Old Ford Lover

I see the ads for electric water pumps that proclaim 15 HP gain or more, by taking the water pump off line and pumping it electrically. But nothing is free. What about the added drag on the alternator to produce the extra watts to power the pump? and how does it compare to putting on the underdrive pulleys? Does it help if they're combined? Is there a "better " water pump that reduces drag at high RPM?

Daniel60

Yes I agree but have no answer.

hawgman

15hp is a bit of a stretch. But yes, there are hp gains from the EH2O pump. I actually run both the UDPs and the EH2O pump. Had the UDPs to begin with, installed the pump later. Gained around 5 or so hp with the addition of the pump. Which I didn't consider being too bad of a gain. I picked up 10hp with the UDPs. The combo of the two was a nice pickup. Just remember that you cannot replace the EH2O pump pulley with the UDP water pump pulley. So if you run both you will need a 99 1/2" belt. Plus with the added cooling you get from the EH2O pump, it is hard to find something bad about them.

As for the added drag on the alternator. Nothing to worry about. Your alternator is going to output maximum at around 2000RPM anyway. So there is no concern unless you plan on sitting around for long periods of time with your car at idle.

4wheelkillr

good topic...
I've been seeing a lot about people feeling the difference with underdrive pulleys and such. Some people say the water pump is great some say it makes no difference in power.

To me it seems that it MUST free up power (the elec water pump). People swear by underdrive pulleys; so if you you're swapping 3 of the pulleys including the water pump and alternator, then obviously those accessories free up some power. It seems however that to make the pulleys worthwhile, and to ensure that the accessories aren't completely worthless then the diameter change would have to be minimal at best.

All things being equal, the waterpump is said to have the largest parasitic affect on the motor. So to completely eliminate the water pump's strain on the engine seems like it would be 10x better than slightly changing the sizes of even 3 or 4 pulleys.
Doesn't that make sense?

The alternator like any motor is a series of magnets and brushes. The alternator produces a set amount of power based on how fast you can spin it. So (correct me if I'm wrong) but simply "drawing more power" from the stream of power already produced doesn't put more pressure on the alternator as far as necessitating more HP to turn the alternator pulley b/c it's thirsty for power. Either the power is there or it isn't, only changing the speed of the rotation affects how much drag is on the alternator, not how many amps it draws.

Anyone? Anyone?

spyder7724

i bought mine just to be able to cool down quickly while at the track but i talked to lidio at alternative auto and he has dyno'd with and without and hawgman is right on lidio gained 4hp with the pump. i went with the fluidamper lower since i only needed to replace that pulley and not the w/p pulley. the fluidamper pulley is supposed to be worth 10hp on it's own due to reduced harmonics and underdriving the accessories. i don't know about gains from it but it seems to work okay. just like a pulley should.

hawgman

You don't replace the alternator pulley on the S197 engines.

spyder7724

i haven't seen any kits yet that include the alternator pulley. i know something is different about the alternator on the 05-up. has something to do with it not producing current when the alternator is running backwards...?... i guess since the car was made to run on 87 they were afraid it might do the run on thing (when the engine is shut off)or something if someone got crappy cheap gas. this shouldn't affect the pulley though.

donnyonee

in the old days, you could put a switch in line with the field wire to actually shut it off. that way there was no drag at all from it, making more hp.
it seemed like....

spyder7724

when i go to bradenton i'm going to get a shorter belt and bypass the a/c and p/s and just drive the alt. i may have to buy another grooved idler pulley to accomplish this. i think it can be done at least the p/s i know can be done with just a shorter belt. maybe worth 5-10 more hp+. i saw a article on the 3V which they tested without any accessories or cats/mufflers and the motor made 351hp at the flywheel. capped up with all the drive accesories it makes 300 from ford. that's a big difference huh? which thing is taking all that power away? i think the p/s pump takes a lot since it's pumping a thicker fluid. think about this the engine makes 350hp on the dyno. in the car it dyno's stock at about 260hp. 90hp is eaten up through drivetrain and accessories!!! i want that 90hp back!![:@]

Old Ford Lover

The torque required to rotate an alterrnator increases with the amount of current being drawn. It has to do with the amount of magnetic flux changing direction, etc. I just don't know to what proportion. I'm beginning to understant that at high RPM it is a small enough difference to become moot.
According to what a Ford mechanic at the place I bought my car said the alternator pulley is clutched to reduce the amount of effort to turn it at higher RPM, and reduce wear on the belt. Haven't read it anywhere, tho. Hence, no alt pulleys in underdrive kits.