Hello,

I am a technician working at Sporthaus in Reno NV. I am working on a 1999 Diablo VT. When the car was new Orange County Lambo installed an aftermarket twin Magnuson supercharger set up. The car has all of 762 miles on it and has thrown 3 drive belts in that timeframe.

It seems like an ill-conceived set-up as the belt seems on the “wimpy” side, considering the loads this engine must produce. I am told that if the tension is set too low, it throws the belt. If the tension is set too high it bends the tensioner (?), thus altering the alignment and throwing the belt. Ideally, I would like to somehow upgrade the system and make it more reliable.

Has anyone “been there done that”? Any leads to a better outcome than put another belt on it, make sure it’s aligned, and send it out for another 1-200 miles would be most appreciated.

Thanks
Mark

Are you referring to the toothed belt that drives the blower? If so, I would think that Magnuson would be your best bet to speak with regarding this. Here's their webpage:

Magna Charger manufacturers intercooled supercharging systems for late model GM and Ford cars, trucks and SUVs utilizing OEM quality Eaton hybrid superchargers.

Thanks for the reply and link. I will contact Magnuson today and see if they can advise me.

No, these are not the superchargers driven by a “toothed” belt but rather a “ribbed” belt. Also know as a serpentine belt. Looking around on their web site I could not find reference to any Lamborghini kits so I’ll contact them.

On a googel search I found a photo of another and attached it (I hope).

Thanks!
Mark

Attached Images

Lambo superchargers.jpg (117.0 KB, 49 views)

No problem and good luck.

Serpentine belts - guess that reflects the change in times. 20 years ago I put one of their kits on my '76 Vette, and toothed "Gilmer" belts were used, just like you see in Top Fuel and Funny car applications using the 6-71 and 8-71 blowers. Now that I think about it, you're right, as my 2001 Grand Prix GTX has a serpentine belt to the blower.

Nice photo. I always liked the looks of that installation, just hope it can be made to work. I think there are one or two folks on this board that have done this mod to their Diablos; perhaps they'll chime in with any info they have.

Contacted Magnuson, not one of their kits, custom install. Talked to the Co. that installed it, and the designer of that system is no longer employed there.

Basically, in my opinion, this is a beautiful install but drastically flawed in that the 20mm wide belt, no mater how well it’s set up can in NO WAY handle the associated loads. Not only does it have to drive two superchargers, but also the alternator, PS, and A/C. I think it’s a matter of the weakest link, the belt just can’t take it.

I am now looking into converting to a toothed belt set up ($$$) or just put another belt on it and sell it. Hopefully someone else will chime in that has gone this route or another acceptable remedy.

Can you have some wider pully's machined for everything including the accessories and then find a wider belt?

That would be a major affair. Would have to move chargers (incl. plumbing) and all other loads rearward by same amount. If we are going to get pulleys machined, we will go “toothed”, and hopefully stick with the current width.

the belt should take it I would think. WHat could be happening is the superchargers are flexing down or the crank pulley is flexing up because of the load and tension. The size of the bracket you need to stop this flexing is actually big. The reasoning I have behind this is I am helping a guy working on a supercharged boat engine with a big ass blower with a serpitine belt on it. It keeps destroying the belt and we braced the blower and it improved drastically but not totally fixed. Upon further inspection the end of the crank was flexing up. So..... We are having a bracket made for the front of this setup that uses a bearing on the end of the crank to support the crank. this bracket is half inch billet and extends up to the supercharger where it is braced on the front also. Big production. The machinist we are using is talented and its costing about 5 grand. THe moral of the story is, you need lots of support. I don't think the diablo crank is designed to be loaded like that. The pulley is a fairly lightweight arrangement also.

The "flexing" is an interesting theory, I'll look into that at work today. The bracket that all accessories mount to is very heavy duty, I'd guess 3/4" aluminum plate, as you mention the crank pully on the other hand looks kind of light duty, I'll definatly check into that today. If it comes to it, can you get me in contact with the machinest you are useing? Also you may want to look into a stronger belt as I did (see below).

At this time the client does no want to spend the time and money to convert to a "toothed" belt. And wants to try again with the ribbed belt.

The belts used thus far are a standard ribbed belt manufactured by Gates. I contacted Gates and they can supply a "Race" belt, they also sell the same belt in HD, that should help. I am now trying to source idler pulleys with shoulders on them hopefully preventing "walk off". Do you know of a source for something like this?

Thanks for the reply!
Mark

Doubt it is an option and definitely expensive, but maybe seeing how much your version differs from the kit the manufacturer offers, and then depending on how much of the hardware you have, purchasing the rest from them and doing their install. Does it at least use the same blowers?

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