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Performance tune for turbo OBD1 S5x M5x
Performance tune for turbo OBD1 S5x M5x
Performance tune for turbo OBD1 S5x M5x
RK-Tunes

Performance tune for turbo OBD1 S5x M5x

Sale price$ 1,600.00
Injectors:

***WE ONLY TUNE WITH OUR SUPPLIED INJECTORS AND MAF. THERE IS NO EXCEPTIONS TO THIS***

 

TURBO OBD1 S5x M5x TUNE

This is our tried and tested tune for turbo OBD1 S5x M5x engines. These tunes were designed on a Dynojet dyno and tested in the real world! OBD1 engines receive a base map on a chip along with free revisions. 60LB injectors are good for 300-600WHP, and 115LB injectors on E85 are good for 350-900WHP.

INCLUDES:
⦁ Blow through MAF
⦁ 60lb, 115lb high impedance injectors 
⦁ Wiring harness adapter
⦁ Aluminium weld-on flange for a 3" pipe In the modification box, please specify all current vehicle modifications and desired options.

🚘 Horsepower Gains

1. Power Potential (M52 / S52 w/ M3 Cams)

  • Stock compression: ~400 WHP

  • Low compression (cut ring + spacer): ~500 WHP

  • E85 (any compression): 600+ WHP

  • Note: 328 cams remove ~40 WHP compared to M3 cams.

2. Turbo Options & Output

Precision

  • 6266 (DBB best, journal works): Baseline turbo.

    • Next Gen version: +50 WHP (~700–850 WHP capable).

  • 6466: Adds ~50 WHP compared to 6266.

Garrett

  • G35-900: Comparable to 6262. Similar to 6266, but 6266 has a better power curve.

  • GTX3582R: Makes similar numbers, but weaker power curve.

BorgWarner

  • SXE362: Matches 6266 in peak power, but spools later and loses boost on shifts.

Smaller Options

  • 6062 (~600 WHP turbo):

    • Makes less power per pound of boost.

    • Limited on pump fuel (expect ~50 WHP less vs. 6266).

3. Engine: Stock vs. Built

  • A built engine adds zero HP by itself.

  • Benefit = durability when mistakes happen (lean condition, overboost, etc.).

  • Real-world examples:

    • Many stock engines survive 600+ WHP for years.

    • Others fail at 350 WHP due to install errors (vacuum lines wrong, bad fuel pump install, etc.).

4. Manifolds

  • Top Mount:

    • Best: Otis / Good & Tight (E36, proven 900+ WHP, ~$600).

    • Other solid options: Jon Vigil Viengineered, 88 Lab.

    • CX Racing: manifold cracks; charge pipe must be fully redone.

    • American-made options: good fabrication quality, but expect long lead times. Do not follow their “tuning suggestions.”

  • Bottom Mount:

    • SPA T4: caps out ~700 WHP (can push ~900, but backpressure extreme).

    • Corey Misko: strong bottom-mount option.

5. Exhaust & Turbine Housing

  • Use large housings (1.0+ A/R) for these engines.

  • 3.5” exhaust helps reduce backpressure and raise safe WHP.

6. Intercoolers

  • TR1035:

    • Fits with A/C.

    • Excellent cooling for most builds.

  • TR1045: Better option if it fits.

  • Rule: Keep IAT low, especially on pump gas.

    • High IAT + high backpressure = knock limit.

  • With big housing + 3.5” exhaust, some unopened S52/M52s can push ~500 WHP on pump gas.

7. Fuel & Octane Guidelines

  • All WHP numbers are on 93 E10.

  • Subtract ~50 WHP for:

    • 91 E10

    • 94 E10 (Canada)

  • E85:

    • Higher octane + cooling effect.

    • Some think it’s a “bandaid,” but it’s actually a huge help in keeping engines alive.

    • Works at 35+ PSI on any compression.

8. Fuel System

  • Over 255 lph pump → aftermarket FPR required:

    • AER13129 fuel pressure regulator

    • TS-0402-1110 –6 ORB to 8mm barb fittings (to OEM line)

    • TS-0402-2023 gauge

    • 8mm E85-safe fuel line (PN: 27340 / 42196039)

  • Radium PTFE in-tank lines only.

    • Do not use pump-supplied or OEM lines.

    • Radium PTFE will outlast the car.

9. Spark Plugs

  • NGK 4091 (up to 700 WHP):

    • .024 gap → 350–450 WHP

    • .022 gap → 450–550 WHP

    • .018 gap → 550–700 WHP

  • NGK 4554 (750+ WHP):

    • .018 gap → 750–800 WHP

    • .016 gap → 850+ WHP

10. Boost & Tuning Practices

  • Always boost leak + smoke test.

    • Even professionals find leaks.

    • Charge pipe popping off is not the most common failure—small leaks matter more.

    • PMAS/VMP MAF housings: they always leak slightly through the connector.

      • Fix: apply silicone to the modification plate (email for images).

  • Run no boost controller first, then add it in (fewer variables).

  • Manual controller: use yours (others are bleed style = slower spool).

  • Electric controllers: most are fine. AEM = hard to read.

  • CX Racing turbo kits → guaranteed boost creep, risk of motor damage.

    • Start with 5 PSI spring.

    • If high-RPM boost exceeds 10 PSI (stock compression) or 15 PSI (low compression), fix manifold/wastegate flange.

11. Intake & MAF Setup

  • MAF must be in straight 3” aluminum pipe (not aftermarket housings).

  • Reducers (3" → 2.75"), even 10” away, = turbulence → drivability issues.

  • BOV must be fully closed at idle/light throttle.

    • If it stays cracked open, use stiffer spring.

    • Even small leaks 10” away from MAF cause surging.

12. Hoses, Couplers & Lines

  • Reinforced silicone couplers only for charge pipes.

  • Pressure hoses: snug, with clamps + zip ties.

  • Vacuum hoses: silicone, very tight fit (Vibrant packs recommended).

  • Wastegate lines: reinforced silicone or AN.

  • Valve cover vent: vent to atmosphere.

13. E36-Specific Notes

  • ICV fitting: clean + epoxy in place OR buy aftermarket.

  • ICV hoses: must be silicone (OEM fall apart/leak).

  • Do not use ICV hose kits going to a CCV separator → will pressurize crankcase.

  • O2 sensor: plug closest to firewall.

  • M50 manifold on OBD2: requires OBD2 IAT (thread to M12x1.5 or buy adapter).

  • Up pipe: idle may sound like a small misfire.

  • SAP valve: no need to plug in fuel rail harness connection.

14. Fuel Octane & Boost Limits

  • Stock compression / 91 octane: 7–9 PSI

  • Low compression / 91 octane: 13–17 PSI

  • Stock compression / 93 octane: 7–12 PSI

  • Low compression / 93 octane: 13–20 PSI

  • Any compression / E85: 35+ PSI

15. Support Guidelines

  • For support, always include:

    • Screenshot of codes (using supplied software).

    • Datalog (single gear pull, 100% throttle).

    • Photos: vacuum routing, ICV hoses, FPR line routing, MAF + charge pipe routing.

  • Do not send logs with multiple gear pulls unless specifically requested.

  • All logs must be full throttle.

    • If traction issues: log in a higher gear.
Performance tune for turbo OBD1 S5x M5x
Performance tune for turbo OBD1 S5x M5x Sale price$ 1,600.00