spyonu2007

I heard some rumors recently that the csi/csr electric water pump is not designed for road racing, that a mechanical pump is better. Is there a shred of truth to this?

I hope not, because I just got one installed on my lt1 383ci engine.

96capricemgr

iTrader: (1)

The electrics result in more power at the wheels by consuming less power, they consume less power because they move LESS water at middrange and high rpms. Some guys who are capable of independant intelligent thought find that the low flow units like the CSR actually result in slightly RAISED temps even at cruise rpms because even by that point the mechanical was moving more.

The mechanical moves like 66gpm at 6000rpms as installed and restricted by the system, the electrics are all rated free flow and MUCH lower. They are adequate for many uses but most road race guys seem to prefer the mechanical. It has it's own hassles like a tendancy to cavitate once up around say 6500rpms but it is the highest flowing option we have at this time.

jester1614

iTrader: (13)

I thought that the benefit of the electric water pumps were due to exactly that...electric
they are not driven off the engine itself and therefore cause no parasitic losses.

if that is true then shouldnt there not be a difference power wise if it flows 10 gpm or 100


other than obviously the difference caused by the engines heat.

96capricemgr

iTrader: (1)

Have you stopped to think the electrical system is driven by the engine??

If it were as easy as using the electrical system to make more power we could just have weedwacker engines turning alternators and have electric motors at each wheel pumping out gobs of power.

Search the web and find a converter for amps at volts to hp and you will find that at peak output the alternator is only capable of supporting like 2hp and that at 8 amps the electric WPs only put out like .15hp, if the mechanical takes 10hp to turn stands to reason it is moving a hell of a lot motre water. Now yes the electrics can have a more efficient impeller because it only need work at one rpm but it is not 50 times more efficient.

jester1614

iTrader: (13)

good answer

i wasnt sure what your logic was behind your statements and now i know, thank you

Mojave

iTrader: (4)

I know several people who have tried electric water pumps for RR/ORR, and most all had issues. As said above, the power saved is because the electric is flowing less water at high rpm's.

While EW have their place, extended high rpm use is their weak point, and for most any RR/ORR application, they are over-matched. Most people have good success with the stock water pump, be it LT1 or LS1, so there is little need to mess with it.

spyonu2007

I suppose a electric helper pump may be in order then.
That and perhaps taking out the thermostat?

BALLSS

An electric flows less because it takes less power…??, not onboard with that theory.
I also would not run without a thermostat in any application, just my $.02

Don't know the GPM the CSI is but FWIW the Mezeire HD pump moves 55 GPM at ALL RPM's. In hot summer stop/go traffic the greater GPM of an electric is certainly a benefit in moving more water. My $.02 is a constant GPM flow has advantages in any driving application.

If Dwayne's assumptions are correct a stock mechanical unit moves 66 GPM @ 6000 RPM's which is a RPM range "most" cars do not see for any "sustained" period. Auto X being the exception given the duration of race time but how much of that time the motor is above 5500 RPM's would have to be confirmed.

Mechanical pump is gear driven from the engine which like any "mechanically" driven accessory takes HP. The electric draws a few amps constantly from an alternator that puts out 135 amps (b-body SS alternator) at all RPM's. It would be hard to argue there is not a HP advantage for the electric. Reported HP difference on a dyno is 10 HP electric vs. OEM.

If Auto X application RPM's are higher on average in the 5500-6500 range vs. lower than in 'theory" an OEM mechanical one putting out 66 GPM at 6000 RPM's may in fact pump more water in the same time period as an electric. You would have to calculate how much time your motor is above 5500 RPM to see if the math dictates a mechanical will pump more than a constant 55 GPM.

I have had a Meziere on for 7 years with no issues, something I cannot say for the OEM units which worked in terms of "cooling" but leaked. I did not do the swap for any HP increase but there is a benefit there.

IMHO, the B-body should have a dual core radiator. If so the OEM unit or electric would not matter in terms of cooling.

Jon A

That's its rated Free Flow, as in dumping into a bucket. What do you think its actual flow rate pumping water through the engine is? A whole lot less. The GM numbers are for flow through the entire system using the stock pump. This means the RPM at which the stock pump begins flowing more water is going to be even lower, likely in the 3500 to 4500 range at best (if Mezeire would provide system flow rate we could tell exactly). Data acquisition confirms the amount of time I spend above that when on track is the entire time until the cooldown lap.

A bigger radiator will always help and I'd certainly suggest it for a 383; but that won't save you if you can't move enough water. An electric pump is simply a poor choice for this application.

Now for the street, where many have problems with overheating in traffic an electric pump would be better. It may even be better in some cases for autocrossing where a run only lasts a minute or so and you get time to cool down in between. But go to the racetrack and put your foot to the floor for a solid 30 or 40 minutes and those 10 ponies you gained will be the least of your worries....

FASTFATBOY

iTrader: (23)

Only so much water is gonna move through the thermostat anyway. I could see a SMALL difference in the stocker moving more at high rpm. The thermostat seems to me to be the limiting factor as to how much is ACTUALLY moved through the engine.

BALLSS

Jon:

Thanks for pointing out the flow value of the Meziere vs "actual" pumping through the engine.

for me I did not get a electric for HP gain....it was because OEM units continually leaked (AC Delco) for me. i have a NIB AC Delco I got from the dealer as a replacement 7 years ago after they replaced the 8th WP under warrenty. I will put it on my "spare" 355 iron head motor I am slowly building.

96capricemgr

iTrader: (1)

This is news to you because you choose to argue with me rather than read what I write. I have presented this same argument dozens of times on several boards you frequent.

Your theory about electrical load being near meaningless is silly seeing as the electrical system is powered by the engine and when using an electric pump you turn rotation into electricity and back to rotation which is inherently grossly inefficient. You are talking perpetual motion machine here, just have a weed wacker engine and a series of alternators and electric motors driving each other and increase output exponentially.

I had made a mistake, upon closer inspection the SAE document I get my info from says the pump moves 66gpm at 6000 pump rpms, the cam spins half engine speed but the WP gears are a 2.48 ratio meaning the engine is turning 4840rpms. These numbers are even with the thermostat closed since given the stat/pump design the stat does not actually restrict flow just redirects it and this is specifically stated in the SAE document that these numbers are for open and closed stat.

The mechanical moves 30gpm restricted at 2340 engine rpms which is verified what the brighter guys who have used the 30gpm electric see in that engine temps at cruise rise slightly over the mechanical.

Jon A, Mohave, thank you it is so good to see that there are a few other guys capable of coherent thought and some understanding of physics, really rare these days as exhibited in these threads.


I am sure many are sick of my ranting on this subject, but others are still learning, and the leason is much greater than just water pumps, it should be teaching them about how to think and avoid many of the other popular misconceptions because there are so many other topics that "common knowledge" is just as bad as it is on this subject.

spyonu2007

Thanks for all the replies fellas. This is one of those cases where proper research was not done before leaping..

That being said, it looks like I screwed for the hpde events, Im certain my engine is above 4000rpm for most of it...

So.. Back to my original thought, another helper pump, perhaps a dual core radiator..

I got in touch with EMP, and am looking at helper pump options.
http://www.emp-corp.com/products/adv...tricWaterPump/ being one of the options Im looking at..

Figure the csi/csr pump flows X amount and this other one is nearly 30gpm at 12vdc, probaby a bit more at actual charging voltage from the alternator. She is hungry though looking at 20amps current draw.. With both running, I would hope that my flow resistance would drop. Beauty of the brushless emp, she is good for 10,000 hrs.

I have half a mind to go back to an oem style pump.
Since its together Ill go ahead and get it tuned and see how it does.

Jon A

The thermostat will only provide a resistance, as does everything else in the system. Increase pressure and you increase the flow rate, much like increasing voltage increases current through circuit with a resistance.
Sure, no need to panic, just be very aware of it and see how it does, especially if you're a beginning driver. Then you'll have a feel for how urgent a change is.

A helper pump would work, Stewart often recommends their 55 gpm electric to augment a mechanical when extra help is needed. Though that's not cheap and might be more of a PITA than going back to stock.

And you might as well start saving for a bigger radiator and oil cooler too. Depending on your climate you might be OK with the stock radiator for a while; I'd do the oil cooler first if money is tight.

spyonu2007

Could you post more info on the stewart helper pump?

96capricemgr

iTrader: (1)

This forum is strict about non-sponsor links. Stewart's site is not completely working at the moment so just go to Jeg's and search "#935-E558A-BK " and you can do some reading.