Electric Water Pump questions ... - ZR-1 Net Registry Forums

RussMcB · 06-09-2015

Last month at NCM (C4 Gathering) and Road Atlanta yesterday I couldn't drive more that a lap or two at speed without the coolant temps quickly reaching 124-127 degrees C.

I still have a stock radiator, which I plan to replace, but I'm not sure that by itself will solve the problem, which (I assume) is primarily due to the LT-5's unique high-RPM radiator bypass system.

If I switch to an electric water pump system (along with an improved radiator), will that solve the problem? Has anyone done that and confirmed it keeps an engine cooled during semi-sustained high RPM's?

Are there any good write-ups describing how to do it, parts needed, what to do with the original water pump, etc.?

Thanks.

GOLDCYLON · 06-09-2015

I suggest a Dewitts radiator with SPAL fans. Not sure if an electric water pump will solve your issue due the LT5s bypass system that you mention. However extra cooling capacity and faster fans than stock will.

Dynomite · 06-10-2015

Quote:

Originally Posted by GOLDCYLON

I suggest a Dewitts radiator with SPAL fans. Not sure if an electric water pump will solve your issue due the LT5s bypass system that you mention. However extra cooling capacity and faster fans than stock will.

I do not see Dewitts Radiator in you signature??

Which Dewitts Radiator are you using and where did you get the Dewitts Radiator?

secondchance · 06-10-2015

Quote:

Originally Posted by Dynomite

I do not see Dewitts Radiator in you signature??

Which Dewitts Radiator are you using and where did you get the Dewitts Radiator?

I know you are asking Daryl but in my case I got 1139090M - double row/manual. These are $495 plus $50 shipping direct from Dewitts. However, the same radiator on Ebay put up by Summit Racing showed up at $495 including shipping.
It's a good quality unit.

GOLDCYLON · 06-11-2015

Quote:

Originally Posted by Dynomite

I do not see Dewitts Radiator in you signature??

Which Dewitts Radiator are you using and where did you get the Dewitts Radiator?

Im losing track of ALL my mods. Its the all aluminum 2 row replacement with the SPAL fans and from Dewitts

cvette98pacecar · 06-11-2015

I have the same setup as Jerry. I drove the car hard for 6 days straight above 5500 RPM for hours on end and had no issues. Ron Davis Radiator, Stock thermostat with 3 small holes drilled to reduce back pressure to keep the antifreeze flowing through the radiator.

Dynomite · 06-11-2015

Quote:

Originally Posted by cvette98pacecar

I have the same setup as Jerry. I drove the car hard for 6 days straight above 5500 RPM for hours on end and had no issues. Ron Davis Radiator, Stock thermostat with 3 small holes drilled to reduce back pressure to keep the antifreeze flowing through the radiator.

I am thinking the radiator allowable pressure is increased with the Ron Davis (structural capacity of the radiator) or the Coolant flow resistance is decreased such that greater Coolant Flow will not contribute to higher radiator pressure. In the case where the Radiator has greater burst pressure capacity it would be time to increase the Return Spring Pressure on the Thermostat dis-allowing some Coolant to return directly to the engine. In the former case where the Coolant Flow Resistance is decreased through the Radiator, nothing would have to be done to the thermostat to realize the benefits of the larger capacity radiator.

Ron Davis Radiator w/o transmission cooling

Coolant temperature stays at a constant 185 deg (70 deg F ambient) with 180 deg thermostat.*
a. 1989-1996 C4 Type V8 All Part No. 1-16CV8996
b. Rated 800 Hp
c. Manual transmission
* Coolant Temperatures will climb a bit with AC on (100 deg F ambient).

RussMcB · 06-09-2015

Thanks. I'll look into that radiator.

I don't think fans come into play with my issue. I think they are just freewheeling at speed.

GOLDCYLON · 06-09-2015

Quote:

Originally Posted by RussMcB

Thanks. I'll look into that radiator.

I don't think fans come into play with my issue. I think they are just freewheeling at speed.

Take it from a Daily Arizona driver. The fans matter!!!!! Anything that can dissipate heat faster coupled with increased CFMs movement across the cooling surface matter.

RussMcB · 06-09-2015

I believe you, regarding street driving, especially stop & go, idling, etc. My problem is when I'm driving 70 - 150 MPH.

I'm assuming a C4 Corvette has sufficient airflow at speed (high pressure ahead of the radiator, lower pressure behind).

I do think better fans could help it cool faster after I come off the track, and I also think (based on what I've read today) that a better radiator, and perhaps holes in the t-stat will reduce the pressure, raise the bypass RPM and allow more coolant to go through the rad, but I don't think that is enough.

I wonder what Morrison, Rippie and others might have done to their race cars?

06-09-2015	#1
RussMcB Join Date: Jan 2015 Location: Marietta, GA USA Posts: 1,160	Electric Water Pump questions ... Last month at NCM (C4 Gathering) and Road Atlanta yesterday I couldn't drive more that a lap or two at speed without the coolant temps quickly reaching 124-127 degrees C. I still have a stock radiator, which I plan to replace, but I'm not sure that by itself will solve the problem, which (I assume) is primarily due to the LT-5's unique high-RPM radiator bypass system. If I switch to an electric water pump system (along with an improved radiator), will that solve the problem? Has anyone done that and confirmed it keeps an engine cooled during semi-sustained high RPM's? Are there any good write-ups describing how to do it, parts needed, what to do with the original water pump, etc.? Thanks. __________________ Russ McBride, [COLOR="Red"]Car Sold 8/2020[/COLOR] #1635, Marietta, GA USA, 1991 ZR-1, #766 (bought 1/1/2015) MS3-Pro, OBX, SW X-Pipe, Borla, Hurst, SLP, Goodyear F1 GS-D3, Kenwood. HOTB 2016Q3 [IMG]http://zr1.net/forum/picture.php?albumid=316&pictureid=2873[/IMG] [IMG]http://zr1.net/forum/picture.php?albumid=336&pictureid=2985[/IMG]

06-09-2015	#2
GOLDCYLON Join Date: May 2007 Location: Peoria, AZ Posts: 9,155	Re: Electric Water Pump questions ... I suggest a Dewitts radiator with SPAL fans. Not sure if an electric water pump will solve your issue due the LT5s bypass system that you mention. However extra cooling capacity and faster fans than stock will. __________________ GOLDCYLON - 91 ZR-1 #2014 GOLDCYLON - 90 ZR-1 #2794, 4L60e (Formerly Schrade's) GOLDCYLON - 11 CTS-V Arizona State Director 91 WHITE/BLACK #2014. 380 P&P&PCed,Ported Heads, Jeal Long tubes, Corsa Exhaust/FIKSE FM-5s /LED TLs, LED Headlights, Front Wilwood 6 piston narrowlite calipers and rear Wilwood caliper street shop mod,CNCed Coolant Pipes,TPI Cvr,Filter cover,Stainless Bolts, DRM/DOM PROM /ZFDOC mod build #102,DRLs,BMAD with stainless Debris Screen,Coplan Air Blaster, Pioneer APP Radio 4,Brey-Krause HB,Sub Bar,Fire extinguisher seat mount,DRM Coilovers,LEDs everywhere,Compass mirror (orange),V1 DIC hidden display, Homelink sun visor, Carbon Fiber top x3 and APSIS Carbon Fiber interior, APSIS CF Steering Wheel/NAPA Leather, Banski trailing arms, Guldstrand front suspension,urethane bushings from Prothane (total suspension) ZFDoc drive shaft safety loop, raptor shift light (orange),AO engineering louver front plate, Console seat cushion, 96CE seats with black custom Sheepskins, ss billet catch can,Viper remote entry/alarm,Cragar Rear Louvers,LED side louver lights, Dewitts Radiator with SPAL fans and a Woods 160 T-Stat 90 RED/BLACK #2794. 4L60e Automatic Stage V by RPM Transmission, TCI Dedicated TCM, OBX Stainless Headers, Corsa Exhaust, SAN Secondaries and Haibeck PROM, Exotic Muscle Coil overs, LED Interior Lights, LED Tail Lights, LED Headlights, 94 Sport seats with black custom Sheepskins , Cragar rear louvers, GS Front calipers, Banski Trailing arms, APSIS Carbon Fiber steering wheel, Front and Rear Baer Eradispeeds, DRLs, Guldstrand front suspension,urethane bushings from Prothane (total suspension), Dewitt's Raditor with Dual SPAL fans and a Haibeck 170 T-Stat 11 RED/GREY CTS-V

06-11-2015	#6
cvette98pacecar Join Date: May 2011 Location: Sydney, Australia Posts: 2,479	Re: Electric Water Pump questions ... I have the same setup as Jerry. I drove the car hard for 6 days straight above 5500 RPM for hours on end and had no issues. Ron Davis Radiator, Stock thermostat with 3 small holes drilled to reduce back pressure to keep the antifreeze flowing through the radiator. __________________ Robert J. DeMarco [SIGPIC][/SIGPIC] [COLOR=blue]G[/COLOR][COLOR=red]rand[/COLOR] [COLOR=blue]S[/COLOR][COLOR=red]port[/COLOR] Registry Lifetime Member NCM Lifetime Member #2655 Pacecar Registry Member [COLOR=red]ZOOM Charter Member - ZR-1 Owners of Michigan[/COLOR] [COLOR=plum][I]ZR-1[/I] Registry member since 2012 [/COLOR] [COLOR=black]1990 LPE "368" Aerobody ZR-1, Last ZR-1 built by John[/COLOR] 1991 Callaway Aerobody ZR-1, DRM 500 1991 Shinoda Aerobody Spyder, 1998 Pace Car

06-09-2015	#8
RussMcB Join Date: Jan 2015 Location: Marietta, GA USA Posts: 1,160	Re: Electric Water Pump questions ... Thanks. I'll look into that radiator. I don't think fans come into play with my issue. I think they are just freewheeling at speed. __________________ Russ McBride, [COLOR="Red"]Car Sold 8/2020[/COLOR] #1635, Marietta, GA USA, 1991 ZR-1, #766 (bought 1/1/2015) MS3-Pro, OBX, SW X-Pipe, Borla, Hurst, SLP, Goodyear F1 GS-D3, Kenwood. HOTB 2016Q3 [IMG]http://zr1.net/forum/picture.php?albumid=316&pictureid=2873[/IMG] [IMG]http://zr1.net/forum/picture.php?albumid=336&pictureid=2985[/IMG]

06-09-2015	#10
RussMcB Join Date: Jan 2015 Location: Marietta, GA USA Posts: 1,160	Re: Electric Water Pump questions ... I believe you, regarding street driving, especially stop & go, idling, etc. My problem is when I'm driving 70 - 150 MPH. I'm assuming a C4 Corvette has sufficient airflow at speed (high pressure ahead of the radiator, lower pressure behind). I do think better fans could help it cool faster after I come off the track, and I also think (based on what I've read today) that a better radiator, and perhaps holes in the t-stat will reduce the pressure, raise the bypass RPM and allow more coolant to go through the rad, but I don't think that is enough. I wonder what Morrison, Rippie and others might have done to their race cars? Last edited by RussMcB; 06-09-2015 at 06:37 PM.