7th Gen ('06-'07): Hi pressure radiator cap
#2
10-09-2012, 10:03 PM
What is wrong with the stock one?
If stock is really 18psi and not 15 as you have stated- that is already relatively high.
If stock is really 18psi and not 15 as you have stated- that is already relatively high.
#3
10-09-2012, 10:42 PM
Join Date: Apr 2009
Location: Pittsburgh, PA
Posts: 11,978
Chad, (bumpin) I think he's looking for something for a friend for this build?
Car is near complete. A lot of updates, mostly rework to things that either I did not like or just wasn't working. 2 big issues left. Front end is slamming/crashing when I hit a bump over 20 MPH. All new LCA's. Could be the issue. My tech thinks its the change in cradle geometry causing the banging, cradle has been lowered. Has to put a scope to several areas when driving and try and reproduce sound and exactly where it is coming from to fix. The other issue is cooling. Running 205 F / 195 F on the highway and the fans do not shut off. Airflow needs to be re-directed or more air flow needed - my tech is in the middle of doing that now. Rear suspension reworked to fit larger tires. Dash reworked and repaired. Redoing again to use dual gauges for more monitoring. New front end (Impala). Hood vents installed ('94 GTP) may need NACA's vents also not sure. Tranny pan spacer installed. New BHJ damper installed. Larger Turbo installed. Water tank & ice box in trunk for intercooler. Oil accumulator installed, remote battery shut off installed. New 150/170 AMP alternator installed. Exhaust recoated. New LED platium tailights/Depo heatlights. Leather shift ****. Drivers racing harness. Fire extinguisher. New Waldon fuel pump. Final dyno numbers 814.8 WHP. Lost 8 HP with 2 rerouted header tubes due to melting plug wires. Line lock installed on both rear wheels - single covered switch at shifter. Lots more - too much to remember - any questions ask. Thank you for the interest. Got to meet XR7supercat - great guy. Our cars look like twins, his is '06 & mine is an '07
#4
10-09-2012, 11:21 PM
If that is the car that it is about, then a high pressure radiator cap isn't the answer at all IMO.
Rolling down the highway, it shouldn't be making drastically more heat than any other LSx powered Wbody. There are plenty of LS4 guys with bare headers, and LS4 guys with cartuning turbos (even with air to air ICs blocking the radiator) that don't have cooling issues.
I realize at WOT, this thing will generate some significant heat- and the radiator should be upgraded to match based on the extra heat input, and the time the engine will stay at the elevated power levels (not sure if his radiator is upgraded or not)- but driving around, especially at highway speeds and given SE MI's current weather (weather.com said Detroit today was a high of 51, low of 35)- there is absolutely no reason for it to be having trouble keeping cool unless there is a problem in the cooling system.
Upping the rad cap a couple pounds (I've never seen one over 20 psi)- isn't going to magically help the car run 30+* cooler (or whatever thermostat is in there).
My other concern- if it is that cool out, and even with both fans running while driving down the highway- it is having a hard time staying cool at very low power levels; then any decent length WOT runs are completely out of the question because the system is nowhere near sufficient to be able to cope with that extra heat, once you add in the extra heat absorbed by the engine from fuel processing efficiency, plus the heat generated when the exhaust is forced through the turbo (instead of bypassing it through the wastegate), plus the added heat of the intake air and piping from compressing the extra air.
Rolling down the highway, it shouldn't be making drastically more heat than any other LSx powered Wbody. There are plenty of LS4 guys with bare headers, and LS4 guys with cartuning turbos (even with air to air ICs blocking the radiator) that don't have cooling issues.
I realize at WOT, this thing will generate some significant heat- and the radiator should be upgraded to match based on the extra heat input, and the time the engine will stay at the elevated power levels (not sure if his radiator is upgraded or not)- but driving around, especially at highway speeds and given SE MI's current weather (weather.com said Detroit today was a high of 51, low of 35)- there is absolutely no reason for it to be having trouble keeping cool unless there is a problem in the cooling system.
Upping the rad cap a couple pounds (I've never seen one over 20 psi)- isn't going to magically help the car run 30+* cooler (or whatever thermostat is in there).
My other concern- if it is that cool out, and even with both fans running while driving down the highway- it is having a hard time staying cool at very low power levels; then any decent length WOT runs are completely out of the question because the system is nowhere near sufficient to be able to cope with that extra heat, once you add in the extra heat absorbed by the engine from fuel processing efficiency, plus the heat generated when the exhaust is forced through the turbo (instead of bypassing it through the wastegate), plus the added heat of the intake air and piping from compressing the extra air.
Last edited by bumpin96monte; 10-10-2012 at 04:57 AM.
#5
10-14-2012, 06:02 PM
Looks like I opened a can of worms here. Maybe I can give you some info so you know where I am coming from. This is my car. Driving with the fans on constantly was done at 4000 feet plus elevation on a 98F day in Utah not Michigan with the car continually at 205F. The consenses is I am not getting enough air flow through the radiator to cool down the coolant. The car no longer has the original factory air dam just a flat piece of ABS underneath - this may be a main source of my problem - yet to be determined or we have to evacutate more heat out of the engine compartment - we just don't know for sure yet. The stack I have in front of the radiator consists of the following: A smaller low temperature radiator, the intercooler and two pusher fans and the A/C condensor. And the radiator has been upgraded. 18 fins/inch and 1-1/4" tubes. And the volume of water itself around my cylinders has been reduced from stock because I do not have a cast block but an aluminum machined block.
My reason for the question is that I have been researching pressurized cooling systems that NASCAR is starting to use because alot of Nascars have restricted air flow which is what I believe may be my case. Nascar systems typically run with a pressurized system 33/35 PSI without boil over. My thought was if I could increase the boiling temperature on my system as a precautionary measure i could minimize the chances of a boil over. this way the liquid stays liquid and does not turn to steam, steam does not cool. I was reading some road racers using LX motors run 265F all day with pressurized systems with no overheating at all. I just wanted to boost my pressure up a couple pounds as added insurance that's all and I did not know where to purchase a 20# cap. But as I have found out - some newer LS motors are running hotter from the factory and GM has increased the pressure rating on some of their newer cars (information I got from Stant). I was able to find a 20# cap - one off a 2011 6L Camaro. It comes stock with a 20# cap. Thanks for all our help.
My reason for the question is that I have been researching pressurized cooling systems that NASCAR is starting to use because alot of Nascars have restricted air flow which is what I believe may be my case. Nascar systems typically run with a pressurized system 33/35 PSI without boil over. My thought was if I could increase the boiling temperature on my system as a precautionary measure i could minimize the chances of a boil over. this way the liquid stays liquid and does not turn to steam, steam does not cool. I was reading some road racers using LX motors run 265F all day with pressurized systems with no overheating at all. I just wanted to boost my pressure up a couple pounds as added insurance that's all and I did not know where to purchase a 20# cap. But as I have found out - some newer LS motors are running hotter from the factory and GM has increased the pressure rating on some of their newer cars (information I got from Stant). I was able to find a 20# cap - one off a 2011 6L Camaro. It comes stock with a 20# cap. Thanks for all our help.
#6
10-15-2012, 08:06 AM
Are you sure that all of the components in the cooling system will be capable of handling the additional pressure? The cooling system of race cars that utilize high pressure are designed to handle the additional pressure - braized/welded radiators, high performance water pump, braided hoses, no heater core, premium gaskets, etc. Higher pressure will raise the boiling point of the system, but it won't decrease operating temp. I just don't think a higher pressure cap is going to offer the results you're looking for, but it could create bigger problems. I'd look for ways of getting rid of underhood heat and actually lowering the coolant temp rather then increasing system pressure.
#7
10-15-2012, 07:23 PM
Well the radiator will take the pressure - that is absolutely not an issue, I have a stock pump designed for 18# and I am only going to 20# (that's a chance I will take, an 11%+ increase over stock). I have added an inline Meziere pump to the system. I have all new stock hoses and a 160F thermostat and running a 70/30 coolant mix with Redline water wetter. I am trying to eliminate underhood temperatures but lowering the temps has been a bit elusive. Have cowl vents and hood vents. As I have mentioned I believe I have to figure out how to increase air flow through the radiator and I am just not sure how I can accomplish this. Will be measuring the barometric pressures next in front of and behind the radiator and hopefully this will give me some clue where the problem is exactly and then just figure out how to direct/redirect air flow. My lower stock air dam is gone and this maybe some of my problem. I do know higher pressures will increase the boiling point of my coolant and not lower my coolant operating temp. In that case I just want a little added insurance against boil over. I really have appreciated all the feedback I am getting.
#8
10-15-2012, 07:48 PM
Join Date: Jan 2011
Location: St.Louis , MO.
Posts: 7,523
Well the radiator will take the pressure - that is absolutely not an issue, I have a stock pump designed for 18# and I am only going to 20# (that's a chance I will take, an 11%+ increase over stock). I have added an inline Meziere pump to the system. I have all new stock hoses and a 160F thermostat and running a 70/30 coolant mix with Redline water wetter. I am trying to eliminate underhood temperatures but lowering the temps has been a bit elusive. Have cowl vents and hood vents. As I have mentioned I believe I have to figure out how to increase air flow through the radiator
#9
10-15-2012, 08:00 PM
With the additional pumping action and the 160° stat it makes me wonder...Maybe the air flow to the radiator is sufficient. Maybe the coolant isn't remaining in the block long enough to collect much heat and/or stay in the radiator long enough to radiate that heat?
#10
10-17-2012, 07:40 PM
Well the trial and error experiments will be going on this week and next - I will post updates on the findings as I get them. I just don't know how to solve this issue, hopefully my tech will find an answer. Running 205F with the fans running constantly at highway speeds is unacceptable and must be corrected. I have my fingers crossed.