As some of you know after my '92 double sided belt decided to shred and toss itself for the second time since I've owned the car, I opted to convert to the single sided belt. While I was at it, I decided to go ahead and install an underdrive pulley set, the only reason I had never done so before is because it would have required a conversion to the single sided belt. I figured I would install the underdrive pulleys "while I was at it" because it would only take 5 extra minutes..... wrong.

The parts list, which I'll update with actual part numbers when I get home, is as follows.

93L+ style power steering pump pulley
93L+ tensioner pulley
93L+ idler pulley
ASP 2 piece underdrive pulley set
new single sided, shorter belt

On to the installation. My first issue was to remove the R&D Racing Camber Brace. The camber brace is a fantastic product, and the three piece version for the electric water pump is even easier to deal with. No matter what though, it is a ROYAL PITA to deal with the belt if you have a camber brace. Likewise, in 5 years I've had the balancer off of my car many times. After the first time it has never been a problem. Well this time, since I didn't have the water pump out of the way, it was a bit more difficult. I did have to result to using the block of wood and persuading the balancer off from the bottom. Hot tip: When using a sledge hammer to persuade a the balancer off, don't try to cushion the hammer's impact on the wood with the tip of your finger.

Anyway, after I finally got the balancer off, it wasn't too much trouble to put the new one on, just had to get it lined up first. With some help from my lovely assistant, I was able to get all the bolts back into the new balancer and get them all tightened down.

Installation of the new idler pulley and the tensioner pulley were very straighforward, one wrench each, no problems at all. The alternator pulley is supposed to be a royal pain unless you have an impact wrench. I do have an impact wrench so it zipped right off without any problems at all, and the new one went back on just as easily.

The power steering pump pulley was also absolutely no problem at all because my friend Todd let me borrow the proper tools. THANK YOU Todd. After all of that was back together the only other issue was putting the belt back on around the camber brace. Well I got everything all worked out and low and behold, wouldn't you know it, the belt is too short. Jen bought exactly the belt that is called for by ASP for their 2 piece pulley set, and it is too short. I knew better than to try and go to Advance, AutoZone, or O'Reilly and try and tell them that I needed a special belt, so we made a trip to Scotty's Speed and Custom. The gentleman there was able to give me a belt that was one inch longer than the one called for, and it worked perfectly.

After the new belt was on, Jen and I wrestled with the camber brace again, and then put her all back together. When I first started her up she sounded a little loud, but I poked around under the hood and couldn't really find anything wrong. Ultimately it just sounded like all of my rockers were a little loose. I drove her anyway and by the time I got to the first traffic light, she was nice and quiet again. I don't think charging is going to be an issue either unless I happen to be running at night with all my lights and every accessory known to man running.

All and all a very straightforward job. We started at 7:30ish and were done by 11:00 a.m. It would have been even easier without the camber brace and the trip to the parts store. Jen's help made it much easier as well.


Thanks sweetheart, I'd still be working on it without ya.

 

Nice report. It would also be interesting to see what is real gain with underdrive pulleys.

 

My "ASSITANT" is sick with Bronchitis....

So I have had plenty of time to work on the Vette!...all kidding aside though...she loves the car more than me! I would like to upgrade to an LT4...she wont let the car go....

Interested in your long term gains!

 

Awsome.....well it looks like more parts to add to the list.

 

I'm very interested in the gains as well. I've got dyno results from many different things, perhaps some day I'll get back out with the pulleys. Being that the LT1 water pump is not belt driven, AND I've already converted that to electric, I don't expect a huge gain.

In any case, I've got a "standard" belt now, my power steering pump should last longer if I do any autocross and my alternator bearings might last longer when I'm racing, etc. I also keep a very close eye on on my gas mileage, so that will be interesting to watch as well.

Anothe reason I might not see much on the dyno is because of my wheels. I have recently upgraded to chrome ZO6 style wheels and they are heavier than the stockers. Oh well, it might not be good for anything tangible but I'm sure it won't hurt anything.

 

Hey Brian, if you don't want to go with the underdrive pulleys I've got a stock size single sided belt you can use, brand new. Or if you want to order the underdrive pulleys I'll return the belt and get my money back

 

Nice write up. There is often more to the matter than is first
apparent.

The LTx folks might be interested in
- OEM vs Underdriven pulley diameters
- Before & After VDC readings
- Before & After coolant temps

For the L98 folks, here is a link with some info on the
March 'Power & Amp' pulleys
.

 

Moot point on the LT1

I intended to measure the crank diameters but I was so interested in getting it back together that I forgot to measure the new one. Alernator would be easy. If Brian orders the underdrive pulleys I'll measure the crank.

 

True enough.

Someone posted before that the gain for the LTx will not be as
prominent as for the L98 because there is no speed reduction
at the water pump for the LTx.

For the L98, GM High Perf tested an f-body and reported 12-15 HP
at the wheels as recorded at SLP's facility. Presumably, the LTx
gain would be somewhat less.

.

 

Nate, was the clutch kit you got the RAM Powergrip HD?

 

That's what it says on my web page.

 

Well yeah....if I would have looked at that....

 

Good info. And we always enjoy looking at your "assistant" again! I've seen your picture, she's too pretty for you!
Some guys are just born under a lucky star....

 

I have considered this for mine and would be interested in knowing:
What, if any effect does it have on the steering (feel wise, sluggish etc.)?
What have you seen so far regarding voltage on gauge (or scanner) and or w/lights on etc.? (don't remember if you have a std. alt.) Thanks

 

That's what I wonder. I like the "feel" and feedback that the P/S on the C4s have. That's one thing that I noticed about driving a C5, the steering has much more assist, much like any average car. I didn't like that about it, not enough road feel. That being said, I'd hate to lose any more assistance from the C4, it's just about right as it is. I've heard that this mod on the LTx cars is good for 5 HP tops, and probably less, for the reasons already mentioned. However, if there's a noticeable increase in mileage (a fact which I had never considered before but makes perfect sense) and the steering still works about like stock, I might be very interested. I know you'll keep us posted, Nathan.

 

Yeah I'm just hoping she doesn't figure that part out!

There is no negative impact on the steering at all. My car is highly modded and has a heavy accessory load (MSD Digital 6 Ignition, Electric Water Pump, radar detector, stereo amp most of the time, upgraded fog lights, etc) I've intentionally got her programmed to idle as low as possible and still run with the cam because I like the lumpy idle. Even at that the idle is probably slightly faster than stock. Now with all of my accessories and my headlights on (Jen always drives with the headlights on, there is a reason) she settled down to 12.5 volts at idle when we went to lunch. That may sound pretty crappy, but my battery was drained the other night due to my stupid keyless entry / remote start system acting up. As such when I got in the car before starting her, the digital volt meter on the dash read <12 volts. Therefore logic states that if she's showing anything above 12 volts is still technically charging, although maybe not much. Give her any RPM at all and it jumps up to 14.4 volts or so. I need to park her and put the charger on her overnight before I can really determine how well the alternator is going to do. Considering the very poor condition of the battery currently, I am actually very impressed with how well it's been doing.

I imagine that if your car doesn't have all of the electrical goodies on it that mine has, you'll probably be just fine.

 

Well you guys know I keep very close watch on my gas mileage and Jen is well aware of my mileage log, so if she ever gets gas she knows to log it. She's a little obsessive compulsive about a few things so the mileage log didn't bother her a bit. The difference is going to be between our driving styles. She's used to driving a 4-cyl Mustang and isn't completely used to the Vette's power curve yet. As such she'll be driving around at 3000 RPM's in second gear at the same speed that I would be doing 1700 in 4th. As such my gas mileage will likely suffer somewhat, but it's so not a big deal. As she gets more familiar with the car she'll get used to it's power band. Right now she just focused on getting good and familiar with the clutch.

I've been driving it so long that I instinctively drive for fuel economy, lower engine noise, and less spinout potential since I never use the traction control. She driving for don't stall it, don't stall it, and please don't stall it, and she doesn't turn off the traction control, in fact I don't think I even told her where the button is, so it should be all good.

 

Good info ,Thanks! Mine doesn't have a heavy elec. load and I didn't lower the target idle (850) motor is modded (sig.). It sounds like mine would be ok, it likes to operate between 13.8 and 14.4 v.average.
As much as I'd like to get an extra gain, I don't want to sacrafice regular driving needs....still like to do some cruising

 

Well mine is an absolute daily driver so if it turns out ot be a problem you'll certainly know about it.

Then again it may just give me the excuse I need to buy that powermaster 200 amp alternator. They're suppose to put out as much at idle as my 92 did at full output. Oh, I believe the 94& up alternators were rated higher as well. I know there was an upgrade in there but I'm not really sure of the year.

 

Huh? Ding, ding, ding --- TILT!

Sorry, I was napping. Did I really read that? First an itty, bitty pulley
- then a big honkin alt?

.