How can I identify the underdrive pullies on my 88 IROC's 5.0 TPI setup. They were on the car when I got it but I want to ditch them due to issues with the charge system and dim headlights. There are better ways to make HP for a street/strip daily driven car (IMO).

Looking at the pullies I can't see anything to distinguish them. If I knew the diameters or the stock pullies I could compare, but alas my Haynes manual does not contain this info. How can I tell which pullies are stock and which are underdrivers?

Hell, if someone wants 'em I may be willing to trade for a set of stockers that are in fine working order.

Thx!

 

I'm not in a situation where I can get to my car to give you a measurement, but guessing, an underdrive pulley is only about 5-6 inches, while a stocker is about 8. As far as the waterpump pulley and alt. pulley, i dont have either on my car....i guess that why i've had no problems w/ cooling or charging. Oh, and the underdrive pulleys have a gloss finish...wipe them off and check out the finish...if their underdrives, they wont look like they've been on the car 13 years. Sorry I couldn't be more specific, but like I said, i cant get to my car right now....but i'm pretty sure those meaurements are close enough for you to determine. Wish I could have been more help.

 

Thx for the reply.

I figure I will try swapping out just the alternator pulley to stock and keep the other underdrives on.

What about upgrading to an alternator with a higher idle o/p. I'm not sure what the stock TPI 5.0 alt is rated for at idle.. less than 100 amps maybe? With headlights, radio, a/c etc all off, just 3 starts are enough to prevent the car from starting again. I don't have a re-programmed ECU prom yet, so the car is touchy at idle and easy to stall.

Besides the underdriven alt. pulley, would an aftermarket ignition setup (HEI coil, wires, new distributer etc) also contribute to draining the battery so quickly?

 

Yes....remove the underdrive alt. pulley. Like i said, i'm running only an underdrive crank pulley, and have had no problems. As far as high amp alts...i dunno who makes good/affordable high amp alts...i've been trying to figure that out myself, and all I can find is a chrome one. When you say 3 cranks, do you mean you crank it up and cut it off 3 times consecutively and it doesn't start, or do you mean you'll crank it and drive it 3 times before it goes dead? Aftermarket wires, coil, etc. wont put any extra drain on the battery.

 

I mean like turn key, start car. Kill engine. 3 times. So actually firing up 3 times.

As for aftermarket TPI alts... looking at prices on Summit I see they have em (Chrome) for $165 for a 140 amp with o/e wiring. Was that the one you were refering to?

Heck I see you can buy 300A alternators - not sure what you would need those for.. big sound systems I s'pose.

 

Yea, that's the chrome alt. i was talking about. But i've yet to find a high amp alt w/ a normal finish...i'm sure they're around, i just haven't looked very hard. Man, if after 3 cranks your car goes dead then it's not your pulleys or alt. I'd check out the batter first....get it tested for free at autozone or such. The only time pullies or alt. affect it is if you do some driving. So test the battery. When it wont crank, does it turn over slow, starter click, or nothing at all?

 

By the 4th start it doesn't even click.

I recently just dropped a brand new Altima red-top battery in there. The guy checked it was ok before he sold it to me. Sure enough, it checks out fine with my own tester.

Guess I'm just gonna have spend some quality time hunting this gremlin down. Thx for the pointers!

 

If it doesn't even click, then i'd look into the starter/solenoid, or maybe even the ignition switch. good luck, lemme know what you find

 

Went over the entire charge system again last night. Looks like the alternator charge connector boot was the culprit. It obviously needs replacing - it seems to come loose real easy and it's hit and miss as to whether it makes a good connection. Doh! After I crutched it I was able to fire the car up many times in a row no problem.

 

Glad you found the problem....you got off easy ($$FREE$$)