difference between 986 vs 987?

[SoNiC]

I was wondering what is the different between the 987 2.7L engine vs. the 986 1st gen 2.7L engine?

Is it the same block with alittle bit of change to gain the extra HP?

VarioCam could be one of the major differences. This adds to the HP.

[Rail26]

One difference to note is that the 987 ends in a 7 while the 986 ends with a 6. That equals more horsepower also.

[SD987]

Rail26 provides a nice summary, but off the top of my head, I'd say the specific differences between the two engines are:

* 987 crankcase has a fully aluminum bearing saddle for a reduction in weight vs the 986 which has cast iron inserts

* 987 crankcase has a deeper central hole for a .7 lb reduction in weight

* The tensioning rollers and deflection pulleys in the 987 belt drive are made of plastic in engines with a manual gearbox while the 986 are made of steel

* 987 has a new air cleaner with new housing

* 987 resonance intake system has a twin-branch distribution pipe with intake-manifold flap

* The electric fans in the engine compartment of the 987 are infinitely adjustable where the 986 fans are two-stage

* 987 exhaust sytem has lower gas back pressure due to larger cross sections and damping of drive-related vibrations by heat-resistant damping elements among other things

* 987 standard manifold is lighter

* 986 3-way catalytic converter has one converter left and right, where the 987 has one pre- and one main catalytic converter left and right (the lightest catalytic converters in the world)

* 987 silencer is lighter with improved flow rate; and 2 parallel silencers with crossover pipe and integrated main catalytic converter

* 987 water pump has an optimised impeller for increased flow rate and improved component cooling

* 987 water bearing casing is plastic and flow-optimised, where the 986 is die-cast aluminum and 1.9 lbs. heavier

* 987 tandem pump has a vacuum for brake boosting provided by a mechanical vacuum pump where the 986 has a sucking jet pump and vacuum reservoir

* 987 oil extraction pump has lower frictional losses and higher delivery capacity

* 987 doesn't have an oil dipstick (which saves .39 lbs(

* 987 radiator air flow is closed, directing air to the front wheel housings where the 986 is open, directing air in front of the wheel housings

* 987 radiator fan control is continuous, where the 986 is two-stage

* 987 engine compartment scavenging blower is dependent on intake air and ambient air temperature, where the 986 is dependent on intake air only

* 987 secondary air pump is fastened directly to the engine where the pump in the 986 is fastened to the body

* The 987 generator cranks out 420 more w (2100 to 1680)

* The 987 uses motronic 7.8/40 DME which has enhanced computing and memory capacity

* 987 engine weighs about 10lbs less in manual and 12 lbs less in auto but produces 12 more hp, 7 lbft more torque with a 3kW increase in specific output

That's all that comes to mind, but if I thought about it for awhile I might come up with a few more differences.

[FIG]

Originally Posted by SD987

* 987 doesn't have an oil dipstick (which saves .39 lbs(

[racer_troy]

Sonic,

I'm a little fuzzy...but I think I can add some benefit to this conversation...

Firstly, bmussatti is right...the first significant upgrade to the original 2.7's (7.8.2, variocam, twin resonance induction, 4 cat system, 217bhp) release came in MY03 when VarioCam was upgraded (2.5's had 5.8.x, variocam, 2 cats, 201bhp). Power increased to 225bhp and I think there was a slight bump in mpg from the 25-26 original. Oddly enough, torque ratings remained essentially the same. Also, the MY03's got a new exhaust system under the auspies of sound, but I'm not sure if this didn't really add to the power output as well. I've heard that the tell-tale dimple from the earlier 2.7L header system was removed. This dimple seems to have no other purpose other than to choke down the exhaust system prior to entry to the primary cats. Albeit rumor, street beat says that a 232bhp base model may have encroched on sales of a 250bhp S.


MY05 2.7's benefitted from varioram (same system proven in the 996's). Varioram consisted of a 3 length intake system that the Motronic would choose depending on engine loads and chassi and driver inputs and is likely responsible for the majority of the +15bhp over MY03. FWIW, I think here is where we also saw the upgrade from the Motronic 7.8.2 to the below mentioned 7.8.4.

MY07 sees the incorporation of variocam plus (continuously variable rather than 2 profile cam lock-out available with variocam). +5bhp

Hope this helps...most of this is from memory when I was researching my 986 purchase. If I've something amiss, please correct.

Cheers,

--troy

[RandallNeighbour]

Sonic, are you asking this to determine whether to trade up or buy a 987 compared to a 986?

lets not forget that the 987 is a new model and everything that the 986 lacked, the 987 has. the 987 is a better car then the 986.

i really love the front end of the new boxster's....gorgeous.

[racer_troy]

...the x51 upgrade...i think mine is lacking appx 200bhp and 200ftlbs...no 987's i've heard of have made up this gap..........yet....


...still waiting

--troy

[SoNiC]

The reason why i was asking...is my boxster is currently at the dealer getting service. I was thinking about motor swap....and i know most people go with the 3.2. But I was just wondering what is the difference between the old 2.7 and the new 2.7. Maybe I could update my old 2.7 to the newer version of the 2.7.

[TriGem2k]

Originally Posted by SoNiC

Maybe I could update my old 2.7 to the newer version of the 2.7.

Well that would just be a waste of money now wouldnt it.

[Adam]

Originally Posted by TriGem2k

Well that would just be a waste of money now wouldnt it.

Word If you are going to swap, bump up the damn displacement!