baronb55

I have a track-dedicated 996 (1999) with snell headers and mufflers and fabspeed xpipe (catalytic deleted). I am considering removing the mufflers and installing straight pipes from the xpipe out. Any idea if the reduction in back pressure that I expect to obtain will decrease the performance (that is, reduction of low end torque)? Any detrimental effects of this mod? Is it worth doing? Thanks for any input.

Hello, I will be installing a new idle control valve today. After installation, is there a special procedure to initiate the new control valve? I know there is a sequence that has to befollowed after installing the throtle position sensor and wonder if the procedure is the same for the ICV. Thanks for your help

Thanks. Will try your suggestion.

Hi everyone! I have been having a recurrent problem with idle. It happens only with the engine hot after my track session. As soon as I finish my track session. the idle RPM fluctuates wildly and many times the engine quits. I don't notice any problems at speed. The only codes I get on the Durametric are does related to the removal of the cats. I had the indy look at this but it did not do it with him. Friends tell me that this could be a vacuum issue. 6 months ago I changed the throttle snesor after getting a fault code. This problem started about 1 month ago. The car is a 1999 996 that is dedicated to the track. KN intake , headers and removal of teh cats are the main modifications in the engine. Any ideas on how to tackle this gremlin? Current odometer 85,000. New spark plugs and plug cables.

I was wondering if using a conventional oil with very agressive change intervals will not be detrimental as opposed to using the synthetics. Also, do you think that changing the oil as frequently as I do for track days is unnecessary? Just trying to make the sport more affordable but without hurting the service life of the engine.

Sorry to bother everyone with a topic that has been discussed "ad nauseaum". I have searched tin the files and still find myself confused about choice of oil for my application. I have a 1999 996 with catalytic converters removed and LN IMS conversion. The car is a dedicatred track car. I change the oil and filter every two events (approximately 200 miles of use). I have been using Mobil 1 15w50 (silver cap) on every change. I also add one bottle of ZDDP plus to boost the zinc and phosphorus higher than the 1200 ppm that Mobil oil has. This is turning to be somewhat expensive and I also have issues with availability of Mobil 1 15w50 in my area. Have been thinking of switching to Valvoline VR1 20w50. Valvoline has a higher zinc and phosphorus content but is not synthetic. Would it be ok to switch to the Valvoline and save $4 per quart since the intervals for change are 200 miles? I would continue using the ZDDP Plus zinc additive. I live in South Florida and the temps are obviously warm. Thanks for any advise I can get.

Thank you very much. The corner balancing has been done as well as the ride height (H&R coilovers dropped it by 1.5 inches). Got worried when I saw a guy in a BMW put racing fuel and then experiencing engine trouble at the race track. The race fuel is expensive but conveniently available at the track. It will save me a drive out of the track to refuel on extended track weekeends.

Hello, I own a 1999 Carrera and have been doing lots of track events lately. The car has not been "chipped". The cats were removed and headers and mufflers replaced with FabSpeed. At the track they sell 98 and112 octane fuel (at a very high premium). My question is, can this fuel be safely used without any modifications on the engine or electronics and if so, will it improve performance to justify paying 8 dollars per gallon? I live at sea level in Florida. I searched the site and could find nothing on this topic, just references to low octane fuel. Thanks for any help.

First in 1990 at age 30....a 1989 944

Second 2011 at age 51... a 1999 996

Third coming up this week.... a 1986 944 to prep as a track car.

Yea... I know the feeling. All I could come up with was 68mm offset rims. So, because I wanted some Phat

295's on a narrow body 996, I got a hold of Eric Vaughn and Vaughn Machine in Monrovia, California.

It doesn't matter if they are 17, 18, 19 or 20's, he will cut them and widen the rim.

If you aren't into the real agressive stance and spacers (plus longer lug nuts), I highly suggest you check him out. No fender rolling, camber adjustments, spring and coil changes.. etc.

I don't track but like the look of huge tires on a Carrera. Poser I guess. I just took pictures of the rear and

with the help of my wife... will show how awesome the car's stance looks when we figure it out.

I will post pics as soon as the car gets back from fine tuning teh suspension and getting corner balanced. I know the feeling, my wife also was very helpful in helping select the wheels. They have to be involved or else.......

Thanks to everyone who commented. I will forget about that idea. Will leave the 100LL for my Beechcraft. Don't have access to race fuel in Key West so I will stick to 93 octane and save myself a lot of money in repairs. Thanks!!

Changing wheels and tire sizes (offsets/backspacing and diameter) is one of those risky calculations.

If they don't fit... you could be out a lot of dough.

I am glad it worked out for you.

I took a gamble and had some 17X9's with et 55mm widened to 17X10.5 et 74 mm for my NB 99 996.

They fit! No rubbing, no nothing. I went from 255/40's to 295/35's all going towards the center of the

car. I was sweating it out while they were being modified. Thankfully, things worked out fine for both of us.

Happy motoring.

Trust me, I know. I was very scared until I got them and tried them. Thank God I did not have to roll fenders either. 74 offsets! Where did you get them? My problem was that i could not find any offsets above 62 for the back

Repeat: Reman engine probably means no IMSB retrofit for your car.

I bought a 1999 996 with 78,000 miles. I made all the mistakes you can make including not getting a PPI. Thank God, I lucked out and no major issues were found. I did have to change the control arms (one was broken and just decided to change all of them,. I immeditely changed all the fluids, clutch, suspension (installed H&R street performace coilovers), rotors, pads, chain tensioners, polyrib belt, spark plugs and harness, light weight flywheel, headers, mufflers and installed cat by pass pipes. The IMS bearing (L&N engineering) and rear seals were also replaced. Finally, I installed 19 inch wheels with new tires. I paid 20K for the car and have spent about 12 K in improvements and maintenance. The end result is a 32K 1999 996 that looks and performs as good as any 12 y/o car with 78K miles can. Was it worth it? I think so. Looks to me that you may be getting more car than I did. Just be careful with the engine seals. 17K miles in 12 years does not seem to be much. These seals (I have been told) will dryrot in old low mile garage queens.

The mechanic told me that the replaced IMS bearing in my car was still good. I intend to drive the car in DE events and autocross and enjoy it. For this reason, I probably went overboard with maintenance and upgrades. I personally like my lightly optioned 996 more than the newer cars with GPS systems and lots of electronics. My humble opinion...go for it after a good PPI so that you know what you are getting into.

I will like to share with everyone my experience in trying to fit wheels on a NB 996 . I was able to fit 19 x 8.5 ET45 in front and 19 x 10.5 ET 52 in the back on my 1999 996 NB without any rubbing. The wheels are very close to the calipers on both wheels but nothing rubs. Wheels do not protrude from the wheel wells. I was not sure if they would fit because the offsets are so far from factory recc but it turned out really nice. Hope this information helps somenone.

Will it be detrimental to the 3.4 L water cooled engine to use 100 LL gas on ocassions? I have removed the catalytic conveerter. Also, if I use it and mix it with 93 octane, will teh two mix or will the heavier 100LL sink to the bottom of the tank in a separate layer? I drive a 996 1999 with manual transmission and 81,000 miles. Thanks for any inputs.

1999 C2 82,000. So far so good. New everything but no IMS failure yet. Have not done the IMS conversion.

Have been trying for months to find aftermarket wheels for my 1999 Carrera C2 NB and can't find anything that will fit. I have spent a lot on all the other mods and my cash reserves are limited now. Can't afford to have custom made wheels. Looking for 18x8 front and 18x10 rear. The offsets that the manual calls for are 50 in front and 65 in the back. I have lowered teh car by 1 inch in the four corners with H&R street performance coilovers. Wiht the OEM 17 inch wheels with an offset on 55 in the front, I get tire rub in the plastic of the front wheel well when cornering agressively. All the wheels I find have offsets that are way off of the factory recommendations. When I call the tire places they tell me that those wheels will fit but I am not so sure. I have to order by mail since there are no local shops specializing in this close to me. Can someone help me with info of what offsets will work with nmy current setup? This is my last mod (for now) and can't wait to finish it. The only wheels that I found within these specs are the 997 Turbo wheels from Wheel Dynamics and I don't like them that much.

Well, P1121 (Porsche code 430) is Oxygen sensor heating 2 behind catalytic converter – below lower threshold.

So I guess that would explain it. Best file a bug report with Durametric...

Thank you. Will do that. Guess that explains why it still runs smoothly.

Wait, did you have 2 faults?

P1121 is Oxygen sensor heating 2 behind catalytic converter – below lower threshold

What is the current fault code?

The Durametric is saying throttle position sensor 1 after the p1121 code 430. Yes, I have oxygen sensor fult due to the cat by pass. Whats interesting is that the car appears to be running perfectly fine as far as I an tell.

:lol: :lol: 35 years of working on Porsches probably helps. That and up to date service manuals.

Loren, if you read this post...I did the adaptation as you instructed (twice) and after driving for 15-20 miles I get the same fault code on the TPS. CHecked again the connection and is firm and adequate. Any other ideas or is it time to take it to the experts?

I have the same problem on my 99 996 Coupe. How did you remove the mirror to replace the motor?

Thanks Loren! Will do it. You have been a savior! How do you know all these info? Hope to get to your level one day.

No, I didn't. Had no idea I had to do this. I have been using the car like this. Can I do the adaptation now? Thanks for all your help Loren. Hopefully I will stop asking questions sometime soon!

I did write before about my fault code regarding the throtle position sensor. I checked the connectos and found them ok. I ordered a Bosch OEM TPS for the throtle body and replaced it. Cleaned the electrical connector with electric contact cleaner. It worked fine fo 20 miles then the CEL came on again. The code is the same: P1121 fault code 430 Throtle position sensor 01. I could not retrace the entire connecting wire to the TPS and only checked the actual connector. My car is a 1999 Carrera C2. I did installed headers, free flowing mufflers and cat by pass. I get the CEL for the oxygen sensors due to the cat by pass. The car has 81,000 if it matters. Any help or ideas will be greatly appreciated. I live 200 miles from the nearest Porsche dealer. By the way, the car appears to be performing flawlessly. If it was not for the Durametric reader, I would not know about this fault. Thank you all!

I assume it is a '99 C2 (mechanical throttle). The throttle position sensor is held onto the side of the throttle body with 2 screws. As far as I know there isn't any special procedure or setup.

Are you sure you didn't disturb one of the ABS sensors when you disconnected the brake wear sensors? The plugs are next to each other.

Front:

Rear:

Thank you for your help RIchard. The pics were very useful. Problem has been solved