lets start some tech discussion - cooling

General Engine Discussion

Moderator: John_Heard

Post Reply
Message
Author
amature
Posts: 21
Joined: Fri May 13, 2005 11:23 am
Location: Spokane, WA
Contact:

lets start some tech discussion - cooling

#1 Post by amature » Fri May 13, 2005 11:54 am

I run a 540 BBC that runs on pump gas. I drive it quite a bit on the street and obviously race it as well.

The cooling system has always sufficed, but just barely. On 90+ days, it runs pretty hot when not on the freeway. I don't mind it getting hot, the car loves hot. On the dyno and on the strip, it runs best when it is 200+. But the ~230 on hot days makes me nervous.

I run a CSR 35-37 GPM and an aluminum radiator.

I gave Evan's Cooling a call this morning and told him what I have. If you haven't heard of them, they offer a non-aquias (no water) solution to elminate boiling. He gave me some good info. Said I could switch to there NPG-R coolant, but would likely run the same temps. The electric pumps can't handle their normal coolant because it is too thick. The NPG-R is more fluid but does offer the raised boiling point. Basically, gave it to me straight and didn't try to sell me, though I will likely buy some anyway for piece of mind and to eliminate any potential hot spots in the engine.

He did share some info with me that I have never heard of or seen before but will definitely implement. On chev's he said that the electric pumps can get air in the impeller cavity. When the engine is off but the pump is on, he said you can here the water sloshing around. This is very true in my case. I've always noticed the sound, but figured it was normal. With the air in there, the pump isn't operating nearly near it's peak potential. He told me a great idea to solve the problem. Take a small bit (.1") and drill down straight from the top just into the impeller cavity near the inside edge (top towards the engine). You are trying to get the edge of the bit to break into the cavity while the majority of the hole is in the aluminum. A .090" hole is the max you want. They drill and tap the top with an 1/8" pipe thread and run a line (he uses -3 teflon brake line) to the thermostat housing. This will allow the air to escape and thereby increase the efficiency.

Sounds pretty good to me. What does everyone else think??
- Greg

User avatar
John_Heard
Site Admin
Posts: 5734
Joined: Thu May 12, 2005 11:20 am
Location: Resume Speed, Kansas
Contact:

#2 Post by John_Heard » Fri May 13, 2005 12:43 pm

I've got I believe the same pump on my car.. I can't remember hearing water noise, only the hmm of the electric motor. However I don't run a thermostat - just a restrictor and my block has a short fill - maybe that's the difference.

The modifications to the pump sound reasonable. I can't visualize them without looking at a pump but that makes sense to bleed some air out of it. Worth trying I'd say.

amature
Posts: 21
Joined: Fri May 13, 2005 11:23 am
Location: Spokane, WA
Contact:

#3 Post by amature » Fri May 13, 2005 1:09 pm

I agree. Mine usually happens after a drive and it's hot. Which makes sense as well. I do run a thermostat too. That is something else he mentioned... if I switch to the Evan's, dump the thermostat.
- Greg

User avatar
Craig W.
Posts: 1257
Joined: Thu May 12, 2005 11:01 am
Location: Columbia, KY
Contact:

#4 Post by Craig W. » Fri May 13, 2005 2:34 pm

My electric pump makes some gurgling noises too. I have to wonder if a belt driven pump might make the same noises, but we just can't hear them because of the engine running. Anyone with an electric drive on a belt driven pump want to chime in on this?
Craig Watson
2QuickNovas Racing
5.23@131

Sponsors:
AEM Electronics
Carnivore Performance
Rapp Racing
VFN Fiberglass
Fast Shafts

Racer704
Posts: 166
Joined: Thu May 12, 2005 9:23 pm
Location: Raleigh NC

#5 Post by Racer704 » Fri May 13, 2005 11:22 pm

Hey guys

I sell a great product from Justice Brothers called Radiator Cool. I dont mind send a few bottles out to let someone try for free and all I ask is your honest opinon if it helped at all.

The first time I used it was on a street car that had a 468 and it got up to 225 to 230 and 2 bottles of this and it never went over 210 on the hottest days. Please dont everyone expect to get a free bottle but i dont mind a few. Its about 10 bucks a bottle and it depends on your rad size if you need 1 or 2.

Johnny B.
Johnny B.

User avatar
Craig W.
Posts: 1257
Joined: Thu May 12, 2005 11:01 am
Location: Columbia, KY
Contact:

#6 Post by Craig W. » Sat May 14, 2005 10:44 am

That's a nice improvement in cooling.

My wife's Chevy II has always run a little hotter than I like. I tired Royal Purple Ice but it didn't really seem to do much. I've heard others say it worked for them and the same for Redline Water Wetter. So maybe its just our particular application that isn't well suited for this type of product. Not sure.
Craig Watson
2QuickNovas Racing
5.23@131

Sponsors:
AEM Electronics
Carnivore Performance
Rapp Racing
VFN Fiberglass
Fast Shafts

Ron Clark
Posts: 25
Joined: Thu May 12, 2005 10:46 pm
Location: california

engine temps

#7 Post by Ron Clark » Mon May 16, 2005 10:14 am

but everyone has failed to give the proper info..this is where we start arguing about iron head vs aluminum head power vs weight issues..i view aluminum heads as big radiators, sucking heat away from my engine...i want heat..heat is power...but in some cases, the weight savings are needed, and mandate aluminum..but the alloy heads tend to change jacket temps..iron motors are much easier to control at a constant temp, given an adequate cooling system..(people tend to disregard temperature differences as reasons for engines to fail, especially with nitrous)

if you want your pump gas street car to run cool, forget drag race tech..go endurance racing..road course or nascar..see how they set their systems up..if they run hot, they are out...the best systems are costly, and require mods to your engine, but you will stay cool, or at least at a constant usable temperature...add that with your fancy coolants and its all good..

yes , pumps cavitating is a very bad thing..steam bubbles are bad.. 8)

User avatar
sixty_foot
Posts: 75
Joined: Tue Jul 26, 2005 3:16 pm

overlook.....

#8 Post by sixty_foot » Thu Jul 28, 2005 11:12 am

i know this may seem off base.........but....nowdays with the hot ignitions,electric fuel and water pumps, and electric aux fans, many people over look at what their alternator output is with everything on. i recently lost a alternator at the track and replaced it with a 140 amp powermaster.....and it was amazing how well the car responded. do a check and see how many amps you are putting out at idle and at 3000 rpm.........could be your answer.your water pump max rpm could be low due to low alternator output "under load".
also......running at 230 is just fine ! look at the new emission cars and think about why they run them so hot. a engine produces the most horsepower just before it overheats. the hotter the engine is. the most efficient it is in "completely" burning fuel. a alcohol engines biggest problem is, it cant generate enough heat because it runs so cool.
.....relax on the temp thing, at 230 degrees, you are in the sweet spot !

amature
Posts: 21
Joined: Fri May 13, 2005 11:23 am
Location: Spokane, WA
Contact:

#9 Post by amature » Sun Jul 31, 2005 7:48 pm

I know what you mean!

I have a 140amp CS130 Delco one wire that was standing on its last leg. I tore it apart and tested everything and it all tested fine. The regulator is the only thing you can't test, so I replaced it with a heavy duty 3-wire. Best thing I have ever done! No more of that one wire crap for me.

Now I have 14.6 volts at the ignition no matter how many accessories are on (fuel pump, fan, water pump, headlights, wipers). I just put my sense wire down on the starter (where all my power branches off of). Works great. I still run up to 230-235 sometimes, but it has also been ~100 degrees too!
- Greg

User avatar
John_Heard
Site Admin
Posts: 5734
Joined: Thu May 12, 2005 11:20 am
Location: Resume Speed, Kansas
Contact:

#10 Post by John_Heard » Mon Aug 01, 2005 8:46 am

I'll have to agree too.. I use the three wire and put the sense wire at the main power connection where the MSD box, etc. gets juice. 14.5 or so volts with everything running. Take a look at the new alternator mount I made. Ran out of room for everything so I flipped it around and put it on the frame, works fine running backwards.


Image

User avatar
sixty_foot
Posts: 75
Joined: Tue Jul 26, 2005 3:16 pm

#11 Post by sixty_foot » Mon Aug 01, 2005 10:11 am

pretty cool stuf........i like the way you think ! :D

amature
Posts: 21
Joined: Fri May 13, 2005 11:23 am
Location: Spokane, WA
Contact:

#12 Post by amature » Tue Aug 02, 2005 11:43 am

Wow... Clever idea!

I too had to build new brackets. I'll try to get pictures up in a day or two. Though mine still faces the normal direction. :)
- Greg

amature
Posts: 21
Joined: Fri May 13, 2005 11:23 am
Location: Spokane, WA
Contact:

#13 Post by amature » Wed Aug 03, 2005 1:51 pm

Here is a picture of the alternator bracket I fabbed up. The pivot point is bolted to the lower head bolt. One of the support bolts goes to the same hole as the water pump mount. A third support bolt is at the bottom and bolts to the block (you can barely see it behind the lower portion of the belt).

Before I had ran just a pivot point bolt to the water pump. Then a bracket off one of the block holes to adjust from. The damn stud to the water pump kept bending due to lack of support.

This new mount is working out very well.

You can also see my bleed tube off the water pump that I mentioned earlier in this thread. And my real nice wiring of the water pump too!

Image
- Greg

User avatar
YD-LUZ
Posts: 46
Joined: Wed Aug 03, 2005 10:17 pm
Contact:

A good cooling system article

#14 Post by YD-LUZ » Thu Aug 25, 2005 7:10 pm

This is a cooling system article a friend of mine recentely wrote as a post on my site - maybe it will be of some help!

Workmonster



Joined: 19 Jul 2005
Posts: 1
Location: Missouri
Posted: 05 Aug 2005 01:39 am Post subject: Cooling System Myths Debunked

--------------------------------------------------------------------------------

From time to time, I am going to start discussions on various engine systems here, and will share some of the knowledge I have accumulated since 1965, when I ported my first head. Since then, I have always been involved in racing in one way or another, including motorcycles, drag racing, karts, midgets, sprint cars, drag racing again, head porter, and engine builder. I am currently the majority partner in, and engine builder for, an asphalt late model team(Super Late and CRA Super Series). My way is not the only way, just what has worked for me, and is based on (hopefully) sound reasoning.

When we were dirt track guys, we constantly fought engine cooling problems, like so many street and drag guys do. The things I were reading did not make sense to me, and contradicted the thermodynamic training I had in college and the US Navy. That is, until I attended the Superflow Advanced Engine Technology Conference (AETC) in 2000. It was there that a couple of GM engineers gave a presentation called "Optimization of Coolant Flow in a NASCAR Winston Cup Engine" (SAE Paper #983024). These guys used the late Dale Earnhardt's(RCI) engines and dyno to test dozens of combinations of flow patterns to arrive at the best one. Their talk told me that I was not off base in my thinking, and since we implemented their system, we sometimes have to tape the grill to get to 160 degrees. This is in 358 cubic inch SBC engines of up to 15:1, 540hp, with either 500cfm 2bbls or 390cfm 4bbls. 8400 rpm. All season long. The NTC guys are approaching 800hp, and it works for them, too.

Myth #1: "You need a restrictor (or T'stat) to SLOW THE COOLANT DOWN in the radiator, so more heat can be extracted." How many times have you heard this? What is not addressed by this misstatement is that according to their theory, if the total flow rate is decreased, then the coolant also spends more time in the block, PICKING UP MORE HEAT. It's a push!

Truth: It's a closed system. The temperature of the coolant will increase to reach a state of equilibrium, where heat in(engine) = heat out(radiator). If this temperature turns out to be greater than the boiling point of your coolant, bad things happen.

The coolant is circulated by the pressure drop across the water pump. The point of highest system pressure is at the outlet of this pump, and every time the flow encounters a restriction, the pressure drops, until it is at it's lowest point, which is at the inlet of the pump. Since the boiling point of a fluid rises with the pressure of the fluid, you want the highest pressure possible at the point where you are extracting the largest amount of heat. The effect that is present when the coolant system is operating at max effiency is called "nucleate boiling". This is when the layer of coolant that is in contact with the heat source is boiling into very tiny bubbles of steam, which are then swept away from the surface, and immediately condense back to water, and are immediately replaced by non-boiling water. This utilizes the latent heat of vaporization of the coolant, which is a very efficient thing to do(like an A/C unit). This phenomenon depends on a rapid flow rate to sweep the bubbles away, so any reduction in that rate hurts us.

So why does a "restrictor" work? Because the flow path in our engines is not a pipe, nor a carefully laid out path of equal pressure dropping passages like a radiator. Its more like a cave, with all kinds of paths, nooks and crannies, which do not present themselves well to coolant flow, and offer resrictions(pressure drops) to what flow there is. So the "restrictor" (located at the outlet of the engine) actually serves to raise the pressure inside the heads and block, which helps to prevent steam pockets from forming. Steam pockets reduce flow to zero wherever they are located. In a typical block(or head), the pressure drop needs addressing more than the flow rate, to prevent those steam pockets. Low pressure drop with high flow = best. High pressure drop with low flow = worst. Everything's a compromise.

So we must try to redistribute the coolant flow to make the block and heads more like a radiator or heat exchanger. We will do that by using a combination of "pressure regulators"(restrictors), and coolant supply and return hoses.

This is specifically for the SBC, but the principles hold true for any engine. In stock form, the water pump forces water into the front of the block, and is taken out at the top front of the intake manifold. It is left to itself to find and cool all the hotspots in between. We are going to help it out.

Water pump: Edelbrock or Stewart. We buy used Edelbrocks from the Cup teams, have not failed one yet. You need the auxilliary outlets this pump has. A brass restrictor is put between the pump outlets and block, with a 1/2" hole in them. Two -10 lines are ran from the auxilliary outlets to a drilled and tapped hole between the center 2 cylinders on both sides of the block. Locate these holes at the top of the block, just below the deck. These lines , in combination with the 1/2" restrictors, force a lot of water into the block towards the rear.

-10 lines are ran from the coolant outlets on the rear of the heads(newer intake manifolds have provisions for this) to the thermostat housing, or to the front of the intake. A 1/2" brass restrictor is used between the intake manifold and the head at the rear outlets, and a 3/8" restrictor in the front outlets. this gives the coolant an easier way to go if it comes out the back of the head.

So all the water necessary to cool an SBC comes through a total area of about .61 square inches!

You can underdrive the water pump to approx. 67% of crank speed. Less(higher % #) wastes horsepower, more means possible overheating. Moroso 50% pulleys should be marketed with a Overheating Warranty. "If it don't overheat, you get a refund!"

Using a 20-24psi cap will give about 40 psi in the block with this setup, and about 35gpm (at high rpm).

There you have it. There are more tricks which involve some fairly involved machining to get water between the exhaust seats and between the cylinders in a siamesed block, but that is pretty esoteric stuff, and not needed unless you are racing at a pretty high level. However, if you want it, I'll give it. This is what that little coolant hole outlet is for on some aluminum heads.

This setup forces water to take the path of "most heat removal" instead of the "easiest", which it does in stock form. It forces water to the rear of the block and heads to even out flow past each cylinder as much as possible.

Later,
Mark Workman(aka Workmonster)

Post Reply

Who is online

Users browsing this forum: Google [Bot] and 15 guests