Outer Limits 4x4 Board

Since having a set of Pacemakers fitted to my patrol i find that the under bonnet tempreture is very high.
after a long climb in low range and flip the bonnet i can hardly put my hands on the top off the guards and all my wiring looms that run down the inner guard are quite hot, i even get steam out off the washes were water has sat in the tubes for a while.
Engine temp is normal and there is no heat sheild on the extractor.
Would a turbo desiel bonnet scoup help this heat escape ?
Has anyone else crossed this problem ?

im fitting a deisel scoop on my bonnet at the moment for exactly the same reasons..mine is a petrol motor running straight lpg. underbonnet temps are always high so im hoping that the scoop will push out the hot air when moving, and give it a passage to escape from when stationary. painting up the scoop and bonnet in the next few days so will let u know how i go..

i had the same problem in my GQ LPQ/Petrol. I have since put a 4.2 Diesel in and the temps are still damn hig. It will be good to see how the scoop idea goes as i might try it out. That much heat can't be good over a long period for the electrics

Ther is a heat resistant tape that can be bought from anywhere that sells performance parts. Sorry I cant give you any more information.

I fitted it to my brothers XB as the extractors were melting the carpet when it was worked hard.

It is usually advertised in Street Machine but a Performance retail outlet or an exhaust shop who deals with performance vehicles should be able to help.

Could also get it all jetcoated. It is a fancy paint stuff that they can put on near anything. To help with heat. I know a bloke with his whole turbo thru to exhaust tip is coated in this stuff. He seems happy. Can also put this stuff on top of your pistons if you want.

Dont know where you could get it done localle. Pretty sure you can get it done in Castlemain, VIC.

I would just get the scoop and let the heat escape the way it is.

viperguy wrote:im fitting a deisel scoop on my bonnet at the moment for exactly the same reasons..mine is a petrol motor running straight lpg. underbonnet temps are always high so im hoping that the scoop will push out the hot air when moving, and give it a passage to escape from when stationary. painting up the scoop and bonnet in the next few days so will let u know how i go..

Good to know others have thought of this!
Question. How much is the GU scoop ? And how does it attach to the bonnet.

Thanks Guys. Grant

GUEEY wrote:Question. How much is the GU scoop ? And how does it attach to the bonnet.

Bout $100ish + fitting

you could just go some GTS grills in the guards like the old XU-1 ??

i gought mne from parramatta nissan for $116 trade..it comes gray plastic and needs to be painted..it is designed to be bolted onto a gu bonnet and comes with fittings and rubber gaskets etc...

i fitted mine using bolts and applied urethane instead of the gaskets..this will seal and glue.. making it almost impossible to remove.

mine is painted black on my white bonnet.. looks like something from mad max..lol

the biggest hurdle to fitting is that the gu has a place for the scoop with no bonnet reinforcing in the way.. on the gq u will have to cut out reinforcing from ur bonnet to get it to fit. i solved this by welding in steel angles around the scoop to strengthen and reduce flop in the bonnet around the cut out.

Was at Big Balls Offroad today in Blacktown and saw that they sell the extractor heat bandage there. Not sure how much but its on the top floor hanging up.

cheers

My experience of the heat wrapping is it will kill the extrators, the heat build up combined with any moisture between the tape and the steel pipes will cause the pipes to break down and fall to bits. The headers are replaced regularly on race cars that use this tape.

I would prefer the ceramic coatings but its not cheap.

Have a look at HPC http://www.hpcoatings.com.au/pages/auto.htm

viper guy do you have any pics of yours installed?

You can wrap pacemakers but nothing else. But whether it is any good in the long run is the question. Go the scoop first. Will look good even if it dosnt improve anything which is highly unlikely.

If you are not interested in wrapping the exhaust, go to the nearest reputable exhasut shop and ask them if the can have the extractors HPC'd. ( high performance coating) They dip the metal objest in this chemical, and it acts as an insulant, keeping the heat in. I Had the exhaust side of my turbos coated on my 300zx, aswell as the dump pipes, and half of the exhaust. You actually get less heat soak into the block, and surrounding areas, and due to the exhaust gas staying hotter, it actually flows faster out of the system, and gives you more power.

Some drag racing teams actaully have their pistons coated to keep combustion temps down, and it give massive amounts of extra power due to lower combustion temps.

If I can find some info I will post it here.

Pete

Heres the www for jet-hot. http://www.jet-hot.com.au/index.htm

no pics just yet.. will be taking some pics soon so will post them up when they done..

I had a GU coil cab and never ran the heater becuase the temp in cab was always warm. I will be fitting a GU scoop to my GQ facing backwards. This alows air to flow through the engine bay. I will also be fitting 20mm packers to the hinges and bendind the wiper grill backwards. I noticed years ago when I removed a scoop from an XE ute the difference in power without it.

Do bonnet sccops have any negative effect for water crossings or is it a non-issue?

I think anything that can reduce underbonnet temp must be good for the electrics and all the plastics being used now...

Especially since the ECU/computers are sometimes put in the engine bay....

Went to licola on the weekend and drove McMillans track,piss easy but long and fairly steep.
Extractor heat stuck agian! boiled the fluid in the steel Clutch line near the top, Clutch peddle went to the floor.
After looking under the bonnet i noticed the steel line is only about 30-40mm away from the rear cylinder extractor pipe.after 10 minutes the clutch can back and working fine.
Spoke to the exhaust crew that put on the Pacemakers and they said Heat Rap tape will destroy the extractors in 12-18 months.
Has anyone else had this problem.

yes, go the ceramic coating as above

GUEEY wrote:Spoke to the exhaust crew that put on the Pacemakers.

did they have any suggestions?

GU Bonnet scoop back th front. Works really well. If you want to get heat out it has to point backwards as hot air is blown back back the fan + hot air rises.........from there it makes sense to me.

but wif it facing forward air is forced in pushing it through the engine bay and out the bottom, which is where every other cars heat escapes, dont you think that if they worked better facing backwards nissan and every other company who put scoops on would put them on backwards? now befor you start yes VH SS commodores do have a reverse scoop along with the SS torana and SLR's but thats about it.

just something to think about, cos i dont have enuf money to buy another bonnet cos my scoop didnt work as well as i though facing backwards.

This piont could be argued all day, so I'll use the example of the Walkinshaw commies. The bonnet scoop/vent draws air in through a front facing vent ( for induction) and vents underbonnet heat via an opening at the rear.

Another effective way of releasing the heat under your bonnet is to space the hinges up, creating a gap at the rear edge of the bonnet. V8 drag cars, and the like use this technique.

I'd go with the rear facing vent.

JMO.

Pete

Im pretty sure birdy has blocks at the rear of his bonnet hinges to raise it a little, to try and curb the heat from his turbocharged, winch challenge weapon.

embryo wrote:dont you think that if they worked better facing backwards nissan and every other company who put scoops on would put them on backwards?

They dont do it to let heat out, they do it to force air thru the intercooler...

now befor you start yes VH SS commodores do have a reverse scoop along with the SS torana and SLR's but thats about it.

and they were to let heat out, and it worked

But the forward facing scoop is usually to force air through an air-air intercooler.

If you just force air into the engine bay without pushing it through the i/c core then you may cause havoc due to a big pressure change and the engine fan or thermofans on the radiator won't be as effective then

Giving you a different heat problem. A rear facing scoop is a vent so should cause more air to flow in through the front.

Thanks for all your input reguarding my problem.
I am going to space my hinges first before i take to the bonnet with the Jig Saw.

Thanks Again . Grant