I read through the threads, but I didn't see one that's fits the bill for my '88 GT. I bought an Underdrive Power Pulley Kit from Rodney Dickman, and it was installed today. I noticed instantly that the car was peppier with the air conditioner running. Since the air conditioning was just completely retrofitted with a new compressor and all, I thought this was the perfect time. Plus the car squealed at every start until it warmed up! Now to the point, my mechanic is panicking that I need to replace my alternator because it won't be able to charge the battery when idling. We live in Chicago, so there is a lot of that! Right now, everything is stock and the car has 63k kilometers (Canadian GT now Stateside). Do you recommend that I actually do this? The gauge was lower, but I don't know how accurate those are anyway. If yes, do you have a recommendation on which alternator is the best choice? I looked at the Fiero Store, but the way it read it sounded like you couldn't use it with a Power Pulley Kit. Thank you all, yet again!
I had an underdrive pulley years ago. They do make a difference but really the car was designed with the right pulleys. Unless you are racing or really looking for optimal power, it serves no purpose. They are easy to swap out. You are basically underdriving everything. My car ran hotter, water pump was not circulating as much. Yes, the alternator was not charging well, and if you are caught in heavy traffic at night (headlights on) you might have a problem. Just my experience.
I'm not familiar with the underdrive pulley setup you installed. Was the alternator pulley also swapped out for a larger one, or was it just a smaller crank pulley that was installed?
Several years ago I installed a smaller crank pulley on my Formula. With the CS alternators that 88's have, there's no issue. The older SI alternators might have a problem with voltage at an idle.
Many have problem w/ "Power Pulleys" and mechanic is correct. And not just Fiero but most vehicles. Yes the small crank pulley will under drive everything. Even if alt charges, the WP and everything else won't see enough input shaft RPM for them to work right. Idle and slow traffic isn't only issue... High final gears or OD transmission cars can have problems at 50-70 mph on the highway.
Depending power used upgrading the alt may not help. All alts have about same minimum input shaft RPM to start and makes a fraction advertise peak amps at idle and any time Engine RPM < ~2500. "Power Pulleys" can fail to spin the alt fast enough to make power in the same settings.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
Going on year 4 with the underdrive pulleys and no problems.
Only time I see any voltage drop is with everything on at idle and then it still doesn't go below 12v on the gauge ( don't know how accurate that gauge is ).
OTOH, I've done a fair amount of measured street testing as I added mods to the car and I didn't see any improvement with the new pulleys.
If I had to do it over I'd probably skip them.
Now, adding the 1.6 rockers, well THAT got my attention.
If you swap out an alternator that produces more power at idle you have negated at least half the benefit of the underdrive in the first place. Next you'll want a water pump that pumps more at idle and you will be back to stock performance with a lot of money wasted.
I agree that stock Fieros have enough issues without adding to them by underdriving your accessories. My recommendation is to go back to stock and sell the underdrive kit.
look at your VOLTS light on the center console. If it is off, your alternator is charging just fine.
By the way this is not true. The Volts light only comes on if you have a serious undervoltage like around 9 volts. It will not tell you if your alternator voltage is too low to charge which is around 13 volts.
I've heard people at the track using an underdrive, maybe swap it out for that day. Or, even pulling the belt off just for a quick drag to see if they can shave a tenth of second off their time.
Many of the bolt-on power adders that are so popular do very little and I have been through just about all of them. The biggest rip-off was the "chips" they sold years ago. The other was the "cold-air" intake.
Coming from new model Mustang and Camaro forums, one of the things I love about this forum is that most folks speak from experience -- not theory, opinion, or conjecture.
The benefit of talking about cars that have been around 30 years, as opposed to 3, I suppose.
I've had both the under drive pulley and the idler pulley on my 88 GT for almost 3 years now and I have not had any problems. Coolant temps stay exactly where they should (verified with ALDL cable/laptop) and volts never dip below 12.5 at idle in traffic.
Admittingly this all depends on what condition all the systems are in. Driving at night with EVERYTHING on (stereo cranked) there is a noticeable dimming of the interior lights (all LEDs) when at a stop light... but as soon as I come off idle and pass 950-1000 RPM it all rings bright. My water pump, alternator and A/C compressor were all replaced new close to the same time and coolant tubes/radiator were rodded as part of my restore process. Eventually I would like to clean all my ground points. Car had less than 77k when I got it. Just hit 88k after 5 years of ownership.
