Is it a bad idea to supercharge a 170k mile t100 with a used supercharger off a totaled t100 that had the same mileage on it when wrecked?

 

Personally I'd do a compression test to make sure your engine is in good condition, and make sure the rest of your truck behind that supercharged motor are in good condition otherwise (transmission and the rest of the drivetrain).

 

It would be a bad idea to put a S/C on an engine with fairly high miles that has never had one. After that many miles your engine (sensors, gaskets, seals etc.) gets "used to" the normal operating conditions of your truck and your driving style. If you put the added stress of a S/C on without replacing anything else many things will have to adjust and some parts might just be too old/worn to do so properly. I would be amazed if you made it very far without blowing a gasket or sensor. I would do a minor engine rebuild at the least. Replace head, valve cover, exhaust, intake gaskets; Replace the O2 sensors; replace all belts, tensioners, and bearings that will be used to power the S/C (not sure if the S/C has its own belt assy or if it uses existing ones). It would also be a very good idea to have to the top end gone through and cleaned out, adjusting the valve clearances and timing precisely (I would leave the later two to the pros since they require precision equipment to get it right). Also you would want to re-tune your ECU I imagine since you would be dealing with very different air/fuel quantities. The best way to do it, and the way it is usually done is to put a new S/C on a new engine and let them acclimate to each other together. I know the S/C is very enticing since it adds a boat load of power, but you would need to be very careful to make it work well it adds a lot of extra stresses to the system.

 

what year T100? the early 3.4 ecu's had problems retarding timing when there was knock.