivalent. Recommended for towing applications and compound setups.
Which Stage Should I Choose?
Towing and daily driving (stock to 500 HP): Stages 1.5 through 3.5 with the 62mm or 63mm compressor and 68mm turbine. These spool quickly and outflow the factory turbo by approximately 70%. The S362 offers spool behavior very close to stock while delivering dramatically lower EGTs and 45–85 additional rear-wheel HP depending on fueling modifications.
Performance builds (500–650 HP): Stages 4 through 7.5 with the 73mm turbine wheel. The S366 can spool nearly as quickly as a stock turbo while delivering nearly double the airflow (approximately 930 CFM vs ~550 CFM stock). These are popular with 12V trucks that have modified P7100 pumps, larger injectors, and adjusted timing.
High HP and competition (650–775 HP): Stages 9 and 9.5 use the S369 for maximum single turbo airflow on the 12V platform.
1st gen (VE pump) trucks: HP gains on 1st gen trucks are typically 10–18% depending on fueling modifications. The VE pump limits fueling compared to the P7100, so turbo choice should match your fuel system capability. Contact DPS if you're unsure which stage matches your VE pump setup.
No ECM or Programmer Required
The 12V Cummins uses the Bosch VE (1989–1993) or P7100 (1994–1998) mechanical injection pump. Neither requires electronic tuning, a programmer, or any computer interface to work with an aftermarket turbo. The injection pump responds directly to the increased airflow from the DPS turbo. Most 12V turbo builds pair the turbo upgrade with modified P7100 delivery, larger injectors, and adjusted timing to match the increased airflow capacity. This mechanical simplicity is one of the key reasons 12V trucks remain so popular for performance builds.
1st Gen vs 2nd Gen Installation Notes
- All 12V trucks: A 4" exhaust downpipe is required (sold separately). 12V engines have a single oil drain port.
- 1st gen trucks (1989–1993): A new intercooler hose is included with the turbo. Some 1st gen configurations may require additional intercooler hose modifications depending on the specific truck.
- 2nd gen trucks with automatic transmissions (1994–1998): Some trucks with the 47RH or 47RE automatic require relocation of the trans oil cooler on the side of the engine block. DPS sells a trans cooler relocation kit for $149.
What's Included
- DPS S300 Turbocharger (stage selected at checkout)
- DPS 6-pad 360° thrust bearing (50% more thrust capacity than standard)
- Forged machined compressor wheel (FMW)
- High-flow dual valve wastegate (flows 2x standard S300 wastegate)
- Adjustable wastegate (turn of a nut)
- New intercooler hose (black)
- Installation hardware
Not included (sold separately): 4" exhaust downpipe (required), exhaust manifold, gaskets, oil lines. Available as add-ons or see Related Products below.
Turbonator® VGT Upgrade
Every DPS S300 turbo for the 12V Cummins can be upgraded with the Diesel Power Source® Turbonator® VGT exhaust housing. The Turbonator® is completely self-contained and works on all 12V truck years, including 1st gen trucks that never had exhaust braking from the factory. This is the only way to add variable geometry performance and exhaust braking to a 12V Cummins.
- VGT Without Exhaust Brake (+$950): 3-stage mechanical actuator. Improves spool by 200–300 RPM.
- VGT With Exhaust Brake (+$1,850): Electronic actuator with exhaust brake. Same spool improvements plus exhaust braking on any 12V truck.
Key Features
- Direct Bolt-On — Fits factory T3 manifold location on 1989–1998 12V trucks
- No ECM Required — Mechanical injection responds directly to improved airflow
- 360° Thrust Bearing — DPS 6-pad design, 50% more thrust capacity
- Forged Machined Compressor Wheel — Stronger than cast, improved airflow
- High-Flow Dual Valve Wastegate — 2x flow of standard S300 wastegates
- ~930 CFM vs ~550 CFM Stock — Near double the airflow of factory turbo (S366 stage)
- 10 Stage Options — 420 to 775 HP, journal and ball bearing at every size
- Turbonator® VGT Available — Add exhaust braking to any 12V truck
- Compound Compatible — Can be used as primary turbo in DPS compound system
- Outperforms Competitors — Outflows comparable HTB2, Phat Shaft, Super B, and Aurora turbos
Start Single, Go Compound Later
Many 12V owners start with a single S300 turbo and later add a second turbo using the DPS Add-a-Turbo Kit or upgrade to the full Complete 12V Compound Kit. If you plan to go compound in the future, let DPS know when ordering so the wastegate can be configured with a spring gate to handle the higher boost pressures without damage.
Head Studs and Fire Rings
On 1989–1998 12V Cummins engines, head studs are recommended for boost pressures over 48 PSI. Fire rings are recommended for boost pressures over 55 PSI.
Fitment
This S300 turbo fits 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, and 1998 Dodge Ram trucks with the 5.9L 12-valve Cummins engine. Covers both 1st gen (1989–1993 with VE pump) and 2nd gen (1994–1998 with P7100).
Have a different Cummins platform?
- S300 Turbo for 24V Cummins 1998.5–2002
- S300 Turbo for 5.9 Cummins 2003–2007 (3rd Gen)
- S300 Turbo for 6.7 Cummins 2007.5–2018
Related 12V Cummins Products
- S362/68/.70- 450 Max HP- Stg 1.5
- S362/68/.70- 420 Max HP Ball Bearing- Stg 2.5
- S363/68/.70- 500 Max HP- Stg 3
- S363/68/.70- 500 Max HP-Ball Bearing- Stg 3.5
- S363/73/.80- 530 Max HP- Stg 4
- S363/73/.80- 530 Max HP-Ball Bearing- Stg 4.5
- S366/73/.80- 650 Max HP- Stg 7
- S366/73/.80- 650 Max HP-Ball Bearing- Stg 7.5
- S369/73/.80- 775 Max HP- Stg 9
- S369/73/.80- 775 Max HP-Ball Bearing- Stg 9.5
Yes. This S300 turbo fits 1989–1993 1st gen and 1994–1998 2nd gen 12-valve Dodge Ram trucks. Both generations use the same T3 manifold flange. The turbo bolts directly on. A 4" exhaust downpipe is required on all 12V trucks (sold separately). Some 2nd gen trucks with automatic transmissions may need a trans cooler relocation kit ($149).
No. The 12V Cummins uses mechanical fuel injection (VE pump on 1989–1993, P7100 on 1994–1998). Neither requires any electronic tuning to work with an aftermarket turbo. The injection pump responds directly to the improved airflow. This is one of the biggest advantages of the 12V platform. Bolt the turbo on, and the engine responds immediately.
For towing and daily driving, Stages 1.5 through 3.5 (S362 or S363 with 68mm turbine) offer the best spool, EGT control, and drivability. The S362 spools very close to stock while outflowing the factory turbo by approximately 70%. For 1st gen VE pump trucks, contact DPS to match the turbo stage to your fuel system since the VE pump limits fueling compared to the P7100.
Yes. The Turbonator® VGT upgrade adds variable geometry performance and exhaust braking to any 12V Cummins truck, including 1st gen trucks that never had exhaust braking from the factory. The Turbonator® VGT electronics are completely self-contained and work on all 12V truck years. Select the VGT With Exhaust Brake option at checkout (+$1,850).
Yes. All 1989–1998 12V and 24V trucks require a 4" HX40/S300 style exhaust downpipe when running an aftermarket turbo. The downpipe is sold separately. 2003–2007 trucks do not require a downpipe as those bolt directly to the factory exhaust.
Yes. The DPS S300 turbo becomes the high-pressure turbo in a DPS compound system. You can add a second turbo later using the Add-a-Turbo Kit or upgrade to the Complete 12V Compound Kit. Let DPS know when ordering if you plan to go compound so the wastegate can be configured with a spring gate to handle the higher boost pressures.
The 12-valve 5.9 Cummins is mechanically straightforward in ways that make it ideal for turbo upgrades. The P-pump mechanical injection system has no electronic limits on fueling - it responds directly to physical adjustments without ECM interference. This means the engine can take advantage of increased airflow from a larger turbo immediately, without requiring complex tuning workarounds. The engine's iron block and head are also exceptionally strong, handling significant power increases with fewer supporting modifications than more modern common rail engines typically require. Combined, these characteristics make the 12V one of the best platforms in the diesel aftermarket for building real power affordably.
For a 12V P-pump build, the right S300 size depends heavily on how aggressively the pump is turned. For mild to moderate P-pump adjustments targeting 500 to 550 HP, the S366 is the most popular choice — it provides excellent airflow without excessive spool lag and pairs well with P-pump fueling characteristics in the mid-RPM range where 12V engines make their best power. For more aggressive pump work targeting 600 HP or higher, the S369 or a compound setup becomes relevant. For a more stock-presentation daily driver with moderate fueling, the S362 or S363 delivers excellent street manners and EGT reduction without overwhelming the pump's output.
Yes, and the 12V is one of the best platforms for compound turbos. The Diesel Power Source® compound kit for 12V Cummins fits both 1st gen (1989–1993) and early 2nd gen (1994–1998) trucks and is available in S300/S300 and S300/S400 configurations. With a P-pump and compounds, 700-plus HP is achievable with appropriate supporting modifications. The S366 is the most common high-pressure turbo choice in 12V compound builds — if you are planning to go compound eventually, starting with an S366 single is a logical first step that preserves your investment when the secondary turbo is added.
Yes. The Turbonator® VGT housing is available as an upgrade on S300 turbos for the 12V Cummins. It provides the same 200 to 300 RPM spool improvement and exhaust brake capability as on other generations. Exhaust braking is particularly valuable on older trucks that never had any form of engine braking — it significantly reduces brake fade on mountain grades and extends brake life on trucks used for towing. The Turbonator® VGT option is available with or without the exhaust brake controller depending on whether the application requires it.
2 Reviews
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1994 Turbo
I’m really happy with it! The turbo works great and has made a big difference in my truck’s performance. I was surprised by how fast it got here—it showed up way quicker than I thought it would. The only downside was that the box looked like UPS had been pretty rough with it. Luckily, everything inside was fine because it was packed well. If you’re looking for a solid turbo upgrade, I’d definitely recommend this one!
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The REAL Deal
Looks solid good quality. Great price, fast shipping!
