1. The FAST™ LSXR™ 102mm Intake looks massive when compared to the stock intake. How much of a power increase can I expect to get from this thing?
This is a major misunderstanding in our market. Throttle “diameter” has absolutely nothing to do with torque curves or if an engine makes power down low or up high. All it does is dictate how much restriction the intake will see (less is better), and the size is directly proportional to throttle metering. If you open a large diameter throttle 10%, it is equivalent to opening a smaller diameter throttle 15%. To address this, the FAST™ Big Mouth 102mm Throttle Body™ (
part #54102) has a convoluted shape to help with low speed drivability. FAST™ only recommends 102mm throttle bodies with “convolute” barrels for proper drivability.
2. Regarding installation, what all is included for installation into GM Gen IV LS3, L99 and LS7 engines? What all is needed?
All hardware and fittings are included. The only intake that “comes with” intake port seals is the LS7 (part # 146203), because only the FAST™ seals work. All other manifolds do not include intake port seals, but we do offer and sell them separately. In some cases, fuel rails are required – refer to the application chart below.
3. I recently purchased a 2010 Chevy Camaro. I noticed that the LSXR™ package includes a spacer and special instructions for the idler pulley. Please explain.
The factory idler is offset inboard, slightly misaligning the belt drive. FAST™ took advantage of this fact and spaced the idler pulley and belt forward, placing them properly in-line. If a customer doesn’t want to run the spacer, they can swap on an aftermarket throttle body, or flip the stock throttle body up-side-down. All three of these options work. The reason for this was to maximize plenum volume; moving the throttle body out of the way allows for this slight gain.
4. I noticed the vacuum port on your manifold is in a different location. Please explain.
The FAST™ LSXR™ series of manifolds is designed to fit model years 1997-current. This requires using one common location for some fittings; certain applications may require routing hoses or wires accordingly to mate to the FAST™ Intake Manifolds.
5. The MAP Sensor harness will not reach. What do I do?
The FAST™ 102mm Manifold has provisions for either a front or rear mount MAP sensor. It is necessary to select the proper location and drill through the center of the desired location (refer to directions). Pull the wire out of the loom a little bit to make it fit. Also new for the LSXR™ and LSXRT™ series of manifolds is a bolt-down provision for MAP sensors. All manifolds include this bolt.
6. How long does it usually take to install the LSXR™ Manifold?
It takes a professional an hour and a half to install it. Your average wrench will take about 2.5 hours, and a beginner “do-it-yourselfer” can easily do it in an afternoon.
7. Do I need fuel rails, injector spacers or any other upgrades in order to properly install it?
Possibly, refer to the application chart. FAST™ recommends using
FAST™ Billet Fuel Rail Kits for the best appearance and performance.
8. What difference does the Big Mouth 102mm Throttle Body™ make on the performance of the manifold?
Performance testing has shown up to 5 horsepower over 92mm throttle bodies, and throttle response is much higher with the 102mm.
9. Will the LSXR™ Manifold fit a Corvette?
Yes, our clearance testing was based around a stock C5 with a completely stock engine. Please be aware that aftermarket heads or otherwise modified engines/cars "could" impact manifold clearance. The manifolds were designed with minimal clearances to enable maximum performance.
For more information on the FAST™ LSXR™ 102mm Intake Manifold or any other product from FAST™, please call EFI HELP™ at 1-877-EFI-TEKK (334-8355) or visit the
FAST™ website!
FAST™ LSXR™ Manifold Q&A 
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