When i got my car a few months ago it came with these bonnet raisers on it and was told they actually help with underbonnet temps?? Never really liked them and due to the following reasons took them off today.

*Never see high powered cars running them

*Get fed up with people saying "your bonnets not shut properly mate"

and finally *when you wash the car water gets in everywhere under the bonnet

But was wondering do they actually work keeping temps down and does anyone run them with a high powered car?

Have put a poll up to for people who are 'for' them and people who are 'against' them.

 

Might be worth having a word with Simon smail at Sitech, reading an article in fast ford about his late S2 he seemed fairly clued up on what does and doesn't work with regards to engine bay cooling on the S2's.
Think some little flaps on the standard air intakes that disrupted the air flow causing an area of low pressure wihch helped draw warm air out of the engine bay work ed better than a raised bonnet IIRC

 

dunno if they help anything but they look fucking gay.

sweet motor though kid

 

lol i love the honesty in that answer, so i take it you voted 'leave them on' lol

 

they aid cooling but they let water into the engine bay and let the weather in if ur botherd about appearence, for example whenever it rains or u jetwash it.
but i think they look pretty cool.

 

You can just about see what i'm on about in this pic, infront of the bonnet vents:

 

Most engine bays are designed to output the hot air underneath the car though the bottom of the engine bay (low pressure area). Bonnet raisers ruin that and mess the whole thing up.

 

Now these dont look so bad as are more discreet.

 

your bonnets open mate

 

i think tehy looks good tbh, god knwos if they help cooling though

 

It aint a Renault 5 it dont open that way lol

 

they help with cooling but there are for better methods imo

and i dont think they looked right on your car

some cars look good with them but some dont

 

fuck them off,i had them on my old one briefly and got sick of being told my bonnet was open

 

Nice car, but can not stand bonnet raisers, look shite.

 

i've heard that they can make the cooling worse, as the upset the designed airflow of the engine bay, the same way misplaced bonnet vents can.

it may help on some cars, its all to do with who you believe imo.

 

superchavtastically gay, imo.

 

on my 5, which hinges at the front,
i didnt close it properly one day, and at 50ish mph the bonnet raised itself at the back, so i assume at that speed and over it will let air out, and again i assume its hot air as hot air rises.
so i would say, yes theyre functional.
im going to make a way of getting mine like it.

but if youve not got heating problems and dont like the look then take em off.

 

They're definately functional and do make a difference in my experience....don't have an issue with temps on the road but on track mine tends to be getting too hot by the end of a 20 minute session......tried bonnet raisers last year and definately noticed a difference. As said though pain in the ass when washing the car and had loads of people telling me my bonnet was up

 

tell ya straight me me man

 

Thats my experience as well mate, hate the looks but they do seem to work

 

Will see if the under bonnet temps are any higher now ive taken them off then,if so will need to come up with another way to get the hot air out.

 

they look shit

 

I think it depends on the look of the car tbh

 

My friend had quite a big spec and was worrying about heat etc. So he had bonnet raisers and the ammount of heat that was escaping turnt his radiant red scuttle panel pink in a few weeks!

So I suppose it shows that they work, just a shame they look pants really.

 

Yes they do....























they make you look like a right CUNT FLAP

 

on mine you can really see the heat coming out from the now gap, and it runs a hell of alot cooler. they do work!
i agree some cars they dont look good on but some they do. its all personal preference really like everything, each to their own aye. plus some cars need to have them out of nessesity (i know i spelt that wrong) because of the engine and or pipework to clear under the bonnet, zvh in a ka for example.

 

I found on my old S2 that the temps were lower with the raisers on. As you said I got fed with with people telling me my bonnet was open

 

I must admit when the engine does get hot you can see the heat vapour coming out of the gap and up the windscreen.

 

And oil when you blow the engine as I found out with the Gooon

 

Its not a surprise you can see heat vapour coming out when you're stationary.....but of all the peeps saying they make a difference has anyone actually taken a log of measurements to prove it, as personally I doubt they do much on the move.

 

Fucking Hell I've missed you Dave

I ran them briefly, ime they did seem to aid in keeping the underbonnet temps down a little but to be honest when I put a new rad in that cured the problem anyway so the raisers were filed in the skip

 

when your moving how cant it possibly make the car cooler? hot air will NOT exit there.
at the back off the bonnet is an area off high air pressure, air enters there when moving not escape.

 

Yeah, if the car looks shit it stays looking shit.

 

Easy way of telling is simply stick a temp probe in like a AIT gauge and see if it makes any difference.

Something to consider though, by exactly how many degrees do those fucking queer things actually keep cool by and secondly the engine itself probably won't be kept cooler but the outer casing and head may lose be kept cooler by a few degrees. In the grand scheme of things is that going to make any difference. IMHO if you need better cooling get a bigger rad, decent hoses, decent cooling fans, decent coolant fluid and if you must quick opening stat and wire fan to cut in earlier.

 

just a theory but has anyone put fans underneath the bonnet vent's would this aid cooling at all is there enough room surely it'd be better than relying on convection to pull the hot air out?

i may get shot down for this reply never owning a rst but its just a general question .

 

Fucking gay. Bin them!

 

 

you could remove the lower part of the bumper and allow more airflow in (the bit under the main centre span) smooth out the edges etc ...

 

Not a fan of bonnet raisers.

 

This is one mod i will be doing as its fairly simple and as you stated allows more air to travel through