redington

i know some of you guys say that the pulley is a waste of money but i figure every bit helps..... so my question is.... would i be fine usuing a bbk underdrive pulley on a dailey driver. How hard are they to put in?
-Mike

speed_demon24

If you get an underdrive pulley, get the ASP 23% underdrive pulley, it replaces the stock crank pulley, its not a POS piggy back one. I have one and the quality is top notch too.

redington

what about the asp kit -----ASP LT-1 pulley 23% Crank, 15% Alt ''Nitride'' or just gow with the underdrive? What all do i have to take off so i can put the underdrive pulley on.
-mike

3gc

I just installed an ASP one a few weeks ago. It's a real simple job, getting the car in the air took longer. You just remove the belt, remove the three bolts and pull the damper off the hub. You may need a three jaw puller in order to get the damper off. You should be able to pick one up for less then $20. Once you have it off, slide the new one on, torque down the bolts and put the belt back on.

This combined with an ewp gave me 2 tenths and 3mph.

Bersaglieri

Just get the crank only verison for $144. The Alt pulley has seemed to cause problems for some folks.

I went with the 23% too and the car rev'ed quicker and seemed to accelerate perhaps a tad faster.

-Dustin-

speed_demon24

How was the weather on both runs? 3mph for an u/d pulley is a huge gain...

Paul94Z28

I went with the piggyback version. No problem on the install, but I had heard that M6 cars had no charging problems once these were installed.

DEAD WRONG.

If you install an underdrive pulley, you had better get the corresponding underdrive alternator pully or your car is gonna leave you stranded, especially if you like your nice delco bose stereo and lights at night.

I was very much suprised at the gain though.

speed_demon24

With my ASP pulley and an 800 RPM idle, I have no charging problems at all. With a scanmaster, my volts always stay above 13, even at night and idle with the lights and AC on.

3gc

That was 2 tenths and 3mph with an underdrive pulley and an electric water pump. It was about 10* colder too so i guess a little of that gain can be attributed to that. I also have absolutely no charging problems with my ASP 23% underdrive pulley and the stock pulley on the alternator.

Injuneer

I had the ASP 23% U/D crank pulley/damper and the 15% alternator U/D pulley, and on a hot day, sitting in traffic, with the A/C and the brake lights or the headlights on, the volts dropped into the red (car was still the M6 back then, with stock 800rpm idle speed). I was unable to measure any performance increase. With the water pump not driven by the belt, there is not a lot to be gained by slowing things down.

There's a dyno test of an "add on" pulley at ws6.com, and he saw a peak HP increase of 0.7rwHP, although the average gain was higher.

http://www.ws6.com/mod-2.htm

RedsTA

I have a 34% underdrive aeromotive crank pulley on my car, no real charging problems, its sits right at the 8. I have 2 10's plus all speakers have been replaced along with the receiver. Ive had it through winter and summer, works fine, rev's quicker, thats about all i noticed from it. Oh and my lights dim down a bit til i start to move, but thats not really a big deal.

96flame

I have the March underdrive and have no charging probs. I didn't buy it to gain power I bought it to save accessories from spinning so fast. I saw a car on the dyno pick up 15 RWHP and 10 RWTQ by removing his belt but he had stock pulley. Obviously it will help a bit.