To start off with to anyone planning to use this topic as a forum to knock the "S". Please don't bother wasting my time. That also includes responces like why not just buy an S2 or Turbo or so on and so forth.
I love my 88 944S, it has gotten better and better at 118K miles and mostly because of a mechanic that knows how to time the cams and how to diagnos the car (not an easy feat in the "S"). Furthermore, Bosche Patinum Plus 4's, Mobile 1 0W40, Sunoco 94 octane ONLY and driving it like a Porsche rather than a trophy.
Now to my query. I have heard from some very reputable sources (for instance a former mechanic of mine that moved back to England who was on a Porsche Factory racing team!)that a good and cheap (relatively) way to improve responsivness of the "S" engine while getting more midrange + a little extra on the top was to install S2 cams. The shop that I currently go to may be able to source them from another customer for between $300-$400 USD (not including labour to install)
I wanted to know:
a)If anyone has ever tried this and if so what their opinion was.
b)Possible problems or other issues that you've got.
If anyone has questions about maitanace or performance for the "S" I've got quite a bit of good experience on the subject and have pleanty of seat time as well in pre + post 85&1/2, including an S2, and Turbos (standard, 88 Silver Rose models, lightly + heavly modified street models + a couple of full out racers)models.
Hope this generates some interesting discussions and looking forward to the responses.

 

First off let me reach out and brush that chip off of your shoulder.. jeeze. Cams are the duration of opening and closing of the valves. the longer you hold them open (intake side). you get more mixture. (lobe duration). the only other way to get more is either more valves or more flow.. I have to assume that the S2's have a longer duration. or bigger intake valves. I have no idea. But exaust is equally important. the longer the duration the more exaust leaves.. If the valves are not matched to the cam yield will be little. to much exaust left will kill the intake stroke.. Duration maximization is the key. but flow capability has to be taken into account.

 

Looking at this website, on the surface they seem to make no distinction between the 944S, 944S2 or 968 cams: <a href="http://webcaminc.com/porsche-auto.html#9" target="_blank">http://webcaminc.com/porsche-auto.html#9</a>

They also offer modified cams. <img src="graemlins/burnout.gif" border="0" alt="[burnout]" />

Perhaps contacting them would yield better information.

 

Ahhhhhhh - another "S" owner!!

Well, let me start off by saying just how much I HATE the "S". It's so bad!!! The head blows up on every one and the Cam Tensioners go at like 15,000 miles on every car. It's not even as powerful as the N/A from 0-60. Nobody likes them or wants them, that is why they are so cheap!!!

......got cha!!! I ABSOLUTELY LOVE MY '88 CANADIAN VERSION "S"!!!! LOVE IT, LOVE IT, LOVE IT!! Just doing the, "I'll trash it cause I'm supposed to, but don't really know if what I'm saying is even true" speel that we S owners hear all the time - I'm now impervious to that foolishness.

Anywho - have you done the Cam Tensioner yet?? I'm doing mine in a week or so and was looking for some tips. I know it's not that huge a job - but should I replace everything, or just the rails and tensioner unit (J-Tube included)?? Is the chain itself a worry??

 

I love my 88 S too I havent done the tensioner yet.. but I plan to do it with the belts/pump/mounts over the summer.. hope the car lasts till then Good to see some proud S owners.

The only weird thing with my car that worries me sometimes is the amazingly prevelant belt whine when kicking into second gear.. weird.. other than that peachy, what is that?

 

My car is getting a fresh coat of paint and a suspension upgrade, hopefully all done by the April 19/20th date for a run up to Hershey. Nice to see some S owners out there, I love NA performance and I always liked 16v cars, I'll post some pics when the project is done. Keep this cam discussion going, I'd like to know if it worthwhile. <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />

 

I too love my "S" but haven't owned it long enough. I have changed the timing tensioner and was considering changing the chain, because it might be stretched. But, I read if you change the chain you might be doing more harm than good, because of the wear on the sprockets. Is it true that you should change the chain and the sprockets?

Does anyone know what Porsche recommends? Changing the sprockets involves changing the cams right (one piece)?

Thanks,
Mark
'88 944S

 

[quote]The shop that I currently go to may be able to source them from another customer for between $300-$400 USD (not including labour to install)<hr></blockquote>
If you decide not to go with those cams I'm interested in them. Do you know how I can get into touch with the customer, or perhaps your mechanic?

PorscheG96@yahoo.com

 

I'll have to wait until I get home to verify this information in the workshop manual, but as I recall, the 'S' cams have more duration than the 'S2' cams. If that's true, you'd be taking a step backwards.

Either set of cams IMO is pretty mild. You'd be better off having them reground if you are looking for more power.

 

Aaron, you never said what goal you was trying to accomplish with the cam upgrade. The 944S/S2/968 cars are similar to the Japanese TypeR motors you see all the Honda ricers driving around. They have revvy peaky powerbands that are highly optimized by the time they leave the factory. It's very, very easy to over-cam these types of engines and end up with a slower car.

In essence what you're doing with cam changes is shifting your powerband around, while the TOTAL amount of power you have is still the same. You'd be taking away from low-end torque to have more high-end HP. The only way to have both, is to have two cam timings, one for low-RPM and one for high-RPM, hence VarioCam in the 968. A more advanced version is VarioCam+ which also change the valve-lift (or VTEC in Hondas). Even more advanced versions of variable cam techniques are used in BMW, Toyota, and Ferrari engines which provide continously variable timing and lift. Rather than switching and forth between two different cam lobes, they can smoothly change timing and lift in small increments to optimize for each RPM range.

An upgrade for the 944S that doesn't have compromises between low-end torque and high-RPM power would be higher-compression pistons, which would give you increased power all across the powerband.

 

"An upgrade for the 944S that doesn't have compromises between low-end torque and high-RPM power would be higher-compression pistons, which would give you increased power all across the powerband."

Again this is dependent on the end use, but given that the 944S/S2 are already at 10.9:1 (S at least) and like to eat at least 91 octane, any increase in CR could end up making it very difficult and/or expensive to feed the car. For a track car this wouldn'y be a problem but the rules and class for any organized competition could make a difference.

 

To start out with, thanks to all of you for getting into this. I appreciate all the angles. It is an interesting problem. Will replacing the cams only shift the power curve? Not really sure, that's why I'm asking. Even if $3-400 is cheap for the cams, if it's not going to make things better than why bother.
To Prince and Chrackhead944S - I did my chain tensioner January 2001. I did the tensioner (just buying the plastic rub pieces wasn't an option at the time), the chain (it stretches as the lobs wear out until it finally snaps, jumps off the teeth, or breaks the teeth all together - therefore as long as the teeth are ok than always at least replace the chain (it's cheap - what happens if it breaks is not!), finally I had the cams properly timed. This amazed me to find out but most (Yes I do mean most) machanics do not time the cams properly when they are worked on (of course they have to come out when doing the tensioner). It requires someone that knows what they're doing and the proper tool (another one of those marvelous Porsche specialized tools). When the "S" is mistimed it becomes what people who love to trash it believe it is, "hardly if at all quicker than the standard 8valver".
For the first year that I owned the car the cams were mistimed, however being that it was the first "S" I had ever driven I didn't know any different and therefore also questioned the merits of the "S" over the standard '44. The car was not slow but it was getting 35miles/gallon on the highway without even trying. Most people wondered why I was complaining about that but I wasn't impressed that it was gutless under 5000rpm. When the cams were finally timed properly and the engine had a few more thousand miles on it to really open up after years of mistreatment (b4 I owned it), the true nature of the car came out. I LOVE THAT ENGINE!!! Wow, the differnce was night and day, two separate cars and I've never missed the gas milage I used to enjoy. So if any of you have an "S" that isn't all you think it should be....there is hope.
Oh, at that time I also did all the belts and rollers (big mistake to miss those rollers as I' sure you guys are aware---if not--be forwarned!), the massairflow assembly was also replaced. The car had developed a nasty habbit of not redlining, and that alone with relpacing a relay or two solved it.
Anyway, Nova Scotia huh, I went to University in Newfoundland---(not really that close but in the same direction : ))
To Crackhead944S - Do yo ever make it to the PCA-CVR autocrosses @ the Smith&Wesson Factory in Springfield, Mass? I'm there quite a bit.
To OperatorSX - Where are you in CT? I went to highschool in Stamford and am down there constantly. Oh, and as far as the cams go...Not sure if I can get them yet, I've been waiting to hear. But if I decide I don't want to bother, go for it. The shop is Fairfield County Motorsport. I'll give you all the details if you want. I know everyone there, but that is a whole other topic.

Anyway-I'm writting way too much, I'm loosing track of whatever it was I was saying.
Thanks,

 

Great, we're getting the details. Ok, so you see the tug-of-war battle between high-end HP and low-RPM torque now with the same engine in the same car. Most likely the cams were too retarded with a later intake closing in your initial set-up. This is great for high-RPM power, but as you found out, it was gutless at lower RPMs. By advancing the cams somewhat (probably 9-degrees/1-timing belt tooth), you regained a lot of that low-end torque.

Now aftermarket cams are typically geared towards high-RPM HP. This means they increase the duration and lift, thus increasing the overlap period and delay/retard the intake close. This would have the same effect as the mis-timed stock cams you had earlier. So you would be taking a step backwards in drivability by going to aftermarket cams.

As to the difference between S & S2 cams, without the specs I wouldn't be able to speculate as to exact what the benefits are. One typical tuning procedure with DOHC engines to install adjustable timing gears on each of the cams:



This allows you to individually time the cams to give you the power characteristics you desire. On stock cams, typically retarding the exhaust and advancing the intake a couple of degrees gives the desired result. The earlier intake closing gives better low-end torque and response, yet the extra overlap give you high-end power as well due to extra scavenging.

 

wow Aaron, im from Stamford. I went to WHS and I still live there when I'm not up @ UCONN. Great advice and stuff on the S. I just got mine a month ago.. and.. I guess its all good for now.

I, like yourself, have never driven any other S's and dont know if my low rpm power is sluggish or right on, seems weak compared to the high end as well.. but I'm guessing they came out of the factory that way?

Over the summer i want to do my belts/pump/motormount and the cam chain tensioner... now im started to hear I have to do a few other things too? new rod bearings? new cam chain? whoa.. anything else? and how do I know if my mechanic knows what hes doing? he seems fairly knowledgeable but I dont know if he really has any true experience with S's. Could always take it to the dealer but thats going to cost 5 grand for all that.. well hopefully the car wont explode until the summer. great info here.. keep it coming for the clueless (like me). <img src="graemlins/a_smil17.gif" border="0" alt="[blabla]" />

 

My next engine project's going to a turbo S2 or 968; the upper-RPM breathing is SO much better than the 2-valve cars. That said, it does have some peculiar problems with the 4-valve heads:

<a href="http://forums.rennlist.com/scripts/rennforums/ultimatebb.cgi?ubb=get_topic&f=15&t=004064" target="_blank">ANOTHER 968 failure...</a>

Also lots of cam-chain issues on <a href="http://www.968.net." target="_blank">www.968.net.</a>

As for the rod-bearings, it's the same issue with the #2 bearing as all the other 944 cars. Here's a picture of my rod-bearings when I pulled them out last weekend:



People have seen this kind of wear and failures at 80k-miles or 180k-miles. It all depends upon the previous owners driving pattern and maintenance. Just for peace of mind, I'd do them just to be safe. And replace all the front engine seals too while you're doing the water-pump.