upgrade water pump for higher flow at idle?
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upgrade water pump for higher flow at idle? Working on a swap ls3. Its in a bmw so the 2010 Camaro radiator would not fit. Very limited space up front to fit larger radiator. No issues when cruising. Starts running hot when at idle. Changed the T-stat to a 160. Any suggestions on water pumps that are upgrades over the ls3 stock water pump, especially at idle as well?
You need to fit electric fans. If room is too tight, maybe try pusher fans on front side. I don’t think a high flow water pump is gonna help you at idle. At speed yes, but your fine at speed with cooling. PRW makes a high flow pump. I run one on my 434” build.
You didn't say what BMW you swapping the LS into but on my E36 swap I used a stock fbody pump. Upgraded to a Mishimoto radiator and then put a Spal 16" puller fan on the engine side of the radiator. Left the stock BMW pusher in place.
My LS1 chassis dynoed at 400 RWHP. It always seemed to run a bit warm.
The stock BMW fan ran off the radiator sensor would kick in about 205. The Spal fan was programmed to kick in at 210.
It never overheated but could hit 215-220 in heavy traffic when the temps where in the mid 80"s.
I think the big problem was the hot air can't get out of the engine compartment. I almost put hood vents in to get hid of some of the heat.
My LS1 chassis dynoed at 400 RWHP. It always seemed to run a bit warm.
The stock BMW fan ran off the radiator sensor would kick in about 205. The Spal fan was programmed to kick in at 210.
It never overheated but could hit 215-220 in heavy traffic when the temps where in the mid 80"s.
I think the big problem was the hot air can't get out of the engine compartment. I almost put hood vents in to get hid of some of the heat.
Some guys have put vents in the wheel wells. I've even heard of people putting electric fans on those vents.
An electric water pump will allow you to vary the water flow in response to engine temp and might give you some additional room up front for fans. Expensive fix though.
Shrouds are good. Make sure the fan blows through the radiator and not around it.
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Its not so much a problem as it isn't helping with your cooling issue. Once the engine is up over 200 degrees it doesn't matter whether the thermostat opened at 160 or 180, it is fully open either way. I run a 160 degree thermostat so that part is personal choice
Can you post a picture of your fan/radiator set up?
How did you bleed the air out of the system when filling it? Also what coolant mix are you running.
Can you post a picture of your fan/radiator set up?
How did you bleed the air out of the system when filling it? Also what coolant mix are you running.
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From: Harford Co. Maryland
Be sure the bottom hose is not collapsing.
Lose the 2 smaller fans and get a Taurus or Mark VIII fan; has 2 speeds, flows 4000+ cfm, and has it's own shroud.
Coolant flowing too fast could cause issues at speed due to little/no time to lose the heat.(passing through the radiator too fast)
https://www.ebay.com/itm/18-Electric...VamBnF&vxp=mtr
IF you have room ?
Mark VIII dimensions are 18.5 x 22 x 6 and 18" blades, not including the tabs.
Mark VIII w/ trimmed tabs and trimmed depth dimensions are 18.5 x 22 x 5.25 and 18" blades
Lose the 2 smaller fans and get a Taurus or Mark VIII fan; has 2 speeds, flows 4000+ cfm, and has it's own shroud.
Coolant flowing too fast could cause issues at speed due to little/no time to lose the heat.(passing through the radiator too fast)
https://www.ebay.com/itm/18-Electric...VamBnF&vxp=mtr
IF you have room ?
Mark VIII dimensions are 18.5 x 22 x 6 and 18" blades, not including the tabs.
Mark VIII w/ trimmed tabs and trimmed depth dimensions are 18.5 x 22 x 5.25 and 18" blades
Last edited by Doug G; Mar 28, 2018 at 05:31 PM.
I willing bet the Taurus fans won't fit on a E36 swap. Too wide and too tall.
If I was to do it again I would byy a thicker bigger core radiator possibly a dual pass and offset the 16" fan so it won't touch the water pump pulley.
Might be interesting to punch a few "bypass" holes in the current shroud to see if it might help air flow.
If I was to do it again I would byy a thicker bigger core radiator possibly a dual pass and offset the 16" fan so it won't touch the water pump pulley.
Might be interesting to punch a few "bypass" holes in the current shroud to see if it might help air flow.
I worked on a swap that would barely stay cool with 70 degree F outside temps unless it was moving. The builder used a parts store electric fan that would barely hold a piece of letter sized paper to the radiator with any authority. I installed a Derale 16" fan as a puller with a custom shroud and tossed the kids toy from the parts store in the trash. The Derale fan would stick a business card to the radiator and needed to be turned off to release the card without damaging fins. After that the vehicle never had a cooling problem again.
Another big thing is a proper fan shroud. Open radiator area = no forced airflow. No forced airflow means no cooling at idle or in traffic. I prefer the fan shrouds that cover the entire radiator except where the fan is and a few small holes to allow flow at speed.
I had a similar issue on an E36. Ended up going with a Corvette water pump (spaced to match Fbody balancer) a dual pass radiator and a Taurus fan. The Corvette pump gets rid of that big bell on the LS1 pump and gives you just enough room to get that big Taurus fan in there.
You have plenty of water pump -- that's not the issue. As for t'stat -- if the cooling arrangement won't reject enough heat to keep it from overheating at idle, how is it going to reject the ADDITIONAL heat needed to get down to 160F? Put the stock t'stat back in.
The heat rejection requirement at idle is about as small as you'll ever see when operating the engine. Doesn't take much radiator to keep one cool at idle. As others have pointed out, you likely don't have enough air moving across the radiator at idle. If the fans you're using are the no name cheap specials, they're not up to the task. I don't have any more room for radiator than you do. Got Howe Racing in MI to make a custom aluminum 24"x16" (core size) with 2 1" rows. I have twin 11" shrouded SPAL fans controlled by a DCC variable speed controller -- keeps the LS3 in mine between 195F and 205F under all circumstances.
Once you get fan flow figured out -- then you can task the system and see if you have enough radiator or not.
The heat rejection requirement at idle is about as small as you'll ever see when operating the engine. Doesn't take much radiator to keep one cool at idle. As others have pointed out, you likely don't have enough air moving across the radiator at idle. If the fans you're using are the no name cheap specials, they're not up to the task. I don't have any more room for radiator than you do. Got Howe Racing in MI to make a custom aluminum 24"x16" (core size) with 2 1" rows. I have twin 11" shrouded SPAL fans controlled by a DCC variable speed controller -- keeps the LS3 in mine between 195F and 205F under all circumstances.
Once you get fan flow figured out -- then you can task the system and see if you have enough radiator or not.