Z/28: improving radiator and oil cooler?

[McRat]

Well, I could not find either the protect tables or AC Overtemp setting with HPTuners.

But I installed it as "normal" not "advanced".

It is free to download and look at the Z/28 file that is posted.

All I can tell from it is:

Fans are not 2 stage, they are PWM. Full speed (91%) occurs at 214°F.
A/C is programmed off at 5000 rpm or at 200% throttle (no WOT cutoff).

I'll reinstall it as Advanced and see what else is visible.

I don't have an EFILive file to look at. :(

[90503]

...I think you guys are trying to fix something that isn't broke and perhaps forgetting one of the main features of the car that you paid for...It's under warranty....

If something fails or breaks due to the warrantied design, not your problem....I'd just drive/track the crap out of it, regardless of the temp readings....Mess with it to try and make it better at your own expense, and you may ironically void your warranty....Good luck....

[brt3]

Originally Posted by McRat

...Fans are not 2 stage, they are PWM. Full speed (91%) occurs at 214°F.

A/C is programmed off at 5000 rpm or at 200% throttle (no WOT cutoff).

Very nice to have this information; thanks!

[brt3]

Originally Posted by 90503

...I think you guys are trying to fix something that isn't broke and perhaps forgetting one of the main features of the car that you paid for...It's under warranty....

If something fails or breaks due to the warrantied design, not your problem....I'd just drive/track the crap out of it, regardless of the temp readings....Mess with it to try and make it better at your own expense, and you may ironically void your warranty....Good luck....

I did use the term "overkill". However, I think there's a valid need -- for people running this car hard in very hot weather -- to add a little margin of safety. My last run of the day I ran the car around the access roads for 5-10 minutes to get the temps down. I have had other stock production track day cars that handled the coolant temps better, so I'd like just a little bit better cooling to eliminate any issues.

Note that I won't be doing this today, tomorrow, or even this year. I'll figure out the best way to do this, look at the cost, and then decide whether or not it's worth it.

Like they say, one man's meat is another man's poison...

[brt3]

Originally Posted by backtotintops

great idea brt...I don't think that would mess with the warranty....cover the front of the oil tank.

on the Stohr we used the gold shielding...apparently the same as nasa uses and the only place I could ever find it was here http://www.britsinc.com/

anyone know any other sources? It's the best.

Here's one from DEI on Amazon: FOLLOW THE LINK.



I also see this stuff on Pegasus Racing, Jegs, etc...

[cdb95z28]

Originally Posted by backtotintops

looks like they forgot to take the rain shield out....doooooh...or more likely they knew nothing about the proper track prep for the car. sloppy sloppy!

That was the first thing I noticed when I received that issue, then I read the article. It was the first time I had a desire to write a magazine and chastise them, but Chevrolet deserves some fault. The Chevy people who send them the car, they should be on top of it....

Removal of rain shield was my 2nd mod, and a cool benefit is seeing the heat escape from it while sitting at a stop

[madmax13]

Originally Posted by backtotintops

yes I heard about that...please explain "overheated" at that event?...was it spurting out coolant???...and do you know if they followed the guidelines as in using mobil-1 15-50, removing the rain shield and changing the coolant mix??? I never heard the answer to that so until I hear otherwise I'm very confident in this well engineered car. It has not been an issue for me so far but I have only run it 30 minutes at a time and at no more than 85 degree ambient.

Understood... I do not own a Z/28 nor have I driven one... just reporting what I've heard... it seems that they did not follow procedure (stupidly).... time will tell

[McRat]

I have not figured out what GM considered to be overheated for the Z/28. Other GM engines are in the 250's.

BUT... If have done the req prep, and your coolant temp is over 235, I'm now thinking that there is meat on the table. I was thinking the high speed fans were coming on late, say 224+, but that's not true. The higher that temp is, the less HP you make, and the more octane is required before Knock Retard kicks in.

So while I will run a 160 therm, it's not related to the high temps seen. It's used to move your fan points down.

Wish my car would arrive. I'd like to look at how they did the radiator airflow. There might not be enough flow. But the more air you allow into the radiator, the more aero drag you get.

The saving grace is that the hotter the coolant temp gets, the more heat the radiator moves.

[McRat]

Originally Posted by madmax13

Road and Track did a Z/28 compro this month and it overheated three laps in (this was in the desert, but the other cars, Viper, GT-R, Aston, etc,did not). So... it sounds like this might be an "issue".

I doubt they overheated it.

There is a difference between running hot and overheating.

Note that speed comes into play, not just DA. The slower the track is, the less air the radiator gets. While fans are great, no fan in any car can compete with 100mph airspeed.

[X25]

At the track lower thermostat would not help on anything at all. We're well past 215s on coolant temp at the track, so OEM thermostat is already fully open. Changing A/C shut off point also sounds like a very bad idea. Moving on, why change fan settings? Fans don't help once your car starts moving, and you won't be hitting a traffic light while tracking your car.

The real issue is the cooling capacity. Z/28 already comes with enlarged heat exchanger, so upgrading the radiator might help. Upgrading radiator helped me drop oil temps by about 15 degrees with my 2013 Corvette Z06, but it did not help with my 1LE with its smaller heat exchanger. For this reason, I ended up replacing the stock engine oil cooler with an air-to-oil cooler as I've explained here: http://www.camaro5.com/forums/showthread.php?t=381050

If I had a Z/28, I'd first replace the radiator and see if it helps enough. If not, when you replace the oil cooler and add a big oil cooler core in front of your radiator, the upgraded radiator will still be helpful since it will be able to keep cool with less cool air now flowing through...

I'll be testing my new oil cooler tomorrow at the Oregon Raceway Park. I'm a little nervous, in case I have a leak or something like that; wish me luck

[sho928]

I would concentrate on oil cooling, with piston squirter 50% of engine heat is carried away by the oil.

I do not recommend a larger rad unless you need AC for each 30-min session.

Formula One engines purposely run hot in order to gain combustion efficiency to increase HP

The LS7 is borderline in passing emissions thus GM intended it to run hot; again to gain combustion efficiency, if a rad large enough to keep temps at 185 degrees is used, the LS7 may run to rich and actually loose HP.

As per convention any way to reduce IAT's is beneficial for HP

The key to longevity is to keep oil temps down, the viscosity loss at 290 degrees off set any oil film strength gained by using 15-50W M1.

Can cooling air be directed at the sump tank, every bit helps?

[X25]

I don't think sump tank is a good conductor. Isn't it just plastic?

[sho928]

Originally Posted by X25

I don't think sump tank is a good conductor. Isn't it just plastic?

the top 1/3 is plastic but the lower is all aluminum on the newer Z06 C7 tanks and I thought the Z51 C7 as well, my thinking is these went into the Z/28 as well.

http://www.camaro5.com/forums/showthread.php?t=285402

Actually the write up on the 2014 Z/28 confirms this, thus basically the oil in the tank is fully contained by the aluminum portion at the fill level line, an opportunity for added cooling by putting the tank in a sealed water bath that then gets circulated to a large front mounted water to air exchanger.

This avoids getting your large aftermarket front mounted oil cooler holed by running too close to cars kicking up broken asphalt cutting the apex too much.

The stock oil cooler is placed in area safe from this hazard.

[X25]

Originally Posted by sho928

the top 1/3 is plastic but the lower is all aluminum on the newer Z06 C7 tanks and I thought the Z51 C7 as well, my thinking is these went into the Z/28 as well.

http://www.camaro5.com/forums/showthread.php?t=285402

Actually the write up on the 2014 Z/28 confirms this, thus basically the oil in the tank is fully contained by the aluminum portion at the fill level line, an opportunity for added cooling by putting the tank in a sealed water bath that then gets circulated to a large front mounted water to air exchanger.

This avoids getting your large aftermarket front mounted oil cooler holed by running too close to cars kicking up broken asphalt cutting the apex too much.

The stock oil cooler is placed in area safe from this hazard.

I think even if you added a tiny little oil cooler core to the line going to the sump, it would still cool the oil better than the sump ever would.