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#21 | |
![]() Join Date: Jul 2010
Location: Woodstock, Ontario, Canada
Posts: 1,275
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Looks like increasing w/p speed is the "correct" way to tackle this. The 1st world issues that we have. The ZF trans combined with high rear gears, coupled with a high rpm LT5 all combine to give us non-optimal off idle cooling.
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peace Paul ZR-1 Net Registry Member #1494 |
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#22 |
![]() Join Date: Jan 2015
Location: Decatur, AL
Posts: 93
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I think I've installed over 50 sets of underdrive pulleys in my life, maybe many more than that. The percentage reduction has little effect with cooling at high RPM, but at lower RPM and idle it is more noticeable. Alternator and cooling can be greatly impacted at idle. So, if you are underdriven by 25%, at the 15 gpm flow rate listed by Dynomite at 800 rpm, your waterpump is seeing only 600 rpm equivalent. That would be around 11.25 gpm. Underdrive pulleys are great for a small increase in HP as long as cooling and charging is not impacted.
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1990 ZR1, 1987 Mustang GT (since new), 1973 DeTomaso Pantera, 1987 928S4 Passed on: 1984 930S (gray market), 1988 Mustang Coupe Trooper car(drag) |
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#23 |
Join Date: May 2007
Location: Chicagoland, IL
Posts: 9,697
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The previous thermo had 4 holes drilled. I'm going to drop the coolant and put 2 small holes in the stock 180. We'll see if that mitigates the effect of under drive pulleys at idle and slow cruise.
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[SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX |
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#24 |
Join Date: May 2007
Location: Chicagoland, IL
Posts: 9,697
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Ok, coolant is back in the car. We put 2 holes in the thermo. Previous therm had 4. Haven't driven it yet, but I started it to get coolant back through the system and burp it. Temps got to 104C and then stabilized. I was able to then put another 3 quarts in. I'll let it sit overnight to burp it further, then maybe get a chance for a run later this week after the rain. Maybe a pizza run.
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[SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX |
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#25 | |
![]() ![]() Join Date: Aug 2009
Location: South Dakota/California
Posts: 3,794
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Let us know what happened. My experience is just a bit over 200 deg F in sixth and drops to less than 190 deg F in fifth on relatively cool days such as you will have in Chicago on Fri or Sat but will run that experiment again on Thur and Fri here in South Dakota. I will run an identical experiment in SD on Thur or Fri (will be very close to 70 deg F) and report back to you using a relatively stock 90' with Haibeck Chip, Multi Core Aluminum Radiator, and Stock DIfferential. I will report Speed, Outside Air Temperature, HVAC Coolant Temperature (Go to #16), Gear, and assuming no wind that may effect Air Flow one way or other. I wil also report the approximate time Coolant Temperature re-stabilizes after shifting from sixth to fifth gear. Again......this experiment will be done at 70 deg F Outside Air Temperature within a couple degrees. In CA at 100 deg F outside Air Temperature it is quite obvious the differences in cooling running moderate speed (55-60 mph) in sixth gear vrs fifth gear except the Coolant Temperatures do run a bit over 200 deg F even in fifth Gear and approach 215-220 deg F in sixth gear. This using a 90' ZR-1 with Haibeck Chip and Multi Core Aluminum Radiator. Oh.....I run with Debree Screen Clean Radiator, Clean Oil Cooler, and Clean Air Condensor and Green Antifreeze good to minus 20 degrees F in all vehicles. One 90' I am running is good to 0 deg F which I may add some antifreeze ![]()
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Left Clickable links ![]() -Solutions- LT5 Modifications/Rebuild Tricks Low Mileage ZR-1 Restoration 1990 Corvette (L98) Modifications LT5 Eliminated Systems LT5 Added Systems LT5/ZR-1 Fluids 1995 LT5 SPECIFIC TOP END REBUILD TRICKS Last edited by Dynomite; 10-26-2016 at 09:39 AM. |
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#26 |
Join Date: May 2007
Location: Chicagoland, IL
Posts: 9,697
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That's part of my plan. I'll do some idle testing today, then the FBI is having a Pizza Night Friday for our Corvette Challenge victory (again).
BTW, the 92 has a direct Coolant readout, along w other gauges, on the Speedo display.
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[SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX |
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#27 | |
![]() ![]() Join Date: Aug 2009
Location: South Dakota/California
Posts: 3,794
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Ron Davis Radiator. Haibeck Chip (fans ON 205 deg F, OFF 200 deg F). 1990 ZR-1 #72 (40,000 miles). Stock Exhaust. 180 deg F Thermostat. Green Antifreeze down to -10 deg F. 6th Gear 65 mph 1,500 rpm 207 deg F Engine Coolant Temperature 5th Gear 65 mph 2,200 rpm 190 deg F Engine Coolant Temperature 17 deg F cooler running 65 mph in 5th Gear rather than running 65 mph in 6th Gear. Did the cycle several times with identical results. Coolant Temperatures moved from min to max and back in a minute or two after shifting Gears. Idle at 850 rpm 203 deg F. Got this Alternator diagnosed on this run and it turns out the Rectifier was burned/shorted....New Rectifier on Ebay for $68. This Alternator will go into 1990 #72 later on (130 amp Alternator) ![]()
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Left Clickable links ![]() -Solutions- LT5 Modifications/Rebuild Tricks Low Mileage ZR-1 Restoration 1990 Corvette (L98) Modifications LT5 Eliminated Systems LT5 Added Systems LT5/ZR-1 Fluids 1995 LT5 SPECIFIC TOP END REBUILD TRICKS Last edited by Dynomite; 03-30-2017 at 08:42 PM. |
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#28 |
Join Date: May 2007
Location: Chicagoland, IL
Posts: 9,697
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Ok so today, first try
Ambient Intake Temp 53F/12C Idle condition 850-900rpm Coolant Temps 86C Stable Fan 1 operating
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[SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX |
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#29 | |
![]() ![]() Join Date: Aug 2009
Location: South Dakota/California
Posts: 3,794
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You have a fan running at 187 deg F??? When do your fans come on and off? My fans with Haibeck Chip (fans ON 205 deg F, OFF 200 deg F). What Radiator are you using? I will do some idle tests tomorrow also at 70 deg F outside Air Temperatures ![]() I am assuming you have stock Differential and would run same RPMs at 65 mph as I noted. I just observed my Speedometer and RPMs so could be off a bit but think I am pretty close to speed vrs rpms.
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Left Clickable links ![]() -Solutions- LT5 Modifications/Rebuild Tricks Low Mileage ZR-1 Restoration 1990 Corvette (L98) Modifications LT5 Eliminated Systems LT5 Added Systems LT5/ZR-1 Fluids 1995 LT5 SPECIFIC TOP END REBUILD TRICKS Last edited by Dynomite; 10-27-2016 at 11:54 PM. |
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#30 |
Join Date: May 2007
Location: Chicagoland, IL
Posts: 9,697
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I do my own calibrations. Fan 1 comes on at 83C, Fan 2 @ 89C
I am using a Fluidyne rad and 180 Thermo. Diff is 4.10 BUT w 19" Z06 wheels/tires. So overall ratio is more like a 3.55.
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[SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX |
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