Help needed - under bonnet temps too high!

[someonestolecc]

I opened my engine bay yesterday and put my hand on my air filter. It was hot to touch.. infact uncomfortably hot.

That's THROUGH the darn air shield. So my plan is-

1- heat tape wrap my inlet pipe (as it's metal it probably soaks a lot of heat)

2- re-do my air shield so it's more heat resistant and air tight

My questions are-

I have a cheap chinese style stainless manifold - if I wrap this I heard it may brake, I have a smaller type (x force) dump pipe that then goes into what I would call the front pipe, which leads into the cat.

Would there be any benefit in wrapping the length from just after the dumppipe, to the cat? or should I just wrap my stainless manifold?

If I make a custom heat shield of some sort to keep the heat away from the rest of the engine by basically sitting in front of the extractors/turbo, will I risk damaging anything by concentrating the heat in that area?

The car is a sr20 cefiro.

Thanks.

[R31Nismoid]

If I make a custom heat shield of some sort to keep the heat away from the rest of the engine by basically sitting in front of the extractors/turbo, will I risk damaging anything by concentrating the heat in that area?

this is the ebst option.

wont break anything.

will stop the transferrence of heat a great deal and reduce temps a reasonable amount.

mine makes a massive difference

[someonestolecc]

Any other suggestions?

Is getting a bonnet vent cheap?

I'd like a low key one so not a scoop but a vent, ie somesort of meshed cutout at the rear of the bonnet as to draw hot air out over the windscreen?

Either that or one of the sunken in vents that sit just after the radiator, but i think those are more to get more air through the radiator right?

Cheers

[Oosh]

putting a vent in is as cheap as cutting a hole, making it look half decent is another matter, try the heatshield option first.

Something I've seen the japs do which MIGHT be effective, albeit a bit dodgy looking, is to get slightly longer bolts to hold the bonnet hinge to the body and chuck some washers in between to space it up a bit.

[Gary2]

Raising the back of the bonnet is an old trick that does work but don't go the washer way as the bolts will come loose but make up some small blocks one for each side I have tried this and it enabled me to run a car with no fan.

I'm going to do this to my Stag but first I will try 1 inch and then go from there to see how much of a difference it will make.

Give it a go as it dosen't cost much.

Gary

[someonestolecc]

Thanks for the suggestions - This is something I've always thought of doing as I've heard that the lowest air pressure on a car is in the middle of the windscreen - so raising your bonnet is a great idea from that perspective.

One thing that someone did mention that put me right off the idea is that when you're in a crash the bonnet won't crumple, instead it will go straight through your windshield and probably hurt you.

This is the only reason I haven't done this.

[MANWHORE]

cc, i'd have to agree with you. I've read an article...can't remember where off the top of my head.

basically, the results were 2 degrees cooler oil and water temps doing "normal" driving.

they also highlighted what you said. at the back of the bonnet, there's a latch, such that if the bonnet is hit, it's locked in. the only way it can move is to bend up in the middle. when you raise it, it's not latched in, but rather gives you a nice haircut, or a headcut for some.

[MANWHORE]

I like the idea of that heat shield too, as it's not really concentrating the heat in the manifold or dump, it's just preventing it from heating up your intake etc.

If you do go ahead with it, can I watch you make it? coz i wanna make something similar too. I am on a uni student's budget though....unfortunately.

Another idea that I was thinking of doing with that mod too. you know how on the rb25, the intake pipe crosses right over the engine. It gets ****ing hot - above the coilpacks. I was gonna wrap it with that flashtac shit. It's at bunnings. there's a how to guide on here somewhere.

[Sydneykid]

This topic gets raised at least once a week, a search would give you all of the answers. To save time....

The air travels though the pipe work so fast it doen't have time to get hot. Just because the pipe is hot, DOES NOT mean the air inside the pipe is hot. There is insufficient contact area inside the pipe, do the numbers.......

5,000 rpm X 2.5 litres divided by 2 (it's a four stroke) X 2 (1 bar of boost) = 12,500 litres per minute.

Rule #1, feed sufficient ambient air into the air filter, keep the hot air out.

Rule #2, wrap (or ceramic coat) the exhaust, EVERYWHERE all the way back to the cat

Optioanl rule #3, a turbo blanket can be a good idea on larger turbos

PS; if you have a thin walled exhaust manifold, ceramic coat it on the inside and the outside

[someonestolecc]

Thanks typeM and S-Kid.

Looks like bonnet thing is out for sure.

As for the wrapping I think my manifold would crack ($300 stainless jobbie) although this would be the nicest thing to do in my mind.

I have read your other posts S-Kid in regards to this - most of those threads seem to be directed at reducing certain parts of the engine. I'm not actually worried about the intake temp through the pipe, because of what you've said.

I was going to wrap it because I believe the pipe heatsoaks and warms the AFM and the pod, simply because it's metal. This won't be because of the air inside.

Similarly the heat shield would be there to keep heat away from my wiring, ignition module, ebc solenoid (yay) and pod.

Lastly the actual pod will now be fully partitioned off and the aim will be so it will also be fully air tight to the engine bay when the bonnet is down. But still be able to have ambient air from the gap in the engine bay, the headlight and mostly the CAI pipe from under my spoiler.

If I win the lottery I'll be having an aluminium bonnet made up and when that happens I will be grafting an M3 styled vent at the top of the engine bay on it

Cheers for the help.

[mattysaidso]

Raising the back of the bonnet is an old trick that does work but don't go the washer way as the bolts will come loose but make up some small blocks one for each side I have tried this and it enabled me to run a car with no fan.  

I'm going to do this to my Stag but first I will try 1 inch and then go from there to see how much of a difference it will make.

Give it a go as it dosen't cost much.

Gary

skateboard bearings do the trick on my ceffy!

ps. where is the best place to source heat wrap for my dump and down pipe?

[DAN00H]

Any other suggestions?

Is getting a bonnet vent cheap?

I'd like a low key one so not a scoop but a vent, ie somesort of meshed cutout at the rear of the bonnet as to draw hot air out over the windscreen?

Either that or one of the sunken in vents that sit just after the radiator, but i think those are more to get more air through the radiator right?

Cheers

Hi Mate

I've got a set of Do-Luck FRP vents that I'm thinking of selling - they go in at th erear of the bonnet.

see do-luck japan for the images.

[someonestolecc]

skateboard bearings do the trick on my ceffy!    

ps. where is the best place to source heat wrap for my dump and down pipe?

Aren't you scared of being decapitated?

Try ebay for thermal wrap - there's a lot of crap there but I think the reputable brands too.

Hi Mate

I've got a set of Do-Luck FRP vents that I'm thinking of selling - they go in at th erear of the bonnet.

see do-luck japan for the images.

I wish mate I wish.... : thanks tho.

[Oosh]

I'm pretty sure Bursons has it.

Hadn't thought about that latch that holds the bonnet in, probably not a great idea to "chock" the bonnet hinges up...

[mjfawke]

Actually, the area at the base of the windscreen is a high pressure zone, which is why the air intake for interior ventilation is placed there. Raising the rear of the bonnet causes air to be pushed into the engine bay at the rear, which *can* reduce airflow through the radiator if too much air enters the engine bay. Same goes for bonnet vents placed too close to the rear of the bonnet, and the only ones that will work are ones which have a lip at the front to create a low pressure zone over the vent.