Pulleys, question?

gogo50 · 02-12-2001, 08:23 PM

I have an 87 AOD mustang, 70,000 miles, I wanted to get pullies. I have a magazine called, Texas MustangParts, it says that an 87 needs a 1 inch shorter belt to add on underdrive pulleys. Is this true? any help.

------------------
87' LX,Dark Canyon Red Hatchback,AOD,remanufactured w/Transgo shiftkit
3:27's
Flowmasters
K+N filter E.T.= 14.6@95
no Airsilencer

speed demon · 02-12-2001, 08:37 PM

Of course! The whole purpose of buying pulley's is so you can have smaller pulleys to reduce parasitic drag on the crank. You will definetly need a smaller belt. The size of the belt depends on what size pulleys you get, and how many of them you get.

---------
1991 mustang gt "cobra"
hurst short-throw shifter, mid?-length headers, off-road exhaust, saleen spoiler.

Shotgun28 · 02-12-2001, 09:42 PM

well I thought all 87-93 had self-tensioners. I wouldn't buy a belt without trying to use the stock belt first. As long as it falls between the lines on the tensioner it should be fine. If not, wrap a string or yarn around the pulleys as you would the belt, tie it off and bring it to a local parts store, they should be able to help you find the right belt. Oh and Texas Mustang is were I bought my pulleys, they are a good place to order from.

------------------
91 LX Convertible Gray on Red B&M Shift improver kit,ASP red alum. underdrive pulleys, Richmond 3.73 gears, 1 5/8 Flowtech long tube Headers and off road h-pipe, Flowmaster 2-chamber cat-back with S.S exhaust, MSD 6A Ignition with coil,Cap and rotor, Taylor Pro wires, K&N 12" conical filter system, Jet stage 2 performance chip and just purchased some GT40P heads, looking at exhaust, Lentech Street Terminator plus on it's way...

NO SLO PK · 02-12-2001, 10:38 PM

Yeah, definitely try the stock belt before you buy a new one. I've installed three sets of underdrive pulleys on Fox mustangs, and I don't recall once ever needing to use a shorter belt.

------------------
'91 LX
Procharger, 3 row intercooler, extrude honed Cobra intake, Mac full Length Headers, 30# inj., 73mm C&L, 75mm tb, E303 cam, 289 rods, ported E7 heads, MSD, T-Rex w/255 lph Walbro, 5 lug conversion, Cobra R wheels, 3.27 gears and Moser Axles.

chris91LX · 02-13-2001, 03:14 AM

I agree. I have the stock belt on mine and the only difference is that the tensioner is flexed almost all the way down. Youmight want to go with a belt maybe an inch shorter if your going to replace it, but the stock one has worked fine for me with all three pullies installed.

------------------
91 LX 5.0
Z t-5, 3:73 gear, Vortech 73mm Mass Air, Accufab 65mm TB, BBK underdrives, Crane HI-6S Ignition, BBK unequal length headers, Bassani x pipe, 2.5" Dynomax Super Turbo cat back, Kenny Brown Super Subs, Factory Five Control Arms, Mac cold air kit and more to come!

Phil Ossifer · 02-13-2001, 09:16 AM

Quote:

Originally posted by speed demon:
Of course! The whole purpose of buying pulley's is so you can have smaller pulleys to reduce parasitic drag on the crank.

speed demon,

Remember, the only pulley that's smaller is the crank pulley. The driven pulleys should be larger to further reduce parasitic drag. Most of the newer street pulley kits are designed to use the stock belt.

When I bought my stang new in '89, most guys were just installing a smaller crank pulley and a larger alternator pulley, you HAD to get a shorter belt.

Then the aftermarket came out with 3-pulley kits where the stock belt could be retained...

Phil

Smokedawg · 02-13-2001, 06:07 PM

Just agreeing with Phil here. I recently installed underdrive pulleys on my 90 GT and kept the stock belt. They only pulley that is smaller is the crank so it spins faster. But alternator pulley is larger. Not 100% sure on if the waterpump pulley is the same or larger.

------------------
347 Stroker Motor: Balanced, 30lb Bosch Injectors, Cobra Computer, Cobra Transmission, GT40 Ported and Polished Upper and Lower, GT40 Milled Ported and Polished Heads, B303 Cam, BBK 1 5/8 Headers, March Underdrive Pulleys, Electric Fan, Accel Performance Coil, Accel 300+ Racing Wires, NGK Plugs, Ram Air, K&N Filter, 77mm Mass Air Unit, FlowMaster Exhaust w/offroad H-Pipe, Hurst Short Throw Shifter, 3:55 Gears, Ram Clutch, Cross Drilled Rotors, High Tolerant Painted Calipers and Drums.

02-12-2001, 08:23 PM	#1
gogo50 Registered Member Join Date: Oct 2000 Location: Novato Posts: 46	Pulleys, question? I have an 87 AOD mustang, 70,000 miles, I wanted to get pullies. I have a magazine called, Texas MustangParts, it says that an 87 needs a 1 inch shorter belt to add on underdrive pulleys. Is this true? any help. ------------------ 87' LX,Dark Canyon Red Hatchback,AOD,remanufactured w/Transgo shiftkit 3:27's Flowmasters K+N filter E.T.= 14.6@95 no Airsilencer

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02-12-2001, 08:37 PM	#2
speed demon Registered Member Join Date: Feb 2000 Location: Winnipeg, Manitoba, Posts: 24	Of course! The whole purpose of buying pulley's is so you can have smaller pulleys to reduce parasitic drag on the crank. You will definetly need a smaller belt. The size of the belt depends on what size pulleys you get, and how many of them you get. --------- 1991 mustang gt "cobra" hurst short-throw shifter, mid?-length headers, off-road exhaust, saleen spoiler.

02-12-2001, 09:42 PM	#3
Shotgun28 Registered Member Join Date: Sep 2000 Location: New Hope MN USA Posts: 276	well I thought all 87-93 had self-tensioners. I wouldn't buy a belt without trying to use the stock belt first. As long as it falls between the lines on the tensioner it should be fine. If not, wrap a string or yarn around the pulleys as you would the belt, tie it off and bring it to a local parts store, they should be able to help you find the right belt. Oh and Texas Mustang is were I bought my pulleys, they are a good place to order from. ------------------ 91 LX Convertible Gray on Red B&M Shift improver kit,ASP red alum. underdrive pulleys, Richmond 3.73 gears, 1 5/8 Flowtech long tube Headers and off road h-pipe, Flowmaster 2-chamber cat-back with S.S exhaust, MSD 6A Ignition with coil,Cap and rotor, Taylor Pro wires, K&N 12" conical filter system, Jet stage 2 performance chip and just purchased some GT40P heads, looking at exhaust, Lentech Street Terminator plus on it's way...

02-12-2001, 10:38 PM	#4
NO SLO PK Registered Member Join Date: Mar 1999 Location: Arcadia, CA, USA Posts: 731	Yeah, definitely try the stock belt before you buy a new one. I've installed three sets of underdrive pulleys on Fox mustangs, and I don't recall once ever needing to use a shorter belt. ------------------ '91 LX Procharger, 3 row intercooler, extrude honed Cobra intake, Mac full Length Headers, 30# inj., 73mm C&L, 75mm tb, E303 cam, 289 rods, ported E7 heads, MSD, T-Rex w/255 lph Walbro, 5 lug conversion, Cobra R wheels, 3.27 gears and Moser Axles.

02-13-2001, 03:14 AM	#5
chris91LX Registered Member Join Date: Oct 1998 Location: Suburban Chicago, Hanover Park Posts: 695	I agree. I have the stock belt on mine and the only difference is that the tensioner is flexed almost all the way down. Youmight want to go with a belt maybe an inch shorter if your going to replace it, but the stock one has worked fine for me with all three pullies installed. ------------------ 91 LX 5.0 Z t-5, 3:73 gear, Vortech 73mm Mass Air, Accufab 65mm TB, BBK underdrives, Crane HI-6S Ignition, BBK unequal length headers, Bassani x pipe, 2.5" Dynomax Super Turbo cat back, Kenny Brown Super Subs, Factory Five Control Arms, Mac cold air kit and more to come!

02-13-2001, 06:07 PM	#7
Smokedawg Tires Fear Me... Join Date: Jan 2001 Posts: 867	Just agreeing with Phil here. I recently installed underdrive pulleys on my 90 GT and kept the stock belt. They only pulley that is smaller is the crank so it spins faster. But alternator pulley is larger. Not 100% sure on if the waterpump pulley is the same or larger. ------------------ 347 Stroker Motor: Balanced, 30lb Bosch Injectors, Cobra Computer, Cobra Transmission, GT40 Ported and Polished Upper and Lower, GT40 Milled Ported and Polished Heads, B303 Cam, BBK 1 5/8 Headers, March Underdrive Pulleys, Electric Fan, Accel Performance Coil, Accel 300+ Racing Wires, NGK Plugs, Ram Air, K&N Filter, 77mm Mass Air Unit, FlowMaster Exhaust w/offroad H-Pipe, Hurst Short Throw Shifter, 3:55 Gears, Ram Clutch, Cross Drilled Rotors, High Tolerant Painted Calipers and Drums.