Base vs S - weight
 

Looking thru ads there are alot more bases than Ss, probably 3 to 1.
I want an S, and from reading forums, that's what most Boxsterers prefer too.
For me it comes from driving a light, fun, tossable, but underpowered sports car
for years on end. I lived the 'slow car fast' mantra for over a decade, and I liked it.
But I've already played that song this set. I don't need a redux.

So I'm pretty set on an S from my personal history.
The question is, why so many base models, beside price of course?

What is the weight difference? I'm guessing less than 100 lbs.
Bigger rotors, heavier crank and connecting rods,
beefier drivetrain and suspension components. How much total?

Can you feel the weight?
Is the base model just marginally more light on its feet?
Is the power difference bigger than the weight loss?

And the engine - is it smoother? Does it rev higher?

What are the Bore/Stroke differences? Is the S just a longer stroke -
since you can't really bore it I'm guessing it's a stroke-only change
as that would be more cost-efficient than manufacturing two blocks.

I've read enough posts to see that most prefer the extra torque, as would I,
so I'm asking about handling and engine smoothness.

And any other differences you might notice, like is it louder?,
as you are always revving higher to get the power you want?


That's: weight, power, handling, bore/stroke, smoothness, decibels, anything else ...

Thanks.

The S is more than engine difference

For example on the 2000:
3.2Litre engine 250 HP, increased valves sizes.

6 speed manual trans, 5 speed Tiptronic optional.

Larger brakes.

Stronger wheel bearing carriers,larger bearings, longer control arms.

Larger 17” standard wheels.

Additional front radiator grill.

Left and right radiator inlets titanium.

Twin exhaust tailpipes.

Door sill trim.

Silver look trim in door pulls, lid openers, instrument bezel trim.

3-spoke steering wheel

Cloth headliner and changes to the top mechanism.

Subwoofer speaker system option.

Popular options grouped into packages.

Mike, I know about those differences (I posted that topic earlier). I want to know in what way those base/S differences affect the car - weight, handling, sound, engine smoothness, etc.

(I was reading your site for a couple of hours JUST before I posted this!)

My S is really lightly optioned, and weighed in at 2904 lb with a 1/4 tank and no driver.
I can't speak to a base model being more or less nimble, but I have driven mine rather aggressively on some very twisty two lane roads, piling into curves at twice the posted limit and I can safely say it's the most tossable car I've driven. It has way more grip than I have cojones.
The S model has a higher redline and the larger displacement comes from a larger bore.
I've driven a manual base a few times, and yes, you can lose your license in either car, but it will happen quicker in an S model. Driving dynamics are almost identical, just cornering and braking limits are a bit higher in the S model.

Bore differential, interesting. What are the bore/stroke of the two engines?

So that's either a different (heavier) block, or else the S has thinner cylinder walls.
Any problem there? - I would think the base has a stronger block in that case.
Maybe engine-quieter in that case?

Bigger rotors and heavier suspension components means harder stopping and cornering.
The base has a more comfortable ride then. How much more comfortable?

How did you weigh your 2904 lb 1/4-tank car?

I can't recall the bore/stroke measurements of the various engine displacements.
Allegedly, the 3.2 has the thickest cylinder material of all the M96 variants which explains the nearly non-existent occurrences of D chunking in those motors.
From my recollections, the base was slightly softer sprung than the S, but that would likely vary depending on suspension package options.
I parked my car on the scale at a feed mill to weigh it. They thought I was nuts for caring how much it weighed.

The M96 (986 and 996) blocks all have the same external dimensions. They were made as 2.5, 2.7, 3.2, 3.4, and 3.6 liter versions.

My 98 2.5 liter Boxster has a 3.6 variocam plus 996 motor.

See, that's why these questions are incisive. Paul says the blocks are all the same cast,
or at least the same external dimensions infers that. Which means the 3.6 would have much thinner cylinder walls than the 2.5 if they're simply bored out differently.

While Steve says the 3.2 reportedly has the thickest cylinder material of all the M96 variants. Which means it's not a larger bore out of the same block. Thicker walls could ONLY happen if the 3.2 was cut from a larger block. Also, I don't think the occurance of D-chunks would have anything to do with cylinder wall thickness. Explain how those two follow.

So you guys appear to be saying the opposite. Or maybe I'm just not understanding everything.

First things first. Are base and S blocks the same pre-boring?

Oh and Steve, I think you would be nuts for NOT caring about how much the car weighs.

Weight is THE SINGLE BIGGEST characteristic of a car.
It affects how the car accelerates, corners and stops.
What else affects all that? Not the engine, the suspension, or the brakes.

Boxx, if you want the lightest Boxster and prefer "slow car fast" a base Boxster is the route to go. Lightest car are going to be the 97 to 99s.

From what I've gathered, factory weight figures are:

Manual 2.5 = 2822lbs
Manual 3.2 = 2911lbs

No Porsche9. Like I said, I already played that song.
Now I'm very heavily biased towards an S.

I just want to see exactly how much that costs.
100 lbs isn't too much.

Boxxster, you got the name I tried to get!

OK, about 100lbs.
Now that's 2.5 and since I'm looking at 2003-04 it's actually between 2.7 and 3.2
It's still probably about 100lbs.

I think that could be felt a very little, while the horsepower difference
between Base and S would be more than a little.

Power to weight:

97-99 2.5L: 2822/201 = 14.0 lbs/hp (85.5mm bore x 72mm stroke for a slightly over-square layout)
2000 2.7L: 2778/217 = 12.8 lbs/hp (same bore as 2.5L but increased stroke by 6mm to reach 2.7L)
2000 3.2L: 2855/250 = 11.4 lbs/hp (same stroke as 2.7L but increase bore by 7.5mm to reach 3.2L)

There seem to be many different weights floating around the web. I got the weight & power from Excellence Magazine (manual transmission) and as you can see, the 2000 Boxster's were lighter overall than the 97-99 models (at least that is what this reference says): Boxster Specifications

Thanks thstone, those are good numbers.
Excellence should be a good source.

Overall car weight:
Boxxster has them at 89 lbs apart.
thstone has them at 77 lbs apart.

Just less than 100 lbs is a good rough figure,
and it's not really that much.

Interesting how they stroked the base motor to go from 2.5 to 2.7,
but then bore it for the big motor.

---- (mm) bore / stroke
2.5 ------- 85.5 / 72
2.7 ------- 85.5 / 78
3.2 ------- 93.0 / 78

Maybe this will help...


http://rennology.files.wordpress.com...ns-removal.jpg

My 3.2 figure is for a 03-04 S. Thstone's figure is for a pre facelift S. I didn't think there was a weight difference between the two but apparently there is!

03-04 manual 2.7 is (according to edmunds and a few others) 2811lbs. You were right in assuming ~100lbs.

That's a really cool picture Paul.

I thought the aluminum might be a little thicker
(it really does look about 7 or 8 mm).

What is the bottom half of that cylinder bank,
the part with the checkerboard cast?

^^

That's the oil sump.

Boring is usually something you do when you go to a bigger block.
And the 7.5mm bore increase seems like alot of aluminum to cut away.
I thought that was roughly how thick cylinder walls were in total.
Cutting half the cylinder wall away seems like bad mojo.
-- A 7.5mm bore increase seems like a different block.

On the other hand if an "S" has a bigger block, I would think
it would be more than 80 lbs heavier, especially considering
all the other heavier pieces like rotors and pistons adding weight.
80 lbs heavier total car doesn't seem like a heavier block.
Also, Paul said they were all the same exterior dimension.
-- Same dimensions and not much heavier seems like same block.

So which is it afficianodos?
- Is the "S" a different block, larger and heavier than the Base?
- Or does the "S" block have thinner cylinder walls than the Base.

It's got to be one of those two with a bore change.

Wow, it's almost half the engine width.
Integrated right in the block.

I don't know exactly where or when I read it,
but the Boxster motor seemed real oil-intensive.

Like it was oiled differently, and alot more.
Something like 9 quarts, which is about
twice as much as most 3 liters.

Check this out:

3rd assembly page - Page 3

You're getting hung up in old-school bore concepts.
The cylinder bores on these engines are varied size sleeves that are cast into the block when it's formed. The factory just substitutes different liners for different engine displacements.

He was getting there.... :cheers:

Wow, that is really good. I'm about 2/3 thru and I'm saving the rest for later.

I don't really get the crankshaft 'stroking process' that takes it from 2.5 to 2.9
by going from 72 to 78.4 on assembly page 1 (especially when going from 72 to 78
gets you from 2.5 to 2.7)? You don't just adjust a crankshaft, like with a screwdriver.

I'm going to guess that the 'stroking process' is a euphemism for 'buy and install
a new crankshaft'.

For MY 2004 the weights were:

Base manual 2811 lbs
S manual 2910 lbs

This Really helps!

http://986forum.com/forums/uploads02...1487348025.jpg

I don't really think I am getting hung up on concepts.

I assumed a liner when I got that the engine was aluminum.
The XK Jaguars of roughly the same timeframe used 'Nicasil' liners.
Nickel is a real hard metal.
(They had problems with this alloy but I can't remember exactly what.
Something to do with leaded gas maybe.)

Liners are fairly thin. You don't just shave 4mm off of a liner (8mm bore increase).
You don't start out with a 10mm thick liner. At least I don't think.
What you do is increase the aluminum cylinder size (bore)
and put a similar-thickness liner inside of that.

If you had a liner. But - that is not how Porsche does it.

They have some coating placed on the inside cylinder walls.
I forget the name, but it acts just like a liner.
I distinctly remember reading that is why you can't just rebore
a cylinder in a Boxster.

Cylinder liners are not for changing bore sizes.
And in a Boxster they are not for changing period.

Unless you can show me how, my question stands:
- Bigger block or thinner walls?

(And keep in mind, that is even if the Boxster had cylinder liners instead of cylinder lining.)

I'm not an engine expert, but it seems to me you could maintain the same cylinder wall thickness and block dimensions at the expense of smaller (narrower) cooling jackets?

Someone can probably correct me on this.

Acceleration also depends on the gear ratios being used and the 5 speed and 6 speed are quite different. Maybe a question to ask is how many gear changes do you need to get to speed x?

Maybe, but that would be a different block.

And if it was a different block, they probably wouldn't choose
to narrow the cooling jackets to increase bore size.

From wikipedia:

All 986 and 987 Boxsters use the M96, a water-cooled, horizontally opposed ("flat"), six-cylinder engine. It was Porsche's first water-cooled non-front engine. In the Boxster, it is placed mid-engine, while in the 911, rear-engine. The flat, mid-engine layout provides a low center of gravity, near-perfect weight distribution, and neutral handling. The engines had a number of failures, resulting in cracked or slipped cylinder liners, which were resolved by a minor redesign and better control of the casting process in late 1999. A failure for these early engines was a spate of porous engine blocks, as the manufacturer had difficulty in the casting process. In addition to causing problems with coolant and oil systems mingling fluids, it also resulted in Porsche's decision to repair faulty engines by boring out the cast sleeves on the cylinders where defects were noted in production and inserting new sleeves rather than scrapping the engine block. Normally, the cylinder walls are cast at the same time as the rest of the engine, this being the reason for adopting the casting technolog

Here's a little chart I've put together regarding M96/M97 engines. They all have a very similar block, except for the 996 GT3:

http://986forum.com/forums/uploads02...1487352474.jpg

Be careful comparing factory weight specs. Options can throw things off. Just a guess, but I'd bet that a fully loaded base 00-04 986 manual would weigh about the same as a really low option manual S model.
FWIW, somewhere I read that the 6sp is about 100 lbs heavier than the 5sp.
I don't know the weight of the tiptronic, but it wouldn't surprise me if it weighed the same or more than the 6sp.

The 996 GT-3 and 996 Turbo do not have M96/97 motors.

Thanks that really shows the casting differences.

03/04 S are 258 HP not 250

I can't speak to a base model being more or less nimble, but I have driven mine rather aggressively on some very twisty two lane roads, piling into curves at twice the posted limit and I can safely say it's the most tossable car I've driven. It has way more grip than I have cojones.

And where were you driving this fast Steve?
Not in Muskoka I hope. lol!

Cheers!

I plead the 5th....

I owned a '99 and a '01S. 201 and 250 HP. I never found much difference though I was not racing. The '99 was a bit more to my liking because you could put your foot down harder/longer without attracting government attention. Same tires were on both. Good tires and an alignment to match the type of driving you want to do make a world of difference. Likewise a freshened suspension, the right brake pads...

The 2.7 is a nice motor, it revs freely, sounds great, and has sufficient power. But then I have almost as much fun in my 924S as in any of my other Porsches.