Dyno Test: LSX-R 102mm F.A.S.T. Intake Manifold
Posted at 4:53 AM / July 9, 2009
The new "LSX-R" 102mm intake manifold by F.A.S.T. (www.FuelAirSpark.com) was released for production recently for the LS7 7.0L engine. As we all know, the potent 427 cubic inch mill from GM is factory rated at 505 hp. Until now, nobody had developed a composite molded intake manifold for the LS7, so most owners opted for mildly ported OEM intake manifolds to squeeze a little more output from them.
Planet LSX decided to do its own testing, rather than buy into sales propaganda, or make decisions based on online forum antics. We own a brand new 2009 Corvette Z06, which was completely showroom stock besides a nice set of HRE wheels. It was begging for modifications, and we enjoy testing new stuff. The car had 5,050 miles on it, so it was ready to break the seal.
As soon as the intakes became available, we put our order in for one. When the UPS truck made us happy, we picked up the phone to Late Model Racecraft in Houston, TX (www.LateModelRacecraft.com) to utilize their new state of the art dyno facility and installation expertise. Don't worry, yours truly still gets his hands dirty and did some wrenching as well. It sure is fun installing an intake manifold on top of a hot engine on a 102F day!
Installation was pretty straightforward. The LSX-R intake manifold utilizes a GM LS3 fuel rail, along with some billet aluminum injector spacers. You will not need your LS7 fuel rail, just the injectors off of it. The intake can be swapped out with just a simple set of metric sockets and a fuel line disconnect tool. Figure about 2 hours taking your sweet time, otherwise you may want to leave the chore to a pro. The OEM 90mm throttle body was utilized, and no computer tuning was performed. This is a bolt-on modification in its purest form, no tune required.
We have to admit, we were on the skeptical side before those LSX-R dyno pulls were made. We've all seen the magic dyno trickery that some shops like to meddle with, whether for good or bad intentions. Surely the new intake couldn't be that good, could it? Everyone always claims how nice the OEM intake manifold is, so what could there be to improve on? Well, F.A.S.T. says that the LSX-R runners are 3 inches longer than the OEM runners. They also say those long runners are more efficient with flow. We all understand that longer runners tend to produce better torque results, but the claim that both HP and TQ will increase? A bit hard to believe.
We were wrong. Tests showed that the LSX-R intake walked all over the OEM intake manifold. Up until around 3600 rpm, both intakes perform equally well. At that point, the LSX-R just flat out dominates the LS7 intake, all the way through the 7,000 rpm redline. The torque increase is substantial, showing about an average of 20 ft-lbs gained across the board. Horsepower showed about a 14 rwhp gain across the powerband too. Those of you that can read and understand dynos, you will appreciate the "area under the curve" that this modification makes. E-racers like to brag about peak HP figures, but we all know it is the highest average HP gain that is more important. The LSX-R simply delivers, even on a bone-stock Z06. It should do even better on a more highly modified engine, assuming your builder and tuner know how to maximize the output.
We chose to do a series of tests with the Z06, since it had never been dyno'd before. The car was never allowed to cool down, due to the hot weather and the hour install of the intake between runs. Coolant temps were in the 180-190F range for each pull.
Test 1. Baseline run with the car 100% OEM stock. That means zero mods, nada, nothing. Just like it came from the dealership.
Test 2. Install the Halltech "Killer Bee" airbox on the 100% stock car.
Test 3. Install the LSX-R intake manifold. Use the OEM airbox.
Test 4. With the LSX-R intake installed, Use the Killer Bee airbox.
From these dyno pulls, we end up with the vital comparisons below:
A. Baseline 100% stock Z06 vs Killer Bee airbox added.
B. Factory OEM airbox, before and after LSX-R installed.
C. Killer Bee airbox, before and after LSX-R installed.
D. LSX-R intake manifold, OEM airbox vs Killer Bee airbox.
Time to throw those ported LS7 intakes in the trash. You might pick up some HP from doing the port work, but the torque jump with the 3 inch longer runners found in the LSX-R is hard to overcome. Nice work F.A.S.T!
