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Thread: Rotofab intake restrictions?

  1. #1
    VIP Member STL_G8GT's Avatar
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    Default Rotofab intake restrictions?

    Got the 102 Rotofab tube installed, doing some brake work, and got to looking at the air inlet for the RF in the driver wheel well. The point where air enters is a triangular shape that is smaller than the tube to the throttle body. Does it make sense that this is an air restriction, and if so, has anyone modified that part of the intake system for noticeable gains?

    I've already opened up the air dam underneath to let more fresh air in, curious about the box itself now.
    2009 PBM G8 GT
    Pat G 218/226, ARP Bits, DSteck/Shane Tuned, Magnacharger Chrome 2300 1:1, RCR Ported/Polished TB, Blower, & L92 Heads w/ LS3 intake valves, Comp Cams Trunion Upgrade Kit, ARH 1 7/8 catted/Magnaflow MidMuff/Solo Axlebacks, RotoFab, VaporWorx PWM 1:1 fuel system, ID850 injectors
    Mike Norris Motorsports Catchcan, AEM 30-4100, JHP Boost/Fuel Gauge Pod
    TSW Nurburgring Matte Gray 18" w/Nitto 555 & 555R, Satin Black SS Brembo Fronts, BMR Trailing Arms, Pedders Sway Bars, Whiteline Bushings
    Gloss Black Valve Covers, 6k HID, V6 Handles, Interior/License Plate LEDs, Debadged, Holden Black Trim, Polk Dxi, GXP diffusor, a few bits from Crazy Paul

    Originally Posted by TonyKarter
    Anyone who has ever worked on a car has been in your position, and sitting cross-legged on a concrete floor with a dim shop light is its own kind of hell... Chalk it up as one of the rites of passage.
    RIP Charlie - GRRRR8
    RIP Chris Wells - Panzer Leader

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    VIP Member STL_G8GT's Avatar
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    Default

    So I did some looking into this and actually found that a very well known builder chops off the bottom of the rotofab box to reduce any restriction - so my thoughts were right on!

    I took a simple saw blade and cut some of the bottom off of the air box and opened the effective inlet up from a 6x6x6 triangle (15 sq in) to a 7x7x6 (19.5sq in). For comparison purposes, a 4" circle is 12.5 sq in, and a 5" circle is 19 sq in.

    I'll post some pics later, but I hope this gets the wheels turning for anyone who hasn't looked at this yet.
    2009 PBM G8 GT
    Pat G 218/226, ARP Bits, DSteck/Shane Tuned, Magnacharger Chrome 2300 1:1, RCR Ported/Polished TB, Blower, & L92 Heads w/ LS3 intake valves, Comp Cams Trunion Upgrade Kit, ARH 1 7/8 catted/Magnaflow MidMuff/Solo Axlebacks, RotoFab, VaporWorx PWM 1:1 fuel system, ID850 injectors
    Mike Norris Motorsports Catchcan, AEM 30-4100, JHP Boost/Fuel Gauge Pod
    TSW Nurburgring Matte Gray 18" w/Nitto 555 & 555R, Satin Black SS Brembo Fronts, BMR Trailing Arms, Pedders Sway Bars, Whiteline Bushings
    Gloss Black Valve Covers, 6k HID, V6 Handles, Interior/License Plate LEDs, Debadged, Holden Black Trim, Polk Dxi, GXP diffusor, a few bits from Crazy Paul

    Originally Posted by TonyKarter
    Anyone who has ever worked on a car has been in your position, and sitting cross-legged on a concrete floor with a dim shop light is its own kind of hell... Chalk it up as one of the rites of passage.
    RIP Charlie - GRRRR8
    RIP Chris Wells - Panzer Leader

  3. #3
    Beyond Help tchr49's Avatar
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    Post them up, I need something to mess with!
    things are not what they appear to be.....

    2009.5 Liquid Red,Onyx Red, Premium Package, e85 Surprise Package

  4. #4
    VIP Member STL_G8GT's Avatar
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    In reading what RotoFab went through with the SS, they gained 20deg IAT when they didn't block the intake from the engine bay heat at the hood liner. With that in mind, I wanted to open this thing up as much as possible to air from the fender area, but still keep a nice blockoff to the front/side of the engine. The original 6x6x6 triangle extension goes down past the driver side impact bar. You could cut higher than where I did, but anything more than I did will end up well above the impact bar, and nearer to the source of heat (engine, etc). As it stands now, the cut line follows the contour of the intake box about 1" above the end of the 6x6x6 extension. I used low profile hacksaw because anytime I use a power tool on ABS I end up with a nasty melted mess.

    Intake from the front Left. The 6x6x6 "extension" that I talk about is the triangle at the bottom that extends about 4-5" up from the bottom before opening to 7x7x6.


    In this shot you can see the original opening, a triangle at 6x6x6 that is about 3-4" long. Just beyond that, you can see the contour line of the 7x7x6 section I wanted to get to.


    Cut piece removed. I left the back "flap" because it just follows the wheel well liner arch, you could just cut it all off if you wanted I guess.


    Used 80 grit (seriously) and then a higher grit (smoother) sanding sponge to smooth out my cuts.
    Last edited by STL_G8GT; 08-19-2017 at 06:17 AM.
    2009 PBM G8 GT
    Pat G 218/226, ARP Bits, DSteck/Shane Tuned, Magnacharger Chrome 2300 1:1, RCR Ported/Polished TB, Blower, & L92 Heads w/ LS3 intake valves, Comp Cams Trunion Upgrade Kit, ARH 1 7/8 catted/Magnaflow MidMuff/Solo Axlebacks, RotoFab, VaporWorx PWM 1:1 fuel system, ID850 injectors
    Mike Norris Motorsports Catchcan, AEM 30-4100, JHP Boost/Fuel Gauge Pod
    TSW Nurburgring Matte Gray 18" w/Nitto 555 & 555R, Satin Black SS Brembo Fronts, BMR Trailing Arms, Pedders Sway Bars, Whiteline Bushings
    Gloss Black Valve Covers, 6k HID, V6 Handles, Interior/License Plate LEDs, Debadged, Holden Black Trim, Polk Dxi, GXP diffusor, a few bits from Crazy Paul

    Originally Posted by TonyKarter
    Anyone who has ever worked on a car has been in your position, and sitting cross-legged on a concrete floor with a dim shop light is its own kind of hell... Chalk it up as one of the rites of passage.
    RIP Charlie - GRRRR8
    RIP Chris Wells - Panzer Leader

  5. #5
    VIP Member donkeyGT's Avatar
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    Very nice!! Will be doing this fo sho. Thank you for the share.
    2009 GT PBM Sport/Premium Packs
    Kook's / Corsa / Roto Fab CAI with HSRK / Polished Camaro's with Nitto Invo's / Camaro Brembo's / GRRRR8 Hose & ARP Bolt kits / VG Fin / GXP diffuser / Black door trim & other goodies from CP / UPR catch can / Livernois / BMR / Russell / Jet-Hot / SunTech tint by Drew / MM / Adams / Klearz / TSS

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