My Service manager just left and gave me a Mantis Racing (new style) underdrive pulley for free.

I have to give a big thumbs up to the guys at GSR. I am in Australia and asked them some questions about the right sized belt including shipping from the U.S. - They were really happy to help out and insisted that I buy it locally to save money on freight. They gave me the model number and what vehicles the shorter belt is used for to help cross-reference other brands - excellent customer service.

Here is the link to the belt sizes:

HELPFUL HINT: What size serpentine belt to run when using an under drive pulley? - GSR Autosport Community

Just had a thought...damned engineering education makes you worry about everything.

Aluminum Pulley mounted on a steel? flange.

I am wondering if there is any dissimilar metal contact issues we need to be aware of and whether the two metals need to be separated by a barrier of some kind....plastic, paint etc.

Aluminum strength suffers quickly when this is an issue and with the rubber belt whirring around I imagine there might be some significant electrical potential being developed.

Any reports of issues with this?

The factory pulley is anodized aluminum as well.

Both the aluminum and the alloy used on the shaft are relatively anodic. Also one must consider that is little opportunity for an electrolyte to get to that part of the engine compartment. After all, the block is made of aluminum as well.

I received the UDP and belt today. Will install this weekend.

Let us know how it goes and if you don't mind, who you ordered from?

I installed the UDP and new belt over the weekend. Took about 2 hours (I wasn't in any hurry). Hard to tell if there is more power by the seat of the pants but I'll be at the track again this weekend and will be better able to gauge any improvement there.

UD Pulley alert.

Underdrive Pulley Alert - Rennlist Discussion Forums

The RSS underdrive pulley that I installed is mostly a solid disk (with a lot of solid material between the holes) as compared to the drilled out spoke design of the pulley that cracked. Not saying that the RSS pulley couldn't crack, just saying that it seems less likely.

http://i1114.photobucket.com/albums/...isc/rssudp.jpg

The RSS pulley is currently on sale at GSR Autosport.

https://store.gospecracing.com/underdrivepulleyrssboxster986.aspx

*** Follow up ****

After having the UDP for a couple of months, here are my impressions;

Engine and accessories run and operate exactly like stock with the UDP. I can't say that I notice any increase in engine power but the car IS faster on the track. I picked up about half of the difference in acceleration between my BSX and the 500 lb lighter BSR Spec Boxster race cars. If I could find one more equivalent upgrade, I could give the BSR guys a run for the money. Overall, a great upgrade for the price.

That upgrade is headers, on my 986 they provided at least as much change as the UDP, and maybe more.

hi ghost.
was wondering which headers you use on your 986, and do you experiences any loss in gain at low mid RPM?

thanks.
Meir

I had the Chinese set, I thought they were pretty sweet for the price. The biggest issue for a 986 is not snapping the hardware when you remove and replace. I felt that the headers improved the performance without any sacrifice other than a drone with the top up. I also had a Dansk sausage SS muffler as well. All the small tweaks on a 986 will add up to better performance, what's nice about the headers is they don't truly scream unless you are on it, which is nice for around town motoring.

Good info for rowing a 7 speed Ghosty! I had the same ???s as @Meir.

Did you flash (ECU) when you put in headers? I may have asked this in the past but am closer to doing the mod now….my little 986 is starting to come alive! If you flashed the ECU, where did you get it done, and did it effect gas mileage or drive-ability? Since you are taking away those readings from the ECU. Was the drone as bad as these ???s

The spyder is all stock this was on my 986, I didn't get the ecu flashed as the car died before I got the itch for that mod. I do believe that getting a flash after you have done all your mods by a company that takes into consideration said mods would eek out a bit more. Then again, I have read numerous times how the ECU flash is snake oil it's all personal choices.

gonna embarrass myself (again).
what dose "snake oil" means?
and did you feel any loss of torque at the low/mid RPM?

I didn't feel any power loss at all, snake oil refers to expensive mods and the wild claims of gains they make. You can even see differences between the chip makers that are "tough to believe".

thanks for the explanation.

Meir
Just to put your mind at rest, I fitted a set of Chinese sourced headers (from Delubois Parts) onto my 2001 S. No other mods mechanically. The fitting went well, bolted strait on to the heads & secondary cats with no drama's. There is definately no loss in mid range, and the balanced length header pipes really come into their own at 4,000 rpm. In fact, as far as I am concerned there are no downsides apart from not being able to fit the rear plastic undertray.
One difference for you though is that here in Australia we don't have cats in the header - this may or may not have an impact on US cars.
The headers worked so well that I bought the cat delete test pipes from Delubois, and bolted them onto my stock rear muffler. This combo gives a really good sound above 4,000 rpm without the dreaded drone.