Base Vehicle Overview: The 2003–2005 Dodge Neon SRT‑4

The Dodge Neon SRT‑4 remains one of the most accessible platforms for enthusiasts seeking high horsepower on a tight budget. Powered by a 2.4‑liter turbocharged inline‑four (the EDZ/ED1), it left the factory rated at 230 hp and 250 lb‑ft of torque. The engine features a cast‑iron block, aluminum head, a Mitsubishi TD05LR‑15G turbocharger, and direct‑fire ignition. The drivetrain consists of a five‑speed manual transmission, a torque‑biased differential, and solid rear axle. With a curb weight under 2,900 pounds, even stock SRT‑4s are quick. However, the factory tune leaves room for improvement, and the platform responds well to modifications. To reach 350 hp—a roughly 120‑hp gain—you will need to upgrade the air, fuel, and spark systems, along with addressing driveline and thermal limits.

Essential Performance Upgrades

These modifications directly increase airflow and boost pressure, moving the engine toward the 350‑hp target. Costs vary based on brand, condition (new vs. used), and whether you install yourself.

Turbocharger Upgrade

The stock TD05LR‑15G can produce around 300 hp with supporting mods, but for 350 hp a larger turbo is required. Popular choices include the Garrett T3/T4 hybrid, BorgWarner S256, and a used Precision 5857. A direct‑fit turbo kit or a rebuilt stock frame turbo with a billet compressor wheel can save money. Expect to spend $600–$1,200 for a good used turbo or a budget new unit. If you buy a kit with manifold and downpipe, costs rise accordingly. Check reputable vendors like Modern Performance for SRT‑4 specific options.

Intercooler Upgrade

Higher boost generates more heat. A larger front‑mount intercooler (FMIC) reduces intake air temperatures, preventing knock and preserving power. The stock side‑mount intercooler becomes a bottleneck above 300 hp. A FMIC kit costs $250–$500. Brands like AGP, Turbosmart, and cheap eBay cores all work, but ensure piping has a 2.5‑inch inner diameter. This upgrade alone can net 15–20 hp on a tuned car.

Exhaust System

Restrictive exhaust chokes power. A full turbo‑back 3‑inch system (downpipe, high‑flow catalytic converter, and cat‑back) improves spool and top‑end flow. Budget systems (e.g., MPx Racing) run $350–$500. A downpipe alone for $150 can help, but a full system is recommended for 350 hp. Avoid excessive bends or restrictive mufflers if you want the horsepower number.

Intake System

A cold air intake (CAI) reduces restriction and draws cooler air. The stock air box is restrictive; a simple 3‑inch pipe with cone filter costs $100–$250. Pair it with a proper heat shield. For extreme budget builds, a hacked stock box with a K&N filter works, but a proper CAI is better for 350 hp.

Engine Control Unit (ECU) Tune

Without a tune, bigger parts won’t deliver 350 hp. The SRT‑4 uses a Mopar ECU that can be reprogrammed via the OBD‑II port. Options include a custom flash by a reputable tuner (e.g., Diy‑Efi or SymTech Labs) or a piggyback unit like the AEM FIC. A proper tune costs $300–$700 depending on adjustments (fuel, timing, boost). Do not skip this—a bad tune can melt pistons.

Supporting Modifications

These upgrades ensure the engine and drivetrain can handle the extra power reliably. They are not optional at 350 hp.

Fuel System

The stock pump and injector flow max out near 300 hp. Required upgrades:

  • Fuel pump: A Walbro 255 lph in‑tank pump costs $100–$180. A plug‑and‑play kit is easiest.
  • Fuel injectors: 650 cc (or larger) low‑impedance injectors are needed. Many SRT‑4 owners use EV14 style units. Cost: $150–$300 for a set. Used injectors save money but test them.
  • Fuel pressure regulator: Not always required, but an adjustable regulator ($80–$120) helps dial in pressure if you change injectors significantly.

Total fuel system budget: $250–$600.

Clutch and Driveline

350 hp will overwhelm the stock dual‑mass flywheel and clutch. A stage 2 or 3 clutch kit (organic or ceramic puck) with a steel flywheel costs $400–$800. Brands like ClutchMasters, ACT, and South Bend are popular. Also consider a stronger clutch pedal assembly and a short‑shifter for better feel. If you beat on the drivetrain, you may need to upgrade the axles later—budget for that if needed.

Engine Mounts

Factory mounts flex under higher torque, causing wheel hop and possible engine movement that damages the radiator fan or intercooler piping. Polyurethane or solid mounts cost $100–$250 for the set (upper, lower, and torque strut). This is a cheap and important upgrade.

Boost Control

A manual boost controller (MBC) costs $25–$60 and lets you raise boost easily. An electronic boost controller (EBC) gives more precise control but costs $150–$300. Since you’ll be running a tune that expects a certain boost level, an MBC is sufficient for a budget build. Make sure you have a boost gauge ($30–$60) to monitor pressure.

Additional Key Considerations

Cooling System

Higher boost and heat require better cooling. A larger radiator ($150–$300) and low‑temperature thermostat ($20) help. An oil cooler kit is highly recommended if you track the car. Even for street use, keeping coolant temps under 210°F is wise.

Ignition System

Stock coils and plugs can miss at higher boost. Upgrade to colder spark plugs (NGK BKR7E or 8E, gapped to 0.028–0.032”) for $15. If you experience misfire, replace the coil with an MSD unit ($150). Start with plugs and gap them correctly.

Oil System

Consider a catch can ($50–$150) to prevent oil from entering the intake. Use 5w‑40 oil for track use. No need to upgrade the oil pump unless you are revving higher than the stock 6200 rpm limiter.

Budget Tips and DIY Strategies

Building a 350 hp SRT‑4 on a tight budget requires smart choices.

  • Buy used parts: Many SRT‑4 owners part out cars. Check Neons.org forums and Facebook groups for turbo kits, intercoolers, and clutches. You can often save 40–60%.
  • Do your own labor: The SRT‑4 is straightforward to wrench on. A full turbo upgrade takes a weekend with basic tools. Save $500–$1,200 in labor.
  • Use eBay parts wisely: Some eBay intercoolers and piping kits are fine; avoid cheap turbochargers that fail quickly. Read forum reviews.
  • Incremental upgrades: You don’t have to do everything at once. Start with tune + intake + exhaust, then add turbo and fuel parts later. Each stage brings noticeable gains.
  • Skip unnecessary parts: A blow‑off valve (BOV) isn’t required; recirculating the stock valve works. Ported cylinder heads, cams, and built bottom ends are overkill for 350 hp—stock internals hold that power.

Full Cost Summary (Estimated)

Below is a realistic range, assuming a mix of new and used parts and DIY installation. Prices fluctuate, so treat these as guidelines.

  • Turbo upgrade (used/new budget unit): $600 – $1,200
  • Intercooler kit: $250 – $500
  • Turbo‑back exhaust: $350 – $600
  • Cold air intake: $100 – $250
  • ECU tune: $300 – $700
  • Fuel pump + injectors: $250 – $500
  • Clutch + flywheel: $400 – $800
  • Engine mounts: $100 – $250
  • Boost controller + gauge: $60 – $200
  • Cooling upgrades (radiator/ thermostat): $150 – $300
  • Spark plugs: $15

Total parts range: $2,600 – $5,500 (average ~$4,000).

Labor (if hired): Add $800 – $1,500, bringing total to ~$5,000 – $7,000.

Ongoing Maintenance

A modified car requires more frequent oil changes, premium fuel, and possibly tire replacements sooner. Budget $100–$200 per month for consumables and unexpected repairs.

Final Thoughts: Achieving the 350‑hp Goal Reliably

Reaching 350 wheel horsepower in a Dodge Neon SRT‑4 on a budget is not only possible but has been done countless times by the enthusiast community. The key is to plan your part selection carefully, prioritize the fuel system and tune before adding boost, and accept that some costs (like a good clutch) are not options. The car remains reliable up to 400 hp with the stock bottom end if you keep torque in check and use quality fuel. Use the forums to buy used parts and learn installation tips. With roughly $4,000–$5,000 in parts and a weekend of work, you can have a sub‑13‑second street car that will embarrass much more expensive machinery. Tune wisely, maintain obsessively, and enjoy the results.