3 inch exhaust on a 2.8

[lufkin]

the 2.8s have a fan fitted under the intercooler as standard there are 2 plugs conectors to if you unplug the one that connects to the top of the intercooler fan will run all the time

doesnt this throw a error up though?

[patrol2.8]

Hasnt on mine from what I can see its a temp sensor the other thing about it is the fan actually draws the air upwards towards the scoop not the other way around

[dannysam84]

gday did u put straight system or use mufflers

[robbo0001]

If the fan draws hot air off the engine, then through the fan and OUT the bonnet scoop...isn't it kinda pointless?
How will this cool the heated air in the intercooler, off the turbo?

Going to check mine tomorrow and have a look.
If it is, I might reverse the positive and negative wires, and get it to go the other way. (if its that easy)

[JoseM]

No , it isnt pointless, on the contrary. First of all, the air temp in the engine bay is always lower than the air pumped by the compressor; also, the air enters the engine bay from the nose of the vehicle, creating a hi pressure zone on the fire wall area, which in turn pushes the air forward and out the scoop, contrary to what logic might tell you, as a matter of fact, if you put the scoop facing towards the windshield, then it will draw air in, if facing fwd then it lets air out. You can tie a string of wool to the scoop and actually see it.

So, having explained that, the fan will actually increase flow through the cooler promoting greater heat exchange, if you do it the other way around, the fan would then be combating the natural flow of air, therefore limiting heat exchange. Hope that answered your question...

If the fan draws hot air off the engine, then through the fan and OUT the bonnet scoop...isn't it kinda pointless?
How will this cool the heated air in the intercooler, off the turbo?

Going to check mine tomorrow and have a look.
If it is, I might reverse the positive and negative wires, and get it to go the other way. (if its that easy)

[patrol2.8]

Danny sam my system is a straight through system.
JoseM I was thinking about reversing my fan aswell but what you say makes sense would it be worth adding another fan to the top of the intercooler so it draws even more air up through it ?

[robbo0001]

Thanks for the explanation JoseM....I had a think about this last night, and sort of came to the same conclusion.
But I was thinking along the lines of "air at high vehicle speed flows through the vehicle grille, over the engine and intercooler, faster than the fan, and may make it redundant. However at low speed, or NO speed, the fan allows some air to be pushed through the intercooler and out the scoop."

[JoseM]

Danny sam my system is a straight through system.
JoseM I was thinking about reversing my fan aswell but what you say makes sense would it be worth adding another fan to the top of the intercooler so it draws even more air up through it ?

Why? Are you having EGT problems? Jus slap on a water injection system, and enjoy the extra hp

Thanks for the explanation JoseM....I had a think about this last night, and sort of came to the same conclusion.
But I was thinking along the lines of "air at high vehicle speed flows through the vehicle grille, over the engine and intercooler, faster than the fan, and may make it redundant. However at low speed, or NO speed, the fan allows some air to be pushed through the intercooler and out the scoop."

The fan is always gonna help, if you are moving you have that high pressure area full of not so warm air to blow through your IC increasing heat exchange, if you are not moving you have the fan "sucking" air and generating heat exchange. It works either way. Also, you have that rubber seal around the scoop that prevents what you are referring to...
A buddy of mine took one of windshield watter thingis (sorry, language barrier) and put it up side down, so that he can spray watter on the IC, as crazy as it sounds "It works!"

[T0nka]

That is dirt cheap!

[brucemacca]

Thanks for this info guys, will be looking to do this to my 2.8. A mate of mine who does exhaust builds recommends a 2 1/2 or 2 3/4 for the 2.8. Any thoughts.