Hello all,
I need a set of the blank off plates that fit underneath the 2 bonnet vents on a MY00 Classic shape.

I would be willing to pay a reasonable fee (no rip-offs please!) for a second hand set + postage to South Africa.

Problem here is that there are none available as there are very few classic shapes that are accident damaged or get written off

New they are horribly expensive. My car came without them and from what I have read its not a good idea

please contact me directly on thwane@spg.co.za

Thanks

 

Can you not make some up yourself?

 

Not really as easy as it seems, they have a pretty funny shape + I prefer the original look under the bonnet

 

Grade A Subaru or similar breaker any use?

 

Just curious, what is so bad about removing the blanking plates?

 

Nothing like that in South Africa mate, I dont mind if they come from a smashed car as long as they are in 1 piece

 

Apparently it affects the airflow in the engine bay, plus it allows water in

 

Water is the main issue with one vent being over the airbox or induction kit (if you have one) and the other over the battery.

Its actually more efficient to keep them off if your climate allows.

 

I've taken the one off over the airbox and the heat that escapes is amazing...thats got to be good thing!?!

 

Absolutely.

The cooler your engine compartment, the more efficiently it will run.

This is better demonstrated with induction kit users, where the cone sucks in air from the engine compartment which is usually very hot. The more hot air that can escape via the vents will give an overall cooler temperature which will help with the induction.

Cooler air = more power

 

Good theory but all the hot air is being dragged straight past the induction kit resulting in higher intake temp.
This was proved by someone a while back using a temp probe

Pitzi - i'm sure Grade A will send them to you if you ask nicely

 

How do I contact A-grade?? Is it a scrapyard or what??

 

Surely by allowing the hot air to dissapate from the engine bay, the overall temperature is going to be cooler?

Plus, there is already a direct cold air supply directed straight at the induction kit from the front of the vehicle. (inner wing plastic pipework from o.e. airbox) This cool air is unobstructed prior to being sucked in by the cone.
Not to mention if you add some extra piping from the front of the vehicle aimed straight at the induction kit then you have a direct supply of freezng cold air for it to suck in. This is not affected by the hot air in the engine bay.

Grade A Subaru Link.

 

Harvey did some measuring on this a while back. He said if you remove the plates on a std car, then it's enough to disrupt the flow of air across the engine and will lead to increased temps and hot-spots. He reported that the air is sucked out the vents and not allowed to flow over the engine and out through the transmission tunnel.

Stefan

 

I believ there are some on Ebay right now.

 

The how come so many cars have "operational" vents if they are not productive?

I am perhaps not as qualified as Harvey, but I find it hard to believe that air escaping from a hot engine bay would be enough to cause performance detrimental "hot spots".....

As far as I can see, hot air escaping can only be a good thing. Think of all the cars with functional bonnet vents over the years... surely they can't all be wrong and Harvey right?

 

iam getting some made in carbon if u fancy them m8

 

You got a link mate??

 

How much they cost mate??

 

Thats exactly what I have read, in australia they strongly recommend that you do not remove them as it raises the underbonnet temperatures by quite a bit, thats why they are blanked off in the first place

 

I think the story is different when you use them mini scoops as air is being forced in as opposed to being sucked out

 

Talizman,

Hot air escaping is a good thing, but it's escaping from the front of the bonnet and is preventing some air flow over the rest of the engine.

At the end of the day, Harvey says he used proper measuring gear to see if it was worth it or not. He measured increases in under bonnet temps, not lower. It goes against common sense, but very rarely has common sense proven scientific measurement to be incorrect

Harvey's on 22b.com if you want him to explain his findings.

 

Yes, that's why I mentioned that Harvey recommended against it on a standard car. If you remove them then you should take measures to increase cold-air under the bonnet. Some mini-scoops would be a good start.

Stefan

 

I did quite a lot of work measuring under bonnet temperatures and throttle body temps.
On a standard engine bay layout or with a cone filter only the effect of removing one or other or both blanking vents is to increase temperatures to such an extent it is quite noticable.
These are there on a standard car to allow for removal on rally cars and comply with regulations but the breathing layout is different.
The area above the vents is a low pressure area at speed so air is sucked out and there is no facility for ambient air to go in, unless you were to fit a forward facing scoop.
If you were to build an air box and segregate the filter area from the rest of the engine bay and get a positive air flow into the air box area then it would be worthwhile removing that blanking plate only.

The worth or otherwise of an open vent will depend on the design, model to model and the layout or the way the owner has already carried out other mods.
If the car would perform better in standard form with the vents open why do Subaru leave the plates in place?
Don't take my word for it. You can start with a couple of min/max thermometers from a garden centre and devise a test programme but my test equipment was a bit more sophisticated and comprehensive.
On the STi 6 Wagon I have the driver side vent removed because I have a segregated air box with positive feed but the WRX has both in place.
See here: www.geocities.com/harveysmith3000.

 

"On the STi 6 Wagon I have the driver side vent removed because I have a segregated air box with positive feed but the WRX has both in place."

Newbie question...whats a segragated airbox ? Let me rephrase that how do you go about segragating the airbox?

Cheers,
ian

 

I hillclimb my WRX and a fellow competitor does so in his RA.

He is adamant that his car runs cooler with the vent covers off rather than on although whether he has any proof of this I don't know.

In addition to removing the vent covers, he has also removed the plastic undertrays and uses iced water in his water spray, all of which he says reduces the temperature and increases power.

 

*btt*

 

Pitzi
not sure on a price just yet i can get a ruff figure m8 if u want that

 

Thanks mate, mail me at thwane@spg.co.za