HMT-Admin

lol

had to post that one of beaus car...

kain

i remembered the first time my bro put a front mount on his wrx. i though it would be cool to the touch, but not freezing. yes. it was probobly like 50 to 60 degrees on a summer day. i swear that was some cold ----. he called me up and said he made 300 hp at the wheels now, and i told him... hm... probobly cus its misty and its like 10 degreese out side. he was like... ooooo!!!

hackish

I had a stock STi TMIC on my car (STi V4 swap) and making 320bhp I could really give it then pull over and put my hand on the IC. It was hot to the touch but not burn my fingers hot. Turbo on the other hand would be glowing...

On my 323 (240ish hp) I have a FMIC. I can do a few good full boost pulls and pull over. The inlet tank will be warm to the touch and the outlet stone cold. This was in 15C weather but still... The FMIC shouldn't get that hot. If it is look at airflow through it...

-Michael

Chris Harris

Hackish, i have to say I really dont agree with you. The turbo heats up the air in two ways...one by contact as the air enters the compressor and two by compressing to X times(psi) smaller than it was before it entered. The compression of the air is the major factor in how hot the air is exiting the compressor. And air entering the turbo will never have anything to do with back pressure in the exhaust as you stated above.

Most intercoolers are designed to be close to 80-90% efficient which would get most of the air entering back to the ambient temp outside...turbo inlet temps are not going to play a big factor in that. Some yes, so if you can obviously put the filter where its going to get cool air.

But air under the hood is still very close to ambient already while the car is moving so its not going to make a huge difference. Its all about the intercooler.

91esibtuned

im not boosted yet so i dont know but i would use it for this reason

like the link above, you dont want rocks gettin into the blades, and they grab colder air, and it has less heat soak

hotrex

if its a shitty turbo then who cares.....but if you have a high dollar piece id use protection.

stretch-d

One thing everyone's forgeting....Where do all those little pieces of rock & blade chips go?

Dr.Boost

To the land of the forgotten.



pssst, nobody wants to think about that stuff.


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baldur

Cold inlet air will give you better performance, more density at the inlet means the turbo doesn't need to spin as fast to make the desired boost, meaning less power needed to drive the turbo. The intercooler will never get your air to exactly ambient, but less temp in the system to begin with will bring you closer. It may not make a huge difference but it does make a difference. Another thing about the filters, go with the largest filter you can fit, not only does it flow better but less air velocity through the filter likely means better filtration with cotton filters that rely on the dirt sticking to the oiled fabric. I've seen people exchanging a stock air intake with a big filter and a cold air snorkel for a tiny cone filter placed right next to the engine, can't say it's logical.
Either way, the more air density you have at the turbocharger inlet, the more power you'll make at the same boost level because the entire system gets more efficient.

Just my 2c

hackish

Baldur is right on the money. Many people think about turbos in terms of boost not in terms of CFM's of air that they're flowing. As an example my butt dyno registerred almost the same power output on the 323 at 12 and at 15 PSI. The reason is that it was already maxing out the turbo's flow capacity. As I added boost there was a corresponding increase in backpressure so the net gain was almost 0.

Lowering the temp of the intake air is actually increasing the flow capacity of the turbo since the air entering is of geater density. More flow means more power, quite simply.

As for the temps in the engine bay, people are assuming since the air must be blowing by it must be fairly cool in there. I've datalogged with temp probes and found that the rad and ambient engine/exhaust heat adds a lot to the underhood temps. Not uncommon at all to find +20 degrees under there.

-Michael