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So I was posting another thread and was encouraged to write a review on how I attacked IAT's. We know GM runs the new LT1's hot. I typically was seeing 203-210 degrees water temps and easily climb to 215-220 in some good hot traffic. I live in Minnesota, so anyone South of here should see even better results. My car now runs 180-185 degrees F all day long. And even on those 90 + degree summer days I never seem to lose power. Now if someone can teach me how to log actual IAT's with my Diablo Intune I would be glad to do that. But will be next Spring
My motivation for this came from a another thread (I will try to find it) who did some testing and had data from IAT logging and times at the track. Heat soak is for real, and if you want to keep your HP all day long, this will help the cause. So here you go:
1. Coated headers. If you go with headers, spend the money and get them coated. My LG Super Pro's cost $245 locally with a guy who uses Cerma Krome. They look great and keeps temps down:
2. I wrapped the entire bottom and sides of my AFE cold air intake with Lava Shield. This stuff sticks on and I believe they said is good up to 1,000 F. Installed you can barely notice the it.
3. Wrapped lower radiator hose with an aluminum hose shield from Summit.
4. Removed plenum cover and blanket. This holds quite a bit of heat on top of the motor. You can screw back in the four bolts for the plenum cover and still use your coil covers.
5. Installed 170 T-stat from Summit. Be sure to read the threads about trimming the bottom edge of the spring so it seats properly and doesn't tear the gasket. I have mine on for 5,000 miles and it has been flawless.
6. Remove weatherstrip on cowling by back edge of the hood.
I changed out a Delco 180° thermostat in a '96 LT1 for a Summit (Hypertech) 160° thermostat and dropped 14° at cruise (8-10° in stop & go traffic). Turns out the Hypertech allows more water to flow when fully opened than did the Delco. All thermostats are not created equal, regardless their temp ratings.
Coated headers will also allow for lower temps in the engine compartment.
IAT's will marginally increase volumetric efficiency in the cylinders but have a negligible effect on operating temps. IMHO
IAT is Intake Air Temp. That only has to do with the air temperature coming into the motor. meaning when the car is moving and its 60 degree's outside it should be 60 degree's coming into the motor. Insulating plumbing coming into the motor only affects IAT's when the car is at rest.
Yes on all counts reducing engine compartment heat is great. Just understand the motors are intentionally run hotter for emission reasons. Some has to do with getting oil temp up. I'll let somebody else chime in
IAT is Intake Air Temp. That only has to do with the air temperature coming into the motor. meaning when the car is moving and its 60 degree's outside it should be 60 degree's coming into the motor. Insulating plumbing coming into the motor only affects IAT's when the car is at rest.
Yes on all counts reducing engine compartment heat is great. Just understand the motors are intentionally run hotter for emission reasons. Some has to do with getting oil temp up. I'll let somebody else chime in
Looks like a lot of money spent for a seemingly mostly stock engine. Do you guys actually see high IATs and coolant temps? I have 570 rwhp and have never worried about my IATs nor engine temps on the track. and that's half hour sessions going at it hard. My manual transmission temps is the only thing that gets close to overheating but I've never had a warnng either. that's at 100 degree ambient Texas weather.
Looks pretty though. Just not worth it for me. I need scientific evidence. if anything the engine just won't get to proper operating temps.
As previously posted somewhere on the forum note the additional opening on the bottom of this car. A second passenger side opening provides more air to the air box. Two 2" round holes could also be done with a hole saw (disregard arrow)
In the engine compartment, passenger side there is a gap between the frame and fender in front of the air box. Add a filler panel to close this gap to keep the hot engine compartment air out.
IAT is Intake Air Temp. That only has to do with the air temperature coming into the motor. meaning when the car is moving and its 60 degree's outside it should be 60 degree's coming into the motor. Insulating plumbing coming into the motor only affects IAT's when the car is at rest.
Yes on all counts reducing engine compartment heat is great. Just understand the motors are intentionally run hotter for emission reasons. Some has to do with getting oil temp up. I'll let somebody else chime in
That is correct: IAT = Intake Air Temp. Which is why the if we can lower under hood temps and insulate the intake path, we can lower IAT's in HOT weather conditions which can save horsepower.
If it is 90 degrees outside and you are going 60 MPH, the IAT's will not be ambient. They will be 60 degrees plus the amount of heat transfered from under the hood.
I know, this overkill for most people. My car is bolt on with 525 HP at the crank. All I know is on HOT days my car will produce more of that 525 all day long then a stock car
That is correct: IAT = Intake Air Temp. Which is why the if we can lower under hood temps and insulate the intake path, we can lower IAT's in HOT weather conditions which can save horsepower.
If it is 90 degrees outside and you are going 60 MPH, the IAT's will not be ambient. They will be 60 degrees plus the amount of heat transfered from under the hood.
I know, this overkill for most people. My car is bolt on with 525 HP at the crank. All I know is on HOT days my car will produce more of that 525 all day long then a stock car
Actually if you're cruising at 60 mph and its 90 outside. your IATs on a naturally aspirated engine will be 90 degrees. There is a lot of airflow inside of the engine compartment at 60 mph. Specially at the front where the intake is.
I know my forced induction IATs at 60 mph were ambient while cruising. at full throttle they raised 10 degrees in 10 seconds and were back at ambient in another 10 seconds. (datalogging)
Keeping temps down is cool, but unless you're doing some heavy track sessions, it is transparent in these cars.
Last edited by BrunoTheMellow; 12-06-2016 at 12:31 AM.
Has anyone actually calculated the amount of heat transfer to the intake air? I suspect it is minimal since the air is moving very quickly and doesn't spend much time in the intake system.
Here is a graph of the same run except with the Halltech air intake system.
Note that the IAT increased more than the stock system. This is caused by the air filter box is much larger and very close (or touching) the radiator coolant hoses.
I sold the Halltech and reinstalled the stock air intake system with a K&N filter. I insulated the air filter box and installed sleeves over the coolant hoses. The coolant hoses are now much cooler....I can touch them now where before they were too hot to touch.
Great info. Heat from the engine compartment should not be getting into the air filter air box. I agree that higher then ambient air temperature IAT is robbing power.
Not sure, but look at the other graphs and the ambient stays pretty stable. It does prove my point, once you build some heat under the hood your IAT's are going to climb
Stock stingrays tune show timing reductions after 84 degrees IAT. By reducing IAT's your actually preventing horsepower loss. Also the cooler the intake air, the more power the engine makes. The OP is keeping the intake manifold, water temp and the IAT's lower to promote higher HP and prevent HP loss.
IAT's on a NA engine cannot be any cooler than ambient air temps when everything is ideal. I have gone one step further than the op and made a direct path from the lower rf grill opening (using a brake cooling duct) to the air filter housing.
12-02-2016, 04:00 PM
Lowering IAT's = FREE Horsepower
some good info here
