george996

Comments please - I have four O2 sensors, located just before and after the first set of cats. On most header systems these cats are eliminated, and on most headers there are four bungs to receive the O2 sensors. Sometimes - often I hear - you still throw a CEL because there simply isn't enough difference in readings and the computer has a hissy fit. But even if you don't throw a code here is my question:

What is the computer doing to your mixture?

Seems to me the system will be reading more hydrocarbons without the benefit of a cat, and seeing more hydrocarbons it is going to try to run the engine more lean - cut back on the amount of gas in the mix. That's not good. Comment on that thought please.

Next, I have seen the mod using a spark plug fouling adaptor to remote the sensor away from the exhaust stream but still give it enough sniff to be happy. But again - the sample is going to be different than it would be with a cat in the loop, and the computer is going to make an adjustment, good or bad.

I'm wondering if anybody has actually been able to get a read on what the computer is doing in the case of headers, and if it is a healthy response or potentially harmful response. For example there are some folks that have experienced premature cat failure on the second sets still remaining, and they attribute this to hot gas coming through the headers and burning out the cats. Seems to me a cat makes the gases even hotter than straight pipes - that's how it works - and the exhaust without primary cats should be cooler if anything. But what if the computer made an adjustment to lean the mixture - that would make the exhaust hotter and possibly cause the damage some have seen.

Comments?

Final thought. The second set of cats have a bung not being used. When installing headers why not use O2 sensors up front as normal, but extend the second set to the secondary cats, rather than to the second set of bungs on the headers? This gives you the closest to expected sampling that the computer would be looking for. Might have to extend the wires but that's not a big deal. Anybody tried this?

These things keep me awake at night...

:huh:

from what i read the sensors ahead of the cats are for contolling the mixture and the set after the cats is to confimr that the cats are working (i.e. no effect on mixture). i guess you would get a cel that the cats are not fuctioning.

inspired by pongobaz's mod i attempted the installation and added a few more photos. i had to remove the driver's side vent to acces the screws and remove the duct as well.

Also, the workshop manual did not specify to remove the 4 screws between the steering wheel on the column switch cover to remove it but they needed to be removed as well.

Thanks guys. I could not understand

how a stock caymen S could be a fast as

my 997 S down the straights. I was

told that the car was getting a better launch

out of 14 because it had racing tires and

not street tires like my car. I took 14 faster and yet I could not

pull past this caymen S on the track. Now I

have passed alot of Caymen S's on the track but

this one car had something special about it. Thanks

for opening up my eyes.

Paul

+1 on the APR.

Some people have put 3.8 x-51 motors in Caymens.

Softronic is better IMO

Nick_USA,

Why do you like Softronic? I am interested in software for my 2004 996 but Softronic will not answer any of technical questions.

I would like to know what parameters they change other than throttle response. For example do they do anything with cam timing and cam lift, mixture, etc.

Thanks

Well perhaps this is what you need then...Mine has no boing....

another fix

thanks again. i think you pointed in the right direction. this weekend i will see if there is excessive resistance on one of the camber camber plates causing the spring to bind while turning.

The infamous...boing....yes there is a fix. It actually has to do with incomplete installation. The rubber washer/bushing off the stock suspension needs to be installed. I point you to this thread:

PSS9 Noise

wross996tt,

thanks for the reply and thread. the rubber washer/bushing is installed, please see the attachment. is there anytihng that should be examined?

thanks

I recently installed PSS9’s and sometimes can hear a noise when entering my driveway at an angle (no noise when going over speed bumps perpendicular). The noise is hard to describe, it is like the spring is binding and suddenly is free although I cannot feel anything. I checked the installation and could not find any loose bolts, etc. I didn’t lower the vehicle too much and am confident that nothing is scraping. Also, the noise is only from one side.

Has anyone experienced this and is there a fix?

Thank you.

thanks for the reply wross996tt and dscott.

anyone else out there?

I recently installed PSS9’s on my 996 C2 and while experimenting with the rear dampening settings it seems that even with the most firm setting (no.1) it is not enough. When you push down in the rear the car comes up higher than the resting height and then down again. Unlike the front, push down and it comes to the resting position. On the softer settings (7,8,9) the rear is significantly under-damped. At night you can notice the headlights bobbing up and down.

I am looking for some feedback before sending the shocks back to Bilstein. What settings are people using?

Thank you.

I recently had Darin Fister's ModII done on my 2004 996 and like it very much. No unusual vibrations or resonance. Nice sound.

I experienced something similar after a hard acceleration and after a few more shifts the pedal effort returned to normal. Found some threads that indicated a bad pressure plate and I would tend to agree. I don't think there is anything wrong with your hydraulic system. Low pedal effort means low force pressing against the clutch disc and are observing slipping.

This is great feedback. I wonder why my 04 is higher. Anybody else with an 04?

It would be great to hear from someone who installed H&R and Eibach springs.

Thanks george996 and kbrandsma for your comments. The new flywheel is in and the car runs perfect. I am very happy with the result and would do it again in a heartbeat, although it took me considerably more time than expected. All in all about 10-12 hours, but it was a good learing experience.

Because of your concerns about jackstands I bought a set of 4 double locking 12 ton (!) stands at Northern Tool, as well as their 1.5 ton transmission jack. Once I got the car about 2ft in the air, working underneath the car was a breeze. Getting the transmission jack underneath the transmission and getting it to lift in such a way that the transmission slides off easily was tricky. I recommend attaching it as far away from the bell housing as possible (ie. towards the front of the car) and use the jack's swiveling action to maneuver it around.

If you take the passenger side rear wheel off, you can get to bolt #1 with a 16mm ratcheting box wrench. Like one of the many neighbors that came by this weekend commented, it's like milking a mouse :lol: , but probably quicker than removing the throttle body.

While the tranny was out I took the opportunity to replace the transmission oil as well, so no worries on that one for the next 30K miles or so.

Sorry I did not take any pictures. Maybe next time.

Joost

Congratulations. Glad I was able to help.

2002 C2 Coupe 26.5F/26.375R stock w/18" Carrera II's & newish Sumitomo HRZII tires

perryinva, would you mind checking the color coding on your front springs? There are two markings at the bottom and one at the top.

thanks

I am planning to lower my 2004 996 and while doing research I found some data showing that the 02-04’s are about a half inch higher than the 99 – 01 models. Please see the PCA article “996 Standard and Sport Suspensions Analyzed”. I confirmed this by taking measurements of my 04 and a friend’s 99. Both have stock standard (non-m030) suspension, same O.D. tires, etc. The 04 was 27/26.6in front/rear and the 99 was 26.5/26.23. Next we removed the wheels and took dimensions of the front strut and did not find any differences. The only difference was the markings on the springs. Both were blue and brown on the bottom but the 99 has white on the top and the 04 was blue. Therefore we concluded the difference in height was only due to the springs.

Eibach and H&R offer only one p/n for the 996 and advertise lowering by 1.0” and 1.25”, respectively. Since there were no dimensional differences between the 99 and 04 front struts, I assume that the fender heights of the 99-01 and 02-04 models will be the same after installing any of these aftermarket springs.

I thought it would be helpful and interesting to get some replies of height data, model year and suspension type.

2004 996 C2 Coupe 6sp Standard Suspension – 27 inch front / 26.6 rear

The triple square bolt is 10mm.

I am looking to do a clutch job on my 2000 996 C2 and it seems like kbrandsma knows what he's doing.

I have two concerns:

- Without a lift, how high of a clearance would you need to do this job on jack stands?

- The special 3 square 10 mm bolt. Which one is it? Can you indicate it on the attached picture of the G36 transmission?

Thanks, Joost

the triple square is no. 4.

The jack stands were about 16.25 inches. See attached photo of the jack stand mod.

Deciding whether to replace my clutch myself or have dealer do it on my 2004 996 C2 and looking for some input. It’s been a long time since I replaced the clutch in my 911SC so I have some idea about what is involved. I am not comfortable about replacing the RMS myself.

The Porsche dealer will replace the DMF, clutch disc, pressure plate, throw out bearing and RMS, parts, labor and tax for approx. $2,200. This price discounted for another reason. If I were to do the job myself I would probably omit the DMF and my cost would be about $500. The DMF rattles during shutdown so I am not opposed to replacing it (dealer says this is normal and will not cover it).

I would really appreciate some comments. Thank you.

Hi George,

I have the same car as you with the same clutch problem. Have you decided on DIY? Has anyone posted a step by step process to replace the clutch? I have the same quote as you, $ 2,000 and the labor time was 8 hours. That's all they would share with me.

Thanks,

Ken

Ken,

I ended up doing the job myself. I replaced the clutch disc, pressure plate and release bearing. The clutch feels great, light pedal effort and smooth. I did not replace the DMF or rear main seal. The DMF still rattles during shut down but otherwise I am pleased with the clutch operation.

If you are planning to use jack stands, like I did, I recommend modifying the jack stands to lock into the holes of the lifting points. I didn’t feel comfortable otherwise. I’ll post some pics to show you what I did.

Take a look at this link for some pointers http://www.c-speedracing.com/howto/996rms/rms1.php

I also subscribe to Alldata http://www.alldatadiy.com/ where I got all the procedures, specifications, etc.

Besides standard hand tools you will need a transmission jack, floor jack to hold the engine, triple square socket driver for (I can give you the size later) for one of the bolts on the bell housing and a clutch alignment tool.

PM me if you have any questions.

Good luck

George

Does anyone have information for inspecting/evaluating motor mounts other than leaks? Are there any dimensional requirements? I know that Mercedes specifies minimum height for their motor mounts that are in compression.

Thank you.

I am planning to replace my clutch this weekend and forgot to get a clutch centering tool. One of my co-workers is willing to make one if he has the dimensions.

Does anyone know the outside diameter of the pilot bearing side of the clutch centering tool?

Any help will be appreciated.

does anyone know what this part is? I found it under my seat. The seats are not power operated. 2004 996

Did you read the TSB for how to check the DMF?

TSB 8/02 1360 Dual Mass Flywheel Check Procedure -- dated 12-13-02

yes. The dealer will not perform the test based on the rattle sound alone. They say it is normal and even a new DMF might make the same rattle. Like is mentioend, I noticed the same rattle in a handfull of 996's and 997's recently. I am hoping that while replacing the clutch they will replace the DMF if it faulty according the procedure you referenced. I met with 2 reprensentatives from Porsche, not only thle dealer about this.

Is there a specific reason you are replacing the DMF? They seldom need replacing unless a spring breaks. Complete clutch kit replacement, including parts can run as low as $1200. (No flywheel)

I am having a dilemma about replacing the DMF. It rattles when shutting down; otherwise there are no other issues with it as far as I know. If the dealer replaces the clutch they insist on replacing the DMF as well. The car is under warranty so the benefit of having the dealer perform the work is that if the DMF is found defective they will eat that cost. They will not replace it under warranty because of the rattling. I drove 5 similar 996’s recently and 4 rattled just like mine. So I am looking $2,200 for everything or $500 for DIY (w/o DMF).

Deciding whether to replace my clutch myself or have dealer do it on my 2004 996 C2 and looking for some input. It’s been a long time since I replaced the clutch in my 911SC so I have some idea about what is involved. I am not comfortable about replacing the RMS myself.

The Porsche dealer will replace the DMF, clutch disc, pressure plate, throw out bearing and RMS, parts, labor and tax for approx. $2,200. This price discounted for another reason. If I were to do the job myself I would probably omit the DMF and my cost would be about $500. The DMF rattles during shutdown so I am not opposed to replacing it (dealer says this is normal and will not cover it).

I would really appreciate some comments. Thank you.

Can anyone comment on the difference(s) between LUK and SACHS DMF’s for a 996? From their websites it appears that each manufacturer uses a different design. SACHS offers a “planet dual mass flywheel” that incorporates planet gears. Brochures attached.

I believe LUK is the OEM supplier. Therefore has anyone used the SACHS type? Comments?

I recently spent a lot of time and money to resolve the same problem. One of my rims was slightly bent. Had the rim straightened but the problem wasn’t eliminated. From driving my PS2’s for a few thousand on the bent rim they needed to be shaved. Can’t tell where you are located but I took my car to Nate Jones Tire in Signal Hill, CA and he shaved the tired and did an “on car blancing”. Problem resolved.

I have a 2004 996 w/6spd. I went to the dealer to complain about a rattle noise from the transmission/clutch area when shutting off the engine. It makes a rattle/clanking sound during the last handful of revolutions before the engine completely stops. There is no noise when shutting off the engine with the clutch depressed. I read the bulleting on DMF’s and my symptom is cited as an example.

The dealer let me listen to another 2004 and a 2002 and they both made the same noise. Is this normal? Do these cars have bad DMF’s too? What if I tried a new 997, does it have a similar DMF?