WI and false IAT's
#1
Junior Member
Thread Starter
iTrader: (7)
Join Date: Jun 2005
Location: Texas
Posts: 393
Total Cats: 18
WI and false IAT's
With the water spraying on the IAT, I don't understand how a true IAT measurement can be taken. I don't want to relocate the IAT into the manifold plenum until I'm forced to do a rebuild and it's already off.
Normally while in boost my IAT's are 2-5°C over ambient. When the WI kicks in the IAT's drop around 10°C, which would be way below ambient.
Does anyone care about this?
Normally while in boost my IAT's are 2-5°C over ambient. When the WI kicks in the IAT's drop around 10°C, which would be way below ambient.
Does anyone care about this?
#2
Senior Member
iTrader: (7)
Join Date: Aug 2007
Location: Southern Indiana
Posts: 1,369
Total Cats: -1
It is definitely possible for the IAT's to be below ambient. When the mixture evaporates, it is endothermic, so you are actually removing heat from the charge. If you rub isopropyl alcohol on your hands, they feel cold. Same concept.
#6
Junior Member
Thread Starter
iTrader: (7)
Join Date: Jun 2005
Location: Texas
Posts: 393
Total Cats: 18
IAT upstream of the WI won't catch any of the cooler charge that the WI gives. So that is definitely not a true reading.
I've had manifolds (Racing Beat Dellorto sidedraft setup) sweating and cold to the touch from the fuel vaporization. I understand that. I also understand that WI cools things and steam cleans carbon. That's why I installed it.
I've got the WI to fire in different methods. I do have a manual override so I can fire it whenever I want, provided that the fuel pump is on. (that's my safety to not hydrolock the motor - hopefully). I can pulse the WI for just 1/4 second and the IAT's plummet for 20-30 seconds. No way that's a real reading.
The thing I see happening is that the IAT gets wet and will remain cool until it dries off.
I will have a data point someday when I relocate the IAT halfway down the plenum. Until then, I was just wondering if anyone takes this into account when tuning.
I've had manifolds (Racing Beat Dellorto sidedraft setup) sweating and cold to the touch from the fuel vaporization. I understand that. I also understand that WI cools things and steam cleans carbon. That's why I installed it.
I've got the WI to fire in different methods. I do have a manual override so I can fire it whenever I want, provided that the fuel pump is on. (that's my safety to not hydrolock the motor - hopefully). I can pulse the WI for just 1/4 second and the IAT's plummet for 20-30 seconds. No way that's a real reading.
The thing I see happening is that the IAT gets wet and will remain cool until it dries off.
I will have a data point someday when I relocate the IAT halfway down the plenum. Until then, I was just wondering if anyone takes this into account when tuning.
#7
Senior Member
iTrader: (7)
Join Date: Aug 2007
Location: Southern Indiana
Posts: 1,369
Total Cats: -1
IAT upstream of the WI won't catch any of the cooler charge that the WI gives. So that is definitely not a true reading.
I've had manifolds (Racing Beat Dellorto sidedraft setup) sweating and cold to the touch from the fuel vaporization. I understand that. I also understand that WI cools things and steam cleans carbon. That's why I installed it.
I've got the WI to fire in different methods. I do have a manual override so I can fire it whenever I want, provided that the fuel pump is on. (that's my safety to not hydrolock the motor - hopefully). I can pulse the WI for just 1/4 second and the IAT's plummet for 20-30 seconds. No way that's a real reading.
The thing I see happening is that the IAT gets wet and will remain cool until it dries off.
I will have a data point someday when I relocate the IAT halfway down the plenum. Until then, I was just wondering if anyone takes this into account when tuning.
I've had manifolds (Racing Beat Dellorto sidedraft setup) sweating and cold to the touch from the fuel vaporization. I understand that. I also understand that WI cools things and steam cleans carbon. That's why I installed it.
I've got the WI to fire in different methods. I do have a manual override so I can fire it whenever I want, provided that the fuel pump is on. (that's my safety to not hydrolock the motor - hopefully). I can pulse the WI for just 1/4 second and the IAT's plummet for 20-30 seconds. No way that's a real reading.
The thing I see happening is that the IAT gets wet and will remain cool until it dries off.
I will have a data point someday when I relocate the IAT halfway down the plenum. Until then, I was just wondering if anyone takes this into account when tuning.
#10
Junior Member
Thread Starter
iTrader: (7)
Join Date: Jun 2005
Location: Texas
Posts: 393
Total Cats: 18
Hmm, like you said, there is going to be heatsoak from your manifold. Also, i have heard of problems with the vibrations harming the sensors. I would really like to hear some real input on this though. I am really considering doing this on my built motor before i put the intake manifold on.
Yes, I'm being ---- about this whole thing. I'm not even tuned well enough for this to matter - right now.
#14
With the water spraying on the IAT, I don't understand how a true IAT measurement can be taken. I don't want to relocate the IAT into the manifold plenum until I'm forced to do a rebuild and it's already off.
Normally while in boost my IAT's are 2-5°C over ambient. When the WI kicks in the IAT's drop around 10°C, which would be way below ambient.
Does anyone care about this?
Normally while in boost my IAT's are 2-5°C over ambient. When the WI kicks in the IAT's drop around 10°C, which would be way below ambient.
Does anyone care about this?
#15
Junior Member
Thread Starter
iTrader: (7)
Join Date: Jun 2005
Location: Texas
Posts: 393
Total Cats: 18
I don't like dummy gauges, inaccurate or incorrect measurements, especially when it's an input to calculating fuel and ignition. I'll let it go, I know I'm being nuts. Old habits are hard to get rid of sometimes.
I can put the nozzle about 18" further upstream right at the IC outlet. I doubt this will do anything. W/o WI, the IAT reads 2°-5°C above ambient under boost. I have a feeling that most of the vaporization happens as things get hotter - in the manifold or in the runners, at least with my oversized IC.
Multiple thermocouples would tell the story, but it's not that important.
I had just asked if anyone cares about false IAT readings and I think the unanimous consensus is NO!
Thanks for the responses! I'll let it go now....
Thread
Thread Starter
Forum
Replies
Last Post
Mikel
MEGAsquirt
4
09-28-2015 04:46 PM
Motorsport-Electronics
ECUs and Tuning
0
09-05-2015 08:02 AM