It isn't Fast Enough?


Whether you have the 201HP base ’97 Boxster or the 295HP ’07 Boxster S, you frequently hear that the car isn’t fast enough, the owner wants to make it faster. You see ads promising an easy path to more horsepower … up to 425 … up to 450 …

So what can you do to a Boxster to make it faster?

  1. Reprogram the Engine Control Unit to match any mods you make.
  2. Install a bigger engine (3.2, 3.4, 3.6, 3.8, 4 litre, X50, X51)
  3. Bore the block out , re-sleeve it, and install new pistons to increase displacement or stroke it to do the same.
  4. SuperCharge it
  5. TurboCharge it.
  6. Increase the air flow into the engine by removing any restrictions.
  7. Increase the air flow into the engine by decreasing the resistance provided by the air cleaner.
  8. Increase the ability of the engine to exhaust gases by:
    1. Installing headers that are shaped differently or are of a different diameter.
    2. Removing one of the catalytic converters on each side, replacing the remaining one with a less restrictive cat.
    3. Installing a less restrictive exhaust system
    4. Perhaps one which opens up more the higher the revs climb.

     9. Lighten the car 

    10. Reduce the load on the engine from accessories


      These ideas are bad for your wallet! Someone who did many of the above (all but 2 and 4) estimated it cost him $51k and around $200 per HP!! I know someone who will give you a 4 litre with 350 rear wheel horsepower (probably 400 coming off the engine) for about $30k and it will be driveable on the street.

      TINSTAAFL (There is no such thing as a free lunch.)

      And if you have a 2.5, you aren't going to be able to stay with a 500HP Vette on the straights no matter how many mods you do. Most of these mods short of those that increase displacement result in fairly modest HP gains that aren't going to really change the dynamics of the is a small displacement car and so will lack the torque that big displacement engines have.

      If more HP or Torque were that easy, the engineers at Porsche would probably be using the technique already (subject to the marketing strategy of keeping the Boxster/Cayman having less HP than the 911 variants and keeping the base Boxster less than the S).

      And some of these may be bad for the long term health of your engine. Or result in a car that is less street-drivable.

      Any of them will/may void any Porsche warranty (8.3 won’t if you use the Porsche Sports Exhaust PSE)).

      Many of the claims of the sellers of these products are not backed up by any evidence or the evidence is fraudulent. If it sounds too good, it probably isn’t.

      Research well, ask around. Don’t be the first. Ask for dyno proof. Do things in the right order.

      Consider improving the reliability of your engine first. If you have a base Boxster, install the S-model oil/water heat exchanger (bigger and more effective).  Install the LN low-temperature thermostat.  And if you have a base engine (2.5 or 2.7), consider the third radiator from an S and the bumper cover to go with it.  The idea of all these mods is to prepare your car to handle the additional heat that your mod'ed engine will produce.  

      Consider doing the IMS bearing replacement from LN/Flat6Info lest your expensively modified engine end up in pieces.

      So lets discuss these modifications one at a time.

      These comments are one man’s opinion. Ask on many of the online Boxster forums like Pedros or Renntech. There are people there who have done each of these mods and they have opinions and facts to supply to help you decide. You’ll have to sort out the “justify my decision BS” from the “facts” yourself.

      The “costs” assume you had the items professionally installed unless it is an easy do-it-yourself install of less than 1 hour.

      1. Reprogram the Engine Control Unit to match any mods you make.

      Generally involves taking the car to a shop that specializes in modifications and allowing them to install a new "chip" that is customized to the profile of the car as it exists at the time the shop is reprogramming it.

      Beware of cheap chips that claim to be owner installable as they aren’t going to be customized for your car with the options you have installed on your car and proved by a dyno test on your car. And those are the only kind worth anything.

      Recently, there have begun to be advertisements of what are known as Speed Mod Chips. They claim to boost HP by 10-20 and not void any warranty. And cost only ~$75. WRONG

      These aren't "chips" at all, only a resistor. Many of these "chips" are plugged into the IAT, or Intake Air Temperature Sensor connector. The IAT is a Thermistor that changes a reference voltage to the engine's computer. This voltage is translated onto a "temperature" and the computer will increase or decrease fuel delivery according to this temperature. Cold air is more dense and requires more fuel, hot air requires the opposite.

      This "chip" fools the computer into thinking the intake air is colder than it really is and consequently feeds more fuel into the combustion chamber. While many sellers state that the chip keeps fuel delivery within a certain "curve", this information means nothing. The modification essentially forces the engine to run rich all the time. The idea is more fuel equals more power. Unfortunately, rich running conditions will actually rob the engine of power, as the air/fuel ratio is far from ideal and will make combustion more difficult.

      Today's computer controlled engines rely on a battery of sensors to help it run properly.  If one sensor does not operate properly, the "runability" of the engine is adversely affected.  In the case of a constant rich condition, the oxygen sensors will recognize that there is unburned fuel in the exhaust (due to poor combustion from the bad air/fuel ratio).  They will command the engine to run lean in an attempt to correct the condition. (if the mod chip doesn't cause the engine to run OVERLY rich, the computer can negate all effects of the "chip" by LEANING the fuel ratio, making the mod useless!).  If the rich condition cannot be corrected by leaning the ratio, guess what?  You get a big, fat CHECK ENGINE light!  (They claim the mod won't trigger that, either!)  And if your vehicle is under warranty and the dealership finds that stupid little resistor where your IAT should be connected, you can KISS YOUR WARRANTY GOOD-BYE!

      If your vehicle is out of warranty and you ignore the light, more severe damage can occur.  The catalytic converter cannot cope with excessive amounts of unburned fuel and after a while of running rich and dumping raw fuel into the catalyst, the converter will be permanently damaged.  Raw fuel and poor combustion will also foul the plugs and foul plugs have high resistance.  High resistance can damage the ignition system!  Lastly, raw fuel can wash down and glaze the cylinders, and it can wash out the oil ring on the piston which will negatively affect piston lubrication and will cost compression.

      The bottom line is this: The "mod chips" DO NOT boost horsepower - the graphs they show are fake. They DO set the Check Engine Light.  They DO void the manufacturer's warranty.  And they CAN cause severe engine damage.  Anybody considering this cheap performance enhancing option should think again and invest in a real, professionally programmed performance enhancing chip that REALLY adjusts fuel and timing curves.  These pro chips cost more money for a reason: they work.  These cheap eBay "mod chips"  DO NOT.

      Good programming isn’t cheap.  Few things done right are.  Use a shop that has done Boxsters before, who will customize the chip to your exact car with its mods/options and who will dyno test before and after and show you the results of the re-programming on YOUR car.

      And do this after you have done all the other mods you are going to do so the chip's parameters can take into account the final state of the engine.  You don't want to pay twice.

      Ask about the affects of the chip on the pollution control testing done in your state.

      Cost: ~$???

      Results: Generally affects the top end performance of the car, the rev limits, the optimum fuel/air mixtures. Generally doesn’t affect the performance in normal street driving. Sometimes makes other mods more drivable. May allow you to run with higher octane gas (more expensive).

      Names:,, Autothority,,

      Do-It-Yourself: Some

      1. Install a bigger engine (3.2, 3.4, 3.6, 3.8 or 4.0 litre)

      Generally involves selecting either a new or used engine (from a wrecking yard) and about 30 hours of labor to install it.  Consider the clutch as a candidate for replacement at the same time.  Consider the condition of the transmission and ask if the trans you have is strong enough for the resultant HP/Torque or if you have to replace with a modified trans from the donor car.  Generally you don't have to replace the trans.

      Made easier if you chose a donor engine from the same DME revision as the car’s original engine as the original car’s wiring harness can be reused.

      Best done by a shop that specializes in this sort of modification and has done several before yours. Too many of these result in failed attempts and end up as baskets of parts instead of as satisfying-to-drive cars.

      A new from Porsche engine will cost more than one from a dismanteler but will come with all new accessories (alternator, starter, power steering pump, etc), all the updates that Porsche has added in 6+ years of production (like the new RMS!) and a 2 year warranty.

      When you upgrade the engine, be sure to add the center radiator (and bumper) from an S model for the additional cooling. It is present on all the larger engined Porsche's for a reason.

      Cost: $12k-$25k depending on the donor engine chosen, the source of the engine (new or used), the shop that does it and the other mods or repairs necessary.

      Result: A driveable car with up to 400HP. Maintainable. Recommended.

      Names: RUF, Sportec, FvD, Farnbacher Loles, 9ff, Orton, Jake Raby aka Flat6Innovations

      Issues are that Porsche has 2 kinds of control systems (non e-gas and e-gas) for their water cooled flat-6 engines. And converting between the two can be difficult and expensive. Which is why early Boxster non e-gas engine swaps are usually based on early non e-gas 996 3.4 engines.

      From the Softronic web site: "Softronic makes full install kits to convert a wide variety of Porsche cars. These kits include all hoses, mounts,gaskets, DME programming and required technical information for a complete install. All Softronics conversions are guaranteed to produce full power as specified by Porsche for such said engine. The converted cars are also fully emissions compliant in all states. Softronic offers conversion's that Porsche could have done yet did not., such as a 3.8S ,X51 or GT3 engine in either a Cayman or Boxster." for more information

      A .pdf from someone who has done it showing how.

      1. Bore the block out , re-sleeve it, and install new pistons to increase displacement.

      Or increase stroke, new pistons, new camshaft, re-program ECU (TechArt to boost 3.4 Cayman to 3.8)

      Increases displacement but results in an engine that doesn’t match the other components so consider ECU, air filter and air intake as well as headers and exhaust as things that should be done if you are going this route. Done by engine rebuilders that advertise in the Excellence or Panorama mags.

      Cost: ~$4k-$30k

      Results: Only heard of one 2.7 to 3.0 car this was done to and it was being sold. Don’t know what that tells you.


      Jake Raby aka Flat6Innovations

      Do-It-Yourself: I doubt it.

      1. SuperCharge it

      Increases the density of the air/fuel mixture burned inside the cylinder. Also increases the stress on the engine’s internal parts and the stress on the cooling system. Add the S's middle radiator and bumper. Consider ECU, air filter and air intake as well as headers and exhaust as things that should be done if you are going this route. Limit the boost to increase the chances that the engine holds together. Understand the cooling issues and don’t be shy about spending $$ on improving the cooling or insulation

      Cost: $3-4k



      Do-It-Yourself: No

      1. TurboCharge it.

      Increases the density of the air/fuel mixture burned inside the cylinder. Also increases the stress on the engine’s internal parts and the stress on the cooling system. Add the S's middle radiator. Consider the ECU, air filter and air intake as well as headers and exhaust as things that should be done if you are going this route. Limit the boost to increase the chances that the engine holds together. Understand the cooling issues and don’t be shy about spending $$ on improving the cooling or insulation.

      Cost: $3-4k



      Do-It-Yourself: No

      1. Increase the air flow into the engine by removing any restrictions.

      There are restrictions designed into the air intake on a Boxster to prevent the ingestion of stray leaves, cigarette buts, water, etc. and to quiet the noise to EU standards.  You can remove these by cutting them out or there are third party intake plumbing parts for sale.

      Cost: $0 to $600

      Result: More noise, more risk. A little less restriction. The Porsche engineers say the engine airflow is not limited by the intake.

      Names: Evo, powerflow Pedro

      Do-It-Yourself: Yes

      There is also a modification to the air intake plumbing that makes the air flow smoother. Called the Techno-Torque it modifies the internal shape of the T that distributes air to both sides of the engine from the air intake.

      Cost $230-250

      Result: Modest improvement

      Do-It-Yourself: Yes

      1. Increase the air flow into the engine by decreasing the resistance provided by the air cleaner.

      This is a controversial but easy and cheap mod.  Controversial because there is no way to increase the air flow without using an air filter that allows more and bigger dirt particles into the engine which increases the wear .

      The filter is most often one with larger holes that you coat with a thin film of oil to help trap the particles.  You must be very careful with how much oil you use as the Mass Air Flow Sensor (MAF) is downstream of the air filter and the oil film can contaminate the MAF causing a Check Engine Light (CEL) and a poorly running engine until the MAF is cleaned or replaced ($350 list part).

      Often done with exhaust system mods to allow the whole system to more effectively move the air both in and out.

      Cost: ~$80-$580.

      Result: Potentially more airflow. More engine wear.

      Name: K&N

      Do-It-Yourself: Yes

      There are larger throttle bodies and different intake plenums sold which give different characteristics to the sound and different flow characteristics. IPD and Pedro are sources. Parts from later model Porsches may also be adapted.

      1. Increase the ability of the engine to exhaust gases by:
        1. Installing headers that are shaped differently or are of a different larger diameter.  Ask if the headers are more or less effective at specific RPMs as the tuning of the intake and exhaust systems should match for best performance.  You could end up with a system that hurts you in the lower RPMs while helping in the upper ranges.

      Best done only if you are also doing the exhaust and perhaps other mods.


      Name: Schnell,,

      Do-It-Yourself: No as the bolts that connect the headers to the block are prone to seizing and breaking and you don't want to get half way through the installation and have broken bolts unless you know how to use a come-along to remove such bolts.

        1. Removing one of the catalytic converters.

      Early Boxsters had only one converter per bank.  Later ones had 2 per bank.  It is possible to install a less restrictive single converter but it may be illegal and cause you to fail emissions inspection (if your state has one).  I’ve heard of people having to reinstall the stock headers, cats and exhaust every year in order to pass inspections.  This is normally done as part of a total exhaust replacement, headers, cats, muffler.

      Cost: $???

      Result: Less restrictive exhaust. Emissions issues?

      Do-It-Yourself: Yes

        1. Installing a less restrictive exhaust system

      Porsche had a different muffler for the base and for the S as well as an optional muffler (Porsche Sports Exhaust aka PSE) that opens valves at certain back pressure and revs to allow a louder and deeper tone.  Both of these mufflers are very effective when compared to many of the aftermarket mufflers offered.   You can spend $3k for a muffler and not get a better muffler for HP/Torque.

      Some of the after market mufflers have a nice sound but a resonance at certain critical RPMs that is unacceptable to some ears.  Listen to one that someone else has, even drive in the car before you buy a muffler. You don't want to not be able to drive at a certain speed because of the resonance. You see lots of used mufflers for sale on eBay because people grew tired of them (or are turning a leased car in that they had the muffler installed on).

      In a test of several headers and 7 after-market exhaust systems on the same car via both dyno tests and road tests, only one of the combinations had a better power curve across the full range than stock.  When faced with which one to take home, the stock S exhaust system was chosen.

      The tester (Jake Raby an engine rebuilder with lots of resources) said:  

      "Over time I have tested most every exhaust system on most every size engine. I have yet to be impressed, either on the dyno or on the street.

      I have seen a 3K exhaust system cost an engine 20HP, or a set of cheap headers add 2HP to another. I have yet to see the gains that make the drone at cruise speeds or the cost worth it.

      This year ALL of my updated engines were fitted with OE mufflers, I carried out the development for my engine program and apply what works.

      If you like sound, go for it. If you want less weight, go for it.. If you want HP, reconsider. "

      Cost: ~$500-$2000 depending on brand.

      Result: Less back pressure, louder & deeper tone. Resonance? Ear damage over time.

      Do-It-Yourself: Yes

      Names: Porsche PSE, Gembella, RUF, Borla, Dansk,,, (Billy Boat), tubi, Remus,,

           9. Lighten the car and driver 

                             Robert from Sacrament posted:

                                gt3 seats,-20lbs(-25lbs if your seats are electric)
                                          New exhaust,-20lbs(-25lbs if you have the PSE)
                                          Braille battery,-20lbs
                                          Diet and exercise,-?lbs
                                          Lose the spare tire and tool kit,-25lbs
                                         Carrera Light weight wheels,-?lbs (I lost -30lbs when I swapped them with my                                                     Technology wheels)                                       

                                after this is all done the car is still driveable and will feel more nimble

      Doing several of these things at once can reduce the cost (if you are having the parts professionally installed) or work (if you are doing it yourself).

      Trading your current car in on a stock car with more HP may be a better economic move that trying to modify too much. And would result in a car that is engineered as opposed to added on to. And it would be maintainable and might even have a warranty.

      Modifications seldom return 10% of what they cost at resale time and can make the car hard to resell.

      Consider the need to upgrade the brakes, suspension and tires as you change the way the car accelerates. It could save your life and will result in a better balanced car. 

      10. Reduce drag from accessories

        Use a smaller pulley that simply reduces parasitic losses from your P/S pump, A/C compressor water pump and alternator so power gains occur at every RPM. The gains are small and there is less fast recharge and less battery power to run big stereo amps.


      How about improving the driver instead?

      It is one thing to improve the performance of the car itself, but quite another to improve your own driving skills to the point where you can get 100% out of the car you have.  Many Porsche clubs sponsor Driver Education (DE) days where you take your car to a race track and, after instruction sessions where you learn the track, the principles of driving fast safely, and the meanings of the flags and signals corner workers use, you go out on the track with an instructor who coaches you through the corners.  Generally, during a day you will get several track sessions and several discussions with the instructor.  The DE sessions are non-competitive and don't require all the safety equipment that open-track days require.

      Once you have done a DE, you begin thinking about more track time.  Now go looking for a helmet, roll-bar extensions, fire extinguisher, dedicated track wheels/tires and the like.  Not to mention track ready brake pads, suspension modifications, etc.  It can go on and on with you still learning and improving the car and driver even after years of doing this.

      All this without trying to make the car go faster or louder in a straight line, but faster around a track and faster than you did it the last time.

      It's not cheap once you get into serious race track time, but it sure is a lot of fun.  And it makes you a better street driver too.

      My feelings?

      First let me say that my feelings on the subject of "hot rodding a Boxster" are less important that yours.  It is your car and your $$$.

      Having said that, I bought the Boxster for its handling and balance, not for raw acceleration.  I could have bought a more powerful Porsche or a car with twice as much horsepower.  But either would have the potential for getting me in more trouble quicker and add little to the enjoyment I already feel when cruising with the top down or bending through the twisties.  I don’t track or autocross.

      Still I enjoy hearing about the modifications that are done by those that have the $$ and the inclination.  Good luck in your project.