Potential market for Gen IV bonnet vents

Nearly everything is in here to start with.
If it's about your car, or Subaru's in general, put it in "Subaru Chat".

Re: Potential market for Gen IV bonnet vents

Postby Stifull » Thu Dec 22, 2022 8:28 pm

I think on a turbo model that it would look good with the same positioning/distancing etc as the gc8s have theirs, just to bring back that famous look that had them standing out all those years ago. I'd be up for that and somehow have them secured from the inside so the rivet could be done away with to get completely away to an aftermarket look.
Current Subarus
07 Liberty GT (mine) 180kwt on 16lb
98 WRX Club Spes 2 with 2.5ltr upgrade(mine) sub 14 sec
99 Ver 6 Sti also with 2.5ltr upgrade (son) sub 14 sec
02 WRX Bugeye Hatch lots of goodies(wife)
09 Non Turbo Impreza(daughter#4)
98 GC8 WRX Hatch(daughter#1)
02 Bugeye WRX (daughter#2)
User avatar
Posts: 387
Joined: Sun Nov 18, 2018 11:30 pm
Location: Brisbane
Car: '07 Liberty GT '98 WRX CS2 2.5ltr

Re: Potential market for Gen IV bonnet vents

Postby Yowie » Fri Dec 23, 2022 8:00 am

Now, empirical data:

@ 30°C ambient temperatures, max water and oil temps, whilst sitting in traffic, rise to mid nineties: I've seen 94°C for water and 96°C for oil. It doesn't rise beyond this. Looking at traffic through a column of heat haze is very satisfying. Under-bonnet temps rise to over 50*C (my gauge's max for these two sensors) sitting in traffic too, but cool to low forties when travelling at 60kph for a few minutes. Oil and water cool to low-to-mid eighties when travelling at 60kph for a few minutes, too. The under-bonnet temps used to climb into the 50+°C range and never return under all conditions prior to fitting the vents. I have noticed that 60kph is the minimum speed to start to reduce temps. This must be when the Bernoulli effect starts to draw air out through the vents properly.

I can confidently say that my rig is now Queensland-proof as far a general heat management goes 8)

As far a water management goes, the vents ended up sitting further forward than I had feared and only expose the very front of the power steering pump, alternator and A/C compressor. It essentially has the pulleys and drive belt exposed. One day, whilst parked at work, it drizzled all day and the water ingress was as expected, but to very little detrimental effect. It started up just fine. One pulley had a tiny smidge of surface rust on it that the belt would have eaten quick-smart.

This is pretty awesome by the way.

If you want a cheap sensor or two with more range, consider a mid-priced digital multimeter with "long cable" (separate purchase?) K-type thermocouple temp probes from Jaycar or similar. You could zip-tie the probe wires in place in different engine bay locations during the experimentation period.

Regarding water ingress, is it practical to attach little deflectors so (when the car is parked) rain isn't dripping on the engine accessories?

Great work though - please keep putting up pictures, details & results.
User avatar
Posts: 523
Joined: Tue Jul 21, 2015 10:05 pm
Location: Brisbane
Car: SH Forester XT

Re: Potential market for Gen IV bonnet vents

Postby montyLalor » Thu Jan 05, 2023 2:00 pm

Tonic wrote:Yes looks good. For aesthetics another pair towards the windscreen and a similar distance from the fold would might (at least) look better but may also get more of the hot air out from around the back of the engine? Not much electronics under there being just inside the shock towers?

I'm not 100% happy with the placement & shape from a purely aesthetic point of view. It's a compromise I'm happy to accept, though, given their performance.
Stuck behind those that maneuver with the eloquence of a fiery wall of disintegrating fuselage...
User avatar
Posts: 36
Joined: Fri Nov 23, 2018 11:17 am
Location: Logan City, Queensland
Car: MY09 BLE 3.0R Spec B 6MT 32Jobp
Real name: Luke

Re: Potential market for Gen IV bonnet vents

Postby Taj » Sat Jan 07, 2023 9:53 pm

Hey good on you for following through!

Bonnet vents are always a good idea, and yours are well placed.
The best spot is right above the 'gap' between radiator and engine - pretty much exactly where yours are.

Don't worry about rainwater, unless you have shitty wiring plugs that have perished seals or something, you won't have any electrical issues. And like you mentioned, any rust on pulley ribs etc. will be wiped off quick-smart, just like brake rotors that have been sitting on rainy days.

I think they look good!

Here is what I've made out of an Outback bonnet for mine. On the rain thing, mine are directly above the fuel injectors and their connectors - no issues and it's been on there for probably almost 3 years.
Screen Shot 2023-01-07 at 10.48.38 pm.png
Screen Shot 2023-01-07 at 10.48.38 pm.png (239.03 KiB) Viewed 135 times
2007 3.0r Spec B Wagon "FWD911"
GT3582R turbo setup +/- 300awkw
PB: 12.04 @ 120.2mph (Sydney dragway 3/2/21)
(Built engine in the works)
@taj.fwd911 on instagram for more!
User avatar
Posts: 23
Joined: Tue May 10, 2016 6:47 pm
Location: Sydney
Car: MY07 3.0R spec B Wagon


Return to General Chat

Who is online

Users browsing this forum: No registered users and 1 guest