I am looking to hear from anyone who has installed underdrive pullies. What brand did you use, what items did the kit come with and what kind of gains did you get?

 

As far as i know ASP is the only manufacturer for underdrive pullies for the C5. Some vendors sell the pullies as kit (pulley, belts, bolt) and some just sell the pulley. The performance gains are about 5 hp.

 

The Buck knows his stuff!

 

Mine came from MTI with the pulley, belts, and the new GM aluminum bolt (the old one can not be reused.

I got a solid 8-10 hp for $220 and $180 install labor. It also add torque, of course, but this is usable torque from the entire rpm range...not just when you hit thousands of revs.

There are 3 main bolt ons that are a must if you want to get over 405 fwhp like the Z06. 1. Air intake / cat back exhaust, 2. UD Pulley, 3. LT headers




[Modified by Gary2KC5, 12:18 PM 1/15/2002]

 

Gary2KC5 - FYI: MTI get's theirs from ASP. :cheers:

 

I have this Mod on my car and I really like it. I had a shop install it because it is not an Easy Mod for me to install. When I had the Pulley installed I also had the new Clutch Assembly w/Aluminum Flywheel installed too. The Day after the Install our local Group went Drag racing at the Track. The Cars that I used to be tied with all the way down the track were now one to two car lengths behind me at the finish line. :eek:

I will never forget the look on Rojers face when he asked me "Steve, What Did You do To Your Car??" ;) Rojer and I used to be neck and Neck all the way down the 1/4 mile before the pully install. :) Now he didnt stand a chance in Heck in beating me. :crazy: I do have to say one thing about the Local Group.. even though we have some Cars that are faster than others, we really pull for he members who do more with their cars. There are no hard feelings about one member being faster than another.

I never did Dyno the Car after that install so I am not sure what gains I had. I do know that the car pulled much better and was good enough to make a big difference while drag racing other C5's in the 1/4 mile. :yesnod:

If you are looking to get all the HP out of your engine, this is a very good Mod to do. :smash:

vetterdstr :cheers:


[Modified by vetterdstr, 11:29 AM 1/15/2002]

 

True, but MTI did the actual development for the UD crank pulley...ASP is the manufacturer only.

It is a good mod alright. It gave me 8 Rwhp and a much freer revving engine on the same day as it was installed. :D

 

Jason,

Are you saying that MTI has their own C5 UDP design that ASP makes for them that is different from the other C5 UDP's ASP sells? Or just that MTI did all the intitial C5 UDP R&D for the ASP?


Talk about alphabet soup. :crazy:

 

MTI did the R&D since they were familiar with the part/application etc. ASP was not willing or too busy manufaturing their other pullies to do it themselves I guess.

It really was a joint venture but ASP is the sole manufaturer to my knowledge.

Yeah, serious alphabet soup :lol:

Thanks


[Modified by C5Cemo, 2:40 PM 1/15/2002]

 

I knew ASP was the sole manufacturer for C5 UDP's, but i didn't realize MTI did all the R&D.

Thanks for the enlightenment! :cheers:

 

So all of you running these - any negative effects? Lights dimming at idle or anything?

 

Buckmaster,
Is your car a daily driver? Heavy traffic? Night driving?
I would like to install the under drive pullies.
I have reservation. I was told on my last two Ls1 F-body cars that the pullies would not effect my A/C, Lights, Powersteering.
In both situtations because of my driving environment this was not the case.
I had an Optima battery and at night had to put the car in neutral and keep the rpms around 1200 to keep the battery from discharging...The power steering was notably heavier at idle...The A/C would not cool in the summer traffic without putting the car in neutral and reving the motor to 1500 rpms.
Had the same experience with both the F-body cars.
:yesnod:
Cant believe that I am even considering pullys again...

Any of you guys drive 30,000 miles a year in a warm climate,heavy traffic day and night! Gee my driving environment is lousy :crazy:
Matthew

 

Adman- just stay away from the 2 pulley kit that has comes with an UD alternator pulley and you'll be fine. The UD crank pulley was designed to do the entire job by itself and it does a good/reliable job. I've had mine since 9.16.99 with no ill effects. And, yes I've had multiple pulley kits on previous cars that were less reliable...and harder on the accessories too.

FYI, my car is a weekend toy so it sits all week normally. Traffic is heavy here in H-town as well...not to mention the summer heat.

Thanks

 

Alt. pulls the same 14.5 volts as before the pulley install.

 

Is the pulley from "ASP" the one that kept falling off the engine, or falling apart ? I heard about some problems but don't know which it was, can anybody help ?

 

Personally, I have not heard anything like that about the ASP crank pulley. It is a two piece design, though...click here for a look.

FYI, the stock crank pulley as well as the UD are keyless, so either is capable of spinning/slipping on the shaft due to improper install or a lot of power. It is VERY rare for this to happen but still a possibility. I am not sure why GM designed the crank that way.

 

I already know about the "keyless" crank, but the problem was with the rubber ring that holds the outer section to the inner hub. That is where they came apart. I know at least a couple of guys who had this problem, so before I plunk down my cash I want to know if the problem is solved or not.

 

OK..well, hopefully someone else who has heard of this problem will chime in with their findings. I can understand the scenario but, as stated, I haven't heard of it happening...and I've been around many UD crank pulley equipped C5's.

I would assume that the problem you've seen is not fixed because there has been no redesign of the pulley. Maybe they got flawed/poorly built units. That's how I see it but...

What happened after the failures? I'm wondering if there was any damage to the engine etc...

Thanks