FastMatt2

Is there a way to test if the Stat is opening? Yesterday I got in a race with a C5 on the HW in my 94 ZR-1, and I pulled it up to 180, when I let off and looked down my "check gauges" light was on, and my oil temp was nearly maxed out. I clicked the gages button to pull up what the Oil temp was and it was 272deg! Water temp was only 208 deg . It was about 110deg out side. I put it in 6th and drove at 75mph, and it took almost 20 min for it to drop to 230deg… (I’m running 15W50 Mobil 1)

With the size of the oil cooler I would think the oil would not get near that hot.


do I just need to up-grade the oil cooler for this NM heat?

Bans25

Wow... I wonder if the sensor is getting wacky?

ZR-1DUDE

I put a Fluidyne cooler in and it didnt' fix it. 1994 #103 - Was running a 911 the other day and had the engine in high RPMS for 10 minutes or so - same check gauges and the secondaries kick out. What serial number is your ZR-1?

Of course in Dallas, it is pretty hot. I am thinking of just driving the ZR-1 in the winter and putting it up for the summer.

D.

FastMatt2

How do I know what # ZR-1 I have? is there a way to cross ref the VIN # or something?


did the larger cooler help at all? How On earth did thy run these things for 24hrs at WOT?? less thy found a place were it was night , and 70deg out for 24hrs lolol

At night I have never had it go near this high.

the thing I really find funny is that my the 94 LT-1 vet I had you could run flat your for as long as you wanted and the oil temp never went over 250ish. and it has less oil, and no oil cooler.




[Modified by FastMatt2, 2:29 AM 7/7/2003]

90 Corvette ZR-1

The number of the car is the last 4 digits of the VIN

ZR-1DUDE

Don't get me to lying. I have the fluidyne radiator and oil cooler - didnt' fix it. It is better, but not as good as my z06. Brian says I just beat the pine tar out of it too much...

D.

FastMatt2

cool, I have #207 then:)

xsmph

i dont think that is normal, i have never seen my gage on my 90 go past the mid point on worse case scenarios. During racing is just at 1/3 of the total read out.. it is either the gage sensor, or the thermo on the oil filter housing....
I see the water temp hotter than the oil temp in mine all the time.... around 20 deg. more ...



[Modified by xsmph, 9:19 PM 7/6/2003]

The Lurker

Could it be that the oil, much like the water, kinda goes into bypassmode under high RPM situations? Perhaps, the whole cooler, even filter, may be not "needed" under high pressure, high RPM situations? Ah-ehm, you may want to check the operation of the cooler valves and how they work.

FastMatt2

what are the part #'s for the fluidyne radiator and oil cooler, i'm going to order them.

Tyler Townsley

What he is really trying to say is if you have a stock thermostat you have no water flow through the radiator starting at 5200 and by 5800 it all goes around the radiator straight back into the block. If you don't do something about this all no aftermarket radiator is going to help.

When the water gets really hot the temp guage is inaccurate because the sensor sees more air than water.

Tyler


[Modified by Tyler Townsley, 8:02 AM 7/7/2003]

ZR-1DUDE

So - do I buy another thermostate, take it out, or drill it?

They say they test the ZR-1 out in deather valley, etc - they need to do it in FLA or TX for the real test. :-)

Tyler,
What else have you done to yours to make it run cooler?

D.

ShawnZR-1

There was a very interesting e-mail thread on the ZR-1.net a few months ago about this very same subject. From what I gathered (and there was a ton of reading and mis-information), there is a valve in the thermostat housing that re-directs the flow of the coolant simply because the radiator couldn't handle the pressure and flow at such high RPM's. But that raises the more important question that you already asked: How in the world can you run the car at 6500 rpm for 24 hours??? Something has to be modified.

Now, more to your original question of the oil temp going through the roof. I'd say something isn't flowing correctly. When I had my beast on the road course, my water temps would spike at 260*+ but oil temps didn't get too far above 250. I was running between second and third gear always above 3500 rpm (gotta keep those secondaries open!). I'd be WOT through 2nd right up to 7200 then to third again up to 7000, brake for the turn, feather, WOT, rinse, repeat. 12 turn course.

ZR WON

Shawn:

You wrote:

But that raises the more important question that you already asked: How in the world can you run the car at 6500 rpm for 24 hours??? Something has to be modified.

It was modified.. The car had 3.07 gears and was turning right at 5800RPM as I recall. My guess, right before the coolant bypass completely cut off water to the radiator. Also, it wasn't very hot outside when they made the record run so just a little water into the radiator might have been enough to keep it cooler?!?!? Very interesting

Tyler Townsley

I asked Tommy that same question and his answer was 'Huh? Didnt know that'. Bottom line they got lucky. Outside temps were near freezing and they limited it to 5700 rpm max which allowed enough water flow to keep it cool

If I were to do events with the ZR1 like you guys are doing I would go to an aftermarket radiator that will handle at least 100 gpm and cut the large spring in the thermo which allows water flow all the time(the small spring is for the bypass). In winter use a cardboard cutout to block the radiator for heat or switch back to stock thermo. You have to have a thermo in the system . If and only if you cut the large spring in the therm you can use a 1 in pvc plug to block the bypass route. Never try to use a cut thermo in a stock system its taking a chance you do not need take.
Max HP in a ZR1 occurs at a 157 to 165 deg water temp.

Tyler

PS There are many threads on this problem in the archives.

ZR WON

Tyler:

What do you mean, "Cut the large Spring?" Cut it in what way???

ZR1 MK

I have the Fluidyne stacked 3 row radiator and 4 row oil cooler. The radiator comes in 4 row version, but restricts airflow more than 3 row. With a/c condener in front of radiator, I choose the 3 row unit. I'm planning on trying a 1" plug with 3/8" to 1/2" hole rather than eliminate the bypass entirely. What about the thermostats that have 9 lb vs 5 lb of spring pressure built into them for bypass opening?
Mike

Tyler Townsley

Take a dremell tool and cut it out so the thermo is open all the time.

Do not mess with the bypass unless you are very careful. The system depends on the bypass when its cold to route water to the thermo so it can function. If it is closed and you have restricted the bypass you could be trying to force 90+ gpm through that restriction and that will blow the radiator. Also the motor will get hot faster than the thermo will open in a restricted setup.
http://temp.corvetteforum.net/clubs/tyler//thermo.jpg

BTW the system was designed by a GM engineeer and it is more complex than first glance would suggest.

Tyler


[Modified by Tyler Townsley, 3:22 PM 7/7/2003]

The Lurker

The oil cooler also gets bypassed in high RPM operations. Have fun.

FastMatt2

what it the point of a oil cooler if it get's shut off when you need it?