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| Mike_EA |
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The reason the scoop is "backwards" is because the air pressure is lower which causes a lower temparture
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- mike |
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| EBeast |
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Mike_EA wrote: The reason the scoop is "backwards" is because the air pressure is lower which causes a lower temparture
.- mike oooh, so how effective is it compared to a front facing scoop?
_________________ 1993 EBII GLI, IT'S PERFORMANCE Stage 3 engine,
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| philaddis |
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Mike_EA wrote: The reason the scoop is "backwards" is because the air pressure is lower which causes a lower temparture
.- mike Mike is quite right. If you run your hand along the bonnet of a car with a rear facing bonnet scoop, the ambient air temperatures are at least 5-10 degrees cooler towards the base of the winscreen. I think it has something to do with how cool the actual scoop looks on the car. Is that right Mike?
_________________ ED XR8 Spri-mitatio-nt |
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| EBeast |
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ok, so the air going in is cooler, but with a reverse facing scoop, can you get as much air in as with a front facing one?
ie, would there be more air being sucked in because the air is colder (reverse scoop), or more air sucked in (at normal temp) because the scoop faces forward, and your driving at 60kms? i think that makes sense, let me know if i need to re-phrase it.
_________________ 1993 EBII GLI, IT'S PERFORMANCE Stage 3 engine,
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| twr7cx |
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animal_ef wrote: sounds like option 2 is set up like a wrx
that looks like an intercooler to me on the WRX not a filter! Option 2 would be my way to go. I've often wondered about whacking a pod straight onto the throttle body and a reverse scoop. but the shortening of the intake piping might cause issues. the other thing to consider if you might be going to all this effort and money for f**k all gain when a nice simple 3" piping, ticky snorkel, 2nd CAI through to the brake duct and high flow pannel filter may satisfy you... |
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| twr7cx |
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EBeast wrote: ok, so the air going in is cooler, but with a reverse facing scoop, can you get as much air in as with a front facing one?
ie, would there be more air being sucked in because the air is colder (reverse scoop), or more air sucked in (at normal temp) because the scoop faces forward, and your driving at 60kms? as far as i know ram air induction requires very high speeds to actually be worth anything - like 250km/h plus, so in that sense a forward facing is no better advantage. the other thing i see is that both will probably provide more than enough air than your engine takes in... |
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| MadMatt |
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A forward mounted scoop on a WRX is to force air into the intercooler. It is not an air intake for the engine. A forward mounted scoop would build up too much pressure when off the throttle ie. at a constant speed. That would not be good at all. Have you thought about moving the battery to where the air box is and vice versa (I take it that you have an EF style throttle body setup on it). Run a near straight pipe to the air box and duct a cold air intake from the front bar. No ugly scoop then.
_________________ Member Number 8804 |
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| EBeast |
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matthew5772 wrote: A forward mounted scoop on a WRX is to force air into the intercooler. It is not an air intake for the engine. A forward mounted scoop would build up too much pressure when off the throttle ie. at a constant speed. That would not be good at all. Have you thought about moving the battery to where the air box is and vice versa (I take it that you have an EF style throttle body setup on it). Run a near straight pipe to the air box and duct a cold air intake from the front bar. No ugly scoop then.
if a front facing scoop caused that much trouble then why are they so poplar? and umm, err, ok, here it goes... what's a CAI? and what advantage are there having two of them?
_________________ 1993 EBII GLI, IT'S PERFORMANCE Stage 3 engine,
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| ElwoodBlues |
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matthew5772 wrote: Have you thought about moving the battery to where the air box is and vice versa (I take it that you have an EF style throttle body setup on it). Run a near straight pipe to the air box and duct a cold air intake from the front bar. No ugly scoop then.
The intake would get way to hot over the extractors/exhaust thus reducing any benifit or so i would guess
_________________ EF Futura factory 5 spd
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| twr7cx |
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ElwoodBlues wrote: matthew5772 wrote: Have you thought about moving the battery to where the air box is and vice versa (I take it that you have an EF style throttle body setup on it). Run a near straight pipe to the air box and duct a cold air intake from the front bar. No ugly scoop then. The intake would get way to hot over the extractors/exhaust thus reducing any benifit or so i would guess Possiably at idle. But think about when the car is in forward motion that probably wouldn't be an issue. Fit a vent above say where a Tickford did on the EF/EL XR's and you should be fine as the hot air rises and would go out... The pipe going over the exhaust may still get hot, but that is not much different to the pipe going over the hot rocker cover now is it! And you can fit a heat shield! |
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| twr7cx |
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EBeast wrote: matthew5772 wrote: A forward mounted scoop on a WRX is to force air into the intercooler. It is not an air intake for the engine. A forward mounted scoop would build up too much pressure when off the throttle ie. at a constant speed. That would not be good at all. Have you thought about moving the battery to where the air box is and vice versa (I take it that you have an EF style throttle body setup on it). Run a near straight pipe to the air box and duct a cold air intake from the front bar. No ugly scoop then. if a front facing scoop caused that much trouble then why are they so poplar? and umm, err, ok, here it goes... what's a CAI? and what advantage are there having two of them? CAI is Cold Air INtake, advantage is that cold air particles are smaller, so your getting more air in same size package when compared with air of a hotter temperature... If you've done cemistry, then you'll relise that petrol particles need X air particles for the combustion process, so more air particles in the engine, more potential for more petrol, potential for larger combusion, resulting in more power... I can't think of any cars - there's not many cars standard that have a front forward facing bonnet scoop for induction. Old XY or XW Falcons GT's or something had a smaller one, some of Chrylser Chargers did too. But these days, int eh case of the performance Territory, and WRX's, etc. the forward facing scoop is for the intercooler, the air flow over that lowers the temperature of the air in the intake piping... |
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| playswithnitro |
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Cold air makes power.
Here's a good way to keep underbonnet heat out of the intake. This stuff works well. Thermo Tec Cool Air Tube Heat Shield. It goes over the CAI tube and the laces let you tighten it up. For the colour co-ordinators, they supply it with red, yellow, blue and white laces. Comes in 3-foot lengths. Have a talk to Rocket. I was quoted $80.
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| loopism |
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EBeast wrote: ok, so the air going in is cooler, but with a reverse facing scoop, can you get as much air in as with a front facing one?
ie, would there be more air being sucked in because the air is colder (reverse scoop), or more air sucked in (at normal temp) because the scoop faces forward, and your driving at 60kms? i think that makes sense, let me know if i need to re-phrase it. The reason rear facing scoops are better for under-bonnet temps is because as the car moves forward, they create a low-pressure area under the bonnet, effectively sucking more air in - and letting that hot air out again.
_________________ I'd give my right arm to be ambidextrous |
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| EBeast |
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what problems would i have with not having vrey much pipe to the throttle body? and what problems 'pressure' would i have with a front facing scoop?
_________________ 1993 EBII GLI, IT'S PERFORMANCE Stage 3 engine,
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| BJM |
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Having a rear facing scoop would be the way to go.
When a car is driving you get a low pressure area at the front of the bonnet so having a scoop there will actually work against you. 
As the attached airflow moves over the bonnet it comes to the base of the windscreen where it is forced to change direction. This change of direction creates a high pressure area at the base of the windscreen. Rear facing scoops take advantage of that pressure, making it easier of the engine to breathe the cooler air (effectively forcing the air into the engine at low pressure). 
I am yet to see any production car that comes with a forward facing scoop being used for air intake. Yes the WRX uses a forward facing scoop but that is only for the intercooler. The situation is the same for the Pulsar GTiR and Celica GT4. If you're really interested then here is some recommended reading: Undertrays, Spoilers & Bonnet Vents, Part 1 Undertrays, Spoilers & Bonnet Vents, Part 2 Undertrays, Spoilers & Bonnet Vents, Part 3 |
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