One idea...if you tape it, wrap it!

[Mario_Marques]

I have one idea for people who blocks the front grills...
If you block, the heat exchange of the radiator will be reduced, so, you could wrap your exhaust manifold to insulate the heat of the exhaust.
you could also wrap the intake manifold to be sure your engine it's breathing cold air, it will help to keep the engine cold, or less hot.lol
I hope you guys understand(my english is not very good, please feel free to correct my words or sentences, it will help me to improve myself).

And another thing, if you wrap your exhaust, the exhaust temperature in the pipes will increase, it means, the exhaust gaz will flow faster because they are less dense(thats one of the reasons why sport cars use stainless steel exhaust).

[Ang84Indy]

Good idea, keeping the exhaust heat from raising underhood temperatures.

[Frank Lee]

It's a good idea until the exhaust system rots away prematurely.

[pounsfos]

it is a good idea, but unfortunatly, exhaust wrap "eats away" at the exhaust tubing eventually it causes holes in the exhaust, if you are going to do this either be readu to pay for a new exhaust in approx 2-3 years or get it ceramicly coated, they last forever and work better... unfortunatly you pay for it to but i will be doing this once my new engine is fully rebuilt

*exhaust wrap is poor mans coating
*it does work but rusts your exhaust
*something bad with your cat converter as well if i remember correctly

[jamesqf]

Originally Posted by Mario_Marques

And another thing, if you wrap your exhaust, the exhaust temperature in the pipes will increase, it means, the exhaust gaz will flow faster because they are less dense(thats one of the reasons why sport cars use stainless steel exhaust).

Really? Combined gas law - Wikipedia, the free encyclopedia

[Clev]

Originally Posted by Ang84Indy

Good idea, keeping the exhaust heat from raising underhood temperatures.

Judging by the success people have with warm air intakes in improving mileage, I'm not sure I'd want to decrease underhood temperatures. Sure, it's harder on the battery, but otherwise I think it'd only help.

[redpoint5]

Allowing the exhaust manifold to radiate heat into the engine bay should marginally cool the engine. In effect, the exhaust would be acting as a small radiator, removing the heat from the engine. Having a hotter exhaust manifold would conduct the heat back to the engine since it is directly connected. Perhaps the reduced efficiency of the radiators due to a hotter bay would negate this though.

At any rate, having a warm air intake seems silly to me. You could just be more gentle to the skinny pedal and get the same effect.

[cfg83]

Mario_Marques -

I use an HAI (hot-air-intake) :



Here is where I got the idea :

Modified air intake for hot air added 7.2% to mpg - SaturnFans Forums

That's on an increase in IAT from 37 to 90 degrees, tested on same 25 mi round trip all highway, with cruise set at 2100 rpm (60 mph) both ways, on same day with and without intake mod. Tests done with OBD II scangage.

I insulated the box and tubing today and will see if it increases the IAT and mpg further. With the standard intake I got 40.4 mpg, and with the hot air intake it went up to 42.3. I'll post again if insulating the box improves it further.

I *don't* claim a 7.2% increase in MPG because the scangauge MPG algorithm is being effected by the IAT increase. However, for some (many? most?) drivetrains I do think it helps.

I won't do the exhaust wrap because of what Frank says.

CarloSW2

[Mario_Marques]

Originally Posted by jamesqf

Really? Combined gas law - Wikipedia, the free encyclopedia

Hot gases are less dense and have higher viscosity, density decreases faster than viscosity increases, and one other thing, you have pressure from the engine in the exhaust
You may do this experiment at home with an hair drier and a simple piece of paper
Please, take a look at this examples:
Convective Heat - Air Velocity and Volume of Air Flow
About the exhaust rust, well have in my motocross bike(not a street bike, my bike is only for racing, not road legal) since 2008, and no rust at all, but i think it's possible, but i read a lot about damage in the exhaust but never seen a real one.
And in my car i already kill a turbo manifold with thermal coat(it brokes in tow pieces! i I never thought it was so effective ).

[cfg83]

Mario_Marques -

Originally Posted by Mario_Marques

Hot gases are less dense and have higher viscosity, density decreases faster than viscosity increases, and one other thing, you have pressure from the engine in the exhaust
You may do this experiment at home with an hair drier and a simple piece of paper
Please, take a look at this examples:
Convective Heat - Air Velocity and Volume of Air Flow
About the exhaust rust, well have in my motocross bike(not a street bike, my bike is only for racing, not road legal) since 2008, and no rust at all, but i think it's possible, but i read a lot about damage in the exhaust but never seen a real one.
And in my car i already kill a turbo manifold with thermal coat(it brokes in tow pieces! i I never thought it was so effective ).

I also heard that too-hot exhaust gases can damage your catalytic converter (but maybe that's only under high-RPM performance scenarios?!?!?!?). For racing I think this doesn't matter, but for passing emission tests it does.

CarloSW2