How hot is too hot?
On The Tree
Joined: Jul 2005
Posts: 139
Likes: 0
I really don't think I answered your question...
The objective is to keep the coolant from boiling and thus introducing air in to the system...when a fluid is under pressure, it has a higher boiling point...so if you have an 18 psi cap...your boiling point should be around 250-260 degrees (F) (from what I can remember)
.
But for the engine's sake (I believe the oil temp is typically 100 degrees F higher than the coolant's) at any rpm, I would want it below 200...
The objective is to keep the coolant from boiling and thus introducing air in to the system...when a fluid is under pressure, it has a higher boiling point...so if you have an 18 psi cap...your boiling point should be around 250-260 degrees (F) (from what I can remember)
. But for the engine's sake (I believe the oil temp is typically 100 degrees F higher than the coolant's) at any rpm, I would want it below 200...
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Originally Posted by staringback05
yea i was leaning towards 215....keep it under that, you realize also the tranny will get hotter then that?
Originally Posted by Boostaholic
Moving in the hot summer air it sits at 213-220, at a stop around 230.
Originally Posted by Boostaholic
I have a external B&M trans cooler, also my radiator is much bigger than a stock one.
I was taking my kid to his Karate lessons yesterday. It was around 110*-112* here in Vegas with like 30-40% humidity.Man does it suck. Anyway my car wth the ac on stayed around 230* driving and touched around 240* at long redlights. I have a 160* stat and my fans come on around 185*.
I freak out and usually just turn of the ac. Anytime its under 105* here my car seems to run normal temps. Anything above that and it gets really hot. Especially with this humidity we've been having.
I'm running water wetter and a 75%/25% mix. Is there anything else I could do? Like maybe try a different radiator cap? Could my cap be going out since it never use to do this? The only thing I haven't replaced is the cap. My whole cooling system is new, including all new hoses. Like I said, under 105* it pretty much keeps normal temps.
I freak out and usually just turn of the ac. Anytime its under 105* here my car seems to run normal temps. Anything above that and it gets really hot. Especially with this humidity we've been having.
I'm running water wetter and a 75%/25% mix. Is there anything else I could do? Like maybe try a different radiator cap? Could my cap be going out since it never use to do this? The only thing I haven't replaced is the cap. My whole cooling system is new, including all new hoses. Like I said, under 105* it pretty much keeps normal temps.
When you get anywhere close to boiling on an
average-temp (which the ECT is, pretty much)
basis there is a good chance of hot spots going
over the top, then you get a thermal runaway
locally since steam pockets don't cool for ****.
You need to stay well below boiling. The real
boil temp is a function of system pressure and
the radiator cap sets that. If you start puking
fluid when, say, dropping from a hard pull straight
to idle, you have passed the point of safety IMO.
I don't even like to hear it boil at shutdown but
that's probably over-conservative.
Stock fan settings are stupid hot and allow a
gross water jacket temp swing that then requires
you to leave extra fuel and short spark in the
tune to accommodate the high side. But behind
that is a girly (no offense to the ladies) little
1-core radiator with its air preheated by the
A/C condenser. Us southern / desert folks need
more if you and the motor both want comfort.
average-temp (which the ECT is, pretty much)
basis there is a good chance of hot spots going
over the top, then you get a thermal runaway
locally since steam pockets don't cool for ****.
You need to stay well below boiling. The real
boil temp is a function of system pressure and
the radiator cap sets that. If you start puking
fluid when, say, dropping from a hard pull straight
to idle, you have passed the point of safety IMO.
I don't even like to hear it boil at shutdown but
that's probably over-conservative.
Stock fan settings are stupid hot and allow a
gross water jacket temp swing that then requires
you to leave extra fuel and short spark in the
tune to accommodate the high side. But behind
that is a girly (no offense to the ladies) little
1-core radiator with its air preheated by the
A/C condenser. Us southern / desert folks need
more if you and the motor both want comfort.
So jimmyblue, do you think my cap could be the culprit? Its the original cap from 98'. All else is new except that. My car the last couple of times I drove it got up to around 240* on my scanner. It didn't puke into the overflow untill I shut it off at home. It puked so much it filled my reservoir causing my low coolant light to come on. I just don't understand why when its under 105* and the humidity is down around 10-15* it doesnt do it. For the midwest people, 110* with 20-30% humidity feels like 130* in the desert.
Radiator cap will make it boil at too low a temp. But
the cap won't raise temps until you get into that
and hot-spotting. If it doesn't puke at 240 running
then I figure it's tight. The big problem seems to be
heat off the condenser, stealing from the radiator's
cooling power (less deifference between incoming
air and incoming water temps). I'd look at the rad
for debris / fins bent / obstructions such as cold
air induction setups, trans cooler etc. and try to
free up the stack. But my personal plan is an LT1
rad swap (next coolant change) along with the tank
thermostat scheme and maybe even a large diameter
single fan setup. If I was less of a bottom feeder I'd
go for a 3-core custom like from Be-Cool or such
places. But the LT1 rads are cheap pieces on eBay
etc.
I bet Las Vegas pavement as the cooling air source
helps none either....
the cap won't raise temps until you get into that
and hot-spotting. If it doesn't puke at 240 running
then I figure it's tight. The big problem seems to be
heat off the condenser, stealing from the radiator's
cooling power (less deifference between incoming
air and incoming water temps). I'd look at the rad
for debris / fins bent / obstructions such as cold
air induction setups, trans cooler etc. and try to
free up the stack. But my personal plan is an LT1
rad swap (next coolant change) along with the tank
thermostat scheme and maybe even a large diameter
single fan setup. If I was less of a bottom feeder I'd
go for a 3-core custom like from Be-Cool or such
places. But the LT1 rads are cheap pieces on eBay
etc.
I bet Las Vegas pavement as the cooling air source
helps none either....
On The Tree
Joined: Dec 2001
Posts: 197
Likes: 0
LT1's and LS1's are both single-core radiators.
93-96 LT1 is 1.3" thick core
97 LT1 is 1" thick core
All LS1 use a 0.8" core.
All 4th gen rad's use an aluminum core with plastic side tanks... Automatics have a tranny cooler in the driver-side tank, and 2000 to 2002 4th gens don't have a coolant level sensor on the passenger side (earlier models do though).
Most performance aluminum rads are only dual core, and typically use 1" or 1.25" tubes (there's debate on wether there's any appeciable difference, but I have a feeling it's only in systems that are border-line in their cooling abilities anyway).
93-96 LT1 is 1.3" thick core
97 LT1 is 1" thick core
All LS1 use a 0.8" core.
All 4th gen rad's use an aluminum core with plastic side tanks... Automatics have a tranny cooler in the driver-side tank, and 2000 to 2002 4th gens don't have a coolant level sensor on the passenger side (earlier models do though).
Most performance aluminum rads are only dual core, and typically use 1" or 1.25" tubes (there's debate on wether there's any appeciable difference, but I have a feeling it's only in systems that are border-line in their cooling abilities anyway).
On The Tree
Joined: Dec 2001
Posts: 197
Likes: 0
BTW, the AC condensor core is in front of the 4th gen rad. It serves as a great bug screen 
... but for a race application you defintiely wanta yank that thing out of there.
FYI, it's not an easy job and a total PITA... I'd never yank it unless I KNEW it wasn't ever gonna go back in.... and it has to be the biggest AC condensor I've ever seen. I'd bet it's 22"x17" like the stock rad and just as thick.
... but for a race application you defintiely wanta yank that thing out of there.FYI, it's not an easy job and a total PITA... I'd never yank it unless I KNEW it wasn't ever gonna go back in.... and it has to be the biggest AC condensor I've ever seen. I'd bet it's 22"x17" like the stock rad and just as thick.