raised bonnets

[tony k]

anyone got anypics on raised bonnets was gonna do it to mine but want to have a look at some first

[Leeboo]

There was a thread before but I can't see it in the search.

Why not try it on your car regardless - wooden blocks and longer screws between bonnet and bonnet brackets just to get an idea!

[Stoo]

why?

[Leeboo]

Perhaps to allow hot air to escape from under the bonnet.

[burgo]

Perhaps to allow more cold air under the bonnet.WRONG!!!

[burgo]

Perhaps to allow hot air to escape from under the bonnet.

still wrong lol

[Leeboo]

Edited for the better!

[Leeboo]

Me - OWNED!!

Enlighten me please

Edit - sorry for the hi-jack, your thread never asked 'why' a bonnet should be raised.

[John]

'cos it looks good?

[Leeboo]

Ah, just remembered, the reason a bonnet should be raised, is so that air can flow through the engine bay, however this might not work very well unless you remove the bulkhead.

Back on topic:thumb:

[burgo]

lmao in theory leeboo you would think that would be the case. guess what, your wrong lol

http://www.msprotege.com/forum/showthread.php?t=100489

go down to post 13 and hopefully that should explain how raising the back of the bonnet wont let out any hot air

as for pics
http://i12.photobucket.com/albums/a226/sclurgess/nova98.jpg?t=1203365050

slight raise to clear the master cylinder lol

[tony k]

i have removed the bulkhead forgot to put that in oops

[Leeboo]

Thanks burgo, I had seen a thread ages ago about it and from that thought it was for cooling aid.

[burgo]

most people do leeboo and with some modifications i think it could be made to draw air from under the bonnet but just raising the bonnet wont help and in fact more than likely hinder

[Jim]

Search the user 'dhdev'. I think he's raised his bonnet.

[RSTChris]

I found after raising the bonnet on my old Fiesta RST it made quite a lot of difference to running temps, i only did it at 1st so the bonnet would shut

Pics here:

http://s64.photobucket.com/albums/h175/chill-ebay/White%20FRST/

[BenNova]

was thinking about rasing my bonnet when i have carbs on? is it not a good idea then ?

[Jack]

So according to the link that Burgo posted, air pressure at the back of the bonnet (base of the windscreen) is high pressure, where as at the front is low pressure.

For improved airflow across the coolers at the front, fit a vent near the front of the bonnet.

For improved airflow to inlets at the back of the engine, fit a scoop near the back of the bonnet.

Fitting a vent at the back of the bonnet (or raising it) in theory won't allow airflow out from the engine bay due to the pressure on the outside of the bonnet at that point is higher pressure than under the bonnet.

[lj]

i've done this on track days with also removing head light and not sure it made any difference, but i had 30 AND 40 MM spacers made to sit inbetween bonnet and car, now removed them as it started to split the bonnet from mounts! ops!


http://i13.photobucket.com/albums/a256/leezarins/leesloadedpics2519.jpg

[andy_srt40]

if you remove the bulhead yo lose the high pressure area under scuttle panel due to the fact the air pushes up out of the vents in the scuttle and up over the windscreen, to make it effective you nee a failry big gap to counteract the high pressure scenario

on a further note, if you have a cone filter and angle the pipe to the bulkhead cut a hole and have it where the battery should be then you benefit from the high pressure forcing the air in to the filter ;)

[trackdaynova]

i did tests on this on my white nova and it certainly does drop the inlet temps (engine bay temps) considerably.

First off when I had my throttlebodies, I had a thermometer sensor stuck to the baseplate of my bodies in between pots 2 & 3, so it could accurately read the air temps thats going in the engine

with bonnet fully closed, and firewall in place, after 25mins driving at around 8pm at night, inlet/ engine bay temps were reading 51 degrees constant and remaining

i then removed my firewall, and it allowed more air around that area, so again, 25mins driving, around 8pm at night again, inlet temps were 39deg

then i jacked up the back of my bonnet, and did it again, it came down again to around 29 degrees, which explains that there isn't much flow going in AND out, so alot of warm air was still being held in the bay

then finally added a monteray bonnet vent, and did it again, and it was then literally 3degrees above ambient, circa 17deg at the time of year, reason being was because now air had an even easier way of escaping, more cold air could enter the bay, and so on...

it all makes a difference, you shouldn't have to explain yourself when carrying out mods to your car, if you want to do it, do it, try it, if you dont like it, or it doesn't work how you wanted to, remove it - simple.

still gets me how everyone needs a reason as to why you want to do something to your car.


anyway, as for pics:

http://www.migweb.co.uk/forums/attachment.php?attachmentid=2016&d=1122324819

you can see the 50mm spacers here, with longer bolts

http://www.migweb.co.uk/forums/attachment.php?attachmentid=2019&d=1122324819

[Leeboo]

'cos it looks good?

I think you have got me wrong, I was trying to point out that t's novat shouldn't have to give a reason for his modification. Some people feel the need to ask why.