Wondering what the pros/cons are of the 2 vs. 3 underdrive pulley set ups are. I know with the 2 pulley (no alternator), you need to bump up the idle rpm (which I can do w/ Xcal). On the 3 pulley set up, I'm not sure if the alternator pulley speeds up to compensate or adds more reduction above and beyond the reduction from the crank pulley.

Lastly, the only 2 pulley system that seems to fit my 03 Ex is made by ASP and uses a new crank pulley which is also a dampner. The other aluminum pulleys are bolt-ons to the the OEM crank. Any issues with that set up?

My belt system is a 6 -rib job, so I need a system that has that option. I noticed the BBk set only has 8 rib pulleys, for example.

Just wondering what everyone uses and what they have found out.

Thanks,

 

I use the JET 2-pulley setup. Hadnt heard about bumping the idle up at all. Mine idles the same as always. The only minor issue is at really slow take off, the power steering is a little tight but once the engine gets above 8 or 900 rpm it is fine.

I swear I read somewhere that the typical alternator is putting out max or close to max amp source when its own spindle speed is 850 rpm, which would already occur if the crank rpm is 700 rpm in my case, as the crank pulley is much larger than the alternator pulley.

Mine is also a 6-rib system. MAC makes an 8-rib setup but a source I know sells that for 6-rib belt systems. You might notice issues with alternator output if you have alot of current drawing items on at the same time at idle or moving very slow. It all depends at what spindle rpm the alternator puts out max current draw and I am not sure where to find that spec.

 

Do a search on pulleys for more info on this. I remember reading that on a set of aftermarket pulleys the alternator pulley was the same size as the stock pulley. Many have decided to go with two pulley sets as a result of this. The ASP pulley set is the better set in my opinion because of the replaced crank pulley. The BBK and other sets attach to the stock crank pulley or piggyback onto it. There have been cases where the aftermarket pulley was not seated correctly and cause a knock in the engine.

 

That is correct that the alternator is putting out the majority of its capacity at idle. If you have power windows you may notice that they operate faster at higher idle speeds indicating more amperage.
Becuase the vehicla is computer regulated there is no calibrating of the idle. It will moderate itself fine.

 

my 3 piece pulley kit had the same size alt. pulley, just made of aluminum.

 

My JET pulleys were replacements, got the originals in a box. I guess I am uninformed but thought all underdrive pulley sets were pulley replacements rather than attachments. LOL! Guess I asked for the right thing after all!

 

Anyone know of a set that does not include the crank pulley? I have the water pump pulley from a troyer set but can't use a crank pulley due to the Vortech pulley that has to bolt to the stock pulley.

 

See if anyone on eBay is selling individual pulleys from an aftermarket set. Otherwise, you may have to buy a set and not use the crank pulley from that set.

 

.... and what can one expect for gains on a stock 2V 5.4?

Andy

 

Different kits will make different claims but typically they promise a recovered 15 to 20 hp and similar values for torque over stock. Better pickup and better mpg because the engine is not having to work as hard.

 

Don't bother with pulleys spend you money on Efans I put the Efans on first then bought two pulley kit from T.P. I felt 0% power increase I then installed the Roush S/C so I had to remove the two pulley kit. I then installed that two pulley kit on my 2003 Expedition and got some power and 1.5 better MPG Just my 2Cents

 

That 2 cents worth of 1.5 mpg is what I'm after

I could go from 17.5 (best thus far with efans) to 19 on the highway. I'd be very happy with that.

 

I believe the mileage came from reduced fan speed I do not have Efans on the Expedition but I do have on the F 150 that's Y I did not see much difference in the F 150 And did see the difference in the Expedition
so If you have Efans don't bother with Pulleys
Hope that explains a little better what I was saying

 

I have Efans and I am considering the pulleys. That 1.5 is good if I can get that in additions to my current gains. Who else has Efans and pulleys that can comment? I think there is some gain to be had with the combo.

 

The under drive pulley sets are designed to reduce the parasitic loss driving the accessories. If you look closely the crank pulley is smaller thus increasing the torque available to the accessories. Unfortunately lowering the speed of the accessories. The replacement water pump pulley is larger so it will speed it back up to the stock rpms eliminating potential overheating at idle. Unless you replace the crank pulley don't bother replacing any of the others. So after all is said and done the speed of the Power Steering Pump, Air Conditioner Compressor and alternator is reduced. They catch up to speed when you rev the engine. Because they are being driven by a smaller pulley they will draw less power away from the engine. Your engine throttle response and power available to the crank should increase. This would be one of the last mods I would do. I fried two alternators because of mine and now I can't use them because of the Procharger.

JMC