Intake Temp

[jsicfy]

Does anyone know how hot the air after the intercooler usualy is. Or how hot is to hot. I know this depends on the intercooler but I wanted to know if the I/C I want will be efficient enough.

 

[Blue92]

You can't really believe what somone puts on a website for the IAT for their IC. Everyone gets different numbers. My friend has an F-350 deisel IC on his GN and he gets 78F IAT's at 15psi on his te-62. It all depends on the turbo/boost level/IC/ IC placement/ outside temp/ traveling speed. There are so many variables. Basically front mounts work, as long as they aren't broken or have a lot of pressure drop. Pressure drop is what you don't want, that is more to look for than IATs. Basically top to bottom ICs have more flow and side to side have better cooling capabilities, just as a general rule, not in every case. Just make sure you will have enough flow and not have big pressure drop.

 

[jsicfy]

I see, but at what temp would you say the intake air is way to hot. 100 115 130 145 160 175 190 200 degres. I just wana be able to know what a dangerous levle would be.

 

[Omega]

You really shouldn't be concerned with the temp of the IC. A much more important temp to take note of is the exhaust gas.

Lets say the outlet side of your IC is showing ambient temp (not going to happen BTW) which would mean your IC is really doing a bang up job and you are all grins. At the same time, your tuning is so off, or something happens and your EGT shoots to the sky and you melt a piston. Are you still going to be all smiles because your IC was really cool, but you should have been looking at other gauges?

What are you going to do with the number? Pull over to the side of the road because your AIT is high? The AIT is lower when you are moving anyway. It's a nice to know number that means absolutely nothing to the car.

FYI, generally IC's are 70% efficient. So, depending on your boost level and ambient air temp you can figure out what the IC outlet temp will roughly be.

 

[kpt4321]

You really shouldn't be concerned with the temp of the IC. A much more important temp to take note of is the exhaust gas.

IAT determines charge density, and indicates intercooler efficiency. It also has a big effect on knock propensity. It sure as hell is something that concerns me.

If you're not concerned with it, then why are you running an intercooler?

Lets say the outlet side of your IC is showing ambient temp (not going to happen BTW) which would mean your IC is really doing a bang up job and you are all grins. At the same time, your tuning is so off, or something happens and your EGT shoots to the sky and you melt a piston. Are you still going to be all smiles because your IC was really cool, but you should have been looking at other gauges?

I don't get that kind of an example this is. You're saying that you shouldn't look at your intercooler temp, because then you might miss it when something happens on another gauge like the EGT gauge?

When you drive, do you also not look at the road or the tach? I mean, you don't want to miss something happening on the EGT gauge, by your logic...

What are you going to do with the number? Pull over to the side of the road because your AIT is high? The AIT is lower when you are moving anyway. It's a nice to know number that means absolutely nothing to the car.

If it's too high, then you know that you need to do something to drop it down. It's also good to know for tuning purposes.

It sure as hell does mean something to the car. If it doesn't mean anyway, like I said, why not run no intercooler and suck hot underhood air into the intake?

FYI, generally IC's are 70% efficient. So, depending on your boost level and ambient air temp you can figure out what the IC outlet temp will roughly be.

Intercoolers are anywhere from 50% to 80% efficient. Not 70%, all the time.

 

[kpt4321]

Does anyone know how hot the air after the intercooler usualy is. Or how hot is to hot. I know this depends on the intercooler but I wanted to know if the I/C I want will be efficient enough.

Anywhere from 100 degrees to 200 degrees (F). It depends on a whole ton of things.

 

[jsicfy]

Anywhere from 100 degrees to 200 degrees (F). It depends on a whole ton of things.

Yes I see but lets say my IAT is 175deg is that going to be to hot of an IAT and cause detonation. Should I be looking into an intercooler that will cool better. I just wana be sure when I put it all togather and test it Im actualy looking at a number that can help me and not just some random fact.

 

[Omega]

It's one thing to be concerned, it's another to actively keep track of it. After you properly size the IC, I don't see the need to keep track of it. To me there are other things to look at wayyy before IAT


It's pretty easy to know when the IAT is going to be higher or lower than usual. It's either going to change because of ambient temp or boost pressure.


The 70% efficiency was a rule of thumb.. a decent number to use for calculations.

 

[jsicfy]

It's one thing to be concerned, it's another to actively keep track of it. After you properly size the IC, I don't see the need to keep track of it. To me there are other things to look at wayyy before IAT


It's pretty easy to know when the IAT is going to be higher or lower than usual. It's either going to change because of ambient temp or boost pressure.


The 70% efficiency was a rule of thumb.. a decent number to use for calculations.

I dont think you understand my point. Its not to activly keep track of the IAT. Its mearly how hot is to hot. I know IAT has a number of factors that change it but even with those factors I still dont know if teh IAT is to hot without an actual number. So how about this on an average day how hot is every ones IAT at around 15-20psi. Please include type of intercooler outside temp.

 

[kpt4321]

15-20 psi is not really acceptable, that's a pretty broad range.

Assuming 70% intercooler efficiency, 1.5 psi of pressure drop and 15 psi of manifold pressure, 70%c compressor efficiency, 60*F day, your charge temp is going to be about 116 degrees.

At 20 psi under the same conditions, you are talking about 130 degrees F.

 

[kpt4321]

It's one thing to be concerned, it's another to actively keep track of it. After you properly size the IC, I don't see the need to keep track of it. To me there are other things to look at wayyy before IAT

Nobody ever said anything about actively keeping track of it, until you brought it up. In addition, you seemed to think you didn't need to be concerned with it at all, since you said exactly that.

How do you know if the IC is properly sized, unless you look at things like charge temp?

It's pretty easy to know when the IAT is going to be higher or lower than usual. It's either going to change because of ambient temp or boost pressure.

Correct. I'm not concerned with day-to-day changes, because those are predictible. Howeve, I am concerned with the overall efficiency of the system, so I like to datalog thinfs like charge temp when I make a change.

The 70% efficiency was a rule of thumb.. a decent number to use for calculations.

It's important to note for all the newbs that you can be as low as 50% with a SMIC, and as high as 80% with a really good FMIC.

 

[jsicfy]

Found this.
"Not for the technically challenged". I include a link to a GN web page that has some useful equations for calculating heat transfer, heat loss/gain, pressure drop, I/C design. Also in their equations they compare stock turbo/ stock I/C, and big turbo/ stock I/C. And the best part off all calculating I/C outlet temps.

Also throughout the website, there is lots of great info. Just use the dropdown menus.

Intercooler Page
http://www.gnttype.org/techarea/turbo/intercooler.html

Use the resources bar for more info. "Technical" is where most should go.

 

[pneumo]

Here's a direct link to a turbo outlet temp calculator. www.stealth316.com/2-turbotemp.htm
That will let you plug in the outside air temp, turbo boost pressure (taken from your boost gage), and turbo efficiency (taken from your turbos compressor map).

Once you have turbo outlet temps it's not too hard to figure IC outlet temps if you know the outside air temp (same as turbo inlet temp) and estimated IC efficiency. Here's a formula; Turbo outlet temp minus outside air temp multiplied by the inverse (?) of your IC efficiency plus the outside air temp.
Here's an example,
turbo outlet temp =300
outside air temp = 80
IC efficiency = 65% (aka 0.65)
inverse of IC efficiency = 0.35

So 300-80 = 220
220 multiplied by 0.35= 77
77+80= 157 degrees. That's your IAT as it's called in this thread. A big 16G hits 300 degree outlet temp at only 15 psi, at 24 psi those temps can get over 400 degrees, so these temps are rather ordinary.

You can use this info the next time someone in a thread writes about their boost pressure, IC type, octane used and how much power they made. Then you'll know how hot is not too hot.