Sunday, February 8, 2009

Vents for the bonnet of a VP SS sedan

Obviously it's not only Bolwell people who read this blog. Here's a young person, Kelly, who has written in asking for advice on underbonnet airflow for his VP Commodore. I'd better be careful when I say "young person" but based on what takes place around where I live, I always think of VNs and VPs as manditary equipment for younger drivers. In Kapunda, when someone turns 16 or 17, they automatically acquire a VN V8. Most of them lavish TLC on them and are extremely proud of them. There are exceptions, and when the next one rolls over I might be in for a new set of mechanicals for a Nagari project. Anyway, I digress as usual. I thought I would print Kelly's email here for all to read, to invite comments from people with far more knowledge than I have.

Hello John,
Sorry to bug you.
Wondering if I could get some advice for my Commodore?
I noticed a huge difference in engine temperature with a bonnet open, but unfortunately you can't drive bonnetless on a government road :)
My car doesn't overheat, but being a usual v8, it runs almost half on the guage. I'd like to get the air out quicker as there is no way for air to escape besides underneath.
I've read a bit on aerodynamics and wouldn't want to cut a hole in the wrong place - and I don't have many tools to start right now. Do you have any advice on where I should put the vents?
I atteched a rough picture of the front to show you how there's no ventilation.
Thanks for taking the time to read, From Kelly.

2 comments:

John L said...

Chris G writes:-
"With Kelly's comment I just wonder if it is worth pointing out that in most cars the midpoint on the temperature guage is the optimum temperature and to run it too cool is not necessarily a good thing. Kelly may be best off getting a narrower number plate so as to not obstruct the top centre inlet as it does at the moment and leave the rest alone.

Other than that I thought the item you showed on the Bolwell with the little vents in the rear corners of the bonnet was pretty neat. Then if Kelly gets really serious and flat bottoms the car the outlets will still work. An approach a la Abarth is another option with the bonnet permanently opened a small amount. That could be tried as an initial approach to see what gains are made."

John L said...

What about adjusting the bonnet hinges so that the back of the bonnet is raised up a bit. That'd do it.