219.95 $ USD 185 Pulley Saver Kit Waldig/NeedsWings - United States

Published date: December 25, 2014
Modified date: December 25, 2014
  • Location: Warren, Michigan, United States

Part#: psk185

For use with 185mm pulley kit

After reviewing some of the prior issues Crossfire owners have had with their idler pulley failures, we started to consider the possibilities of an improved design. The real weakness in the design is the idler under the supercharger as it is often the smallest at 60 MM in diameter. With a stock crankshaft pulley of 155MM, the idler is running about 2.6 times faster or 15,500 rpm at our 6000 rpm redline.

The idler pulley is reduced in diameter to allow the stock belt to be used with the 178, 181, and the 185 pulley upgrades. The water pump pulley is also reduced in diameter to ‘free up‘ some additional belt length. This water pump pulley must be smaller in diameter to allow the larger pulley to be installed and does not seem to be an issue overall.

With the larger 185 pulley the idler is now turning at a speed of 3.08 times the engine speed or about 18,500 rpm at full revs. This is excessive and addressed to decrease stress on the pulley and increase its life span. The following design change has been tested on our SRT’s on the street, road trips (Tail of the Dragon, Carlisle Chrysler Nationals), many auto crossing tracks with sustained high rpm operation (4000 – 6000) for up to a minute at a time and over a dozen dyno pulls to date. A Hefty stack of timeslips at the dragstrip and no issues or problems have been detected and all components appear to operate well in this design, the delay in releasing this kit was intentional to gather ample driving time to prove the reliability of the design.

In a nutshell’ the serpentine belt with this kit is replaced with a longer belt to allow for larger pulley to be installed, slowing their rotational speed significantly. The idler pulley is increased in size to 100MM reducing its operating speed to 60% of its previous speed. With the large 185 crank pulley operating at 6000 rpm, the idler pulley is only turning 1.85 times as fast or 11,100 rpm. This is a huge reduction in stress as this pulley carries most of the belt tension and has a 50% wrap which doubles its side thrust load.

Additional improvements include the replacement of the tensioner pulley with another 100mm pulley on the 178 and 181 pulley applications. This allows this pulley to operate at the same speed as noted above and is a 10% reduction from its previous speed. To allow enough belt length to maintain proper tension for the 185 pulley set-up I did not change the tensioner pulley from its original factory 90 MM diameter. A new 90mm pulley is included in the kit for the 185mm customers.

Another improvement feature is the elimination of the TINY grooved idler directly under the supercharger. This poor pulley really gets going due to its small diameter and is a failure waiting to happen. Instead a much larger grooved pulley is located near the alternator on a new grade 8 bolt with a massive ¼” thick stainless steel brace assembly. This brace is the definition of “overkill” and brings everything togather. This larger grooved pulley is turning over relatively slowly and serves to guide and position the belt just prior to it running over the supercharger pulley.

Because of the location of this redesigned groove pulley, the ¼” brace was created to solidly mount this pulley and tie it into the other engine support mounts. The idler pulley is supported on the right (driver side) of this brace providing positive bearing mounts support on both the front and rear sides of these two pulleys as shown in the following photographs. Virtually bulletproof engineering.

It should be noted that the supercharger has an increased amount of belt “wrap” due to the repositioning of the grooved ‘guide’ pulley. This would increase the load handling ability of the belt and in Waldig’s car has prevented belt slippage even though he has been experiencing manifold boost pressures of up to 25 PSIG. The belt wrap increase is helpful as a side benefit, and the improvement is probably in the order of a 10% torque handling capacity.

This improved pulley kit will provide you with additional pulley life and a caged pulley support capable of reducing damage in the unlikely event of a spun bearing caused by an age related failure. The supercharger has additional belt wrap / contact to prevent belt wear due to slippage under severe driving and high boost operation. Overall this kit will materially improve the reliability of your pulley and belt system.

Custom machined stainless steel spacers (thanks MikeR), custom ¼” thick stainless steel water jet brace, 3/8” grade 8 bolt/nut/washers, grade 10.9 metric bolt, 3 new pulleys and new longer belt will be included with the kit. This kit has been going thru testing on 4 different srt6’s to date. We are finally comfortable releasing this kit for the masses. Kit will fit srt6/slk32amg/c32amg vehicles with a 178mm, 181mm or 185mm aftermarket pulley kits.

As a side note, when we removed our 30k mile OEM belt we noticed a great amount of cracking in the stock belt and were relieved to be installing a new belt at that time. 4 of the 6 ribs were cracked on our belt in several locations. All components of this kit are readily available now and in the foreseeable future.

We have no problem warranty’ing the parts in the kit with a 1 year unlimited mile coverage but we will NOT put a blanket warranty on the engine/vehicle, USE AT YOUR OWN RISK! (See our disclaimer on our website for further details). We are planning on making very little off these kits if we even do recoupe the r&d/parts/materials, this kit was designed by Waldig, tweaked by us and should help keep the SRT6’s turning heads on the road or track!

These kits are custom build per order, please allow 3-5 days for us to build your kit before shipping.

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