[DeTomaso] Fwd: Re: Meziere water pumps

Dave Londry davel at emspace.com
Mon Jan 16 17:48:50 EST 2012 

The Meziere pumps work fine down to about 100Hz
   but they are noisy down there just as you'd expect.
They're happy and quiet with 2 kHz (my choice) and dissipation
  starts to climb somewhere around 5 KHz so it should be well below that.
I limited the low-end duty cycle to 20% which gives me about 10% flow
and a warm-up that's gentle on all of the involved parts.
Meziere ran this setup on their test-tank and liked it a lot.
(apologies for the name-dropping Don)

My Pantera fans are also happy and quiet at 2 kHz,
   but they're a modern, rare-earth magnet design and there might well
be some variety in best frequency for older types.

dave


On 16/01/2012 1:20 PM, Kirby Schrader wrote:
>  Ken,
>
>  I've been watching this thread with interest. My point of view which mostly
>  agrees with what Julian said...
>
>  I have a Meziere 337 55gpm remote pump in my GT40. I went this route based
>  on advice from Mike Trusty and I haven't been disappointed.
>  I did try their block mounted model, but it is even longer than the
>  standard water pump, so your 'hump' gets bigger! Now, I really like my flat
>  firewall. I sold the block mounted model on eBay.
>
>  PWM - Pulse Width Modulator does just what it says. It 'chops' DC into 'AC'
>  of varying frequency so the pump turns off and on rapidly. The shorter the
>  on time compared to the off time, the slower it goes.
>  I have a PWM on my GT40 which controls the inside blower fan for the A/C.
>  It really buzzes at the lower speeds.... when the pulses are very short.
>  But now you've got me wondering... I should measure the frequency and look
>  at the pulses on the 'scope. The PWM I have might be 'dirty' and I'm not
>  getting 'clean' pulses.
>
>  Nevertheless, I wouldn't use a PWM on a $400 water pump. I feel that
>  sticking with the thermostat doing it's thing and letting the pump do its
>  thing is the best.... At least, it works for me. My Meziere runs constantly
>  whenever the ignition key is on.
>
>  My remote Meziere and my thermostat (Mustang remote housing) are up front
>  right behind the radiator in the GT40. I have two braided lines running
>  from it to the block. The engine warms up by the time I'm driving out the
>  front entrance of my estate, so I don't consider warm up time to be an
>  issue.  The longer path for the bypass also reduced the temperature swings
>  I saw on the temp gauge in the block from the thermostat opening and
>  closing. They were as much as 10degC with the block mounted thermostat.
>  Yes, it could have been the thermostat...
>
>  I've got right at 4,000 miles on the car with the Meziere and it works
>  fine. Asa Jay asked, but I have only done three track events with the car
>  so far and no open road events. It has never overheated. It used to.
>
>  Proof that it works, IMHO... Last summer, in 105F temps in Houston and stop
>  and go traffic with the radiator seeing nothing but exhaust fumes from the
>  car in front, I was sweating but the engine temp climbed slightly and just
>  sat there. As soon as I got moving and the space between cars opened up,
>  the temp dropped back down. That means air flow to me and I have a project
>  pending to put larger wire to the radiator fans. Not fond of the wire
>  gauges SPF used...
>
>  My Pantera has a similar remote thermostat setup (the BMW model), but I'm
>  still running a Edelbrock mechanical water pump. If/when it dies, I'll
>  convert the Pantera also and finally get a flat firewall with it, too.
>
>  Hah... just realized I typed almost the same thing the other day on the
>  GT40s forum.... Oh, well.
>
>  FWIW,
>  Kirby
>
>  On Mon, Jan 16, 2012 at 14:42, Ken Green<kenn_green at yahoo.com>   wrote:
>
>>  Dave,
>>
>>       I think with a PWM power supply the frequency can be in the kilohertz
>>  range (Dave Londry would know).  I would imagine the inertia of the water
>>  flow would keep the coolant flowing pretty steadily and that the pump never
>>  stop spinning.
>>
>>  Ken
>>
>>
>>
>>  ________________________________
>>  From: David Nunn<dnunn at telus.net>
>>  To: detomaso at realbig.com
>>  Sent: Monday, January 16, 2012 11:34 AM
>>  Subject: [DeTomaso] Meziere water pumps
>>
>>  Asa Jay,
>>
>>  About two years ago, I moved my Laminova heat exchanger from the engine
>>  compartment to under the car. While I was at it, I decided to replace all
>>  of
>>  my coolant tubing. Before doing so, I called both Stewart and Meziere and
>>  asked their tech depts. for their advice on improving a Pantera's cooling
>>  system. To my surprise, both tech guys were very familiar with the Pantera
>>  and its cooling system. In fact, both guys had identical thoughts and
>>  recommendations. Both felt the Pantera's biggest problem was the resistance
>>  to flow that's inherent in pushing coolant through 22 feet of tubing. They
>>  both told me that the Pantera's belt driven water pump cavitates badly at
>>  high RPM's because there's simply too much resistance to flow. Both
>>  suggested the same solutions: a single pass radiator and a remote, electric
>>  booster pump, installed as close to the radiator's outlet as possible. I
>>  decided to follow their recommendation and I went with a Stewart in-line
>>  booster pump, for the simple reason that the Stewart pump creates zero
>>  restriction in the cooling system when it's not running, whereas Meziere's
>>  remote pumps create a substantial restriction when they're not running.
>>
>>  Here's the part that was surprising to me: both tech guys advised me
>>  against
>>  running an electric water pump as my only water pump, on a street driven
>>  car, for two reasons: reliability and warm-up. The reliability matter is
>>  what it is. Their concern with warm-up was that electric pumps simply flow
>>  much more coolant at idle than a belt driven pump and so warm-up takes
>>  longer and sometimes, much longer. I asked about controllers that regulate
>>  the electric water pump until the engine is up to temperature but they both
>>  did not like them because the way they work is to "stutter" the flow. That
>>  is, they turn the water pump on and off at intervals that depend upon the
>>  temperature of the engine. The problem, both felt, was that every part of
>>  the cooling system gets "shocked" by cold coolant every time the controller
>>  turns the pump "on" during warm up. It also takes a fraction of a second
>>  for
>>  coolant to boil in a cylinder head, so the pump should never be "off".
>>
>>  When they told me that, I immediately recalled reading, on the GT40 forum,
>>  about owners with electric water pumps having radiator failures for unknown
>>  reasons. It turned-out to be those "stuttering" water pump controllers. It
>>  seems that aluminum rads don't like being warm, then getting hit with cold
>>  coolant.
>>
>>  Both companies said they were working on controllers that vary the voltage
>>  to the electric pump, so they will operate continuously, with the speed of
>>  rotation of the pump's impeller depending on temperature, but neither knew
>>  when such an item would be available. Maybe they're available now? In my
>>  case, with my booster pump, it's controlled by my EFI's ECU, so it stays
>>  off
>>  until my engine temp hits 180 degrees. I also incorporated one of John
>>  Taphorn's remote "high-flow" bypass thermostats into my revised cooling
>>  system, but that's another subject entirely.
>>
>>  I hope this helps,
>>
>>  Dave
>>
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