canbaufo

Well my BD-11 broke the upgraded "Gates" internal belt a couple weeks ago at 5,500 RPM while in gear (it wasn't a shift that killed it but simply engine RPM at the time and general wear). 928 Motorsports makes a belt that's stronger than the Gates (rated to 50,000 impeller rpm) and I'm thinking of only replacing it rather than rebuilding the whole unit ($60 vs $250 basically) as long as everything's ok once I get the cover off. Check out their rebuild kit:

http://www.928motorsports.com/parts/...rebuildkit.php

But if I want to go belt only (which may be all that's wrong with my 6,000 mile rebuild):

http://www.928motorsports.com/parts/...ultra_belt.php

From what I've read it's much easier to simply replace the belt than do all four bearings. Honestly I thought I'd be done with the Powerdyne and on to a Vortech or ATI years ago and don't want to sink much more money in it. I still plan to go Vortech or ATI when the time is right. Considering all options ..... selling Powerdyne with broken belt, doing the $245 rebuild, rebuilding with belt only (if bearings appear ok), or doing one of those two options and then selling. Figure it's worth my time to fix it to sell at least. One very generous member in here upgraded it for me once before and it has stronger ceramic bearings and low miles on that rebuild (6K) ...another reason to consider only replacing the internal belt and bolting it back on and/or sell.

Anyone know of a better rebuild kit or belt than what 928 has to offer? I may pulley up just a "tad" more to make it worth the effort (2.87" to 2.75" blower pulley with my 6.45 crank ....~44 - 45K impellor rpm @6,200 - 6,300 engine RPM). Not fooling with more than that without an intercooler and I figure the BD-11 couldn't handle it for one reason or another anyway.

Anyone looking to sell a used complete Vortech or ATI kit? Also, if anyone's interested in this Powerdyne kit (as is or rebuilt) let me know ...it's actually a nice kit for a Powerdyne (has bypass valve, 6.45" crank pulley, all solid tubing, stock 6.0" crank pulley included, huge K&N filter). Made 450 RWHP with mild heads/cam/full exhaust on a 93* day with so-so tuning, probably capable of 470+ rwhp on this engine. If anyone wants to buy my kit, know that it will last longer between rebuilds if you don't over-pulley it like I have (use the 6.0" crank pulley I would include in the sale).

My gut feeling is I'll replace belt only if possible and drive it a bit longer while shopping for Vortech/ATI deal ....I don't want to do a 3rd rebuild. Have yet to pull the pulley off and open the casing ...I have never diagnosed bearing damage.

Gtpguy

How much would you sell for it in either condition, fixed or as is?

canbaufo

I have now pulled the pulley off and removed the cover to access the belt. Seems impossible to replace the belt without pressing bearings out of the way. Anyway, I think I'm rebuilding it regardless since I've gone this far. I won't be selling the kit unless I get a Vortech kit first to bolt on in place of it (low priority and will be a long time). Probably going to fix it and just replace for awhile at least (like 6 months to two years).

I do wonder what people think about replacing belt only if the ceramic bearings are good (only 5K or so on them) and switching from 2.87" to 2.75" blower pulley (4% increase in impeller RPM).....with the "super strong" belt from 928 Motorsports.

Gtpguy

What kind of times have you gotten with it?

canbaufo

Back on stock engine and headers with crappy 2.02 60ft and 384 RWHP I ran a 8.28 at 90 MPH. I'd say upper 7's @ 95 or so now with the built engine if I could hook it up ...haven't run it in the 446 RWHP configuration

Gtpguy

Just headers and the 6psi pulley, and thats it? Thats pretty good.

canbaufo

Yes, pretty much but there's a little more. I did use a smaller 6.45" crank pulley to make a little more boost ...it made about 7 PSI on the stock engine with headers. Wound up needing new valvesprings because the dyno showed a weird roller coaster curve above 5200 RPM ....finally determined it was valve float. Soooo ....got better valvesprings and 1.6 roller rockers to cure the float and make an improvement at the same time. So technically, the 384 rwhp number was with a virtual 7 PSI kit (btw the torque was even better ....402 lbs at 4,400 I believe), Hooker long tubes and 1.6 roller rockers. I used 42# SVO injectors to be ready for the future and use them now with the built 446 rwhp engine. I figure a switch to an aftercooled Vortech at 9 PSI will have me at 525+ RWHP ....although my 42# injectors may not handle that, we'll see one day ....

Anyone have opinions on my original inquiry? Basically wondering if I should rebuild with a full 928 Motorsports kit with bearings and all or just replace the belt with their best belt as long as my 5K mile ceramic bearings are good? ....that and I wonder if the 928 belt could hold up to a 2.75" blower pulley with my 6.45" crank pulley....at least for a little while. I know it all "depends". My current pulley combo is 2.87" blower and 6.45" crank ....so we're talking a 4% increase in impeller RPM if I switch to 2.75" blower if you plug it into the impeller RPM formula.

Gtpguy

Did you rebuild it or just get the belt?

canbaufo

I replaced the belt and top impeller bearing and put it back together. I have it back on the car now and the only thing I'm waiting on is a new external belt (the smaller blower pulley made my external belt slightly too large to use). No place around here had a Goodyear Gatorback replacement belt (only one I'll use) so I had to order one from Amazon. lol got it for $9 and free shipping ...beat that! Ordered it a few days ago and should have it in a couple days. I figure the car will be up and running again within a week. My fingers are crossed ...hope the new belt and bearing (and smaller pulley) work out well. I have a good feeling about it, I was meticulous with the R,R,R. Hope I pick up 1/2 PSI and don't have another internal belt failure. Been driving it N/A for awhile now ...gonna be fun to go back to FI.

Gtpguy

I found a Powerdyne (pretty sure its the BD11a) that I might be getting and the guy says the kit is good to go. Not rebuilt, but that he had no problems with it on his car. The thing that Im worried Ill do is over tighten it and breaking the bearing or something. How do you go about getting it snug and tight but not too tight?

canbaufo

I jack the car up and put a metal ramp under it. Remove the bolt that obstructs your access to the lower edge of the tensioner bracket. Use a bottle jack on top of the ramp and under the tensioner. I just undo the tensioner bolts enough that you can't move it by hand but the bottle jack can. Reach above and around the crank pulley to grab the belt from the top as you tighten it. Once you can grab the middle belt and only get about a 1/4 turn on it (the "old quarter turn rule") it's about right. Start with the belt as loose as you can get by with without losing boost and tighten in increments until you don't lose any...that way you're not any tighter than necessary. This is what I like about the Vortech units ...they have spring loaded tensioners so you don't have to fool with this. BTW my PD is back on the car and is no longer "silent drive" lol ....sounds more like a V1 with this smaller pulley ...I love it. So far so good .....

NJ-LE

canbaufo:
I use the head of that foudation plate bolt, just below the tension pulley slider, as a fulcrum point for a large, heavy duty screwdriver that I use as a lever to apply pressure to the slider assembly.
When I changed from a 3" to a 2.75 SC pulley , I was getting some twisting of the tension pulley post because of the higher load. I was ready to drill and tap a hole for a third bolt to be as near as possible to the post to prevent twisting but tried a pair of large, heavy (1" x 1/8") washers under the two slider bolts. Clamping the slider over a larger area appears to stop the twisting. BTW, though I only rev to 5900 and atmospheric conditions are ever changing, with my setup I appear to get 25 to 30 extra grams of airflow because of the smaller SC pulley (my crank pulley is the 6"). You should see at least that much. Yee-Haa ... Happy Motoring!

canbaufo

Yikes, you must be seeing like 8 PSI on that engine with that pulley combo. Yeah my mechanic friend has a pry bar and a long time ago he showed me a way to tighten it like you're describing. I love the bottle jack method though, it's easy as pie and I already had one (I've since found many uses for the little bottle jack ...handy little tool). I would love to really try this thing out but there's not enough traction available on the cold pavement right now (1/4 throttle in 2nd gear rolling along at 2,500 RPM and it just spins like it's on ice ...lol like trying to suck hard concrete through a straw). It sure sounds nice and responds well though.

NJ-LE

canbaufo:
Changing the SC pulley brought that recommended 36000 SC internal continuous duty rpm down from 6000 to 5500 engine rpm and fattened up the midrange some. I have a Cyberdyne max recording boost gauge on it and see 5 psig but the record function only 'plays back' integers ... I think I've seen 5.5 out of the corner of my eye (it's in an A pillar gauge pod) I haven't seen any problems with fuel pressure (still the factory pump - I think they were 190 l/hr in 95) but I'm probably close to it's capacity (probably clutch capacity too) The base duty cycle on the 37 #/hr injectors gets into the low 80% range. This is the 1st car I've boosted and I still find it interesting to be fully hooked up in 2nd and part way through start buzzing the tires on new, clean, dry roads (with the stock 3.42 rear - in colder weather anyway). It's very nice having the midrange torque of a decent big block in a small block. Makes me wonder how the serious players with 8 to 12 or more psig keep the tires under them! I guess they're tubbed out with really wide MT Street ET tires in the back.

canbaufo

Well crap, everything was going great on my rebuild but now I hear a slight chirping sound, kind of fluttery sounding and sometimes sounds like crickets or serpentine belt squeal. It's really strange, it goes away or gets quieter once warmed up. Usually when totally cold it doesn't make the noise but give it two minutes and the noise appears. Then it goes away or gets quieter a few minutes later once warmed up.

I had to shim the crank pulley with some crude washers I "made" for it to align with the new 928 Motorsports 2.7" blower pulley (it lacked the 1/10" or so notch on the back side that the previous pulley had, so it couldn't slide quite as far down the shaft and sticks out from the ribs on the blower a little further). Anyway the crank pulley has a very VERY slight wobble, I don't think it has anything to do with it. BTW I have yet to do a stethoscope test.

My concern is that the inner impeller bearing took a little too much abuse when I tried to slip the internal belt over the outer impeller bearing to get it on. Eventually I gave up and pulled the outer bearing off properly with a bearing separator, then the internal belt slipped on easier but still with some effort. I decided to replace the new outer bearing with a new ceramic one from 928 Motorsports. One thing I noted about the new bearing is it didn't spin NEARLY as freely as the old one (also a ceramic bearing from the previous rebuild). The old one seemed perfectly good but I had pried on it with different tools before finally ordering a small bearing separator (since no store around had one) ....so I decided to replace it just to be "safe".

Tensioner pulley seems fine. Have to do some stethoscope diagnosis and then I'll know more ... unfortunately I suspect one of the bearings in the blower .....

...nothing more fun than pulling it all apart again .....