Some drawings and pics for my serpentine project.
http://www.renaissanceracing.com/images ... dapter.JPG
http://www.renaissanceracing.com/images ... Slant6.JPG
http://www.renaissanceracing.com/images ... tMount.JPG
http://www.renaissanceracing.com/images ... 6Crank.JPG
http://www.renaissanceracing.com/images ... ntSerp.JPG
http://www.renaissanceracing.com/images ... Braket.JPG
Ider pulley is still in rough form. You can see the tapped spacer laying on the block.
The hub adapter is welded to a six grove crank pulley of a B3000 pickup 5/93 V6. The mounting surface was turned off to weld in the adapter.
I have decided not to make a combo system because though it is possable, its not practical. All combinations can be done with two iders in fixed positions and just change the wraping route, but they all can be done with one "floating" ider which would make more sence. The ider pulley came out of a 96 explorer. The water pump pulley came from a 96 Sable which still needs to have 4 holes drilled in it.

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

very nice. I appreciate the work you have done.

I must ask though, just for my own ignorance, did you do this mainly for the added stability and the ability to get newer parts or was it something else that motivated you?

it is a good idea, especially if you print out a list for us when your all done- or sell a kit.

Looks very good.

One thing that concerns me though...the lack of belt wrap on the waterpump pulley. It looks like less than 1/4 of the pulley circumference from your drawing.

I remember (vaguely) running the numbers for assumed HP drag from the waterpump at high rpm, and needing nearly 1/2 circumference belt wrap on the waterpump pulley (which we made the same diameter as the original). This is the reason my automatic tensioner is positioned so low...to achieve extra belt wrap on the waterpump pulley.

You might want to consider raising the existing idler pulley (if there is room) or adding an idler on the passenger side of the waterpump pulley, between the waterpump and alternator.

Just my $0.02

-S/6

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The "Silver Bullet"
87 Ram D150

okay, I knew about less drag = more horsepower, but since I only have an alternator, it really wouldn't help me much then.

I also thought most of the drag from the water pump was caused by having to spin the fan, which is why I went electric.

are there other benifits besides the ones I previously mentioned?

I would have to find the design report that was written for my conversion (it was done as a mechanical engineering senior design project) to find exact numbers, but IIRC we assumed around a 10-12 HP drag for the mechanical fan, and 3-4 HP to actually turn the waterpump impeller (all maximum values for say, 5000 rpm.) At the time, I had a mechanical fan, now I do not.

If Bren's setup does not plan to use a mechanical fan, it should be okay as-is. But I would not be surprised to find the belt slipping on the pulley with a mechanical fan.

AFAIK, the main benefit to serpentine setups is the serpentine belts' ability to make tighter bends, which allows for more compact mounting of accessories in today's overcrowded engine compartments. My main motivation for doing my conversion was (1) to be different and (2) I was very tired of throwing power steering belts, and not being able to tighten the power steering belt enough to stop squealing in all situations (mostly parking lots). Not having to remove one belt to get to another is also a very nice 'bonus'.

okay-

one last (maybe) question: how do you figure out your ratios of pulley to pulley? I know there must be a mathmatical formula, because an alternator has to spin at X rpm to put out its given power, and I assume that an AC compressor and a power steering pump are the same way. when switching to a serpentine system, if you mess with the pulley diameter something maybe over or under the standard RPM, and potentially effecting output.

I am just wondering what the formula is.

I think "march" pulleys does this sort of thing all the time and there must be some ratio they are following.

My crank pulley is now 6" dia. and the water pump in now 5.5" dia. Stock crank pulley is 7"dia and water pump is 6.5" dia. The ratio between the two is very close. The water pump should spin very close to the same speed as stock. The alt. has a little smaller pulley also so I should be good there too. The A/C and power steering will spin a little slower but I don't think it will be a big deal.
The reason behind this project was to play a little and be a bit different. If I had to do it again, and still may depending on how big my new air cleaner will be, I wouldn't. I gained about 1/4 fan clearance with the serp setup. In the future though bolting on a supercharger should be easy

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

All that is needed is to compare the ratio of the crank pulley diameter to the accessory pulley diameter. In my case all pulleys were effectively the same diameter as the stock V-belt pulleys (within 1/16"), except the alternator pulley which was about 1/4" smaller in diameter, so my alternator is slightly overdriven.

The power steering pulley was the most critical for idle, as it has to be spinning fast enough at idle to provide the pressure necessary to move the wheels. Fortunately, the newer power steering pumps appear identical to the older P/S pumps, with a serpentine pulley instead of a v-belt pulley. As my crank pulley was the same diameter as the stock v-belt pulley, all I had to do was press the v-belt pulley off, and press a serpentine pulley (which was also the same diameter as the V-belt pulley) on to my original p/s pump.

I thought about under-driving my waterpump pulley, but figured it would not gain much, and did not want to chance over-heating problems.

Centrifugal supercharger was one of the things I thought about as I did the conversion as well. I may still try to adapt one in the future.

yeah, it would make adding a supercharger much easier.

my compression is to high though.........

10.5 to one is a bit much for a supercharger.

Lower the boost psi a bit and use a small shot of nitrous (50) to cool the charge a bit more.

Permission given to beat me about the head and shoulders

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

oddly enough, I have heard that before.

(the nitrous, not the beating you up part )

Me too, but I thought I'd try to avoid the verbal beating by down playing the idea.

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir