Lemming

SC is back and in the car. As you can see, I have moved my air intake to the driver's side. The MAF is now post SC and can be seen in the first photo. Second photo shows the test rig for better IC and radiator air; IC air will be fed from the lower opening, rad from the upper. I should have the BOV back from the welder tomorrow (I'm not set up to weld alum), will get a pic when installed.

Carl Fausett

Lets not totally loose this thread, please.

This thread is about a street kit for the 968 that hits a price point and retains the air conditioner.

There are so many posts about 968 motors in 944's, 968 racers, and the double-sided belt concept that I fear if John Q Public stumbled into this thread he would think he'd have to do all manners of mods to get it to work.

TO THE READER: photos of carved up and heavilly modified cars with this kit on the are the EXCEPTION and not the rule.

Our 968 kit installs without mods to the car, and functions well when used as intended.

Racers are pushing the kit in directions it was not initially intended for, and we are grateful for it. We are supporting their efforts by making a larger crankshaft pulley for them (I just came back from the machine shop on this) that will provide more boost without belt slip for their application.

ninefourfourt

Have never dealt with Carl personally, but have been lurking on this thread and keeping up with it with great interest. I fully understand (from the posts) what a few of your customer are doing with your kit. What I take from this, is you dedication to helping them. Your excellent customer service, I believe, makes you kit much more valuable. You seem to care about the kit, it's performance, and your customer's satisfaction.

sydneyman

i agree. Im a potential customer that would use Carl's kit as intended. just trying to scrape together the clams! Its Carl's dedication to those that are using the kit for their own purposes that is pushing me even more towards buying the kit! Thanks for all you do Carl!

mikey_audiogeek

OT post deleted.

Cheers,
Mike

Carl Fausett

Thank you very much. Not everyone can separate "kit as shipped" from "mods made above and beyond the kit" and I am glad you can.

I fully support the racers, if I can make the street kit a bit more suitable for them, I will. As it has for years, racing a product has shown weaknesses that were not exposed in street-driven service.

I think the updates I am now designing for the Stage 2 kit will be the cats meow and I'm excited about them. Each current owner of a Satge II kit will have the option of updating up into the newer parts if they choose.

edz968s

I`m waiting on tender hooks for the stage 2 upgrade, however the car is a nightmare at the moment. Replaced the 02/lambda sensor without any success, so am now waiting for a HALL sensor to arrive from Germany, the one behind the cam pulley. Car will not run at the moment, keeps miss-firing and cutting out, the A/f meter goes to zero when it happens like an on/off switch with the fuel.
But got the new fully knurled pulley fitted and looks as though the answer to the belt slip is sorted, cheers Carl.
Just got to wait now until parts turn up, also got the GSC head gasket fitted and new engine mounts, which would explain the extra forward positioning of the rad

tim944s

Carl

Where did your test mule end up? Any reports on how it is running? This car was setup as you had intended, street only. It would be great for the street setup buyers to post here. I think it would help this thread as you are correct in this confusing the issue. I for one have been following this from the beginning and can certainly see that most of the posts can lead to lack of consumer confidence. I don't think I have really seen alot of feedback from satisfied street owners. Anyone out there care to comment on the performance and reliability of the kit?

Jfrahm

I have the test mule. It's on ramps while I get around to cutting a custom pulley to fit the double sided belt.
I have not tried the knurled pulley, I'd started fooling with the double sided belt before it arrived in my mailbox.

Before I got into the double sided belt project I did have idle problems which I solved by moving the MAF farther from the SC, and I did find that the belt needed to be quite tight and not allowed to loosen up or slip would appear at high RPM. In normal driving it required a boost gauge to detect the slip, I could not really feel the power dropoff but I could see boost flatten out or flutter.

Lately progress has just been a time issue, I need a solid evening to cut this pulley and while that might sound easy I am not a machinist by trade and the pulley has to match the belt profile very closely for maximum surface area contact. Plus it has been nice out, so I went outside.

If you read my numerous posts in this thread (easily searchable) you can see how I've been getting on with the mule both in stock and proto-double sided belt form.

Cheers,
-Joel.

Carl Fausett

Not every Porsche owner is a Rennlist member (I know, shocking!) - so although there are 14 of these marching around the planet at the moment, I cannot get them all to comment here.

We have provided replacement Stage 1 pulleys at no cost to current owners, and I am funding the development of the Stage 2 crank pulley upgrade out of my own pocket....but with only 14 kits sold, a business case will need to be made before much more investment can happen.

edz968s

Well car is now running fine.
One problem was where the MAF is positioned near to the rad and air plate, it was close enough to tilt it slightly and break the connector to the MAF, through vibration, movement, giving an intermmitent connection, causing the mis firing, no feed to pin 2 of the MAF, giving the on/off/on/off/etc; signal.
This has now been sorted and with the new pulley, so far no belt slip and a nice even knurling imprint on the belt giving me from 4000 rpm to the red line 4-5 psi
It`s taken a while and been frustrating, but I think we are there.
Carl, how is the crank pulley mod coming on?
With that and a faster impeller speed, we should be up there with good figures.

Jfrahm

I just took mine for a drive with the knurled pulley stage 1 setup. It worked fine, and I saw maybe 5.5psi on my gauge at redline. It was over 5, but things were moving fast so I could not really concentrate on the reading. I am also at altitude so the pressure ratio on the supercharger is different for me. I also saw 2psi at 4000 rpm.

My double sided belt setup was hitting a mysterious wall at 4 or 4.5 psi so I wanted to try the knurled pulley and see how that worked. That pulley arrived after I broke ground on the double sided belt project.

One issue I had was that the woodruff key poked out a bit and would have caused trouble with the washer on the supercharger shaft. I took a 3/4" copper crush washer and nipped a section out of is to fit around the key. Nipping also made the washer grow enough to fit over the 17mm shaft. I topped that copper washer with a flat washer and a split ring lockwasher and then the nut.

Belt tension was set to 100lbs on the run under to coolant hose on my KR-2, but I suspect this would drop as tension equalized and the belt settled in. I'll check it again once the motor is cool.

My setup is currently stock except for the MAF relocated to under the header panel, after the air filter.
That was done to cure a bouncing idle, stalling on lift-throttle and MAF signal problems throwing a CEL.
(All problems now gone.)

Lunch!
-Joel.

Mark944na86

How do you expect this sort of tension to affect the life of the alternator and A/C compressor bearings?

Jfrahm

It doesn't seem much tighter (if any) than I used to run the belt just to keep the alternator from slipping. What is the recommended stock tension? I'm not sure I could measure the tension the same way it gets measured stock and compare the two, but it would be interesting to know.

I have heard of much higher tension measurements for some cars but I do not know how this measurement translates to using the krikit took on a 968. I could try the krikit on my Audi A8, which has a spring tensioner, and see what that reads.

Also - I haven't tried to see how loose I can run the belt, I could try running it at stock tension (whatever that is) or stock +20% or something I guess, but any belt slip might damage the pulley's grippy surface.

I never concerned myself with the stock belt tension on my stock 968 as I just kept turning it up until it stopped squealing in the morning.

-Joel.

Jfrahm

Update - I dug out the FSM and found the spec for the alternator belt tension. For AC equipped cars you set the belt to 9,5 +/- 0.3 on the 9201 on the run between the AC and the crank, and then add one full turn of the jackscrew. To me this suggests 100 lbs. on the Krickit is actually about right. I will check it with the 9201 the next chance I get.

Also after my short drive my belt tension measured 90 lbs on the Kricket. I can twist the belt 90 degrees with the weaker of my two mighty hands.

Also the kricket measured 90 lbs. on my Audi's serpentine belt, which is maintained by a spring tensioner.

All in all: Early results suggest the belt tension is not atypical and not worrisome.