meintag's 360 photoshoot !

Post by **Nikdev** » 10 Mar 2008 06:28 am

meintag wrote:
I decided then to raise the bonnet a bit... Some extra cooling is good when you spend 1 hour of abuse in 2nd gear ! Very easy, just adding some nuts and washers to bonnet retains and a longer stud !

Raised bonnet it don't help the cooling a bit..Because of airflow and some other yada yada yada.. Just ask the guys on driftworks, they are all against raised bonnets

I want those wheels

You haven't lowered it any at the back?

Post by **Fuse** » 10 Mar 2008 06:46 am

Well.. Our GL Turbo had a scoop with the opening at the windscreen side. Mostly because the hood wouldn't have closed without the scoop, because the plenum was on the way. But anyhow it had much lower underhood temps than my GLT Turbo has. When the engine was running the airflow through the scoop was significant. Though of course if the opening isn't on the vacuum area, there might not be any airlflow. Might be the case with the raised bonnets?

Post by **Jason B** » 10 Mar 2008 11:52 am

fairly sure raising the back of the bonnet ought to increase airflow! not actually ever tried it, but it seems logical just by looking at it

Post by **Chris_C** » 10 Mar 2008 12:01 pm

Since when has aero ever ever ever been logical

Post by MJ » 10 Mar 2008 12:49 pm

I thought the drifters used to pop the bonnet to the second catch to aid cooling...

It seems logical, but as Chris says, aerodynamics aren't always logical

You'd think that at very low speed, the gaps would allow the hot air to rise out, and I've been tempted to to that on occasion when stuck in traffic on a hot day with the temp needle leaning too far to the right. Actually when I cut the engine (but left the ignition on) the temp kept rising.

Is that just because of the location of the sensor, or would it actually be better to keep the car ticking over, and the water pumping, if the engine gets too hot? Answers on a postcard...l

Post by **Chris_C** » 10 Mar 2008 01:27 pm

It's a lot better to leave the engine on, else all the hot water stays in the engine, and can't get to the radiator to be cooled, and new cold water can't get into the engine! As soon as the engine stops, the waterpump stops, even though the electric fan might come on, thats pretty useless as the hot water is in the engine, not the radiator where the fan points at!

Do you remember when we were at Haynes, and after I'd been on the track I left the engine of Fake on for about 10-15mins to soak the heat out of the engine, was for that reason.

Only time you wouldn't is a hose leak, as the water wont be flowing.

Post by **Jason B** » 10 Mar 2008 02:05 pm

well, I know aero isn't logical (I have done a few fluids modules

) I was just trying to keep it simple for a bit

While the reality is a very complex system, the main principles of mass flow apply. If you are driving along then air should be entering the engine bay through the grill etc (and underneath the car to a lesser extent). Therefore by raising the bonnet at the end near the windscreen you are creating a path of lesser resistance for the net mass flow of air entering the engine bay (largely ignoring compressibility as in reality the air will reach and maintain an average pressure within the engine bay). The problem becomes more complicated if you consider that by raising the bonnet, the possibility of causing more immediate boundary layer separation (as flow passes over a shear drop near the windscreen) will increase. Hence creating a region of turbulent eddies around the gap that we wish the air to flow out of the engine bay through.

I'd still think that raising it a bit ought to help and may even try and test it sometime, but tbh my temp gauge has never gone above 1/2 anyway even when being absolutely thrashed for 90+ miles

Post by MJ » 10 Mar 2008 05:05 pm

Ah yeah, I remember that.

It's just when your stuck in a jam behind an accident in the mid summer sun and have no idea when your moving again, the temp needle is leaning right, the electric fan is on and you've got the heaters on full blast to help, it just feels wrong keeping the engine on. But yes, I see the point, I'll remember that next time I'm in a similar situation.

Why don't they invent electric water pumps to keep cooling the engine after you've stopped...

Post by **SteveP** » 10 Mar 2008 05:16 pm

The temp needle shouldn't lean right

Both of my 360's sat practically dead centre in the hottest conditions possible in jams in the UK and never get any higher. Although with an electric fan I expect the temperature to fluctuate a little more with the fan coming on/off I suppose.

You can get electric water pumps, common mod in the Skoda tuning scene where they tend to eat head gaskets for a living in rear engined cars

Post by MJ » 10 Mar 2008 05:38 pm

Of course the needles normally vertical, but ours leans a bit to the right in the hottest stationary traffic. Not very far right, but noticeably off vertical, even with the cooling fan on and heater on. Whether that should be the case or not I don't know, but it only happens a few times a year...

Post by **Jason B** » 10 Mar 2008 05:43 pm

not too much to worry about then by the sounds of it

Post by **germ** » 10 Mar 2008 10:23 pm

you dont have to worry about it aslong as it doesent go any further or at a quick rate, worry more if it touches the red... which should never happen.

Post by **Jason B** » 10 Mar 2008 10:26 pm

which is strangely enough, the opposite to the econometers which should always be in the red

Post by **meintag** » 10 Mar 2008 11:43 pm

What a thread hijack !!

Back to the raised bonnet question, my experience with a Polo G40 was a engine bay WAY cooler with the bonnet raised a bit, and I was worried about airflow at high speeds and the car reached 230 kph !

I'll try and if it become worse, turn back, like everything in the life ! haha

I'm glad you like it !

Regards !

Post by **Frits** » 11 Mar 2008 12:19 am

Good work there! Sexy car. hehe

I think I'm still gonna chop the front springs, aint got money