For those of you following the previous thread on limiting supercharger boost levels, I thought I would follow-up with the solution I went with. The main discussion centered around the best solution for limiting upper psi range while allowing for the greatest boost through the most rpm range.

The options, as discused, where to either install a wastegate type system on the pressure side, or restrictor plates on the inlet side. After mucho researching, I decided on the latter to attempt to get my maximum boost limit with minimal increase (or even a decrease) of parasitic loss.

I began by ordering 5lbs (about 11) 3.75" od x 1 3/4" id x .153" flat washers from from Mcmaster-Carr (about $12.00). I then visited my favorite machine shop, and had them enlarge the i.d. to a range of 2.5"-3.25" cutting a new plate for every 1/8", since it will take some testing to get the flow restriction correct.

Here are the plates:



Installation into the filter



Secured the plate in the filter by using a 4.25" band clamp



And reinstalled the assembly



I can wait to get started testing the plates. It will probably be a few weeks before I can get out to Moroso.

For those curious about the belt wrap issue, I stepped up to a 3.5" alternator idler (from 2.25"), and I will most likely install the 2.25" idler close to the blower, just to be sure.

I'm hoping to have my 9-10 psi from 5,000 up to my max compressor speed of 5,700 engine rpm (2.40 pulley drive ratio).

Total cost of the plates, incuding machining, about $172.00 . The machining labor was the kicker, as I don't have the ability to cut metal this thick. But I should have almost full boost tuning capability, and it takes only about 2 minutes to change out the plate.

Thanks for all the great input!