MSD 2922 Installation

Atomic EFI Return System

PN 2922

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Thank you for selecting the Atomic Fuel Line Return kit. This kit is recommended for use with the Atomic Throttle Body EFI and Atomic LS EFI systems.

Parts Included:

1 - Adjustable Regulator 1 - -6AN Port Plug 3 - -6AN Straight Port Fittings 2 - -6AN 90° Push-Lock Fittings 2 - -6AN Straight Push-Lock Fittings 15 Feet - High Pressure Fuel Hose

CAPABILITIES

The Atomic Adjustable Regulator is conﬁgured for a single -6AN inlet, and dual -6AN outlets (for regulator-to-tank line routing ﬂexibility). The recommended operating range is 0-90 psig (pounds per square inch gauge). The maximum recommended ﬂow rate is 500 liters/hour (2.2 GPM). The vacuum/boost compensation ratio is 1:1.

1 - Regulator Parts Bag includes: 1 - Regulator Mounting Bracket 1 - Brass Hose Barb Fitting 1 - Stainless Steel Pipe Plug 2 - 10-32 x 0.375 Button Head Cap Screws 1 - High Pressure Fuel Hose Clamp

RECOMMENDED PLUMBING SCHEMATICS

Use the schematic below as a guide when installing the kit in conjunction with an Atomic throttle body EFI system. There are two possible connection points on the throttle body unit, one of which will be the fuel supply in an operational system. DO NOT “tee” into the supply line and leave the -6AN port plug installed in the remaining throttle body port. Remove the -6AN port plug from the throttle body and route fuel from that port to the regulator inlet port (using the supplied hose and ﬁttings). The hose length between the throttle body and regulator is not critical, but generally speaking, should be kept to a minimum. Route and secure the hose as necessary to prevent chaﬁng, stretching due to engine movement, and heat-related damage.

CORRECT FOR RETURN STYLE FUEL SYSTEM.

FUEL

FILTER

MSD ADJUSTABLE

REGULATOR

FUEL

PUMP

FUEL TANK

Figure 1 Atomic TBI Return Fuel System.

MSD • WWW.ATOMICEFI.COM • (915) 857-5200 • FAX (915) 857-3344

2 INSTALLATION INSTRUCTIONS

, MOUNT

ACCOMMODATES

Use the schematic below as a guide when installing the kit in conjunction with an Atomic LS EFI system. There are two possible connection points (one at the rear of each fuel rail assembly). One rail will be connected to the fuel supply in an operational system. DO NOT “tee” into the supply line and leave the opposing fuel rail plugged or capped. Fuel from the opposing rail should be routed to the regulator inlet port (using the supplied hose and ﬁttings). The hose length between the rail and regulator is not critical, but generally speaking, should be kept to a minimum. Route and secure the hose as necessary to prevent chaﬁng, stretching due to engine movement, and heat-related damage.

FUEL RAIL

(UNDER COVER)

FUEL RAIL

(UNDER COVER)

MSD ADJUSTABLE

REGULATOR

FUEL

FILTER

FUEL TANK

FUEL

PUMP

IT IS RECOMMENDED TO MOUNT THE FUEL PUMP IN THE TANK WHENEVER POSSIBLE. IF IT MUST BE MOUNTED EXTERNALLY THE PUMP WITHIN 2-FEET OF THE FUEL TANK SENDING UNIT.

Figure 2 Atomic LS Return Fuel System.

The regulator-to-tank connection should be made using the supplied hose and ﬁttings. Install the supplied -6AN port plug in whichever regulator return port is not used. Depending on the conﬁguration of your fuel tank / fuel cell, the supplied high pressure fuel hose clamp may be used at the tank ﬁtting connection.

Use care when routing the hose from the regulator to the tank. Route and secure the hose as necessary to prevent chaﬁng, stretching due to engine movement, and heat-related damage.

REGULATOR MOUNTING

Using the two (2) supplied 10-32 x 0.375 Button Head Cap Screws and a 1/8-inch hex key (Allen wrench), attach the regulator bracket to the regulator body. The regulator may then be mounted to the ﬁrewall, or other convenient surface. Regulator orientation is not critical, but be mindful of adjustment screw access and hose routing. Refer to Figure 3 for a mounting bracket template.

2.200”

#10 SCREW

Figure 3 Regulator Mounting Bracket Template

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INSTALLATION INSTRUCTIONS 3

VACUUM / BOOST

ADJUSTMENT SCREW

INLET PORT

GAUGE PORT

REGULATOR CONNECTIONS AND ADJUSTMENT

The regulator inlet port is located on the bottom surface, and clearly marked with an identiﬁer machined in the housing (see Figure 4 below). Two (2) outlet ports are available, but typically only one (1) will be used. Install the supplied -6AN port plug in the unused outlet port using a 5/16-inch hex key (Allen wrench). The -6AN straight port ﬁttings should be snugged with an 11/16-inch wrench or deep socket.

Install the supplied 1/8-27 NPT brass hose barb ﬁtting in the upper regulator housing (see Figure 4 below) using a 7/16-inch wrench or deep socket. Thread sealer is not required on this ﬁtting, but can be used if desired. Connect an intake manifold vacuum / boost source to this ﬁtting, or leave it open to the atmosphere if manifold pressure compensation is not required. DO NOT plug this opening. Ensure that contaminants (such as water and road spray) cannot enter the open ﬁtting. In the event that vacuum / boost reference is not required, a more cosmetically pleasing option is to install a sintered metal exhaust mufﬂer in this port (such as McMaster-Carr PN 4450K1-Bronze or PN 4402K51-Stainless Steel)

The 1/8-27 NPT port in the lower housing allows the installation of a fuel pressure gauge (direct or remote-reading). If use of this port is not required, install the supplied stainless steel pipe plug using a 3/16-inch hex key (Allen wrench). Use of a fuel compatible paste-type thread sealer is REQUIRED on this plug. Thread sealing tape is also an option, but not recommended due to the potential for particulate and debris generation.

Use a 5/32-inch hex key (Allen wrench) to adjust the regulator set point. Clockwise rotation (screw advancing inward) increases the set point, and counter-clockwise rotation (screw advancing outward) decreases the set point. When the desired set point has been reached, snug the jam nut using a ½-inch wrench.

Refer to the user installation instructions, supplied with the Atomic EFI kit, for regulator set point recommendations.

Note: An overly lengthy and restrictive return line routing scheme may result in a non-negligible

pressure rise across the regulator-to-tank portion of the system. For this reason, the ﬁnal regulator adjustment should be made while monitoring the system fuel pressure (on the Atomic hand-held Dash) with the engine at idle.

AND LOCK NUT

REFERENCE PORT

(1/8-27 NPT)

MOUNTING

BRACKET

OUTLET PORT

(1 OF 2)

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Figure 4 - Regulator Feature Identiﬁcation Guide

4 INSTALLATION INSTRUCTIONS

STOP HERE

REVIEW YOUR INSTALLATION

Take a few extra minutes to check all aspects of your return fuel system installation at this point. Cycle the key on and off several times to ensure a complete fuel system prime, and verify that all connections and ﬁttings are leak-tight. Don’t forget to make the ﬁnal regulator adjustment with the engine idling.

REGULATOR SERVICE

The regulator diaphragm assembly is available as a service kit from MSD and considered a userserviceable item. Detailed instructions are available in the service kit, but for completeness, the following guidelines must be observed if it is necessary to separate the regulator housings.

• Usea9/64-inchhexkey(Allenwrench)toremovethethree(3)8-32x0.375SocketHeadCap

Screws

• Usecarenottoloseanyinternalparts(particularlythe¼-inchballbeneaththeadjustmentscrew)

• Uponre-assembly,ensurethatnodebrisorparticulatesaretrappedbetweenthehousingmating

surfaces (these may cut or damage the diaphragm)

• Alignthediaphragmslotswiththethree(3)screwholesandstackthespringassemblypriorto

installing the upper housing

• Installthethree(3)8-32x0.375SHCStoastagednaltorqueof25-28*in-lb.

o Stage 1 Torque: 10 in-lb o Stage 2 Torque: 20 in-lb

o Stage3(nal)Torque:25-28*in-lb.

*VerifytheStage3torqueafteratleastonehourhaselapsed(toallowfordiaphragmcompressionset)

Completing the installation of your MSD Atomic fuel return kit will require that several connections be made using the supplied high-pressure hose and push-lock ﬁttings. Use compressed air (or equivalent) to ensure that all complete hose / ﬁtting assemblies are clean prior to ﬁnal installation.

To ensure that your connections are safe, durable, and cosmetically pleasing, we recommend that you adhere to the guidelines in the following section:

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INSTALLATION INSTRUCTIONS 5

PROPER INSTALLATION OF PUSH-LOCK AN FITTINGS IN AEROQUIP AQP HOSE

Proper installation of push-lock ﬁttings BEGINS with the ﬁrst cut of the hose. The hose end must be cut squarely and cleanly. If these two requirements are not met, the connection is compromised from the start. See Figure 5 and 6 for additional information on achieving a proper cut.

Apply a light coating of fresh motor oil to the fitting barbs. More is NOT better – too much oil results in a slippery mess which makes it impossible to get a tight grip on the hose.

To the extent possible, make sure the push-lok ﬁtting is well anchored – whether it is in a vise, connected to another stationary ﬁtting, or against a hard surface. You WILL NOT get good results by trying to hold the ﬁtting in one hand, and the hose in the other. Likewise, you WILL NOT get good results if you cannot apply sufﬁcient force to fully engage the ﬁtting barbs in one smooth motion. Having to stop and twist, and then resume pushing, typically results in an inferior connection - requiring that you cut the hose off the ﬁtting and start again. This means that you should not try to push the hose on the ﬁtting when leaning over the engine while standing on an old milk crate.

NOTE: THERE IS MINIMAL DISTURBANCE

OF THE OUTER JACKET, BRAIDS, AND INNER LINER. THIS TYPE OF CUT IS ACHIEVED WITH A HOSE CUTTER, NEW RAZOR BLADE, OR EXTREMELY SHARP (NON-SERRATED) KNIFE. THE HOSE SHOULD BE SEVERED COMPLETELY – REQUIRING NO TEARING OF BRAIDS AND / OR RUBBER MATERIAL WHEN THE CUT IS COMPLETE. THE CUT PLANE IS PERPENDICULAR TO THE LONGITUDINAL HOSE AXIS.

Figure 5 Correct Clean, Square Cut

NOTE: THERE IS VISIBLE DAMAGE TO THE

OUTER JACKET, BRAIDS, INNER LINER, OR ANY COMBINATION THEREOF. THIS TYPE OF CUT RESULTS FROM THE USE OF A DULL KNIFE, SERRATED KNIFE, “SAWING ACTION” WHILE CUTTING, THE USE OF SIDECUTTING PLIERS THAT CRUSH THE HOSE WHILE CUTTING, OR ANY TYPE OF CUTTER THAT UTILIZES SHEARING ACTION. THE CUT PLANE IS GENERALLY NOT PERPENDICULAR TO LONGITUDINAL HOSE AXIS.

Figure 6 Incorrect Jagged, Rough Cut

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6 INSTALLATION INSTRUCTIONS

The depth to which the ﬁtting is inserted into the hose is EXTREMELY IMPORTANT. Stopping too soon, with the end of the hose positioned directly above the inboard hose barb, will result in excessive hoop stresses in the braids and outer jacket. Pushing too far, such that the hose starts to ride up on the beauty ring lead-in chamfer, will have the same result. In either case, the residual hoop stresses (in the braids and outer jacket) will lead to the formation of splits in the outer jacket once the hose has been exposed to under-hood temperatures. See Figure 7 for an example of an improperly installed ﬁtting. See Figure 8 for an example of an improperly installed ﬁtting – which resulted in splits in the outer hose jacket following heat exposure.

Use the thin edge of the beauty ring as a depth gauge for the end of the hose. STOP pushing when the end of the hose is ﬂush with the thin edge of the beauty ring. At this point, the end of the hose should have “rolled over” the inboard barb and conformed snugly to the ﬁtting neck. See Figure 9 for an example of a properly installed ﬁtting.

NOTE: EXCESSIVE GAP BETWEEN END OF HOSE AND THIN EDGE OF BEAUTY

RING - RESULTING IN RESIDUAL HOOP STRESSES IN BRAIDS AND OUTER JACKET. CONNECTION INTEGRITY HAS BEEN COMPROMISED, AND OUTER JACKET WILL SPLIT WHEN EXPOSED TO HEAT.

Figure 7 Improperly Installing Push-Lock Fitting

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INSTALLATION INSTRUCTIONS 7

SPLITS IN OUTER HOSE JACKET (BEAUTY RING REMOVED FOR CLARITY)

Figure 8 Improperly Installed Push-Lock Fitting

END OF HOSE IS FLUSH WITH THE THIN EDGE OF THE BEAUTY RING.

Figure 9 Properly Installed Push-Lock Fitting

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8 INSTALLATION INSTRUCTIONS

TECH NOTES

_________________________________________________________________________________________________________________________

Service

In case of malfunction, this MSD component will be repaired free of charge according to the terms of the warranty.

When returning MSD components for warranty service, Proof of Purchase must be supplied for veriﬁcation. After the warranty period has expired, repair service is based on a minimum and maximum fee.

All returns must have a Return Material Authorization (RMA) number issued to them before

being returned. To obtain an RMA number please contact MSD Customer Service at 1 (888) MSD-7859 or visit our website at www.msdperformance.com/rma to automatically obtain a number and shipping information.

When returning the unit for repair, leave all wires at the length in which you have them installed. Be sure to include a detailed account of any problems experienced, and what components and accessories are installed on the vehicle. The repaired unit will be returned as soon as possible using Ground shipping methods (ground shipping is covered by warranty). For more information, call MSD at (915) 855-7123. MSD technicians are available from 7:00 a.m. to 5:00 p.m. Monday - Friday (mountain time).

Limited Warranty

SDwarrantsthisproducttobefreefromdefectsinmaterialandworkmanshipunderitsintendednormaluse*,

when properly installed and purchased from an authorized MSD dealer, for a period of one year from the date of the original purchase. This warranty is void for any products purchased through auction websites. If found to be defective as mentioned above, it will be repaired or replaced at the option of MSD. Any item that is covered under this warranty will be returned free of charge using Ground shipping methods. This shall constitute the sole remedy of the purchaser and the sole liability of MSD. To the extent permitted by law, the foregoing is exclusive and in lieu of all other warranties or representation whether expressed or implied, including any implied warranty of merchantability or ﬁtness. In no event shall MSD or its suppliers be liable for special or consequential damages.

 *Intendednormalusemeansthatthisitemisbeingusedaswasoriginallyintendedandfortheoriginalapplication

as sold by MSD. Any modiﬁcations to this item or if it is used on an application other than what MSD markets the product, the warranty will be void. It is the sole responsibility of the customer to determine that this item will work for the application they are intending. MSD will accept no liability for custom applications.

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FRM31527 Revised 4/13 Printed in U.S.A.

MSD 2922 Installation

Specifications and Main Features

Frequently Asked Questions

User Manual