What's normal engine temp for spirited driving?
10-09-2017, 08:03 PM
#1
What's normal engine temp for spirited driving?
Last year I bought a 91 ZR-1 with 12,000 miles. I flushed all systems (cost me nearly $800!!!), changed the oil, and balanced the wheels. Then I started driving it in the twisties here on the Colorado Front Range.
Since the ZR-1 had set all those endurance records, I thought it would handle 30-minute sprints between 4000 and 6000 RPM without breaking a sweat. After all, that's where the fun is! But I noticed that after about 20 minutes my engine temp (the coolant, not the oil), hit the grey line that's about 2/3 of the way toward the end of the dial (don't remember what that temp is). A few particulars:
I expected the LT5 engine to handle spirited driving for quite a bit longer. Mind you, I did not abuse that engine, I simply drove it the way I thought it was designed to be driven, given that the torque peak is at 5700 RPM.
Does this sound right to you? Could there be a problem with a thermostat or other system? In regular driving, the engine runs quite cool.
Thanks for your help,
ape
Since the ZR-1 had set all those endurance records, I thought it would handle 30-minute sprints between 4000 and 6000 RPM without breaking a sweat. After all, that's where the fun is! But I noticed that after about 20 minutes my engine temp (the coolant, not the oil), hit the grey line that's about 2/3 of the way toward the end of the dial (don't remember what that temp is). A few particulars:
- I was not using the A/C.
- I was taking my turns at about 4000 RPM, accelerating, and shifting at about 6000 RPM, not what I would call pushing the engine, but not cruising, either.
- My speeds were between 40 and 60 mph most of the time.
- Engine coolant was full.
- Oil level was full.
- I didn't let the engine heat go over the grey "recommended" line. As it approached, I shifted into higher gears and cruised.
I expected the LT5 engine to handle spirited driving for quite a bit longer. Mind you, I did not abuse that engine, I simply drove it the way I thought it was designed to be driven, given that the torque peak is at 5700 RPM.
Does this sound right to you? Could there be a problem with a thermostat or other system? In regular driving, the engine runs quite cool.
Thanks for your help,
ape
10-10-2017, 09:14 AM
#2
Tech Contributor
That temp seems a little low IMHO however what was the outside temps as well? Its possible the Previous owner installed the fans on early mod to keep things cool as well. I would not be concerned. GC
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apehair (10-10-2017)
10-10-2017, 09:32 AM
#3
I believe that you get a "scanner" on it to actually confirm the temps and don't rely on the cluster gauge for anything. You can actually access the temps the ECM is seeing using the AC controls to compare. Rely upon the cluster gauges for nearly nothing other than an occasional glance.
if the TACH parks at 0 with KEY-ON but NOT RUNNING you can assume that the tach is reasonably correct. Check that when you use the scanner. RPM can also be checked using the AC controls. It might be interesting to just do comparisons of TEMP and RPM using the AC control.
You have the FSM I'm sure?
if the TACH parks at 0 with KEY-ON but NOT RUNNING you can assume that the tach is reasonably correct. Check that when you use the scanner. RPM can also be checked using the AC controls. It might be interesting to just do comparisons of TEMP and RPM using the AC control.
You have the FSM I'm sure?
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apehair (10-10-2017)
10-10-2017, 11:34 AM
#4
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your running too much rpm for the given speeds any engine will heat up some doing that
Last edited by cv67; 10-10-2017 at 11:36 AM.
10-10-2017, 12:06 PM
#5
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OP: The key point too is the the cluster gauges are notorious for being, lets say, less than precisely accurate. One would need to see what the digital readout was to be sure.
Marc Haibeck provided me with a chip that turns BOTH fans on at 205ºF, and both off again if temps fall below ~ 200ºF. My temps seldom get much more than about 220-225ºF in spirited mountain twisty driving - for what that's worth.
I'm familiar with those roads on the front range. Looking forward to doing them in the Z next summer!
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apehair (10-10-2017)
10-10-2017, 01:20 PM
#6
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When i first got my 93 temps would creep up to 225-230 even with fans on and stay, I replaced the thermostat and all was good I also went with Marc Haibeck's chip, never see over 205- 210 now.
Last edited by FASTAZU; 10-10-2017 at 01:21 PM.
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apehair (10-10-2017)
10-10-2017, 05:49 PM
#7
Burning Brakes
First verify the accuracy of the gauge.
If the gauge checks out, I would remove the fan shroud and inspect between the back of AC condenser and front of the radiator for debris - leaves, grass clippings, dead rodents, etc...
Also, shine one side of the radiator and see if the light comes through. Pretty much all ZR-1 radiators I have seen were hampered by years of vacuuming the roads.
If the gauge checks out, I would remove the fan shroud and inspect between the back of AC condenser and front of the radiator for debris - leaves, grass clippings, dead rodents, etc...
Also, shine one side of the radiator and see if the light comes through. Pretty much all ZR-1 radiators I have seen were hampered by years of vacuuming the roads.
Last edited by secondchance; 10-10-2017 at 05:51 PM.
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apehair (10-10-2017)
10-10-2017, 07:14 PM
#8
I believe that you get a "scanner" on it to actually confirm the temps and don't rely on the cluster gauge for anything. You can actually access the temps the ECM is seeing using the AC controls to compare. Rely upon the cluster gauges for nearly nothing other than an occasional glance.
if the TACH parks at 0 with KEY-ON but NOT RUNNING you can assume that the tach is reasonably correct. Check that when you use the scanner. RPM can also be checked using the AC controls. It might be interesting to just do comparisons of TEMP and RPM using the AC control.
You have the FSM I'm sure?
if the TACH parks at 0 with KEY-ON but NOT RUNNING you can assume that the tach is reasonably correct. Check that when you use the scanner. RPM can also be checked using the AC controls. It might be interesting to just do comparisons of TEMP and RPM using the AC control.
You have the FSM I'm sure?
Lots of good suggestions. I've got a temp scanner, but have never gotten it out of the drawer to use it. I'll start doing that, now.
Rick
10-10-2017, 07:17 PM
#9
The 24 hour speed/endurance record was set at Stockton, operating within those rpm parameters. Just sayin.
OP: The key point too is the the cluster gauges are notorious for being, lets say, less than precisely accurate. One would need to see what the digital readout was to be sure.
Marc Haibeck provided me with a chip that turns BOTH fans on at 205ºF, and both off again if temps fall below ~ 200ºF. My temps seldom get much more than about 220-225ºF in spirited mountain twisty driving - for what that's worth.
I'm familiar with those roads on the front range. Looking forward to doing them in the Z next summer!
OP: The key point too is the the cluster gauges are notorious for being, lets say, less than precisely accurate. One would need to see what the digital readout was to be sure.
Marc Haibeck provided me with a chip that turns BOTH fans on at 205ºF, and both off again if temps fall below ~ 200ºF. My temps seldom get much more than about 220-225ºF in spirited mountain twisty driving - for what that's worth.
I'm familiar with those roads on the front range. Looking forward to doing them in the Z next summer!
Thanks for the Marc Haibeck reference. Looking into it ...
Rick
10-13-2017, 04:26 PM
#10
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One of the priorities is gathering data on those very roads with regard to scenery, road condition, etc., and a modestly priced hotel to serve as our base of operation for 2-3 nights.
I'm on the committee. PM me and we'll see what shakes out!