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.

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?

secondchance · 06-09-2015

I think for high speed driving high performance radiator and one or two 1/" holes on thermostat flange should keep engine coolant in check. I believe LT5 water pump moves sufficient coolant. If anything I suspect too much coolant at high RPM combined with relatively weak aluminum/plastic radiator may have resulted in radiator bypass. Once radiator is beefed up, Drilling one, two or three holes on the thermostat flange will allow more coolant into the radiator reducing bypass effect - non-cooled coolant back to the motor. Also, bear in mind that coolant moving too fast through the radiator will also return in sufficiently cooled coolant back to the motor.
I suggest high performance radiator such as Ron Davis or Dewitt and experiment with number of holes on the thermostat flange.
For street driving, especially in stop and go traffic in 90 plus day, higher flow fans become essential also.

efnfast · 06-09-2015

Have you checked to make sure the radiator isn't blocked? Our cars are bottom feeders. I'm not sure you want to defeat the bypass arrangement. The reason the radiator has a bypass is because at high speed the water pump will do over 100 gpm. The radiator can't handle that.

XfireZ51 · 06-09-2015

You have warning if a mechanical water pump is going out. Not so w an electric one.

Kevin · 06-09-2015

After marker rad and a modded stat will do you just fine

Pete · 06-09-2015

Russ,i have done electric WP.

The issues your having at or above 5800 rpm the water does not go thru the radiator it goes thru the bypass back into the motor (never cools).

With a 55GPM electric you won't have to worry about the factory bypass.

I think for what your doing, a bigger radiator and 55 GPM should do you fine.

That 5800 RPM bypass is terrible i had done a few highway runs on a hot day and boy temp went up like a son of a gun.

I have used Meziere http://www.meziere.com/ps-1148-1116-wp336s.aspx
Then went with the Stewart inline http://www.stewartcomponents.com/ind...&product_id=69

Both worked same the Stewart fit nice over the cross member inline the lower radiator hose.

Send me your email i can mail you some pictures my email: petezr1@gmail.com
I still have the complete kit (no electric pump) i will tell you how to do this very simple really.

I also have Under Drive Water Pump Pulleys that will raise the bypass RPM to about 6100 RPM
Pete

06-09-2015	#1
RussMcB Join Date: Jan 2015 Location: Marietta, GA USA Posts: 1,148	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.

06-09-2015	#2
GOLDCYLON Join Date: May 2007 Location: Peoria, AZ Posts: 9,120	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

06-09-2015	#3
RussMcB Join Date: Jan 2015 Location: Marietta, GA USA Posts: 1,148	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.

06-09-2015	#5
RussMcB Join Date: Jan 2015 Location: Marietta, GA USA Posts: 1,148	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 05:37 PM.

06-09-2015	#6
secondchance Join Date: Aug 2006 Location: McLean, VA Posts: 3,738	Re: Electric Water Pump questions ... I think for high speed driving high performance radiator and one or two 1/" holes on thermostat flange should keep engine coolant in check. I believe LT5 water pump moves sufficient coolant. If anything I suspect too much coolant at high RPM combined with relatively weak aluminum/plastic radiator may have resulted in radiator bypass. Once radiator is beefed up, Drilling one, two or three holes on the thermostat flange will allow more coolant into the radiator reducing bypass effect - non-cooled coolant back to the motor. Also, bear in mind that coolant moving too fast through the radiator will also return in sufficiently cooled coolant back to the motor. I suggest high performance radiator such as Ron Davis or Dewitt and experiment with number of holes on the thermostat flange. For street driving, especially in stop and go traffic in 90 plus day, higher flow fans become essential also.

06-09-2015	#7
efnfast Join Date: Nov 2011 Location: Dunbarton NH Posts: 7,589	Re: Electric Water Pump questions ... Have you checked to make sure the radiator isn't blocked? Our cars are bottom feeders. I'm not sure you want to defeat the bypass arrangement. The reason the radiator has a bypass is because at high speed the water pump will do over 100 gpm. The radiator can't handle that.

06-09-2015	#8
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,686	Re: Electric Water Pump questions ... You have warning if a mechanical water pump is going out. Not so w an electric one.

06-09-2015	#9
Kevin Join Date: Jun 2005 Location: pittsburgh Posts: 4,624	Re: Electric Water Pump questions ... After marker rad and a modded stat will do you just fine __________________ It's not the car, it's the people - Doug Johnson 90 r/r "KEYS ON" nick named "T.L.B"

06-09-2015	#10
Pete Join Date: Dec 2003 Location: Chicagoland,IL Posts: 2,667	Re: Electric Water Pump questions ... Russ,i have done electric WP. The issues your having at or above 5800 rpm the water does not go thru the radiator it goes thru the bypass back into the motor (never cools). With a 55GPM electric you won't have to worry about the factory bypass. I think for what your doing, a bigger radiator and 55 GPM should do you fine. That 5800 RPM bypass is terrible i had done a few highway runs on a hot day and boy temp went up like a son of a gun. I have used Meziere http://www.meziere.com/ps-1148-1116-wp336s.aspx Then went with the Stewart inline http://www.stewartcomponents.com/ind...&product_id=69 Both worked same the Stewart fit nice over the cross member inline the lower radiator hose. Send me your email i can mail you some pictures my email: petezr1@gmail.com I still have the complete kit (no electric pump) i will tell you how to do this very simple really. I also have Under Drive Water Pump Pulleys that will raise the bypass RPM to about 6100 RPM Pete __________________ '91 #1635 PoloGreen 350 LT5 11.09 @ 129.27 11.04 @ 128.86 474RWHP 400RWTQ http://www.youtube.com/watch?v=SFNFOhGGlR4 http://www.youtube.com/watch?v=ZlRIOMwaDYY https://sites.google.com/site/peteszr1garage Last edited by Pete; 06-09-2015 at 08:20 PM.

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