| From | Message |
Olindo
Dodge Dakota
JOIN HERE
11/22/2005
10:27:50
|
 Subject: Underdrive Pulley/TPS mod
IP: Logged
Message:
Can someone clear things up a bit for me...? 1) what is an underdrive pulley, what does it do, and how does it differ from the factory pulley, 2) with the TPS mod..what am I trying to do here? am I just trying open up the holes? from what I can piece together this mod implies the voltage varies with tps positioning...so opening the holes allows some wiggle room to tweak the tps to the optimum voltage..am I right?
Thanks
Olindo
99 3.9v6, iat relocated/switchable, dynomax superturbo, homebrew K&N cai, autolite 3923's, metalic blue (that the wife hates...too bad!)
|
daveshotdako
GenIII
11/22/2005
12:23:58
|  RE: Underdrive Pulley/TPS mod
IP: Logged
Message:
you are correct about the tps mod. and for your other question... an underdrive pulley is a smaller diameter pulley makes it easier on the engine to turn by slowing down the speed of the belt. the only downside to this is if you replace your alt pulley, it can cause charging problems, especially if you have a system or off road lights and are sitting at a redlight or just idleing. it cause the alt to not charge enough. with underdrive pulleys, you also have to get a shorter serpentine belt to make it all work. if you have any more questions, feel free to ask. thats what we are all here for.
GET IN, SIT DOWN, SHUTUP, AND HOLD ON
custom 48mm tb, tps @ .768, relocated IAT, 180 t-stat, autolite double platinum, taylor wires, flowmaster 40 delta flow single in/dual out, CAI
|
Olindo
Dodge Dakota
JOIN HERE
11/22/2005
12:59:23
| RE: Underdrive Pulley/TPS mod
IP: Logged
Message:
Thanks Dave...I've been to the ASP site and the pulley (I assume its a 'street' pulley)description is different for three applicable items...one is a "25% reduction" one is "25% crank", one is "25% crank/25% alternator", and the last is "25% crank/25% alternator/17% water pump"...gotta admitt, its kinda confusing...but based on what you said, I think I should go with just the "25% crank"? and of course the matching serp blt. Am I on the right track?
|
daddio
Dodge Dakota
JOIN HERE
11/22/2005
13:29:44
| RE: Underdrive Pulley/TPS mod
IP: Logged
Message:
you're on the right track. i have an underdrive crank pulley on my '00 QC 3.9/5spd. i have had it about 2 yrs and no problems whatsoever. i even have my original battery. 6 yrs old this January coming.
basically what it does is give the engine a little more leverage to turn the accessories. mine seems to rev a little quicker. no charging or a/c cooling problems even with everything on high and a 300watt amp cranked.
|
Hammerhead
GenIII
11/23/2005
07:56:42
| RE: Underdrive Pulley/TPS mod
IP: Logged
Message:
I've had the underdrive pulley on for less than a week, and I have not seen a drop in the charge or any other negatives. My battery is not the original but I've had it for about 3 years.
2000 CC 3.9
Dave's bored 48mm tb, Magnaflow cat-back exhaust, Airiad intake, superchips, JBA power cables, Denso plugs, ASP underpulley
|
Olindo
Dodge Dakota
JOIN HERE
11/23/2005
08:16:54
| RE: Underdrive Pulley/TPS mod
IP: Logged
Message:
A couple of more questions...If the belt runs slower, as Dave mentioned, wouldn't engine cooling be affected since the water pump would be pumping slower...also if the belt is running slower it sounds like it doesn't matter if you repl the alt pulley since even the factory alt pulley would be running slower and thus be affecting alt performance....last one...what needs to be removed to get to the crank pulley?
Thanks
|
daddio
Dodge Dakota
JOIN HERE
11/23/2005
09:03:43
| RE: Underdrive Pulley/TPS mod
IP: Logged
Message:
Olindo, if you change the alt pulley also the alt would spin even slower at idle and you will have charging problems at low speed.
Now cooling, on my truck i have removed the clutch fan and have a 195 tstat. even during the hot south louisiana summer, idling in traffic with the a/c blasting my temp never got to 210, which is the middle of the temp gage. you should have no problems if your cooling system is up to snuff.
|
Olindo
Dodge Dakota
JOIN HERE
11/23/2005
09:08:48
| RE: Underdrive Pulley/TPS mod
IP: Logged
Message:
Cool deal...daddio...(no pun intended)...so whats the crank pulley installation like? radiator gotta be taken out, coolin syst drained?? Just want to know what I'd be gettin into...
Thanks
|
daddio
Dodge Dakota
JOIN HERE
11/23/2005
09:33:16
| RE: Underdrive Pulley/TPS mod
IP: Logged
Message:
Oh NO. take the belt off. take out the 4 bolts the hold the pulley to the balancer and reverse to install the new. it's that easy.
|
| | P 1 |
|
Post a reply to this message:
Username Registration: Optional
All visitors are allowed to post messages
|
