Hey guys, my opti has failed me at 69000 miles on my 94 lt1 auto. While i am down there i was thinking about a electric water pump and a under drive pulley set. Any recomendation on the brands. And does the electric water pump come with parts to run the belt.. And is the underdrive pully system worth the 100 dollars. thanks for the help

 

First off welcome to the forum.

Secondly, your water pump is driven by a gear ran from the timing set, not a belt. So, no belt rerouting is necessary. IF you do the e. pump upgrade, get the Meziere HD pump. And from what I've read there is very little HP to be gained on the LT1 from an underdrive pulley.

 

I just did the electric pump conversion. I used the Meziere as suggested by STL, but I've heard the CSI brands are good as well. Summit carries both and they're price comparable.

The kit comes with the pump and fused wiring. You can remove the old drive gear behind the timing cover or leave it on, your choice. You'll need three gaskets, two from the pump to the block and one for the pump front plate (this one can be tough to find).

One thing that was not obvious was how to press the old pump guts out...use a press or air hammer and apply force to the center pin in the pump impeller from the front. I first tried to push the spline on the back of the pump and almost cracked the housing.

It's a claimed 7 rwhp to do the electric conversion...

 

where did u find the hard to find gasket

 

Sir Scary ! - part number for front plate seal if you got it written down somewhere please

 

I'll see if I can find the PN. I can't remember where I got it, but one of the following ordered it for me:

Advanced Auto
Pep Boys
Murray's
Autozone
Mid-5 auto (this one's local )

I went to all of them about 100 times over the course of my motor conversion, can't remember which one actually had it.

They all have the other gaskets (pump to block) but this one seemed alien to them. One thing to watch - there is another gasket that comes up which is very close - round with six holes. I bought one of these and got home to find that the hole pattern is different. Before you pay for the gasket get it in your dirty little fingers and check out the hole pattern. It should be obvious.

I would assume you can get it from a dealer, I just hate going to the dealer for anything. They charged me $2.74 each for flywheel BOLTS fer cryin' out loud.

 

Remove the impeller gear behind the timing plate and you will get more hp. Eventually it will work loose and cause problems anyway, so just remove the load.

 

If you can't find it, buy the RTV gasket maker. There's a silicone that is designed specifically for water pumps (coolant resistive) that you could use. Not as good, probably, but it'll work. I've used it before, just not on this application.

 

Ok guys i just ordered the meziere elctric water pump. thanks for the inputs

 

Enlighten me, please, guys...

I'm not trying to hijack a thread here, but I've been puzzled about this electric w/p conversion since I first heard of it.

I can see the benefit of it for a dragstrip-only car, where it can run on battery only. Less parasitic drag on the engine. Makes perfect sense.

But on a street car... Are you guys using an alternator cut-out switch for WOT blasts? If not, please help me to understand the benefit of the electric pump. I would think that it would be a more efficient use of energy to drive the pump mechanically than to convert mechanical energy to electricity, then convert the electricity back to mechanical motion to drive the pump. Seems to me the increased parasitic drag caused by the increased load on the alternator would more than offset the elimination of the drag imparted by the mechanical pump drive.

Am I missing something here?

TIA,

Be well,

SJW

 

The torque required to turn the alternator is not proportional to the current draw. The alternator provides a set amount of current (i.e. 120 Amps) and it's output will vary based on engine speed (which is directly proportional to pulley speed),which is why cars with high current drains can kill the battery at idle. The draw on the motor is the force it takes to turn the brushes inside the alternator which rub against the copper coil to generate electrical current. The current draw is on the battery, the alternator just keeps the battery charged (a bit simplified).

Pulling more current from the battery to run a new component (Electric WP, in this case) won't cause the alternator to work harder, it will just drain the battery quicker. As long as it's not too much drain the alternator will keep up by providing more current to the battery than the electrical system is draining.

I think I'm doing a poor job explaining this, but I'm tired of Corvettes right now...

 

Benefit is no more gear driven waterpump. In my case, the bearing went bad and the extra drag ruined the gears which ruined the motor.

This whole gear driven water pump thing was just not a bright idea.

 

Yowch!!! I feel your pain. That's a real drag. Sorry to hear it. I can see why you made the switch to electric...

Be well,

SJW

 

With all due respect, some of this is not quite correct...

The torque required to turn the alternator is proportional to the current it delivers. If this weren't true, perpetual motion machines would be easy to build.

The alternator delivers a fixed voltage for a given ambient temperature, as set by the voltage regulator.

The current delivered by the alternator to the electrical system is determined by the system voltage (as set by the voltage regulator) and the load across that voltage. If the load increases, the current varies proportionally.

The current rating of an alternator is an indication of the maximum amperage it is designed to deliver, but it shouldn't be operating at it's maximum most of the time.

The brushes don't turn. They're held in place in the alternator housing, and only move as they wear, and then only move toward the slip rings so that contact will be maintained between the brushes and slip rings (there's a spring behind each of the two brushes to maintain this contact).

The brushes rub against a pair of rotating slip rings, which are connected electrically to the armature windings. A small amount of current passes through these brushes and slip rings, and generates magnetic fields in the armature. As the armature rotates, the lines of flux from these magnetic fields pass through the windings in the stator, and it's this action that induces an alternating current to flow in the stator windings. This induced alternating current passes through the diode bridge, which rectifies the current to direct current. The DC then passes out of the alternator and into the electrical system of the vehicle, and this current is dependent upon the load across the output.

Unless the load placed across the alternator exceeds the alternator's current-delivery capacity, no current will be drawn from the battery -- in fact, current will flow into the battery (thus charging the battery) unless the alternator is unable to deliver enough current becaue of excessive load.

The alternator will work harder if additional loads are placed across it. There are no free lunches where energy is concerned.

Be well,

SJW

 

OK, in trying to simplify the system I made myself look like an idiot.

Let me start at the beginning, but the bottom line is the one equation we need to answer this question is one I don't have...

The torque required to turn the rotor in the alternator does increase with current draw but not as much as a mechanical gear (in this case). As the magnetic field between the rotor and the stator increases the torque required to turn the rotor goes up, but it is not a linear relationship.

However, since it's been awhile since I've messed with DC machines I don't have any graphs of T vs I to turn an alternator across various currents. Additionally we'd need to know the current draw requried to run the pump. I might have that in the documentation that came with it.

Nor do I have any torque measurements for how much it takes to turn the impeller in the water pump. I can tell you that the increased alternator load is less than the mechanical load but it won't hold up in court and I am not going to look up either of those numbers today...

So in effect I've added nothing to this discussion.

However, there are less tangible advantages to the elecric system. The increased force required to turn the alternator is independant of motor speed. However, the drag on the motor from an accessory (the water pump gear) will increase with engine speed. I tend to run at high RPM's most of the time. Therefore I am most likely over compensating for the water pump current draw instead of adding more drag due to the mechanical system.

Additionally, impeller speed is now more or less constant with the electric pump, varying with available system voltage (~13-14.5 V) as opposed to engine speed.

Lastly, I can cycle coolant with the motor off which makes things like burping or flushing the system much easier.

 

If you install an alternator that can generate more amperage than the wiring harness can handle, you'll invite trouble.

I've heard that the early C4s had reliability issues with alternators, so upgrading might be worthwhile if you have one of those problematic units (I don't know when that problem was solved in production). Aside from that possible issue, the stock alternator should be sized just fine for a stock '89, unless there's a deficiency of which I'm unaware.

Be well,

SJW

 

I've read enough of your posts to know that you're no idiot, Scary. As you noted earlier, you were tired when you wrote that post.

I would love to see independent test results that might clear up, once and for all, whether or not there's any HP to be gained by switching to an electric w/p. I'm doubtful that it could be worth the switch for this reason alone, for the average street-driven car.

Assuming 100% efficiency in translating mechanical motion to electrical power and vice-versa (which ignores reality), there would be no increase or decrease in parasitic drag at a given pump RPM.

I can see where there might be some reduction in parasitic drag by running an electric pump at a lower RPM than a mechanically-driven pump would run, but this would only be true if the drag reduction gained by the lower pump RPM was enough to more than offset the large inefficiencies inherent to the mechanical/electrical/mechanical conversion process. At what RPM does the electric pump run at a nominal system voltage of, say, 14VDC, BTW?

The idea of eliminating the gear-driven pump to prevent possible gear destruction followed by engine destruction in the event of a pump bearing seizure, and to be able to circulate coolant without running the engine, seem to have some merit. Thanks for raising these points, guys. This has become an interesting discussion.

Be well,

SJW

 

I should add for the benefit of all reading this that the faulty waterpump was a new one, it had but 15,000 mi and 2 years on it.

So, if you have the mechanical waterpump, this is the risk you take.

Maybe it's a good risk, maybe not. I have not heard of any LT1 mechanical pumps failing this way.

Maybe I should try Lotto.

 

you're right, but i'd further qualify it by pointing out that it should be relative to flow, not pump rpm. the impellers are different, so flow per rpm changes. the meziere also spins much slower than the stock mechanical pump does at high engine rpm, so your statement comes into effect as well.

my conclusion is that even the HD meziere flows much less than the stock wp does at higher rpm.

who knows what that rating means, it's not qualified in any way. also, if you look at the meziere catalog, their flow ratings follow the motors used, not the specific engine application. for all we know, the flow rating is in a box with 2" inlet/outlet and no backpressure.

not to say it won't cool the engine. i'm sure it flows more than stock at most sane street speeds. for drag/auto-x it probably cools better than stock. open track/roadracing with a high output engine might be a different matter.

-michael