Install Help
Attention Installers.
Our Product Guides, if available for any given product, will be available to download on the product page. If there is not a link to download a product-specific guide, then there is not one available for your application. The additional tips provided here are written with the assumption you are a professional, have a firm grasp of your vehicle’s fueling and wiring systems, and have the proper tools and expertise to install these types of products.
IMPORTANT SUPPORT POLICY:
WE DO NOT provide installation or tuning support outside of what is provided on this page. We also do not provide support for second-hand purchases or purchases made outside of our authorized dealer network. If you are not 100% confident in what you are about to install, you must consult a qualified professional.
Expert Services Disclaimer:
Expert tuning, calibration, and mechanical installation services are paid professional services. They are not included in the purchase price of SMG products. The professionals who provide these services are compensated for their expertise, time, and skill. Purchasing a product from SMG does not entitle the buyer to free step-by-step installation help, custom tuning guidance, or unlimited technical support beyond what is documented here. If you require such services, you will need to hire a qualified tuner or installer.
AUX, BigBoy, and Flex Fuel Kits REQUIRE tuning to work. They cannot simply be plugged in and used without tuning. Flex Tables need to be activated for the Flex Kits, and FSCM adjustments must be made for the additional fuel flow for the pumps. SMG does not provide ANY tuning advice—consult your tuning professional.
Flex Kit Notes:
Note all current flex kits use a new plug-and-play coil jumper harness and no longer tap the fuse box nor have a dedicated ground wire.
Simply connect our sensor at the fuel rail, then connect the jumper harness at the nearest ignition coil. Lastly, route the white signal wire to the PCM (see our universal pin out guide HERE if you don’t know which one you need).
A handy weatherproof disconnect inline with the white signal wire will allow easier routing and connection at the PCM.
If you need PCM pin out information, refer to the universal PCM Guide HERE (not all years, variations, makes, or models are covered—consult your tuner if you are unsure).
BigBoy Notes:
All BigBoy Pump systems require tuning. SMG does not offer individual tuning support, but we can provide baseline settings for use within HPTuners on the product pages if available. This information is typically vehicle-specific and, if available, will be included with your pump module or on the product page for download. BigBoy pumps utilize OEM baskets and FPRs.
Most FPRs max out at 5 bar before they open and release all pressure. Exceeding this limit bleeds off fuel pressure and reduces performance drastically. If you see a pressure drop at high demand, it is likely due to pressures rising over the FPR’s threshold and bleeding off. Lowering commanded pressure to a reasonable level will often solve this.
HPFP/LPFP systems do not need 70+ PSI to run correctly—they need enough volume to keep the HPFP happy. Commanding a flat 50 PSI typically supports even demanding builds due to the massive volume of our pumps. Be sure to address DESIRED PRESSURE and MAX PRESSURE tables in your ECM and Duty Cycle tuning, as well as license and tune the same FSCM tables.
These pumps move a lot of fuel. We do not recommend running less than 1/4 tank during performance driving, as cavitation can occur, especially on saddle-tank vehicles where transfer to the pump side may lag behind demand.
Aux Kit Notes:
All current AUX Fuel kits feature weatherproof connections for Hobbs, relay, and primary fuse, and use a static Hobbs that is preset to a trigger pressure—no adjustment required.
While designed for specific vehicles, these kits are not meant to be installed only one way. Mounting locations, line routing, tank taps, and harness mounting are at the installer’s discretion. If this flexibility is beyond your capability, seek a second opinion.
Vacuum-rated line and a T-fitting are provided for Hobbs boost reference (tap location is up to the installer).
For non-boosted use, replace the Hobbs with a window or RPM switch. We do not provide support for this configuration, though auxiliary accessories may be available.
Wiring: Underhood—Red ring terminal to Battery +, Black ring terminal to chassis ground, fuse tap to a switched circuit (if unsure how to identify, hire a professional). The long power lead runs to the AUX pump under the car (+ to red, – to frame ground). Corvette kits have both + and – in the long lead.
Fuel Connections: Drill/tap the tank for the provided NPT 90° fitting at a location that ensures fuel pickup under hard acceleration. Pre-terminated lines allow some flexibility in mounting. The kit also connects into the factory feed with the supplied “T” fitting without cutting.
Use sealant only on NPT threads—never on AN fittings. Over-tightening AN fittings can damage threads and cause leaks, which SMG will not cover.
Our guides are a reference for professionals only and are not a complete “how-to.” If you need step-by-step instructions, hire a professional with experience in supplemental fuel systems.
Due to continuous improvement, we are discontinuing vehicle-specific guides and will instead provide pin-out data where needed.
Note: Many older instructions are outdated—current flex kits mount underhood at the fuel rails (except FS GM truck/SUV frame-rail kits), use jumper harnesses (no fuse taps), and include a PCM wire disconnect. Guides should be used for basic reference and pin-out only.
15" Conversion Notes:
Brake modifications can affect safety. SMG is not responsible for decreased stopping performance, faulty installs, or accidents. The installer/owner assumes all responsibility when modifying safety systems.
Our 15" Conversion Kits include all parts for an otherwise stock car. Additional modifications may affect results.
Brake systems are straightforward but require understanding of bleeding procedures. Toe rods and bushings fit only one way—check labels. Using other brands’ toe rods may cause issues.
Bleeder screws are shorter than OEM; some wheels may interfere and require trimming. Always test-fit wheels before driving. Raise the car, hand-tighten lugs, and rotate by hand to check clearance. If rubbing occurs, trim bleeders or change wheels. If grinding calipers/brackets, you do so at your own risk.
Replacement components may be available from SMG.