All Aboard

Squeezing 723 hp and 727 lb-ft With Nitrous Express

A couple of months ago, we outfitted our GM Performance Parts LS1 crate engine with the complete Patriot Performance package ("Patriot Games," Dec. '04), consisting of CNC-ported LQ9 aluminum cylinder heads, a 1.7:1 shaft-mount rocker assembly, a healthy roller cam, along with the factory LS6 manifold, which produced 506 hp and 459 lb-ft. To further take advantage of the increased airflow, we then swapped the potent factory LS6 manifold for the F.A.S.T LSX unit, netting us an additional 16 hp and 7 lb-ft, bringing the total to 522 hp and 466 lb-ft. As impressive as it was, we wondered how much power we could extrapolate from a stock bottom-end LS1. Although our time on the dyno was finished for the day, we had plenty of opportunity to put our warped minds together and concoct various options on taking the LS series to the next level.

For this round, we opted for the Nitrous Express Twin EFI MAF nitrous system, specifically designed for LS1 and LT1 engines. Its method of delivering fuel and nitrous is unique. Unlike other systems that employ a single nozzle, the MAF billet aluminum housing replaces the factory piece and allows the mixture to flow directly into the manifold. The new MAF housing has four inlets, two for nitrous and two for fuel, and can be arranged in a number of configurations. A single-stage system is good up to 250 hp. Using the second pair of inlets creates a two-stage system that'll produce as much as 500, assuming you have an engine with forged components and a fuel system that can handle it.

Since our LS1 features a completely stock bottom end and has already produced pretty stout figures on grunt alone, the object was to see just how much more there was to be gained with the power adder. We'll admit that we initially wanted to limit the testing with a small shot, but our dark side convinced us to try the 200 pills. If you were impressed with the Patriot-equipped all-motor numbers, then you have to check out what a little bit of gas can create.

3

Our Patriot Performance LS6 Stage II cylinder heads are worked over factory LQ9 6.0L truck pieces with their complete line of valvetrain, a newly formed 59cc combustion chamber, along with 2.05/1.60 valves. When matched with a Patriot billet-steel camshaft, 1.7:1 shaft mount rockers, F.A.S.T. LSX manifold, and LSX 78 mm, the formidable combination generated 522 hp and 466 lb-ft on grunt alone!

The NX Mass Airflow (MAF) nitrous system, with its dual AN -3 inlets, can create a two-stage nitrous system. Nitrous and fuel is supplied to each side, where they merge through the billet aluminum housing and exit directly into the manifold.

Start by disassembling the stock MAF housing. Remove the four Torx screws on each corner and gently separate the plastic sensor housing. Be sure to avoid contact with the MAF's hot wire and to retain the O-rings from the factory housing.

Install the O-rings on the new housing, replace the Torx screws, and your final assembly should look similar to this. Last, double-check that the arrow on the plastic sensor housing is pointing toward the inlet side.

Nitrous Express scribes the inlet, outlet, and purge ports on all of its nitrous solenoids. Like most other systems, the inlet is on the side; however, the outlet port is underneath the solenoid. If you don't plan on utilizing it at the time of install, the port opposite of the inlet is the purge and must be capped with the enclosed 1/8" NPT plug.

Before installing the outlet fitting, we installed the mounting brackets with the supplied hardware.

Contingent on the application, there are a number of places to mount the nitrous and fuel solenoids. For our purposes, we found it extremely convenient to piggyback them on the factory coil-pack bolt.

Every kit includes an AN -3 fuel line that allows you to tap directly into the fuel system using the stock fuel test port. Since we're utilizing aftermarket fuel rails, we simply added a T-fitting at the back of the rail.

An SHO AN -4 stainless braided line feeds the nitrous and extends from a solenoid featuring an AN -4 inlet fitting and leads into the MAF housing with an AN -3 fitting.

Should you desire a two-stage system, the secondary inlets can be used for additional big horsepower gains or to help soften the hit with two smaller shots. For example: a 75 hit out of the hole, followed by a 100 shot once you've obtained maximum traction.

Here's a quick tech tip: If your nitrous system is completely wired and the solenoids still won't activate, check the ground. We originally grounded ours to the rocker covers, only to discover that it wouldn't work.

With our timing at 28 degrees total, the 150hp jetting in place, our mule blasted out 672 hp and 677 lb-ft, with the plugs looking perfect! In anticipation of the 175 and 200 jetting, we swapped out the factory plugs for colder Densos, and dumped in a few gallons of 100-octane Rocket Brand fuel to avoid any chance of detonation.

The 175 hit rewarded us with 686 hp and 687 lb-ft, but it was the results of the 200 shot that made a serious impression with a mind-numbing 723 hp and 727 lb-ft.

148_0504_test_15_z 16/16

Under Pressure Maintaining bottle pressure is critical for optimum performance, yet it's still not uncommon for even the most experienced nitrous gurus to neglect it. All you need is a bottle heater, a simple element that wraps around the nitrous bottle and thermostatically regulates the pressure inside it with heat. Consider it vital.

148_0504_test_16_z 17/16

Access the controller by removing the four Phillips cover screws and turning the rotary knob to the desired setting. NX even went as far as to add a second output source to control an additional bottle. Nice!

If you're looking for something a little more exotic, then you'll want to check out NX's new Fire & Ice Pressure Controller (PN Speed00020), an absolute work of science. Heaters bring the nitrous to a preset pressure and then automatically shut down. The Fire & Ice unit features sophisticated circuitry that'll maintain bottle pressure within 5 psi in even the most grueling weather conditions by heating as well as cooling the bottle. Cooling the bottle? Trust us. Those who've had to deal with sweltering conditions will especially appreciate the cooling mode. This means no more stuck solenoids and less nitrous wasted on purging outrageous bottle pressure to safe levels.

 

TEST RESULTS

BASE TEST
3500421.6281
3600422.2289
3700425.9300
3800432.3313
3900438.5326
4000441.3336
4100443.9347
4200443.5355
4300451.5370
4400456.7383
4500463.1397
4600466.7409
4700470.4421
4800470.5430
4900469.1438
5000467.6445
5100467.1454
5200465.2461
5300466.2470
5400464.3477
5500465.9488
5600467498
5700463.5503
5800461.6510
5900454.9511
6000447.8512
6100444.7516
6200438.7518
6300434.1521
6400427.4521
6500420.8521
6600415.7522
150 SHOT
3500400.7267
3600402276
3700408.7288
3800412.5298
3900415.8309
4000417318
4100418.6327
4200421.8337
4300424347
4400429.3360
4500432.5371
4600432.6379
4700435.8390
4800443.8406
4900457.5427
5000677.4645
5100671.2652
5200664.1657
5300657.3663
5400647.6666
5500638.2668
5600630.4672
5700618.1671
5800608.2672
5900596.9671
6000587.1671
6100578.2672
6200568670
6300556.1667
6400545.8665
6500535.1662
6600520.5654
175 SHOT
3500393262
3600396.2272
3700402.8284
3800407.6295
3900408.6303
4000408.8311
4100410.4320
4200415.2332
4300418.5343
4400421.2353
4500421.3361
4600424.5372
4700433.5388
4800448.2410
4900687.2641
5000687.2654
5100679.5660
5200671.7665
5300659.2665
5400649.8668
5500639.5670
5600631.2673
5700622.4676
5800615.8680
5900607682
6000596.7682
6100585.9680
6200580.8686
6300569.9684
6400562.1685
6500548.6679
6600538.9677
200 SHOT
3500398.5266
3600400.1274
3700405.5286
3800409.1296
3900413.3307
4000412.9314
4100412.1322
4200413.6331
4300423.1346
4400424.3355
4500424.3364
4600426.5374
4700426.5382
4800435.1398
4900452.4422
5000452.5431
5100481.7468
5200727.3720
5300716.9723
5400700.9721
5500662.2694
5600637.3680
5700617670
5800600.4663
5900581653
6000569.2650
6100558.8649
6200542.8641
6300531637
6400513.4626
6500494.2612
6600538.9677
Patriot Performance Package (PPP), LSX 78mm throttle body, LSX manifold522/471 @ 6,500/4,800
PPP, LSX 78mm throttle body, LSX manifold, NX 150 hp672/677@ 6,100/5,000
PPP, LSX 78mm throttle body, LSX manifold, NX 175 hp686/687 @ 6,200/5,000
PPP, LSX 78mm throttle body, LSX manifold, NX 200 hp723/727@ 5,300/5,400

Sources

Westech Performance Group
Mira Loma, CA
951-685-4767
WestechPerformance.com
Chevrolet Performance Parts
Detroit, MI 48232
800-577-6888
www.gmperformanceparts.com
Nitrous Express
Wichita Falls, TX 76310
940-767-7694
www.nitrousexpress.com
How To
X
All Aboard
Feb 23, 2005

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