Crankshaft Pulley

[schorvitz]

Last weekend was one AWESOME time at Road Atlanta! We had an awesome showing of Vipers and it was great to see everyone there!

Unfortunately, two of us lost our power steering pump :-(

I have already ordered Roe's PS radiator, but Sean also mentioned a smaller crankshaft pulley would provide much help. He couldn't remember which one he uses, but was guessing a Dodge Dakota pulley. He also said that this is a 6-rib pulley as opposed to the 7-rib pulleys on the Viper and that a 6-rib belt works with no slippage.

I was wondering if there were other solutions out there. I'd be surprised if someone wasn't selling a 7-rib under-drive crankshaft pulley and belt replacement for the Viper.

Also, reading the other posts on this board, here's what I have found to be the required parts:

1) Stock PS pump
2) Roe's 4-pass radiator
3) Redline's PS fluid
4) Under-drive crankshaft pulley (manufacturer TBD)


Looking forward to comments/suggestions!

 

[Vipermed 97.01]

The underdrive pulley you need is off of a ram or dakota magnum 5.2 or 5.9 they utilize the identical pully as the viper,unfortunately you have to go to a 6 ribbed belt as the selection for 7 is slim, we have exhausted all sources.Do not worry you will be fine with a 6, just do not go more than a 25% underdrive,if you go 50 you will need about 1350 rpm idle to maintain your charging system

 

[Jack B]

Here are the parts:

Pulley: Auto Specialties #504500
Belt: NAPA #NBH25060785

Weight: 7.25 lb vs 5.5 lb.

Summit has them in stock, the belts are typically in stock at a NAPA zone warehouse. I just put one on, I did it from underneath, it took about an hour once the car is ready.

The only thing tricky is reinstalling the belt. The tensioning idler is released with the use of long 12 point box wrench (11/16" I believe). I had to put a pipe over the wrench to get enough leverage to relieve the pulley tension. That may have been due to doing the job from underneath. I believe the job would be easier from above, however, I have a plate mounted on the cross brace (for cooling purposes) and did not want to remove it.

 

[FRANK]

Any horsepower gain? I am sure just a few...like 3-5 hp...

 

[Anthony - 98 GTS]

Any horsepower gain? I am sure just a few...like 3-5 hp...

I would guess 3-8 hp - depending on other mods.

 

[FRANK]

Depending on other mods? I don't think other modifications will enhance gained horsepower related to a crank pulley swap my friend...at all...

 

[Vipermed 97.01]

the only true gain you will get with 25% underdrive crank pulley would be that your P.S pump and waterpump have a 25% less workload.H.P gains are non measurable,but as far as enhancing power of other mods with the pully,most certainly an aluminum flywheel would enhance the small gains of a pulley.In my opinion neither are worth doing unless you already have those parts off from other mods being done.

 

[Jack B]

Vipermed:
I am not trying to be smart or disagreeing, however, I don't understand the something and perhaps you could explain:

The rearwheel hp is the output of engine minus all losses. The flywheel hp is the output at the crank minus the losses associated with the engine. The power steering pump and water pump are two of those losses. Both rob the engine of very real hp. If I reduce those losses, while are they not measurable?

 

[schorvitz]

Jack,

www.summitracing.com had the best price for the pulley and I found the belt at www.napaonline.com.

Got everything for less than $100.00

Eric

 

[Vipermed 97.01]

Vipermed:
I am not trying to be smart or disagreeing, however, I don't understand the something and perhaps you could explain:

The rearwheel hp is the output of engine minus all losses. The flywheel hp is the output at the crank minus the losses associated with the engine. The power steering pump and water pump are two of those losses. Both rob the engine of very real hp. If I reduce those losses, while are they not measurable?

if you can count 2-5 Hp gains then i stand corrected,a good cool breeze will give you that

 

[FRANK]

Like Benjamin Franklin once said "A penny saved is a penny earned..."


"A horse is a horse of course of course..." sound familiar lol ???