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#11 | |
Join Date: May 2013
Location: Chicago
Posts: 978
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The AC on my :93 does not work but no cooling issues. Edit: Pete also drilled a few holes in my t-stat to increase flow and I have a DeWitt aftermarket radiator. Ultimately a electronic water pump is best but do you want to risk the pump not working for some reason and risk blowing an engine?
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1993 ZR-1 #211 Yellow On Beige Beast #2 1992 ZR-1 #427 Black On Black *Sold* 1985 L98 Blue On Blue *Sold* Last edited by Karl; 09-03-2019 at 11:19 PM. |
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#12 |
Join Date: Oct 2018
Location: ohio
Posts: 68
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So if you get a better radiator that can withstand more pressure could you take apart the bypass and shim the spring so it doesn't bypass till a higher pressure?
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#13 |
![]() Join Date: Jan 2018
Location: Calgary, Canada
Posts: 72
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im going to find out! just bought a dewitts.
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--------------- VikingTrad3r Calgary, Canada 1991 ZR1 # 888 - daily drive whenever possible 1991 ZR1 engine from unknown sn. 1990 Z51 zf6 being built into narrow body ZR1 racer 1987 z52 auto - sold 1986 'z31' 4+3 - sold 1985 Z51 auto - sold |
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#14 | |
![]() Join Date: Dec 2003
Location: Arcadia,OK
Posts: 3,385
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Installing a different radiator with increased flow capacity, will reduce the back-pressure at the bypass loop. In turn, the bypass valve spring on the thermostat will remain closed until the flow rate is increased sufficiently to once again create sufficient pressure to open the bypass. Bear in mind that the thermostat at the discharge side of the radiator also contributes to back pressure and will at some point, yet to be determined, become the next critical bottleneck to eliminating the bypass system.
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Jerry Downey JERRYS LT5 GASKETS & PARTS http://www.jerrysgaskets.com 1994 ZR-1, Black/Black, Lingenfelter Aerobody, 416cu in, 3.91 gears, coil-over susp, Brembo brakes, etc. 2016 Black-Red, 3LT-Z51 Auto 8-speed. |
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#15 |
![]() Join Date: Apr 2007
Location: Northern VA
Posts: 2,655
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Before you start changing the cooling system design a full understanding of the original system is essential. The original system relies on significant flow of coolant to be continuously circulated through the engine at pressure to eliminate hot spots and steam pockets from developing. The spring loaded bypass control valve on the thermostat plays a important role in this by partially blocking the bypass flow so coolant pressure will build inside the engine. Once the engine discharge temperature is in the control range of the thermostat it begins to open allowing cool water from the radiator to mix with the water making its way around the bypass control valve which shifts due to the pressure differential to compensate for flow now going through the radiator. Another important role of the bypass control is to limit the maximum pressure on the cooling system during sudden high rpm operation. The thermostat by itself is not capable of reacting fast enough under these circumstances to control the peek pressures that can develop.
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Phil Wasinger 1994 Torch Red ZR-1 WAZOO Member George Braml Intake |
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#16 |
![]() Join Date: Jan 2018
Location: Calgary, Canada
Posts: 72
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Coming back to my 2019 post with an update.
I found for quite a while that I simply wasn't a good enough driver on track that I would even push my car to the point of overheating the factory system. This year (after acquiring data, via the Garmin Catalyst) i reached the max capacity of the factory system. I removed the factory unit and installed the full aluminimum unit. Furthermore, I did the Tyler Townsley mod and cut the spring in my thermostat. Results are: Highway cruise is no longer an issue in 6th, it easily holds 70-80c at highway cruise. My AC is actually COLD. sustained high rpm runs where the LT5 is allowed to run up several times per lap above 6000rpm have resulted in a max temp of 113c on and ambient 30-34 day on the tarmac. Typically, temps are not higher than 104 on track. But sustained high rpm will hit 113c. My prior trip to the track they hit 110c. I think I am pushing the car harder and harder (and my performance on track is showing it) and i might bump up against the limits of this setup too. Any comments from the experienced crowd appreciated!!! I suppose the Pirate Team removed the crossover, installed a monster high GPM flow rate rad, and let er buck hey?
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--------------- VikingTrad3r Calgary, Canada 1991 ZR1 # 888 - daily drive whenever possible 1991 ZR1 engine from unknown sn. 1990 Z51 zf6 being built into narrow body ZR1 racer 1987 z52 auto - sold 1986 'z31' 4+3 - sold 1985 Z51 auto - sold |
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