Vman

The car has a new 400 hp 3.8 x51 motor so we needed to upgrade to a stronger clutch, we went with unsprung and full face organic as sachs told us with the flex in the drivetrian inheirant in 99-2000 car's we should be fine. I will ask about the lever thanks. Hi Did you do the 3.8 swap by yourself? I want to do the same, but still collecting information how to do it (egas, variocam + controller, returnless fuel pump etc.). How did you solve these issues? Best regards Kare No way to do the swap yourself only a couple of folks in the country are qualified to do the swap. Send me a PM if you want more information.

The car has a new 400 hp 3.8 x51 motor so we needed to upgrade to a stronger clutch, we went with unsprung and full face organic as sachs told us with the flex in the drivetrian inheirant in 99-2000 car's we should be fine. I will ask about the lever thanks.

I just put in a new sachs unsprung racing clutch in my 996. It has a high pressure 600 NM pressure plate, aasco lightweigh AL flywheel and Sachs race engineering unsprung but full face organic clutch disc. The clutch was a bit more difficult to drive than stock from day one, due to being unsprung, but now after 400 miles the clutch is much harder to drive and randomly will feel like it is slipping under full throttle, sometimes it slips sometimes it does not....very strange as it does not always slip. We already bled it to get some free play in the system, but this did not fix the problem. Also, on a 996, do you need to drop the engine to replace the clutch? Does anyone have a DIY for a clutch replacement? I wonder if I have a defective clutch...slave cylinder ...master cylinder, anyway to test this stuff without just starting to replace things. Thanks, VMAN

Does anyone know if the O2 sensors are different precat and post cat on a 996? Are the OEM O2 sensors wideband (actual values reported) or narrow band (lean, stoich, rich)? Last one, any difference between o2 sensors on a 996 3.6 vs. 997 3.8? Thanks, Vman

I am not clear, if the x51 throttle body(which is larger then the stock one) does fit the non x51 intake (which is smaller then the x51 intake manifold, then how does the inside diameteres match up x51 ID verses the non z51 intake manifold ID , ?/ or are they the same. Ronnie Sorry Ronnie didn't see this..you have to remember that the throttle body doesn't connect to the intake manifold directly. It connects to a plastic intake distribution tube commonly called the "plenum", this is the part that RSS has done through the aftermarket. As far as the X51 throttle body ID vs. this part, well this is the million $ question. Whats nice about the factory piece being plastic you can probably grind it down to gasket match this and you could probalby do it with the RSS aluminum part as well. I was told by RSS that the X51 TB does fit. Haven't seen this myself though...(my disclaimer :D) Dave thanks dave , i really meant the plenul, the irony is i already fitted the rss plenum in the car. I also have the airbox , filler tube, sitting in my house. I was thinking about just getting a silicone transition tube from the throttle body to air inlet hose. i am not sure how much the throttle body is . have you ordered your stuff yet ronnie Hey Ronnie, not yet. Do you have the template for cutting the lower deck for the 2nd airtube?? I saw your post regarding the oil filler tube and the alternator. I will see if I can find out how to do this. I am leaving to Japan for a few weeks, and I will probably order it when I get back. Dave ya the dealer shipped it with the aie box, but unfortunately the scale is incorrect. will keep you posted ronnie I just sent you a PM, but in case you don't check it......... Did you measure the difference, if any between the diameter of the stock 3.8 airbox where the maf is inserted and your new x51 airbox? Also, one would need to measure how far the MAF extends into each intake tube and make sure it was the same. If the two internal diameters are not the same you will be getting a bad MAF reading causing your car to run too lean or too rich. If the intake diameter has increased the MAF would read low and the ECU would respond by running too lean (may not good for engine longevity but can make more power and could also be why at startup you are running a bit rough as the stock program usually tries to run the car rich until it is warm).I am trying to get data on this as I am on the fence on doing an X51 airbox or EVOMS one for my 3.8 x51, so please let me know if you have done the calculations. Just confirmed today that the intake at the point of the MAF sensor is the same inner diameter for 996/997 and 997 x51 intakes. The difference in the X51 intake is that the factory one has two air snorkels and a bigger internal diameter hose to deal with the bigger inner diameter of the X51 throttle body. Also, 3.8 non x51 cars running x51 airboxes may be getting a rough idle because the tubing diameter differential.

I found out today that the intake at the point of the MAF sensor is the same inner diameter for 996/997 and 997 x51 intakes. The difference in the X51 intake is that the factory one has two air snorkels and a bigger internal diameter hose to deal with the bigger inner diameter of the X51 throttle body. VMAN

I am not clear, if the x51 throttle body(which is larger then the stock one) does fit the non x51 intake (which is smaller then the x51 intake manifold, then how does the inside diameteres match up x51 ID verses the non z51 intake manifold ID , ?/ or are they the same. Ronnie Sorry Ronnie didn't see this..you have to remember that the throttle body doesn't connect to the intake manifold directly. It connects to a plastic intake distribution tube commonly called the "plenum", this is the part that RSS has done through the aftermarket. As far as the X51 throttle body ID vs. this part, well this is the million $ question. Whats nice about the factory piece being plastic you can probably grind it down to gasket match this and you could probalby do it with the RSS aluminum part as well. I was told by RSS that the X51 TB does fit. Haven't seen this myself though...(my disclaimer :D) Dave thanks dave , i really meant the plenul, the irony is i already fitted the rss plenum in the car. I also have the airbox , filler tube, sitting in my house. I was thinking about just getting a silicone transition tube from the throttle body to air inlet hose. i am not sure how much the throttle body is . have you ordered your stuff yet ronnie Hey Ronnie, not yet. Do you have the template for cutting the lower deck for the 2nd airtube?? I saw your post regarding the oil filler tube and the alternator. I will see if I can find out how to do this. I am leaving to Japan for a few weeks, and I will probably order it when I get back. Dave ya the dealer shipped it with the aie box, but unfortunately the scale is incorrect. will keep you posted ronnie I just sent you a PM, but in case you don't check it......... Did you measure the difference, if any between the diameter of the stock 3.8 airbox where the maf is inserted and your new x51 airbox? Also, one would need to measure how far the MAF extends into each intake tube and make sure it was the same. If the two internal diameters are not the same you will be getting a bad MAF reading causing your car to run too lean or too rich. If the intake diameter has increased the MAF would read low and the ECU would respond by running too lean (may not good for engine longevity but can make more power and could also be why at startup you are running a bit rough as the stock program usually tries to run the car rich until it is warm).I am trying to get data on this as I am on the fence on doing an X51 airbox or EVOMS one for my 3.8 x51, so please let me know if you have done the calculations.

Does anyone know if the X51 intake is the same size where the MAF sensor sits as the stock 3.8 997 intake? Also, has anyone measured the depth of the MAF sensor protrusion. I am asking as we are considering using an EVOMS intake and want to know how far off if at all the MAF reading would be due to the physicial differences in the intake diameter if any. Also, anyone who has upgraded from a standard 997 intake to a 997 X51 intake should know this answer as if the diameters are not the same they are going to be getting false MAF reading that could cause their car to run too lean or too rich, unless they have someone write a custom program to adjust the MAF reading for the physical difference in intake diameter. Thanks, VMAN

Does anyone know if the 997 3.8 x51 uses a different airbox or maf sensor than a standard 3.8 engine. I have heard from people that the x51 has a unique maf, but my dealer shows that the maf's are the same for the 3.8 x51, 3.8 and 3.6 engines. Also, there seems to only be an airbox offered for the 3.8 engine, and not special one for the 3.8 x 51. Has anyone tried an evom intake with an 3.8 x51 motor instead of the stock airbox? Thanks, VMan

Thanks

Sadly I would say it the exception that a 99 996 motor lasts more than 60,000 miles and that you don't lose 2nd in your gear box. Locally of the 4 1999 996 owners I know that do some autocross, in a mature fashion...no clutch drops etc. 3 out of 4 of us have had intermediate shaft failures result in the need for engine replacement. I am in the painful process of having my car converted to a 997 3.8x51 as who knows how long 996 motors will remain cheap from the dealer and I am hoping the new motor will be an improvement as they have redesigned the intermediate shaft. The RMS leak is a minor inconvenience as it just costs a bit of change to put in a 997 seal, the problem with these motors is the block and intermediate shaft. VM

Does anyone know if a 997 x51 header can be replaced by a 996 custom made Scargo racing header...are the stock 996 and 997 x51 headers the same length and size? I just did an engine swap to a 3.8 x51 and am wondering if I need to buy new headers or if the old 996 headers racing Scargo headers will work...if not I will go with the stock x51 headers that came with the motor. Thanks, VM

Okay,after about 3 hours on the phone with the folks from Sachs, FVD, Aasco, TRG, and others here is what I think I know. It seems the AASCO Aluminum single mass flywheel is the way to go period. Even folks that don't say they use it tend to use it in their kits. Cost about $850-$1000 As far as pressure plates the Sachs Race Engineering High Pressure Plate is the way to go part number 883 082 999 736 Cost about $800-$1000. As far as clutch plates go the Unsprung Sachs Race Engineering Full Face Organic clutch with metaillic backing part number 881 864 999 957 seems to be the best for the performance oriented driver ie. 20% street 80% track or autox. Its full face makes it streetable, even in unsprung form, but you will have to live with increased driveline noise at idle. The above parts are good for up to turbo type horsepower, so should work fine for any hot rodded 996 or 997 (yes they are the same parts for 996 and 997). Issues: some folks prefer to use a sprung clutch with an aluminum single mass flywheel to keep it quiet under idle around town, there is a a school of thought that the spring part helps lessen the load on the tranmission and other parts of the car, the part about being easier on the transmission is not well documented or proven. The folks, like myself that live with sounds in our street legal race cars, are going to go with an unsprung clutch as it has less parts to break, with a full organic face is still streetable, and the clutch weighs in at about 1/2 that of the sprung clutch, less weight = less stress on car. Some folks suggested that even certain 6 puck sintered clutches are streetable and better for track only cars, I am not going to go that route as if a puck clutch breaks it tends to take out things like bell housing which are not replaceable on the 996 transmission. Watch out for cheap price kits that use light weight flywheels and cheaper sachs sport vs. sachs motorsports (race engineering) parts, they will not have proper pressure plates or use weaker clutch discs. Good luck, VM Chatters with the clutch disengaged...loader with AC on. I'm in a cab and it doesn't bother me, but it might bother some. Just engage the clutch and no more sound...or crank up the tunes!

Guys thanks for the feedback, I plan on calling TRG and the folks in CO tommorow. How much driveline noise are the folks with stage 2 sachs kits (ie. unspring but full face disc's) experiencing? Check with Austin from TRG. He may be able to help you. He is very knowledgable and supportive.

I have a 99 C2 that had an AASCO 80% grand am spec single mass flywheel with a stock sprung sachs clutch. After less than 5,000 miles including some autocross and track days it is gone. We have not done any big clutch drops, so the local shop thinks having a sprung flywheel and clutch is just not getting enough pressure so it is slipping too much. The question is what to do next, we have the whole car apart to put in a new motor 997 x51 motor and are going to replace the flywheel and clutch. The car needs to still be drivable on the street, ie. we can't create an on off switch type situation for the clutch engagement, yet we need a better solution than the above. Any one out there with experience with the Rs spec flywheels and organic linec sachs sport unsprung clutches? How about about using Sach motorsports clutches with metaillic pucks..has any one found any of those streetable? Thanks, VM

Does any one know where I can find a Tq and hp curve for the 996 3.4 liter motor. Note - I can't find the car's manual, and it does not seem to be on the download site. Thanks, V P.S. Does anyone know where I can find a TQ and HP curve for a 3.8 with X51, as you might tell, I blew my motor and am trying to decide which engine to replace it with.

Thanks

Anyoone have stats on the TQ increase if any of a 3.6 vs. 3.6 x51? Also, if anyone has some information on whether how the two torque curves compare that would be great. Thanks, Vman

Todd what is invovled in switching to a factory 7.8 dme. do you have to wire egas, do you have to reprogram the whole car to show up as a 2002 or later model ie. abs, instruments, airbags? Also, I may not end up having to use a variocam pllus external controller, to be confirmed, but I have heard variocam only affects sub 2,000 rpm operation, for racing use this would not be a problem, don't know what it would do to driving around town or if it would throw a check engine light.

When you say a 3.4 brain with a external controller box would not be OBD2 compliant are you saying that because you believe it will throw a check engine light? I assume that the 3.6 has a clean emission signature so it should not be the cause of an emissions problem. I will look at your posts on the boxster board...thanks

My 1999 C2 996 with 47,000 miles just died and started spitting up metal in the oil filter. The car has been well cared for by proven shops. I wish this were a joke that a Porsche blows a motor at 47,000 miles, even my dad's old Chrysler Cordoba went to 60,000 before giving up the ghost. At the time of failure their was proper oil and coolant in the car, it was cruising along the highway at 3,500 rpm's. Options 1)Send in the core and get a Porsche factory remanufactured engine $8K with core exchange + $2K warranty, by requiring us to send them an unopened core Porsche keeps to themselves what went wrong. The bigger issue is am I getting an improved motor with the new 3.4L. I talked to 3 dealers today who think but are not sure that the bearing (single) on the 3.4 is now bigger on the intermediate shaft, which could most likely have been the cause of failure. Has anything changed in the remanufactured 3.4 liter engine? I really don't want to spend $10K to get another failure in 50,000 more miles. While I get a 2 year warranty I don’t even come close to 5K miles per year on this car so it will not likely fail again until after the warranty is up. 2)Sell core to junkyard guys, buy a remanufactured 3.6L with x/51 engine for $11K no core exchange (you cannot exchange a 3.4 core on a 3.6), 3.6L is said to have two bearing around the intermediate shaft, and less prone to failure. Problem here is I need to convert from egas to mechanical throttle (can be done in UK by autofarm guys, but no one in the states seems to know how to do this, so far I all I know is I need to change the whole butterfly and center plastic that sits on the mainifold and then change over to mechanical unit anyone who has part numbers or a DIY on this I would really appreciate it). Also, with the 3.6L engine and 3.4 brain apparently you have to buy a break out box to control the cam lift solenoid and a control and link box to mate the 3.6 harness to the 3.4 liter brain (Autofarm in the UK sells a harness conversion for around $1,700). By the time we are done we are into this deal for about $15K, to make matters worse I just heard from several west coast Porsche shops that 3.6L are starting to fail almost as often as 3.4L. Does data exist on failure rates of 3.4 L vs. 3.6 L engine? While I get a 2 year warranty I don’t even come close to 5K miles per year on this car so it will not likely fail again until after the warranty is up. 3) Sell core to junkyard guys, but an engine 3.4 L or 3.7 L engine from autofarm cost of $11-$15K that has their stronger intermediate shaft http://www.autofarm.co.uk/engines/water_cooled/shaft_tech and sisileeve cylinder liners. Either motor will drop right in the 3.7 comes with an ECU map, but if the thing will pass smog in the US is an unknown, also in all deference to the good folks at autofarm I would be proving them right. Any comments on their technical merits of their products please let me know. All in cost with labor for this solution will be about $13K for a 3.4 L to $17K for 3.7L, including shipping my old core to europe. 4)4) Sell core to junkyard, buy a 997 3.8 L engine with X/51, find someone in the states that knows how to convert e-throttle to mechanical and wire a solution to use a 3.4 brain with breaker boxes to control the new variocam plus of the 2007 engine. I think this whole deal will cost about $20Kto $25K. The new engine block on the 2007 is said to be stouter and has a much reinforced intermediate shaft. Any comments or predictions on the increase in longevity on this solution and if anyone out there is known to be able to pull off the install or would be willing for a price to provide me with the parts and knowledge to have my local guys do this install please let me know. Thanks in Advance

Huge expense for little return, a good header like scargo, high flow cats, some lighter mufflers, and running ROW program on your factory DME will gain about 20-25 hp. From those that have spent the time on the dyno you may see another 5-10 from a custom program, but then you are tallking at least a couple of grand for a motronic and alot of $100per hour dyno time...race gas at 104 unleaded will get you another 5-10 hp running the above setup.

I have just set my car up for the track and as such replaced the airbag wheel with a sparco race wheel with no airbag. What is the best thing to do, currently the airbag warning light is on whenever the car is running. Is there a way to put a resistor in the airbag circuit so you don't get the warning light? Note - the car has 6 point harnesses, race seat with seat braces and a roll cage, so I really don ' t need the airbag. Thanks, P.S. With the light on are the side airbags and passenger airbags deactivated? VM

The right software map is in your porsche tech's Porshe System tester 2 it is called ROW software mode and does not look for the rear O2 sensor, also the program is a bit richer and matches really well with high flow 100 or 200 cel cats and high quality Scargo headers, we are seeing about 25 to 30 HP over stock, same set up running U.S. OBD 2 program had 20 hp less and when we tried a chip by one of the tuners it was even worse. Did you ever send the pipes back to Fabspeed as mentioned above, if not drop me a line as I would be happy to buy them and put them on a dyno to see what happens. RedRidge Using hi-flow (200-cell / 100-cell) cats requires a re-map to work properly for exactly the same reasons as a cat bypass. You are changing the operating parameters of the engine. If it flows more exhaust gas more easily as rpms and throttle openings increase then the timing requirement will be different. This effect will be less pronounced with free-flow cats than with a bypass as the increase in flow will be less. Whilst a properly re-mapped ECU will still bring the most benefit, the timing difference required may be small enough that you may still see (an albeit smaller) power increase with the standard map. As an aside (and just to confuse everyone for a moment.....!) we also have no way of knowing how 'accurate' the standard mapping might be. If it is particularly conservative (normal with many manufacturers for reliabililty) the standard timings may even turn out to be closer to the optimal real-world requirement with free-flow cats / headers etc. at some points in the load vs rpm range. This cannot be relied on however and you will certainly get inconsistent results with a standard map and modified components. What you DO gain by using high-flow cats is that the post-cat O2 sensors are now back in the loop correctly. I would recommend using 200-cell cats for road as they don't boom and resonate like 100-cells can. Phillip A worthwhile tuner will offer a range of packages that include known mods and an ECU to match. AFAIK, Fabspeed offers a range of modded ECUs to match their products. Please post the results back - it will be interesting to see how you get along. Ian Thanks Ian. I will let everyone know what I find out. As of now the pipes are going back to Fabspeed. Phillipj Just an update, I have not been getting any ECU light which is strange. :( :huh: I'm going to take the car to my mechanic and have him hook up the PST 2 to see if any codes show up. I'll let everyone know what I find out. Thanks for all the input I really appreciate it. Phillipj

Chasing a ghost..... Today I went back to the two wheeled dyno and the car spiked to over 14.5 airfuel ratio above 5,600 rpm, I was just about ready to spring for a motec or tec 3 ecu and rewire the whole car, then the dyno guy suggested we pull the abs fuse as sometimes even with traction control off the abs/abd system can do weird things on the dyno. With abs fuse pulled, the car averaged 12.5 air/fuel ratio above 5,600 rpm's, so it may have never had a problem in the first place. I am out about a grand in new maf's and fuel delivery, vac testing, and dyno time, but have peace of mind again. Also, it seems the K&N aircharger that I took off that is now in the trash added 7 hp and tq accross the board, but given the oil I found in it (even after letting it dry out over night before installatoin) I am glad it is gone. We added 5 gallons of 100 unleaded race gas to the remaining 3 or 4 gallons of 91 pump gas and found about 5 more hp and tq. I think race gas will not be part of the equation going forward given the fun in storing it in one's garage and dispensing with the cans. All the tests were run on a dyno dynamics dyno - eddy current type (supposedly much more accurate than a dynojet). The numbers.... The car put down 263 hp and 230 tq at the wheels (the gains came from scargo racing headers, high flow 100 cell cats, and switching from OBD2 to ROW DME program (richens up the car to take advantage of more freely breathing headers and cats). Note - the car with the same modifications and the US OBD2 program put down 240 hp on the the dyno. While these numbers may not sound great for those that have seen inflated dynoject dyno numbers ( my car has shown up to 278 hp at the wheels on a dynojet) we are confidant that we have increased real horsepower and torque accross the curve by 20-25, so now our little 3.4 Lis about where the 3.6 L starts out and the car is totally driveable. Note - we tried a custom ECU program from one of the common vendors and gave back 25 hp...so I have little faith in those chip guys, as they seem to be outdone by ROW software which is in your mechanics porsche system tester 2 and should cost you about an hour in labor to get to. Finally, testing has shown us that ROW software adds no measurable horsepower and TQ unless you change the restrictive stock headers and cats.