wicknetzel Posted April 30, 2015 Share Posted April 30, 2015 Sgt.Gator's racecar is a good example of this. Worth reading up on his thread. Just because you haven't found it using search, doesn't mean its true. Nor the opposite. ^This. I've learned a lot from this thread, and there's actually great discussion of aerodynamics in it... with actual theory included, not speculation. It's not just about a chimney effect for the turbo, but also changes in air pressure that affect how air moves though the engine bay and around your car. Also take a look at Subaru Rally Team's cars. They all run FMICs and all have hood scoops. If you look closely at the scoop, it's actually molded to divert air into ducts to carry air to certain under hood locations. I'd put my money on one of those being the turbo. They certainly do test in a wind tunnel and spend a lot of money to make choices. Link to comment Share on other sites More sharing options...
fahr_side Posted April 30, 2015 Share Posted April 30, 2015 I think I remember the rally team admitting that on the FMIC or V-mount cars the hood scoop was left on the car because Subaru marketing insisted. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
wicknetzel Posted April 30, 2015 Share Posted April 30, 2015 I think I remember the rally team admitting that on the FMIC or V-mount cars the hood scoop was left on the car because Subaru marketing insisted. Even if that is the case (which could make some sense), they still include louvers in their hood in addition. Point is... it's not a solid hood. Link to comment Share on other sites More sharing options...
fahr_side Posted April 30, 2015 Share Posted April 30, 2015 Yes, but the amount of heat a WRC car with a V-mount setup chucks out is in another league to what street cars ought to be doing. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
wicknetzel Posted April 30, 2015 Share Posted April 30, 2015 Yes, but the amount of heat a WRC car with a V-mount setup chucks out is in another league to what street cars ought to be doing. Sure. To clarify, that's not what I'm suggesting. I'm simply discussing that there's been some thought put into moving air through the engine bay and that there could be disadvantages to changing that. Certainly, the higher the performance level, the more benefit cooling will provide... but we can probably all agree that the closer to normal operating temperature we stay, the more efficiently our engines can function. I am not saying it's going to be an immediate #YNANSB situation... just thinking about improved performance. Also... like boxkita said, read Sgt. Gator's thread about when he swapped his hood. Link to comment Share on other sites More sharing options...
fahr_side Posted April 30, 2015 Share Posted April 30, 2015 Hard to say if adding cool air via the redundant scoop will add to or detract from the suction at the back of the undertray that helps draw air through the radiator. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
boxkita Posted May 1, 2015 Share Posted May 1, 2015 would be cool to put a car in the wind tunnel and actually see what happens. Been looking for a lgt model to try it out with a small scale tunnel. I know you can CFD all that stuff, but who has time & hardware for that? Build my car Boxkita Track days Link to comment Share on other sites More sharing options...
m sprank Posted May 3, 2015 Share Posted May 3, 2015 . . . and underhood temps will rise, and you'll get knock! The scoop isn't just there to bring in fresh air to the TMIC, it's also there to vent heat from the turbo. Don't believe me -- look at the shroud -- it's got that diamond section where it vents heat from the turbo. In fact, I believe Subtle even makes a turbo chimney for it, ala 1st Gen SS. (90-94). LIEK DIS: http://farm4.static.flickr.com/3478/3457605859_e263714667_b.jpg The point is, until you go low-mount turbo, ala '15 WRX or FXT, you need the scoop for the stock location turbo to vent heat. Absolutely incorrect. Another example of untested hogwash getting spread like truth across the interweb. If you have a FMIC, ditch the scoop (notice in Tris supplied pic it is a TMIC). Your underhood temps will be LOWER. Your radiator will be more efficient! Once the TMIC is gone leaving the open scoop causes a pillow of high pressure air to form under the hood. This decreases air flow through the radiator and increases underhood temps. Track tested truth!!! Link to comment Share on other sites More sharing options...
05legacygtr Posted May 5, 2015 Share Posted May 5, 2015 Like what? I believe MOST other turbos are either on the front or sides of the motor, not in the back. Saab turbos.....although I remember reading something about how the heat generated by the turbo was killing batteries. Which in that car I believe is like 250 bucks. Link to comment Share on other sites More sharing options...
BostonLGT Posted May 5, 2015 Share Posted May 5, 2015 Absolutely incorrect. Another example of untested hogwash getting spread like truth across the interweb. If you have a FMIC, ditch the scoop (notice in Tris supplied pic it is a TMIC). Your underhood temps will be LOWER. Your radiator will be more efficient! Once the TMIC is gone leaving the open scoop causes a pillow of high pressure air to form under the hood. This decreases air flow through the radiator and increases underhood temps. Track tested truth!!! Thanks! Finally, someone with track tested experience on this. Glad to know that someone has actually looked into it! Link to comment Share on other sites More sharing options...
PortCityLGT Posted May 5, 2015 Share Posted May 5, 2015 Once the TMIC is gone leaving the open scoop causes a pillow of high pressure air to form under the hood. This decreases air flow through the radiator and increases underhood temps. Excellent, TY for sharing. What are your thoughts on removing the scoop and running with the open hole as a vent? Link to comment Share on other sites More sharing options...
m sprank Posted May 5, 2015 Share Posted May 5, 2015 Venting seems to work. But it has its limitations. It is not the "magic elixir" you would hope for. We dont have nearly the under hood temps from the EJ's as we do with the FA's. On the BRZ/FRS it can get ridiculous trying to control under hood temps on track (with forced induction). I have never cut a hole in the hood of an LGT just to try a vent (scoop is integrated into the hood unlike early WRX/STi). Its much cheaper to just tape over the scoop if you dont have a hood swap already. Link to comment Share on other sites More sharing options...
Sgt.Gator Posted July 13, 2016 Share Posted July 13, 2016 In case anyone wants to see track tested proof of what problems the TMIC scoop does for your cooling see this post. It's a track test I just did on my STI for airflow. The result is that like my LGT racecar I'll be deleting the STI hood scoop, adding a heat extractor scoop to the front of the hood, and going FMIC or AWIC. http://legacygt.com/forums/showpost.php?p=5414019&postcount=56 Nothing like a race track to find the weak points in man and machine. "Good Judgement comes from Experience. Experience comes from Bad Judgement" Link to comment Share on other sites More sharing options...
m sprank Posted July 13, 2016 Share Posted July 13, 2016 Did this years ago. Reported here on the forum. Its the same on all Subies. If you dont have a TMIC and a slash tray it does not work properly. Hi pressure under the hood decreases efficiency of your FMIC and radiator. If running a TMIC, use a splash tray. If running a FMIC, cover your scoop or swap hoods. Good to see others are at least investigating on their own. Link to comment Share on other sites More sharing options...
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