gq bonnet

[muddies]

IM thinking about lifting the back of the bonnet to let the air flow through easier, will this keep the engine temp down a bit or will it do bloody nothing at all or will it work? anyones theory's on this would be appreciated.

[Bingham]

a couple of threads discussed lifting front up 30mm but back would work well i would imagine allowing heat out......

[ozy1]

and bogged has previously stated, along with many others, lifting the back of the bonnet up, increases the risk of the bonnet heading straights at your head in the case of an accident, all it takes is for the bolts to snap, and your head is cactus,

better off finding the cause of the problem,

[muddies]

The problem is that i have replaced everything from the 3 core radiator, fan has been oiled, new aircon condensorand new thermostat.
the car is 4.2 turbo diesel with the boost at 11psi. it only seems to heat up when you go up hills or mountain ranges. any ideas would be good.
i have to go on the beach on the weekend in a lot of soft sand and are worried about the temp.

[ozy1]

whats the thermostat like? its running 11psi, hows the fuel, has it been tuned correctly, because overfueling can lead to overheating,

do you have spotties or bull bar in path of fresh air? do you have a bodylift?

[muddies]

the car was dynoed about 2months ago so everythingshould be sweet there. did have spotties took them off no difference. what degree thermostat should be used? it has one of the less restrictive ones and is opening up and how long should the take to open up?

[Bingham]

i have replaced all the recomended stuff 3 core radiaters viscous fans thrmostats genuine etc etc and still she warms.... on long hills....
im putting it down to slighly overfuelling..............

[muddies]

its not a gret increase just goes up to 1/2 then comes down quick aircon can be on or off doesn't matter.

[Bartso]

or if you want heat to leave the engine bay put two GU bonnet scoops on backwards i will be doing this prob only try with one first though

[bogged]

have you tried new radiator hoses, and on the lower one, putting the coil in it from a falcon hose.

apparently the lower hoses suck in and block up or some shit like that.

Have you had the cooling system reverse flushed? Complete system?

What cond is the fan in?

Have you tried a new thermostat?

again, theres dozens of GQs out there with turbos and no hassles.

fix it properly before resorting to J&H McBodge efforts.

I agree with the overfuelling. Dynos are usually about getting the most out of them regardless


anyway You must expect the car to get HOT when its working hard.. EG up hills etc.. You would have manure for brains to not think it would happen.

[Mytqik]

and bogged has previously stated, along with many others, lifting the back of the bonnet up, increases the risk of the bonnet heading straights at your head in the case of an accident, all it takes is for the bolts to snap, and your head is cactus,

better off finding the cause of the problem,

I call major BS.

When was the last time you saw a head on car accident with a bonnet still staight with the 4xM10/12 bolts sheared off. Surely the shear strength of 4 bolts would be much larger that the compression/buckling strength of the bonnet.

Also why would the bonnet penetrate the windscreen & not slide up the windscreen??

So for the bonnet to remove your head, it has to shear 4 bolts, then penetrate through the windscreen in one piece without buckling. By now it has moved at least 600mm rearward, to get to where your head would be (worst case scenario - head against the steering wheel ie no seatbelt).

For the front of a GQ to colapse 600mm, the front chassis rails would have colapsed (or would the chassis shear off the body mount bolts, I mean after all it only 10 bolts) & pushed eveything back 600mm, including the bullbar/grill/radiator through the engine block.

Doesn't make sense to me.

The lifting of the bonnet would definately increase through flow & aid in cooling. My only concern would be if you blew a oil/power steer hose & it covered the windscreen with oil. Could be a drama if occured at 110km/h.

[Gonzo]

Whats this talk of overfueling?

When you run rich the temp in the combustion chamber is lower, its when you lean it out (like on aftermarket turbos on full boost without an adjusted fuel map) that it gets real hot.

EG on the speedcar that we run, during warm up we have the fuel line valve half closed - it gets nice and hot real quick

[Mytqik]

Whats this talk of overfueling?

When you run rich the temp in the combustion chamber is lower, its when you lean it out (like on aftermarket turbos on full boost without an adjusted fuel map) that it gets real hot.

EG on the speedcar that we run, during warm up we have the fuel line valve half closed - it gets nice and hot real quick

Diesels are the direct opposite of petrols. Too much fuel --> too hot.

[Gonzo]

oh, in that case i stand corrected.

[adam.s]

This is common practice in japan to lift the bonnets on 180sx/s13's for the "drift look".

It actually screws with the factory heating, because the air is supposed to go over the engine and out the bottom. People in Japan only started doing it because they were shoe horning RB20det's into 180sx's and the bonnet just won't clear the engine by like 10mm. They end up getting oversized radiators anyway, so they don't care, but it's been proven on a stock setup the bonnet is better left sealed as the factory intended.

The other thing is with the air running out the back of the bonnet, your windscreen fogs up in the rain

[GQ TROL]

It actually screws with the factory heating, because the air is supposed to go over the engine and out the bottom

And the problem when you're 4wding, is that when you're up to your axles in mud.....there is no way hot air from around the engine can escape out the bottom. Out through the top is the only way to go.

Lifting the back edge of the bonnet and taking it for a strop will give you an indication if that is the suitable solution. If it lowers under bonnet temps, then fit proper air events to finish the job nicely.

Cheers
Mitch

[muddies]

I lifted the rear of the bonnet by 30mm. went for a drive up the highway and up mt glorious , there was bugger all difference i will be putting the bonnet back to standard. The truck was on boost (flogging her ass) all the time up the range and only went to half so i will stick with the way it is at the moment.

[GQ TROL]

I lifted the rear of the bonnet by 30mm. went for a drive up the highway and up mt glorious , there was bugger all difference i will be putting the bonnet back to standard. The truck was on boost (flogging her ass) all the time up the range and only went to half so i will stick with the way it is at the moment.

I've been told of a bloke by the name of John Bennett who modifies the standard water pump by replacing the impellor with a swiper arm impellor. Is supposed to slow water flow down significantly to increase exposure time within the radiator. Perhaps someone has contact details for him??

Another option is to de-gear the water pump by using a larger diameter pulley??

Cheers
Mitch

[bogged]

I call major BS.

When was the last time you saw a head on car accident with a bonnet still staight with the 4xM10/12 bolts sheared off. Surely the shear strength of 4 bolts would be much larger that the compression/buckling strength of the bonnet.

It doesnt have to sheer the bolts at all.
If it rips the latch off the front, theres nothign holding it down.. Then it can bend the hinge, I have seen several MVA's where the bonnet has come up and done this.. Maybe not gone thru that far, but having seen numerous trainin vids It could happen.

Also why would the bonnet penetrate the windscreen & not slide up the windscreen??

The windscreen, its not made of steel dude, its only glass. Hunks of steel travelling at 100's dont really stop and check the material that they will penetrate...

[/quote]For the front of a GQ to colapse 600mm, the front chassis rails would have colapsed (or would the chassis shear off the body mount bolts, I mean after all it only 10 bolts) & pushed eveything back 600mm, including the bullbar/grill/radiator through the engine block.[/quote]
No, the bonnet itself doesnt have to move the block or anythin to become an issue. Accidents have habits of takin the weakest path thru things.

You would need somethings to be really against you for it to happen, but it could.. Same as NAM could actually fit volvos to a 4wd.

[Stoknisan]

Consider fitting an after market bonnet scoop. I believe these are available from nissan for about $80 new. Easy to fit yourself. If one is not enough you can alwys fit 2

[Stoknisan]

Consider fitting an after market bonnet scoop. I believe these are available from nissan for about $80 new. Easy to fit yourself. If one is not enough you can alwys fit 2

[Mytqik]

I call major BS.

When was the last time you saw a head on car accident with a bonnet still staight with the 4xM10/12 bolts sheared off. Surely the shear strength of 4 bolts would be much larger that the compression/buckling strength of the bonnet.

It doesnt have to sheer the bolts at all.
If it rips the latch off the front, theres nothign holding it down.. Then it can bend the hinge, I have seen several MVA's where the bonnet has come up and done this.. Maybe not gone thru that far, but having seen numerous trainin vids It could happen.
If it has ripped the latched off the front, & ripped the hinges out of the firewall, but has not buckled the bonnet, I must ask, What is your bonnet made of?? 10mm plate steel?

Also why would the bonnet penetrate the windscreen & not slide up the windscreen??

The windscreen, its not made of steel dude, its only glass. Hunks of steel travelling at 100's dont really stop and check the material that they will penetrate...
My point is that as the bonnet is already on a angle (and increased with the spacers) & since the windscreen is raked back the likely result is for the bonnet to slide up the windscreen. There is nothing for the bonnet to "bite" into as the windscreen is smooth. I agree the bonnet could penetrate a windscreen quite easily if the bonnet was striking the windscreen perpendicular

For the front of a GQ to colapse 600mm, the front chassis rails would have colapsed (or would the chassis shear off the body mount bolts, I mean after all it only 10 bolts) & pushed eveything back 600mm, including the bullbar/grill/radiator through the engine block.

No, the bonnet itself doesnt have to move the block or anythin to become an issue. Accidents have habits of takin the weakest path thru things. I agree that accidents take the path of least resistance. However for a bonnet to be pushed through a windsreen, (ignoring the points above), the bonnet would need to be pushed along the entire front edge, eg hitting a brick wall. If you hit something like a power pole/tree the bonnet will wrap around the object struck. Therefore since we have hit a brick wall, the wall needs to move the bonnet 600mm rearward to injure the driver. Therefore for this to occur, the brickwall has also pushed the radiator/grill/bullbar rearward 600mm. Now for this to occur, the motor & gearbox would also have to move. I would be more concerned with the wiplash/spinal injury that would result.

You would need somethings to be really against you for it to happen, but it could.. Same as NAM could actually fit volvos to a 4wd.

Cant comment on NAM's volvo diff's, but I haven't heard anything about them for awhile

My main concern would be oil/water splashing over the windscreen while driving at speed. This could be overcome with a rubber seal/flap between the bonnet & firewall.

[bazzle]

A real lot has been posted re 4.2's running hot with turbos.

http://www.outerlimits4x4.com/PHP_Modul ... hp?t=37141

Bazzle

[mav]

the last contact address i had for john bennet was ECOtrans Pty Ltd 23 webb rd airport west victoria 3042. (03) 9335 4344 or 9338 5311.



I've been told of a bloke by the name of John Bennett who modifies the standard water pump by replacing the impellor with a swiper arm impellor. Is supposed to slow water flow down significantly to increase exposure time within the radiator. Perhaps someone has contact details for him??

Another option is to de-gear the water pump by using a larger diameter pulley??

Cheers
Mitch[/quote]

[GQ TROL]

the last contact address i had for john bennet was ECOtrans Pty Ltd 23 webb rd airport west victoria 3042. (03) 9335 4344 or 9338 5311

Thanks Mav, do you know how effective this water pump mod has been??

Cheers
Mitch

[mav]

i had my water pump for my xw falcon done (351 cleveland) it runs cooler a mate had his water pump done on his 350 chev and it runs cooler john gave me some good info on getting cooling systems to work much better.

also ask john about the bennet bypass system for your cooling system apparently has had a big block running with a 2 core radiator!!

[legsx1]

my 350 chev runs hot (as it meant to) when going slow on 4wd trips, so I have had some louvres punched into the bonnet which allows the hot air to escape better. Think this is a better option than lifting the rear end of your bonnet. Only problem is, you have to get your bonnet resprayed aftewrwards
legsx1

[MKPatrolGuy]

my 350 chev runs hot (as it meant to) when going slow on 4wd trips, so I have had some louvres punched into the bonnet which allows the hot air to escape better. Think this is a better option than lifting the rear end of your bonnet. Only problem is, you have to get your bonnet resprayed aftewrwards
legsx1

Have you got a pic of your bonnet with the louvres?

[bazzle]

Nissan gauge is normal to 3/4 scale. (as advised by Nissan Tech 10 years ago.)

Bazzle

[KIWI]

How about using bonnet vents off a WRX etc? Your local boy racer store should have plenty to choose from.


Dave