I run A/C, I get burned...

[brandonshady]

Well if you are running the A/C then it's most likely hot as hell out. The heat of the day and the heat of the engine will thin the oil out a lot and cause the lower pressure. The car will run hotter as a result of the A/C and the knock you heard may have been clutch chatter from not enough RPM's.

I know my 5.0 was a total dog with the A/C on and even my new '03 GT runs like ass with the A/C on. It makes all sorts of funky noises and it tough to drive. I try not to use the A/C unless i really NEED it as a result.

I've driven other cars that you can't even tell when the A/C is on or feel such a loss of power....but in both my Mustangs running the A/C is such a huge loss of power.

yeah thats why I always run a higher amp alt & larger batt. in trunk mount. Trunk mounting your batt. has also proven to improve road grip, when placed above the right rear tire. I can't remember the exact mesaurment of gain (downforce pressure). But I could tell a diff in the vert. Coupe pulled as hard as before.

 

[HISSIN50]

There are some misconceptions out there. Running any more than 50% coolant does not help keep a car cool. Running any more coolant than necessary for one's climate will hurt performance (said another way, a given car will run cooler with more water/less coolant than it did before when it had more coolant and less water in the system.)

The increase in boiling point from antifreeze is slight (surprisingly so). And when one displaces antifreeze with water, the system is more efficient, so the slight boiling point decrease is offset because of the more efficient cooling media and process.

Each PSI in the system does raise the effective boiling point ~ 3*F. 16 PSI = ~ 48*F. That's right in the sweet spot - I agree fully that this is important.

 

[brandonshady]

There are some misconceptions out there. Running any more than 50% coolant does not help keep a car cool. Running any more coolant than necessary for one's climate will hurt performance (said another way, a given car will run cooler with more water/less coolant than it did before when it had more coolant and less water in the system.)

The increase in boiling point from antifreeze is slight (surprisingly so). And when one displaces antifreeze with water, the system is more efficient, so the slight boiling point decrease is offset because of the more efficient cooling media and process.

Each PSI in the system does raise the effective boiling point ~ 3*F. 16 PSI = ~ 48*F. That's right in the sweet spot - I agree fully that this is important.

so u agree that 50/50 is the best combo? ...I live in Texas "Dallas Area"

 

[HISSIN50]

so u agree that 50/50 is the best combo? ...I live in Texas "Dallas Area"

I live in a similar climate (Tucson). For optimal cooling while being concerned with lubrication and rust protection, I would run 70% water and 30% coolant (or even 80/20). Just check the stoichiometry before it freezes in the winter to ensure you have sufficient protection (it doesnt take much coolant to achieve decent freeze protection).

50/50 is the old standard recommendation for everyone, everywhere, any time of year. I like to fine tune this recommendation.

MHO.
Good luck.

 

[brandonshady]

HMMMM... I was always told a lil extra coolant was better in hotter climates. Guess they were thinking along the same lines as CMANN88 - more coolant helps boiling point mark.

* I'll try your method on my flush this weekend & see what the temp runs compared to before. I'm running straight water this weekend with additives to get the rest of that rust out.

 

[Cman88]

HMMMM... I was always told a lil extra coolant was better in hotter climates. Guess they were thinking along the same lines as CMANN88 - more coolant helps boiling point mark.

* I'll try your method on my flush this weekend & see what the temp runs compared to before. I'm running straight water this weekend with additives to get the rest of that rust out.

Well.. Lets use this as a reference. Its a quick link I dug up..

http://autorepair.about.com/library/glossary/bldef-033.htm

According to the site, a 50/50 mix will raise the boiling point from 212, to 276. Remember the ole formula for calculating the increase per psi? It came out to ~48 degree increase on a 16psi system, right? Well, the increase of a 50/50 mix comes out to a 64 degree increase in the boiling point over standard water. Of course, this is just going by the quoted website, but I know it plays a lot larger role then its made to seem in increasing the boiling point of just straight water. I'm not trying to argue or anything here, I just feel its more important then some people might think in increasing the boiling point as well as the other benefits coolant adds over straight water.

 

[91lxttrim]

Well if you are running the A/C then it's most likely hot as hell out. The heat of the day and the heat of the engine will thin the oil out a lot and cause the lower pressure. The car will run hotter as a result of the A/C and the knock you heard may have been clutch chatter from not enough RPM's.

I know my 5.0 was a total dog with the A/C on and even my new '03 GT runs like ass with the A/C on. It makes all sorts of funky noises and it tough to drive. I try not to use the A/C unless i really NEED it as a result.

I've driven other cars that you can't even tell when the A/C is on or feel such a loss of power....but in both my Mustangs running the A/C is such a huge loss of power.

Wow. I was installing my SC today so I didn't realize how many replies to the post came in...

Any way I agree. It must just be the Stang. I have a 99 GMC Sierra and I run the a/c all the time in that and don't even notice it. (It has the 5.7). I'm really leaning towards the upgraded radiator especially since I installed the supercharger today. Might pick one up this week since it's going to be above 103 ALL WEEK!!!

 

[HISSIN50]

CMan, I think you accidentally compared the BP of water at sea level (not under pressure) to a 50/50 mix under pressure. This would omit the ~ 50*F delta from the pressurization of the system.

From your same website (I chose this since the site was already used, though I found their wording to be a little ambiguous), see the chart half way down the page:
http://autorepair.about.com/cs/coolingsystem/a/aa081101a.htm

It's been some time since I did a lot of research on all this, so feel free to correct me where applicable. I also dont care about arguing - we both just want to put forward the most accurate info to help out others who have cars that are running a little hot.

 

[Mustang5L5]

Lol i am too tired tonight to join in on the discussion about pressures and BP's....brain is fried...