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MSD Atomic Turbo LS Test

The Atomic Elbow

By Richard Holdener, Photography by Richard Holdener

Based on both looks and performance, this Atomic EFI system seemed ideally suited for crate or other mild motor swap applications, but how would it perform on something with a little more zing? Of course, when we say zing, we really mean boost. To put the MSD to the test, we decided to install a new single turbo kit from Designed for an LS-powered F-body ('97–'02), the kit from CXRacing.comwill likely also be employed in swap applications, due to its front-mount turbo position (typical on LS applications). The stainless kit featured dedicated exhaust manifolds, a Y-pipe with T4 turbo, and integrated wastegate flanges. The kit also included a wastegate, a blow-off valve, and a 76mm turbo capable of supporting 800 hp. Keeping things cool was a massive, front-mounted, air-to-air intercooler, complete with all the necessary tubing, couplers, and clamps. The aluminum tubing even features beaded ends to improve sealing. Having used the 76mm turbos time and time again on various projects, it is amazing that all this hardware (minus the intercooler) sells for around $1,000.

We wondered if the Atomic EFI system would be up to the task of properly tuning a turbo LS3, so with fingers crossed, we commanded an air/fuel ratio of 11.8:1, and changed the stock MAP sensor for one of the 2-bar sensors listed in MSD's menu. As an aside, we would recommend MSD list the map sensors under 1-bar, 2-bar, or 3-bar settings, rather than part numbers, but we managed to cross-reference the necessary sensor for our test. You can also purchase a MAP sensor directly from MSD. Once again, the LS3 started on the first try and was humming away with the new turbo kit. Loading the motor with the dyno revealed the air/fuel mixture was spot-on and that MSD's engineers had again erred on the conservative side in terms of ignition timing. Full-throttle runs revealed an air/fuel mixture right at the requested 11.8:1, and we actually had to add timing (the desired method) to improve the power output with the turbo.

Aeromotive's fuel pump was capable of supporting considerably more power, but the limiting factor turned out to be our use of factory 42-pound injectors. The Atomic EFI system will accept larger injectors, but we didn't have any available for this test. Despite the injector snafu, we did manage to coax as much as 660 hp and more than 700 lb-ft of torque before running out of injector flow. These represent gains of nearly 180 hp and more than 225 lb-ft of torque at just 7 psi of boost. Turbo response was excellent, the intercooler kept the charge temperatures nice and cool, and the wastegate never missed a beat. The one area we would like to see improved on the turbo kit is the flow rate of the blow-off valve—maybe running two of the smaller units. With more fuel, the single-turbo system from CXRacing.comshould be capable of getting nearly 800 hp, or you can step up to the twin-turbo system capable of, you guessed it, 1,600 hp. The goal of this test wasn't to maximize the power output of our stock LS3 but rather to illustrate that the Atomic EFI was capable of self tuning both an NA and turbo application. If the results of this test are any indication, MSD just dropped an Atomic Elbow.

Turbo Power Graph

This graph illustrates that both the single turbo system from, and MSD's Atomic EFI system performed as advertised on the LS3 crate motor. Use of stock injectors ultimately limited the power gains, the single-turbo system was capable of supporting 800 hp, and the Atomic EFI System provided a rock-steady (commanded) air/fuel m ixture of 11.8:1. We liked the fact that the engineers were purposely conservative on the timing values, requiring us to add timing to dial in the power. This is exactly the procedure you should take when tuning with a conventional stand-alone EFI system. Using the Atomic EFI, the CXRacing turbo kit increased the power output of the stock LS3 from 482 hp and 483 lb-ft to 658 hp and 709 lb-ft of torque at just less than 7 psi.

Parts List

Description Source PN Price
Atomic LS EFI MSD 2950 $2,495
Twin- turbo kit* CX Racing TRB-KIT-HD-LS1-T76-P96 $1,069
LS3 crate engine Summit Racing 19258770 $6,999.99

*Intercooler sold separately

7805 Barton Street
KS  66214
MSD Ignition
Gandrud Chevrolet
Holley Performance Products
1801 Russellville Rd.
Bowling Green
KY  42101
Lucas Oil
302 North Sheridan Street
CA  92880
By Richard Holdener
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Carroll Smith
Carroll Smith

and Top fuel engines make 7k plus yada yada,nice job here hope they get cheaper and easier to use as updates to older musclecars

Pedro Perez
Pedro Perez

Isn't there a Ford 4 cylinder turbo making over a 1,000 somewhere here? So yeah I guess I am impressed that an ls1 could could almost come close to that little 4 cylinder.

Chuck Thompson
Chuck Thompson

Not really. Nelson racing has been doing this for years and made 4 figure numbers with a 4.3 v6. Now then, impress us...

Todd Spear
Todd Spear

700 HP is a piece of cake for a turbo LS

Mike Batista
Mike Batista

a bbc with that power would fly apart on the dyno

Gary Soares
Gary Soares

Wait a little while----BIG BANG BOOM SCRAP STEEL.

Michael Smith
Michael Smith

Apparently you don't know the kind of power LS engines can make reliably.

Liam Knight
Liam Knight

That kind of power from a LS engine will be short lived. I would wager that you can't peak out the torque on that engine a dozen times before it blows apart.

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