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Hi and congrats on the 3.4 conversion. I also have a 98 boxster 3.4. I also noticed a little rougher idle between the 2.5 and 3.4 motor, but it is nothing to worry about. I have driven a few 3.4's and the stumble in idle seems common or normal. Just as long as the rpm's stay around 800-900 during idle. I also created a small spacer at the very end of the throttle cable where it attaches to the throttle body in order to take up some of the "slack" in the cable. It made a nice little difference in throttle response. As far as ECU... When I purchased my 996 3.4 engine (used, 18,000 miles on engine) we also got the 996 computer that came from the same car with that motor. Then added the "powerchip group" ecu upgrade. Now that I think about it, we had to also use a new key "computer chip" inside the key that the 996 ecu would recognize. same key blade, just different chip in head of key. I have had no problems or "check engine" lights since the conversion and 10,000 miles. 3.4 loves to rev up to 7200 rpm's all day long. Obviously our boxster rpm gauge shows redline at 6600, but the motor should pull even harder all the way to 7200 rpm. I agree with an earlier response as well... while the car is idling look inside the motor on the top at the intake manifold. There should be 2 "resonance" pipes connecting across the left and right intake manifolds. (2.5 liter motor only has 1) 1 resonance pipe is part of throttle body plenum, the 2nd one behind it has a little valve actuator arm that you should be able to see swing open when the rpms rev to over 3000 rpm. Rev the car slowly by twisting the throttle body where the cable attaches and see if the valve actuates. hi flow intake is a big plus. Especially when reving to 7200 rpm. 2.5 liter airbox is too small for those higer rpms. I saw a 10-15 hp increase between 5500-7000 rpm just from adding a cone high flow intake and modified intake pipe. I also modified the air pipe that goes to the throttle body. The stock 2.5 mid section has a lot of "crimps and restrictions" in it. I basically got my hands on a extra pipe, cut off the ends and used the ends to connect to the throttle body and "MAF" sensor housing, but cut out the middle and replaced it with a nice, smooth 3 inch diameter by 10 inch length section of pipe. I then used rubber couplers and hose clamps to connect the new sections together. It worked out great. similar to this design.. http://www.rahul.net/dennisp/boxster/boxst...ds-intake.shtml Dyno's... need to be taken with a grain of salt. I have seen 10-15 hp difference between 2 different dynojet locations even though temp and humidity were similar.. go figure. I would not be surprised if you are seeing 250-275 hp readings depending on dyno's. I purchased a "Gtech Pro RR" that is an in car "accelerometer" and measures g-force in order to give you 1/4 mile times and 0-60 mph times etc. Because that's what it comes down to, acceleration. Currently my 3.4 liter boxster measured these times on the Gtech Pro... with a good launch ofcourse... 0-60 ft 1.9 sec 0-60 mph 4.4 sec 0-100 mph 10.6 sec 0-130 mph 17.3 sec quater mile 12.8@110 mph. based on a online dyno calculator: http://www.corral.net/tech/brakehp.html I entered these values for my car 3000 lbs (2700 + driver+fluids) guess-tamate trap speed 110 mph elapsed time 12.8 seconds =318 hp crank and 280 hp at wheels... cool... I can live with that. This is what will drive you batty on dyno's...I have to admit I never really saw 280 hp at the wheels on any dynojet or dyno machine. Yet my acceleration times are still pretty fast. I really hope you get all the bugs ironed out and can really enjoy the ride. I just drove through the mountains this weekend and I love my 3.4 boxster. After my 3.4 conversion I made myself crazy trying to find 10-15 hp more because of my dyno readings being lower than expected... After you get all the bugs out you will get use to the additional power of the 3.4 all over again and then wish you could somehow afford a 3.6 liter gt3 engine in a boxster... The need for speed never ends ;^) best of luck. Bill

Hey Pete, Now that I have had the plenum on for a couple of months I am still really happy with how it "smoothed" out the power band. Dyno's are taken with a grain of salt. I recently found a different dyno jet shop closer to my house and had a dyno done a few days ago. There is a 10-15 hp power difference between the 2 dynojet shops.... Ofcourse you have to always consider outside temperature, fuel quality and all the misc factors that go into dynoing any car. No two days will ever be exactly the same.... The best thing I can say about the IPD Plenum is that there is a definite increase between 5000-6500rpm. This is where the power really smoothed out and stayed consistently higher than before the plenum was installed. I saw a 15-20 hp difference between 5000-6000 rpm. It was mostly due to the fact that prior to the plenum there was a dip or flat spot in power just before the resonator valve opens and vcam switches. The Plenum really helped smooth out that flat spot for me and increased the power. So for me the plenum was worth it. Outside of that rpm range the plenum increase for me is 5 maybe 10 horspower across the rest of the rpm range. I did some stopwatch times. I know these are not super accurate to press the stopwatch while driving, but still good to see a general idea of where the car is at performance wise.... 3.4 liter boxster. 0-60 mph = 4.4 sec. 0-100 mph = 10.8 sec. 0-130 mph = 19 sec. 0-150 mph = 29 sec.

Thanks so much Phillip for your feedback and input on installation tips. I installed the part last night and put about 60 miles on the car throughout the day. It did take about 20-30 miles of me getting on and off the gas for the ecu computer to pick up the new airflow change and WOW! What a great difference. My seat of the pants told me that the power curve really smoothed out a lot, especially between 5000-7000 rpm. The more I drove the stronger that pull got throughout the day. I then took it to the dyno today as well and I am very pleased. I saw a before and after change of 10 hp and 10 lbs of torque between 2000-5000 rpm. Then wow... from between 5000-6000 I gained 20 hp because my power curve use to flatten out right before the vario cam kicked in and now it just soars and keeps climbing through the old flat spot.. From 6000-7000 rpm the hp gap goes from 15 back to 10 hp up over the old curve... I really am impressed With the difference. Especially the smoothed out curve and 20 extra hp @ 5400 rpm. I wish it continued all the way through the rpm range, but I have to say I am a believer now. I paid about the same price for the powerchip upgrade, but only gained about 10-13 hp. This has to be one of the best and easiest upgrades yet. I am very happy with it and have seen and felt the real world difference of this product. Take care... just wanted to share my findings with you.. Billl

I finally got the kit from Carnewal after a 5 weeks wait. It seems the kit doesn't come with any bumstops and I'll take this opportunity to install new ones rather than re-use my existing ones. Is there anything else that's not included in this kit but would be a good time to get new ones rather than re-use the existing parts from the stock suspension? I want to make sure everything's in place before the swap begins.. Thanks. I ordered mine from Sunset Porsche and it took 3 weeks. It really must be luck of the draw with timing and parts being available in Germany.

Hey Mike, I went through the same thought process... I guess you would have to think more about it if you did not already own a boxster.... Now I mentioned that the cost could be $12-16 based on what you wanted to add, replace, or upgrade. I have met some that have had the work done for closer to $10k. $5000-6000 for motor and $5-6 k for labor... I spent a little extra on having some of those "tired parts" replaced new flywheel, engine mounts, suspension bits etc...etc.. That way I can feel that I have a great car in good condition for the next 5 years.... Now, if I were thinking of purchasing a boxster for the first time... then that's a different story. I would definitely go with the latest model I could afford and lean for the "S" model..... A 2002 Boxster S with an 3.6 conversian will net you a 2855 lbs Porsche with 325-340 hp for about $40,000 ...... The 2007 3.4 Boxster S or Cayman will be in for a surprise and You can get your wife a used Cayenne S with the money you saved.... that's kind of what I did :D So my 1998 3.4 Boxster has the performance and a bit quicker than new Cayman S and Boxster S... Still looks like new too... and is payed off! wooo hooo... another note... I agree the 3.4 liter conversion is more "pure porsche" compared to supercharge or turbos...

Hi Ali, I just had this conversion done a few months ago in Los Angeles. I have owned my arctic silver 1998 2.5 liter Boxster for over 7 years now. It is "the other woman" according to my lovely wife. Needless to say I love it and it is a hobby of mine to work on it and change out interior parts as well as exterior with stuff with more updated parts or go fast goodies. I currently have the 1999 tequipment aero kit on with 18 inch carrera lightweight wheels, 7 mm spacers and RoW M030 suspension upgrade from sunset Porsche as well as Gahh glass convertable top. Misc hacks done for a bit of minor speed upgrades were: --desnorkel air intake -- k&n air filter--power chip. I had the car dyno'd and it made a respectable 220 hp at crank. BUT... as you know, this car can handle so much more power... and I always dreamed of Ruf's 3400 power and reliability. So I went through a lot of research for a 3.4 conversion mechanic. I spoke with several shops and had several recommendations, including Ruf technicians.. Well with 93,000 miles on the 2.5 liter, it was time to buy a Cayman or upgrade my motor... There was something I love about my car and I could not part with it since I have made it my unique hobby. I finally wanted to give it the power it deserves. Plus... at weighing in at 2755 pounds and potential 320 hp.... it was a no brainer for me. First step: I got the 2000 3.4 motor from a good friend "Todd", owner of Los Angeles Porsche Dismantler. (818)-Porsche I was fortunate and we found one with only 18,000 miles on it. Todd was such a great resource of information and very professional, but very busy as well, so patience is key. I also got a boxster S front center radiator as well as Carrera 996 front brake calipers with rotors from Todd as well. He has hundreds of cars that have been totalled in crashes, but yet still have great parts left on them. A porsche enthusiasts buffet table! I later had the steel braided lines installed and system blead while motor was being installed.. The Carrera front brake calipers and rotors are same identical size that Boxter S uses...except painted black. I highly recommend upgrading the front brakes this way. The added hp power justifies the need for stopping power. Super easy installation... Hardest part was just bleeding the brake fluid.... and that is not that hard. 2nd step... Finding the right mechanic with a solid reputation and know how for 3.4 conversions. I finally ended up contacting Claudio Szyszkowski's shop... Foreign Sport Technicians in Santa Monica. 310-394-0369. I First read an article about Claudio in "Excellence Porsche Mag" June 2000 edition. He is Gemballa's go to man for Los Angeles. In the article he performed one of his first 3.4 conversions on a black 1999 boxster owned by Dale Launer. The article mentioned how reliable and "factory installed" the final product looked and drove. So I was already impressed with Claudio. Now, almost 7 years after the article was written, Todd from Porsche dismantler recommended Claudio as one of the mechanics he trusted and that I should contact and see about doing the install. I was pleasantly surprised and happy because I was really familiar with the article and Claudio's name. So I went to Claudio's shop and what do ya know, but the black 1999 boxster that Claudio did his first 3.4 conversion was there at his shop having maintenance and oil changed. He gave me a ride in it and I was hooked. It had lots of power and torque. The torque is not like a big V8 motor... but impressive none the less. Where this motor loves to be is above 3000 rpm. It just hauls *** and screams all the way to 7200 rpm. Claudio admitted that this car was like his prototype and he has learned a lot about the conversion process and what works best since then. He mentioned my car would likely be a bit stronger and faster. Mostly due to updated headers, powerchip upgrade, and I used a 2004 boxter S exhaust where dale still had the original 2.5 liter muffler. So the installation takes 3-4 weeks to be safe and take the right amount of care, preparation, and shake down. Claudio was very professional and allowed me to stop by any time to get quick updates or take photos. He makes fun of me now at how many photos I took. He called me when ever he found a part that needed replacing or just looked "tired" and was ready for replacement. Long story short.... The installation went great. I have had the car dyno'd again and it is making about 310-320 hp at the crank and 270 lbs of torque. Dyno's are a weird science...It is my daily driver and feels like I bought it from the factory with this motor in it. I recently got a Gtech Pro RR Gforce meter that measures time to speed and cornering performance here are my results: 60 foot time for launch on start.. 1.9 sec 0-60 mph 4.4 seconds. 0-100 mph 10.6 seconds... 0-130 mph 17.3 seconds 1/4 mile 12.8@110 mph. I love it! as far as price...??? really depends... but motor + install..... expect to pay $10-12k depending on parts, upgrades, and other stuff...

I may be interested, did it include the boot with horseshoe...qikqbn