Juha G

Actually I didn't... don't know if it would be good to do it or not. Under high rpm (fan blowing) and load (engine sucking air) there is under pressure in the engine bay so it might be bad to leave it open. On the other hand I didn't block and it worked ok. Granted most of my winter driving was low load/rpm driving.

kyle951

Great Build Rich.. I have the TPC SC - Intercooler setup on my 1995 993 Cab and I too run the setup without the Heater Blower. I haven't noticed an issue with getting enough heat into the cabin in the winter time but bare in mind that I am in Texas, and we don't typically have the coldest of winters.
Currently my inlet to the heat exchangers is uncapped but I did ask my friend-technician at the local Porsche store if this would be problematic, and his answer was no unless something happened to fall down in there, lol...
I hope you really enjoy your car with the TPC kit because I certainly like mine.

Kyle

RichPugh

Soooo....

I decided to work a few hours today and hammer out enough to get it started to check the belt alignment. Not so good, LOL

Exhaust done for the most part... just heater tube and tips needed... figured I'd just wait to see if I needed to tear it all down for some odd reason first before putting the rear bumper back together...



I added about a quart of oil (due to the loss changing the lower valve covers), pulled the DME relay and cranked it for a good 5 seconds to get some oil pumped back into the system... followed by another 10 seconds of cranking to check the alignment of the SC belt. I watched it run correct in the grooves and I decided to start it for a brief idle.

I fired it up and let it idle for about 10 seconds (I still have vacuum lines unconnected as this was simply to check belt alignment) and the belt walked towards the rear of the car but didnt come off. Here's the pic I took after shutting the car off ...



I repositioned the belt and decided to start it up again to double check it with a video and here's what happened, LOL


Obviously need to shim the pulley towards the engine. There is like 4-5mm gap between it and the fan housing. Most people seem to have 1mm or less so... I'll start with that.

Juha G

Rich, the alignment is critical for making the belts last.
First you must align the supercharger with the engine. Use a liner or something that is 100% straight and put it against the crank pulley and the supercharger pulley. If there is any misalignment, you have to adjust the supercharger position. I think I had to enlargen the bolt holes on the supercharger brackets/feet to align it properly.
Once that is done, then you have to make sure the tensioner is aligned too (under tension), that is more difficult. It is a trial and error really. I put some washers between the sleeves that hold the tensioner plate/bracket in place.
The tensioner may look good when the engine is not running but once you get tension on there, it will lean towards the engine and the belt will either slip off or wore down quicker than it should.

so, first align the supercharger, and only after that start playing with the tensioner! Man, you're almost there!!!!

br,

Juha

Ps. Juuso promised to make you that ECU quickly.

RichPugh

Here's a few more pics of the belt alignment. I'll admit, I'm not a human micrometer but, the SC appears to be in fair alignment and the tensioner pulley is glaringly tilted back towards the rear of the car... si I could assume that would drive a belt towards the rear. I'll start with taking the carrier off and checking the alignment with the crank pulley... then I'll try to shim the front of the tensioner to push it further towards the fan housing and give her another go...

Ducks964

Alignment of the tensioner is a pain as it took several tries to get mine right. My carrier has the rennline gusset reinforcement which made it tricky. Looks like my tensioner is pulled further back when the belt is installed. It is also about 1mm from the fan housing.

993/907

Rich, sounds like we are hearing how much the engine unloads when the belt comes off and is not driving the SC?
(Read somewhere it takes something like 500hp to drive a top fuel dragster SC!).
That loping idle sounds AWESOME!!
Gordo

RichPugh

993/907, honestly it's probably because I have several large vacuum leaks lol. I'm sure it does take some power to run it but it probably surged for many other reasons. ISV is routed. I'm surprised it wasn't worse. Haha

Juha G

To me it looks like your sc is not aligned with the engine. It looks the same on both photos. Did you try to put a linee against the pulleys?
I think you need to push the nose of the sc away from the crank pulley (towards the drivers side).
Look at the first photo, the sc pulley is not in line with the fan housing grooves...

You really want to make sure the sc is aligned well before you start working on the pulley.

Also, don't trust the belt. It is rubber and will bend so it looks like it's straight but its not.

RichPugh

I was thinking that last night but the pics look strange. I was trying to show how out of square the tensioner pulley is... I'll check tomorrow or later today if I can. Thanks for the info. I'm on it!

mr_bock

Rich,
When I had my SC installed (shop near Chicago) they had to machine my fan shroud to allow clearance between the idler pulley and shroud. When I brought my car to TPC, they asked if 'the shim' was installed at the lower idler bracket bolt. No, there was no mention to do so in the instructions. I was given the shim (American front end alignment shim) which I installed and all was good.

Last year as part of my engine rebuild and new clutch install, I welded in the engine carrier brace. I did a major mod to get the idler bracket (with shim spacer) welded in. Seems that the shim tilts the idler pulley rearward without the belt on. It looks counter intuitive. With the belt, the idler tilts forward and aligns. I think some of this is that the carrier twists some. With the brace welded in, I had less twist. I made a shim from stainless steel that covered about 1/3 of the idler mounting footprint (shim was ground to a tapper of almost 0" to about .05"). I applied 3M VHB film tape to both sides and positioned the shim to tilt the idler correctly. After all that, I still had to use a crescent wrench to bend the idler bracket to get the belt to track in the center of the idler pulley.

Check and make sure the belt is in the correct grooves of the crank pulley... I tore up a belt that way already. I need to get a spare belt. TPC said they did not have any... and that the Dayco Dynaflex 490K6 has a new number that needs to be cross referenced. Will have to look into this soon.

Good luck, hope all comes together soon.
I Love my Supercharger!!!!!!

Juha G

You are spot on mr. Bock!!
The engine carrier twists under load. A little when you put the belt on but a lot more when the SC gets loaded. Hence you have to shim the tensioner bracket, as you said, towards the rear of the car. It will then lean towards the engine under load. It is trial and error but you need to make sure the SC is aligned before you start playing with the tensioner. Otherwise you are just shooting blind...

RichPugh

I decided to take 3 minutes and block my vacuum leaks, wedge a prybar between the tensioner bracket and the carrier so that the tensioner pulley came within 1mm of the fan housing, and fire her back up... idles smooth as a baby and belt was rolling perfectly.

The pics I posted are very much not indicative of the SC pulley alignment as I was trying to show the tensioners obvious angle towards the rear of the car. I will definitely check the alignment of the pulleys but Im certain the tensionr is WAY off so I'm gonna address that too.

My issue seems to be opposite of mosts... where the shims people have generally used are necessary to space the bottom of the tensioner bracket out, pulling the tensioner away from the fan housing under load. I need to push the pulley towards the housing... so, should I shim the 2 top bolts, or shave down the bottom spacer? I'm more inclined to reduce the thickness of the bottom spacer because when I muscle the pulley over to where it nearly comes into contact with the fan housing, the bottom of the tensioner roller touches the housing but not the top part of the roller... so giving it a bit of camber towards the fan housing would be ideal. All of the tensioner roller position I'm taking about is while it is under belt load, not resting.

It was lovely to hear it idle I missed it...

axl911

To push it toward is easy. Take off the tensioner pulley. Put a shim between the tensioner arm and the pulley itself.

RichPugh

It doesnt simply need to be pushed over towards the fan housin... the top of the pulley needs to be tilted towards the fan housing and moved closer a few mm. So, thats why I need to shim the top or trim the bottom mount(s) somhow tipping it towards the engine. I considered literally just shimming the part of the tensioner that rests against the bracket plate simply by loosening the tensioner from the plate, shimming the top and tightening it back up. Worth a shot...

This pic shows the tensioner literally pulling the belt towards the rear of the car...