06isDriver

So....as part of my research, I've been measuring intake temperatures during normal daily driving. I started with the come one come all short ram intake with NO heat shield to get (what I consider) to be the absolute worst environment for cool intake charges.

Well guess what, so far I'm right as is everyone whos said they suck to begin with.

On average intake temperatures are 27 degrees HOTTER than ambient air...AND THATS CLIPPING ALONG AT 70 mph. In traffic or waiting at a stop light? 130 degrees ++.

Thats 130 degrees with an ambient air temp of 52!!!! How significant! lets just imagine you're waiting at a light or waiting in line for the 1/4 mile. Your engine is running and heat is sucking power away with every second you sit still. What about WOT, you say? Well according to my super quick temp response times, it doesnt affect that much. Maybe 3 degrees cooler if you're lucky, but still thats 24 degrees hotter.

There also seems to be a distinct point whereby the pipe material becomes super saturated with heat and the necessary time of flowing air increases for the intake temps to lower 1 degree. I havent got the ratio yet but there is a pattern.

Moral of the story....if you've got an open air filter and aluminum pipe, get or build a heat shield pronto. Also, I was able to reduce throttle body temps by about 12 degrees simply by wrapping the intake pipe with header wrap. You'll need 25-30 feet on your average 3 inch pipe.

So have fun with that info and I'll keep you guys updated. I plan on doing the same tests for a completely stock intake system for a base line. Seems it would do the best job possible for reducing heat soak.

lexusscturbo

iTrader: (12)

You could ceramic coat the tube as well

RRocket

This was one of the bonuses of some of the K&N intakes...the tubes on some cars where plastic, and less prone to heat soaking. But the key is most definitely a good, sealed heat shield...

projectdna

iTrader: (56)

... or go w/ a joe z intake.

lexusscturbo

iTrader: (12)

The metal tube will still absorb heat..The only advantage is the OE airbox with the intake by the top of the radiator, but you're maxing out on the volume of air with the airbox....And the gain of less turbulence with the accordions removed and a slightly larger ID of the tube itself...Then again that's what I bought for the parental's IS250

projectdna

iTrader: (56)

sure beats sucking in hot air from the engine compartment.

lobuxracer

iTrader: (2)

Right. But there are times sucking hot air is a good thing. The only time it isn't good is at WOT when you want the densest air possible. The rest of the time in improves thermal efficiency unless it's so hot it causes detonation.

Also, nobody really cares about the temperature before the throttleplate. At part throttle you lose a tremendous amount of heat from the endothermic action the throttlebody imparts. Why do you think the OEMs all run coolant to the throttlebody? They're afraid under the right conditions it will freeze open...

gc86

iTrader: (26)

This makes so much sense now. On my old Acura CL Type-S I re-routed the coolant hoses going into my TB as part of a intake mod... good thing I don't live where its freezing.

06isDriver

so you're saying that I'm losing heat because i'm absorbing heat??

I'm no genius but that doesnt make sense to me.

lexusscturbo

iTrader: (12)

You don't lose power for using excess cold air.... but if the TB sticks open you have bigger problems to worry about

06isDriver

true enough

06isDriver

i suppose this is what lobuxracer was talkin bout:

Higher intake charge temperature has been found to increase the flame speed, the combustion reaction rate, the uniformity of the fuel-air mixture and reduce the heat transfer rate though the cylinder walls. This all adds up to the engine using more heat for physical movement and less being wasted.

The downside to this is that hotter air also tends to retard ignition timing and cause engine pinging. Different engines will react differently to warm air intakes and testing will need to be done to see if it will work for your specific vehicle. Saturns are known to react well to warm air intakes.

http://ecomodder.com/forum/fuel-econ...cations.php#12

lobuxracer

iTrader: (2)

Exactly. This is why increasing static compression ratio improves thermal efficiency. You're using the kinetic energy stored in the flywheel to compress the A/F charge as close to autoignition as you can with mechanical energy instead of taking it from the fuel. This is why lower compression engines are less fuel efficient and why turbo/super charged engines are inefficient off-boost.

Smokey Yunick built an engine way back in the 80's with a 700F intake temperature - it was insanely efficient and didn't detonate itself to death despite flying in the face of all convention. It also made a ridiculous amount of power for its displacement. He built a V-twin version of this and put it in a VW Rabbit (the old boxy one) and made more horsepower than stock with far better fuel efficiency.

All of us speculated he'd figured out some kind of ceramic material for the piston (or some other magic) because the rest of the engine was nothing special - points ignition, carburetor, two valves per cylinder...and his chief discussion point was the high intake charge temperature reducing the fuel's ability to drop out of suspension (extremely small droplet size). This engine also used a turbocharger, but made a very modest 0.7 psi boost. He called the turbo a "homogenizer" because all he really wanted it to do was further improve fuel atomization.

So all the excitement about "cold" air being "better" needs to be taken with a very large grain of salt.

06isDriver

wouldnt you consider that to be an extreme situation? Apparently higher intake temperatures can have an affect on mpg, but how much heat is necessary?

What I'm asking is this, would you, as an everyday performance minded driver, rather have intake temperatures in the 150 + degree range or nice and cool at 60 degrees or lower?

AND...like that snippet said, the ecu will probably reduce output based on the higher temperature readings.

better question is this: Would you buy an intake that could guarantee absolutely no heat soak and give you the equivalent of a cool winter days air?

everything else being the same and knowing how these modern ecus interpret colder air.

lobuxracer

iTrader: (2)

No I wouldn't. Cold air takes energy to warm up, and hot air is what does the work. I'd rather have Smokey's setup by a long shot. Then I get 150hp/liter without high boost forced induction AND I get killer gas mileage to boot. (How about 60 mpg from that Rabbit?)

Cold intake air is half the reason you get crappy gas mileage in winter time. The only time cold air is a good thing is at WOT. Any other time it's a waste of fuel.