What are your IAT temps under boost?
#1
Junior Member
Thread Starter
iTrader: (4)
Join Date: Nov 2011
Location: Ft Lauderdale, FL
Posts: 79
Total Cats: 0
What are your IAT temps under boost?
I have a non-intercooled 7-psi kit on my car right now. I'm seeing 176F under full boost and then is settles down to 133F during cruising. I live in South Florida so ambient temps are generally in the low 90's this time of year.
So what are you guys' IATs under boost? I especially would like to know what the intercooled and water injected guys are seeing.
So what are you guys' IATs under boost? I especially would like to know what the intercooled and water injected guys are seeing.
#4
He's supercharged lol
yeah I was seeing 200-220F temps with the FFS before I yanked it off. I was on e85 and it was just an experiment though. Needed charge cooling ASAP.
176 isn't really too bad considering no intercooling. With how cheap they are though, I'd throw one one asap.
With temps past 200 there's no way to really guard against detonation. You intercool or your cool the charge with fluid injection of your choice. I know that even on magical e85 pimp juice it was severely dropping power when it went past 200
yeah I was seeing 200-220F temps with the FFS before I yanked it off. I was on e85 and it was just an experiment though. Needed charge cooling ASAP.
176 isn't really too bad considering no intercooling. With how cheap they are though, I'd throw one one asap.
With temps past 200 there's no way to really guard against detonation. You intercool or your cool the charge with fluid injection of your choice. I know that even on magical e85 pimp juice it was severely dropping power when it went past 200
#5
Temperature rise in the turbo is pretty close to an adiabatic process. This is because the air is moving through the system so quickly that the temperature rise is almost all due to compression with little other heat transfer able to take place. Adiabatic temperature increase based upon a 90°F/Sea Level starting point is shown in the following graph (note that your starting point would be ~130°F which gives ~185°F at 7psi):
The above came from the attached spreadsheet where I was doing some back of the envelope calculations for power gain from an intercooler (density-based only, not taking into consideration ability to increase timing).
Effective ways to cool the charge:
1. Make sure you've got a good cold air intake. Your steady-state cruising temp of 133°F tells me you need to work on this.
2. Intercooling. 'Nuff said. (And, yes guys, I have an intercooler sitting on the shelf waiting for installation -- I'll get there).
WI/MI doesn't really cool the charge very much (maybe 10°F) but does add good det resistance. For more intake cooling, run a greater percentage of alcohol -- although water absorbs a lot more combustion chamber heat per volume than alcohol (by about 2X). I've read that injecting 100% alcohol pre-turbo gives the most cooling you can achieve with WI/MI. I don't have data on that. All of my direct experience is your basic pre-throttle 50/50 or 100% H2O injection.
The above came from the attached spreadsheet where I was doing some back of the envelope calculations for power gain from an intercooler (density-based only, not taking into consideration ability to increase timing).
Effective ways to cool the charge:
1. Make sure you've got a good cold air intake. Your steady-state cruising temp of 133°F tells me you need to work on this.
2. Intercooling. 'Nuff said. (And, yes guys, I have an intercooler sitting on the shelf waiting for installation -- I'll get there).
WI/MI doesn't really cool the charge very much (maybe 10°F) but does add good det resistance. For more intake cooling, run a greater percentage of alcohol -- although water absorbs a lot more combustion chamber heat per volume than alcohol (by about 2X). I've read that injecting 100% alcohol pre-turbo gives the most cooling you can achieve with WI/MI. I don't have data on that. All of my direct experience is your basic pre-throttle 50/50 or 100% H2O injection.
Last edited by hornetball; 09-16-2013 at 06:48 PM.
#8
Elite Member
iTrader: (1)
Join Date: Jun 2006
Location: Warrington/Birmingham
Posts: 2,642
Total Cats: 42
Water injection is on the cards as an octane booster
#14
I see, at most, a 30-50f increase over ambient. I would imagine it would be a lot higher on track. On the dyno, with 80f ambient, it got to 111f during a 29psi pull. My intercooler is directly pressed against the radiator.
But my IAT sensor may not be accurate so take that with a grain of salt.
Bottom line is, get a huge *** intercooler and run E85 for the cooling effect.
But my IAT sensor may not be accurate so take that with a grain of salt.
Bottom line is, get a huge *** intercooler and run E85 for the cooling effect.
#18
Junior Member
Thread Starter
iTrader: (4)
Join Date: Nov 2011
Location: Ft Lauderdale, FL
Posts: 79
Total Cats: 0
Effective ways to cool the charge:
1. Make sure you've got a good cold air intake. Your steady-state cruising temp of 133°F tells me you need to work on this.
2. Intercooling. 'Nuff said. (And, yes guys, I have an intercooler sitting on the shelf waiting for installation -- I'll get there).
1. Make sure you've got a good cold air intake. Your steady-state cruising temp of 133°F tells me you need to work on this.
2. Intercooling. 'Nuff said. (And, yes guys, I have an intercooler sitting on the shelf waiting for installation -- I'll get there).
WI/MI doesn't really cool the charge very much (maybe 10°F) but does add good det resistance. For more intake cooling, run a greater percentage of alcohol -- although water absorbs a lot more combustion chamber heat per volume than alcohol (by about 2X). I've read that injecting 100% alcohol pre-turbo gives the most cooling you can achieve with WI/MI. I don't have data on that. All of my direct experience is your basic pre-throttle 50/50 or 100% H2O injection.
#19
Elite Member
iTrader: (5)
Join Date: Oct 2011
Location: Detroit (the part with no rules or laws)
Posts: 5,684
Total Cats: 806
Turbo heat shield + air box + somewhat fresh air for box + good ducting for intercooler = cruising temps just above ambient.
Before that stuff, i would cruise at above 100f and in boost temps were silly high.
Before that stuff, i would cruise at above 100f and in boost temps were silly high.
#20
If you think about it, you would recognize that air can only hold so much water vapor. That's why it rains. And when you pressurize air (all other parameters held constant), it holds even less water -- which is why we're always draining water from air compressor tanks. Bottom line, water generally stays in liquid state (small droplets) until the combustion event. It doesn't cool the intake charge. Alcohol, OTOH, will partially vaporize in the intake yielding some drop in temperature.
Some interesting NACA papers attached. They contain lots of hypotheses though, so shlammed may want to stay away.