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YOUR RESEARCH996 3.4L and 986S 3.2L differences
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difference is a combination of everything
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No successful repair reported for this finding.
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Likely the difference is a combination of everything.
Leading evidence: 'difference is a combination of everything' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, the most frequently mentioned possible cause is 'difference is a combination of everything' (1 discussions; 0 report identifying it and 1 suggest it). The most frequently discussed action is 'Test every car' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Suggestion
I have hundreds of comparisons of this from testing every car that we've performed an IMSR procedure on since 2007.
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Suggestion
can't use 911 exhaust on a 986 (points the wrong way) but the cheap chinese ebay stuff is fabspeed knockoff and works quite well, or 987 exhaust bolts pretty much right up and can be found as cheap take-off parts.
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Suggestion
996 or 997 intake plenum is a big improvement (allows use of 74 mm 996/997 throttle body; 3.2 comes with a 67 mm throttle body).
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Suggestion
can't use 911 exhaust on a 986 (points the wrong way) but the cheap chinese ebay stuff is fabspeed knockoff and works quite well, or 987 exhaust bolts pretty much right up and can be found as cheap take-off parts.
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So as some of you may know I know own both of these engines in their respective cars. I've always like having a convertible so now my Miata will be sold and I will keep the Boxster S. I really like the Boxster but the 50hp difference with the 996 is glaring. It's so obvious particularly after 5000 rpm. While the 996 pulls all the way to 7000 rpm the Boxster engine feels very ho hum after 5k. Is it the cams? 0.2L of displacement won't account for the difference I feel in these engines. Is it the heads? Any clues? Is the Boxster DME coding just that conservative? I'm really wondering at this point if a head/cam swap to 996 stuff would really wake up the Boxster 3.2. My instincts say very much yes.
heads are the same (different only to allow for different bore size). pretty sure cams are the same. depends on year, of course; the three variocam versions got introduced in different years between the 996 and 986/987.
engine is held back at intake, tune and exhaust. make it breathe better and it will wake up. for intake you can go OEM - airbox out of a 987 is a big improvement. 996 or 997 intake plenum is a big improvement (allows use of 74 mm 996/997 throttle body; 3.2 comes with a 67 mm throttle body). you can put 996 intake runners on the car, but that requires drilling the head for new mounting points (bosses are there as heads are almost the same) may require slight lowering of the engine, and a bit of fuel line and brake booster vacuum line re-routing. 987 maf holder allows you to push a factory 996 or 2004 SE flash onto your car depending on the year of it. can't use 911 exhaust on a 986 (points the wrong way) but the cheap chinese ebay stuff is fabspeed knockoff and works quite well, or 987 exhaust bolts pretty much right up and can be found as cheap take-off parts.
50HP is quite a bit.
That's about the HP difference between a C2 and a GT3.
But the real question is what does the HP and torque curve look like.
Likely the difference is a combination of everything. (intake, exhaust, tuning, displacement)
A bone stock 5 chain M96.213.2L Boxster will make 225-230HP at the rear wheels on our dynojet. A bone stock 5 chain M96.01/02/04 3.4 will make 240-248HP on the same dyno. I have hundreds of comparisons of this from testing every car that we've performed an IMSR procedure on since 2007.
Thats your differences between the two, and a lot of that comes from the factory crippled M96.21 Boxster intake plenum, and runners.
It could very well come to that in the end. I'm just trying to understand the differences right now. I could dyno both cars. Maybe I have a weak Boxster 3.2 and an unusually strong 3.4, but they feel a lot different to me. The sound sure is different too with the exhaust separated in the 996 and combined in the 986.
I appreciate the reply. It looks like 987 intake runners are affordable and it should be fairly easy to access in the Boxster. I will look into this swap more. I was already planning on addressing the muffler just because I really enjoy my flat 6 music. I have a set of Brombachers for my 996 that still need installed. It makes sense that the high rpm would feel weak if airflow were being restricted by the intake. The engine feels great in the mid range but just feels weak up top.
ARRRGGGHHH... here's to wishing the M96 and M97 were more like Legos with the same bolt patterns. So new we're really looking at upgrading the complete top end.
I have two engine swap kits along with engines,trans..etc turn key. One for V8 chevy and one for Pontiac supercharged v6, just throwing it out there
I haven't decided what I'm doing with my drive train yet and these are collecting dust. Both brand new and still in the box.
Brian
Maybe you�re right. I had a Boxster S and felt it was very close to my 3.4 996. Then again, I didn�t drive them back to back. The 911 is more powerful for sure, I can feel it.
Have you done any intake mods for air filter on the Boxster? That will help with the sound and feeling of power. The engine is closer to your ears in the Boxster. Makes for a more thrilling experience.
I drove both back to back and they both felt the same acceleration wise. However the Boxter had way better handling than the 996. If only didn't have that ugly rear end.
