ANyone run an elec water pump and bypass the pully?
- Thread starter SteveR
- Start date
trinity_gt
10 Year Member
You might consider Meziere's idler-style electric pump. There's a "pulley" there that the OE belt rides on but it's just an idler and consumes very little power.
As for power savings, just remember that the power to move that water is coming from somewhere. In the original config, it's the crank-driven belt. In the electric pump's case, it's the car's electrical system and, ultimately, the alternator which is also crank-driven by a belt. As well, in the case of the OE pump, the connection is direct. In the electric pump config, the alternator isn't 100% efficient. That is, if you need 100W out of the alternator, you have to feed in about 130W of mechanical power because of losses. So in some ways you may actually need more power to drive the electric pump than a mechanical pump simply by switching from direct-belt to indirect electrical.
As for power savings, just remember that the power to move that water is coming from somewhere. In the original config, it's the crank-driven belt. In the electric pump's case, it's the car's electrical system and, ultimately, the alternator which is also crank-driven by a belt. As well, in the case of the OE pump, the connection is direct. In the electric pump config, the alternator isn't 100% efficient. That is, if you need 100W out of the alternator, you have to feed in about 130W of mechanical power because of losses. So in some ways you may actually need more power to drive the electric pump than a mechanical pump simply by switching from direct-belt to indirect electrical.
Electrical supply should be ok, I'm running a 135A alternator and no stereo. The only aftermarket electronics are a tach, pillar gauges, and possibly the water pump. I'm also wondering if by eliminating the water pump pulley, will there be enough traction on the crank pulley to pull the belt? The routing would be from the tentioner right to the crank.
ChillPhatCat
20+ Year Stangneter 
That's not what he meant. By switching to an electric water pump, the alternator needs to resist the serpentine belt more than if you had a mechanical water pump. In essence, you remove the water pump from the loop and increase the power used by the alternator by that amount. In the end you don't really gain anything noticeable. If you had a second battery dedicated to the electric pump, for when you're at the strip, then it would get you somewhere, but it would only be usable for a short time in that configuration, long enough to make a few passes before recharging it or reintroducing it to the charging system.
As far as pulley traction goes, how drastically will the "angle of wrap" change? That's the angle between the belt on each side of the pulley. If not significant then your traction won't change much, but if it is noticeable, then it could be a problem... the angle of wrap is directly proportional to traction (assuming the pressure on the belt from the tensioner doesn't change), so if it is reduced by 30%, then traction is reduced by 30%. The order of the pulleys, or how close they are to the crank has no effect on traction.
The belt wraps around the water pump then down to the crank and around it. By going right from the tensioner to the crank it looks like it would lose about 40-50% of the contact area. I'm curious if the tension on the belt is the same value with the bypass if there will be any belt slippage with the reduced contact area, especially going from idle to WOT.
ChillPhatCat
20+ Year Stangneter
Well, if you can get more tension on the belt, then it would make up for some of the loss, but that's a big loss. That said, there is probably a good bit extra traction there stock... most things are overengineered. I guess you'd have to try it and see what happens.
I'd be nervous using an electric water pump for fear of the pump failing resulting in an overheated engine. For me there is peace of mind knowing my water pump is belt driven and the fact that I'd know if the serpentine belt broke (loss of steering, no charge from alternator, etc...).
That's what I was thinking. I don't know that running an electric water pump for anything other than a trailered drag car is a good idea.
I have to respectfully disagree that an electric water pump is a bad idea for a street car... Reason being, especially on BOOST the POTENTIAL power gains do become more substantial, but more importantly WHEN/IF you break a belt, you can safely drive your car home, AND icing on the cake COOL as a cucumber in all conditions and absolute necessity for a serious drag car if you need to cool it down after a run it can stay on a switch (motor off)...
My 2cents, the Meziere I have was expensive and has the pulley so there was no re-routing BUT has performed remarkably on my 07 GT 331 with E-Force F/I intake... LOVE IT!!!... Before the engine upgrade I had a belt failure and had to off and on limp home to not damage the engine and I was only test/tuning at the time and relatively close, they overheat QUICK off the pump...
To close this convo, I am building a 4V Terminator old school motor and am going to TRY using one of the RT Racing electric pumps with no pulley ($160) and will report back as to the belt routing and whether it is possible or not... It is only $400 more for the pumps with the pulleys WT*******....
HOTROD HARD, drive safe...
Mark
highplace11
Knowledge dropping on a 15 year old thread
My 2cents, the Meziere I have was expensive and has the pulley so there was no re-routing BUT has performed remarkably on my 07 GT 331 with E-Force F/I intake... LOVE IT!!!... Before the engine upgrade I had a belt failure and had to off and on limp home to not damage the engine and I was only test/tuning at the time and relatively close, they overheat QUICK off the pump...
To close this convo, I am building a 4V Terminator old school motor and am going to TRY using one of the RT Racing electric pumps with no pulley ($160) and will report back as to the belt routing and whether it is possible or not... It is only $400 more for the pumps with the pulleys WT*******....
HOTROD HARD, drive safe...
Mark
highplace11
Knowledge dropping on a 15 year old thread
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