Porsche 944
Submitted by Brian Miller
It’s nearly impossible to describe the Porsche 944 without comparing it to the Porsche 924. The 944 is very similar in design to the 924, but very different; in some ways, the opposite of the 924 in purpose. The 924 is a precisely balanced technical achievement--a fuel-efficient sports car with theoretically perfect handling. The 944 is a response to a marketplace demand for a 924 with more power and better brakes and more options.
If the 924 is a nerd, the 944 is a jock. If the 924 is technobeat, the 944 is new wave. If the 924 is punk, the 944 is goth. Where the 924 is a scientist, with an engine optimized for longevity and fuel efficiency, the 944 is an athlete. Those fender flares are the result of all those years working out at the gym, and the rear spoiler is the automotive equivalent of having your baseball cap on backwards.
Okay, so maybe I'm anthropomorphizing just a bit, but the point is that those front-engine water-cooled Porsches, arguably the most "American" of German cars, took an evolutionary step toward American style market-driven production with the evolution of the 924 into the 944. And that’s fine, actually.
Driving the 944 you do get the sense that you’re just driving a quieter, better behaved, but far more powerful 924. The 944's 2.5-liter, 150-horsepower, all-alloy 4-cylinder has counter-rotating balance shafts to harmonically cancel the natural vibrations of the engine, which make it a very smooth revving motor. Consequently, less power is wasted vibrating the engine, meaning less noise and more power to the wheels.
The 5-speed transaxle is set up the same as in the 4-speed in the 924, giving a similar feel around corners, although on my particular example the 924 corners better because it has much shorter tires. The engine is a bit of a trouble-maker, however, being an interference design which will self-destruct if your timing belt breaks. Oh well. That's the trouble with self-absorbed Goths, isn't it? Risk of suicide. Anyway, the car is kind of a monster which will peel rubber from a standstill, and will chirp the tires in motion in second gear--not that I'd ever do something like that.
One thing that kind of bothers me about the 944 is the sheer volume of options. In 1985, the 944 was nearly the cost of a base-model 911, and in order to justify this Porsche had to swamp it with options such as power windows, power hatch-release, (pointless) power sunroof, hydraulic clutch, power steering, etc. The effect of all these options is that you get to lug around all that gear which might break and is really unnecessary. The 924 had none of this; it had a manual sunroof, which was lighter and never breaks, manual windows which never break, and manual steering which is perfect in absolutely every way. Compare this with the 944's common problems, such as 944 power steering lines leaking onto suspension components.
Otherwise, the 944 is easy to live with. It starts as certainly as any fuel-injected Ford might, and gets almost respectable gas mileage depending on your driving style. My driving style doesn't lend itself to respectable gas mileage. It will travel through snow reasonably well on good tires, and starts at relatively cold temperatures (like -10 degrees Fahrenheit). Since I work on it myself, it hasn't been an incredibly expensive car. For the most part, it needed cosmetic fixing up and some mechanical work. This car has a new head, apparently the result of some previous bad luck with a timing belt. I'm not surprised or worried though, because it's common for owners to not know about the timing belt and therefore neglect it. Interestingly, there are some unique options and optional accessories such as a Porsche-designed roof rack for carrying a canoe, ski rack, snowshoes, and the like.
Disturbingly practical, yet with a huge amount of Teutonic bling, the 944 is a car with quiet power: a refined, aesthetic appeal that doesn't quite equal the raw visceral fun of its predecessor. The black 944 pictured above is a pristine 1983 example that was recently for sale on eBay, and the garnet red one here is my own 1984 944.
--Brian Miller
Note from Chris:
This is Brian's post, but since the 944 is a sentimental favorite of mine I wanted to add a few thoughts as well.
When I was a kid, no matter what piece of automotive exotica I was coveting any given week, there was always one constant--the Porsche 944. The 944 wasn't quite as otherworldy as most kids' dream cars, but while those cars existed only in fevered fantasy, the 944 had the grounding touch of reality that made it a far more vital and real piece of my automotive background. You see, my friend's father owned a purple Porsche 944, and he wasn't shy about giving his son's friends rides at exhileratingly high speeds through windy canyon roads. That was my first, mesmerizing encounter with that addicting drug speed--far more potent than its chemical namesake.
It's easy to scoff at that today, since that 944 was powered by a normally aspirated four-cylinder and by today's standards wasn't terrifically fast. But at the time our family car was a Buick LeSabre. The 944 was a Porsche that we got to ride in at high speeds, and that alone was enough to fan the flames of pre-teen admiration.
Even today, now that I own a family sedan that has more power than that Porsche, I'm still taken with the 944--its awesome molded rubber rear spoiler, its hidden headlights and purposeful front view, and, of course, the sweet handling and precise steering that made the 944 one of the best-handling cars of its erea. The 944 was a sweet, nice car that just happened to be a terrific performer. For any kid lucky enough to be pinned to his seat, open-mouthed, as the 944 toyed with the laws of physics at high speed, it was an instant legend.
Mochi Mochi on June 30, 2008 at 07:58 PM
Brian your post is an inspiration - I've gone back to my physics and thermodynamics books. Leaving aside the wonderful opportunity for a drag race (let's throw in a 924S and a 944 with a blown exhaust - just for fun), maybe this will help. I found a few links regarding the affects of Rotational Inertia and Mass on measured horse power. The first link is probably the most readable and generally a good summary - without getting into equations, physics, and thermodynamics.
http://news.carjunky.com/automotive/Rotational_Mass.shtml
"Reducing 10 lbs of weight from parts that rotate at engine speed (crankshaft, flywheel, etc.) will have more benefits than reducing 10 lbs of weight from parts that rotate at axle speed (hub, rotor, wheel/tire, etc.) This somewhat relates to drivetrain loss, which most people are familiar with."
[Mochi: This is in part due to the fact that the rotational speed of a crankshaft is much higher than the rest of the drive train.]
Jonathan Kervin from KervinRacing.com goes on...
"However, even reducing the weight of parts that rotate at axle speed, still far outweighs the benefits of reducing weight from non-rotating parts.
My 2002 Kia Rio [ mochi: any time you can get a Kia Rio and a 944 in the same post you are doing well ] in stock form was rated at 96 HP at the crank, but dynoed at a mere 76 HP at the wheels. Though there are other factors involved in getting power to the ground, such as spring rates and aerodynamics, rotational mass is a major factor in the significant difference between crank horsepower and wheel horsepower. [ mochi: not to mention all the friction losses along the way ]
Another real world example of rotational mass that I was not pleased to learn was that my new tires and wheels were 4 lbs heavier on each corner and I actually dynoed lower HP and torque numbers at the wheels. So, if you have bigger wheels than your factory set, you will most likely make your car more powerful by swapping in your old tires/wheels. "
The next links are to car forums which seem to follow - motorheads and math - I love it:
http://www.physicsforums.com/archive/index.php/t-52827.html
out take from the conversation about calculating the benefits of lightening a flywheel:
pgt95: "Ok guys i still haven't gotten numbers to work out for me.
1: How can i calculate Radians from RPM and time, say i have an acceleration of 3,000 RPM in 1.5 seconds, how do i convert?
2. I know moment of inertia = .5Mr^2 but russ's numbers don't work out so i need to make sure i got this right.
He has Your flywheels are a little under 6 inches in diameter, but probably have more mass out toward the edges, so we'll assume 6 inches. That gives a moment of inertia of 1.1 and 2.9lb-ft
Now in my book .5*9lbs*3inches^2=1.1 but by my math it equals 40.5 so i divided the 9lbs by 23 to convert ot mass and got:
.5*(9lbs/32)*3inches^2=1.76
As well for the 23lb flywheel he got 2.9 and I get 3.2. Some one lemme know if i am missing something please?
My final figures ar as follows:
Weight stock 23lbs
Weight light 9lbs
Diameter is 11.5 Inches, radius 5.75
So i SHOULD get 11.847 and 4.63 respectively, at least by my math... check me out guys and hook a brotha up!"
Integral: "the first error I see is you are using Russ's erroneous conversion of 250mm, the correct number for your radius is 9.8in (the precise number is posted).
3000 RPM is 3000 * 2 \pi = 6000 \pi /min
or ~100 \pi /s now to get
\alpha = \omega /t = 100 \pi / 1.5
The units on that would be in Radians per second squared.
Russ did not convert 250mm correctly see some of the previous posts 250mm is just less then 10in.
I still think you should be converting to metric, then finally convert the last result to HP."
Brian on July 01, 2008 at 01:15 AM
I didn't expect a link to www.physicsforums.com, my old stomping ground for years & years. I do think you're on the right track here, but what I think needs to be compared is the energy to vibrate the engine around on one side, versus the energy saved by not having the belt on. i.e., if it takes more energy to vibrate the motor than you save by losing the belt, you're not getting more power by removing the belt. I'm guessing that at high RPM, the vibrations are minimal (relatively), and so you would be gaining some power by reducing rotating mass. However, at the bottom half of the power band where most of the street driving takes place, the vibrations would rob any power gains you get by removing the belt. Plus your engine would last about a week.
BTW please don't put too much faith in Mr. Russ Waters.
Maverick on July 01, 2008 at 08:46 AM
On the 924 Turbo:
The 924 turbo, also known as the 931, which was Porsche's project designation, used the early 924 chassis and drive train, but with several important improvements. Though it used the 2.0 liter Audi engine, the pistons were uprated and compression lowered (between 7.0:1 and 8.5:1 depending year of production) otherwise the block is essentially the same, and indeed interchangeable with normally aspirated 924. The big improvement was in the cylinder head, which was completely reworked, allowing much more flow, and placing the spark plugs inboard. The biggest go factor was the addition of the kkk26 turbo charger, which was improved upon late in the run (series two cars) by actually reducing its size. This combined with digital electronic engine management, a freer flowing exhaust, and improved engine cooling resulted in 150-177 hp output, depending on year and region of sale. The trans-Axel was beefed up with a thicker central shaft, and hydraulic brake and clutch were added.
The body remained essentially the same as the n/a 924, with the exception of the hood where a naca duct was added to allow heat to escape. The chin spoiler was upgraded to a vented version to direct airflow to the oil cooler, and a small rear spoiler was added to the hatch to improve down force and handling. A rear flair package was also added, with matching rocker covers (rubber and plastic)The resulting CD was a very respectable .33 -.35, depending on what test you read.
Inside the 931 was Identical to the n/a 924, though some received "924 turbo" door sill decals.
the suspension on early 931's is the same 4 bolt set up as the standard 924, though an improved five bolt set up was optional , then later standard on series two models. My 82 averages 27 mpg in mixed driving, when its not in 200 pieces in my garage at least.. :)
The 924 turbo was killed off in 1982, when the 944 was introduced. Sales were low and the price had risen beyond the models appeal. In addition, the 82 924 turbo was both faster and lighter than the 944,AND the base model 911, something Porsche did their best to repress, given the new model marketing efforts. Theres more, actually allot more, but these are the basics of the 931..
Porsche Cars, Products and LifeStyle on July 01, 2008 at 04:40 PM
Brian,
What a fantastically well written article. While I'm more of a 911 guy, I appreciate the entire Porsche line-up.
Regards,
993C4S
C_A_T on July 01, 2008 at 06:00 PM
Brian,
I think you're missing the point I originally made. Balance shafts quell vibration by creating a shaking force 180 deg out of phase with the original vibration. This is normally done by using balance shafts that rotate at twice engine speed. The more shaking that the unbalanced engine does, the more inertia these balance shafts must have (either through added mass, or locating that mass further from the axis of rotation). There are many benefits to counteracting the original vibration (not least of which is reduced fatigue on engine parts), but power improvements aren't one of them.
Here's another way to think of it. The original shaking force is being created by the movement of the pistons and rods (I4s have great primary balance, but poor secondary balance). When you add a balance shaft(s), you haven't reduced those forces from the pistons and rods, the energy is still being spent. But you do pour energy into the balance system. Or, think of noise cancellation. Aiming sound waves 180 deg out of phase to the original waves results in reduced noise, but you require additional energy above and beyond that required to create the original sound.
My company dyno tunes in excess of 1000 cars per year, and a majority of those cars use small displacement 4cyl engines. When you remove the balance shafts on a Mitsu 4G63, or a Nissan QR25DE, or a Honda K24A2 or K20Z3, you will see gains. Honda themselves claimed 6-7 hp lost from the addition of balancer shafts when they went from an non balance shaft motor in the K20Z3 to a balance shaft equipped engine in the K20Z3.
Brian on July 01, 2008 at 11:59 PM
Well, there you go, I stand corrected. However, as you said, HP gains are fairly small compared to the considerable cost of rebuilding your engine frequently. It ain't something I'm planning on doing with anything I'd be driving every day. I'm not entirely convinced, still holding out for the balance belt vs. non-balance belt drag race.
Frank on July 02, 2008 at 11:00 AM
In a year long gone, I returned from overseas and spent an idle couple of hours to watch Middle-Age Crazy on a big screen. After the hero slipped a cog just before his 40th birthday, the background music transitioned to: "He traded in his Olds on a Porsche 944."
He discovered that a hot car was not the elixir of youth -- but it did play a role in his "further education," as they say.
He should have paid more attention to Ann Margaret.
Worth a watch on DVD.
fm
JimW on July 07, 2008 at 08:01 AM
Chris, you remember the 944 fun in Buda TX, but not the belt that failed less than 4,000 miles after the dealer's 30,000 checkup. That was just a year before Porsche changed the "check" to "change" on the waranty to-do list. As a consequence, I had to pay nearly $6,000 for the new head, valves and rods because the waranty expired at 30,000.
Fun to drive, but a spoiled, beautiful woman who dumped on my bank account regularly--new tires because she'd do a 180 on damp pavement; new water pump (@ nearly $500 because it was a thing of beauty, a Teutonic precision milled of brass and aluminum vs. the $75 on Joanne's Volvo); new motor mounts; new radiator.
So she's been gone now for 20 years, a bitter-sweet memory.
JW
ps--the 924 was some sleeker (the fender flares on the 944 finally grew on me), but originally it had an Audi 4-cylinder stuffed in sidways that was routinely grounded for engine problems--who knew Porsche of all people would screw that up.
Chris Hafner on July 07, 2008 at 10:57 AM
Jim, it's fantastic to hear from you. I'm sorry to hear the 944 was so expensive - that $6,000 is a pretty eye-watering pill to swallow, especially only 35,000 miles in. But, speaking for all of us boys, we were glad you had it. It was a gorgeous car.
PATRICK/PORSCHE MOTORSPORTS on July 11, 2008 at 05:46 PM
S
PATRICK/PORSCHE MOTORSPORTS on July 11, 2008 at 06:03 PM
In regards to the balance shafts, the power they rob is actually negligible. Our dynos show a mean loss of 2.73 @ the rear wheels. Simple A/F ratio adjustments easily restore (and improve) this lost power. Not sure if anyone here has actually driven a 944s or 951 (944 turbo) w/o operable b shafts...don't...it is awful. Also I am not sure about the earlier claim of parts being very expensive...since the evolution of parts "netting" 944/951 parts have actually decreased about 20% over the last 2-3 years. I offer this: the 17 (minimum 3 year service history) 944/951's we service (103,256 mean mileage) have averaged a mere $217.86 per year in maint. cost (this does not reflect wear items...tires/brake pads...but does include belts/hoses). And the best news....for around $2K we can add 85-105 HP @ the rear wheels!!!! It is amazingly easy to get more power out of the 944/951's...that is what makes them so fun to have and race. Great blog guys.
Brian on July 23, 2008 at 08:16 PM
It's been a while, but I thought it would be an appropriate place to show off our vacation video, with a good number of photos of me & my wife & my 944 running through some impressive mountain vistas in Alaska:
http://www.denalidrafting.com/Rally/Greatland_Rally_2008_big.wmv
Chris on August 12, 2008 at 07:52 PM
Wow: have spent countless hours searching on google and Yahoo for recomendations on improving NA 944 1985 Euro performance. You know .... Porting, Balancing,Blueprinting, Injectors,Head Mods, Aftermarket heads, Intakes.. Real HOT ROD TECH we can do at home. Let's see I can get a KN filter and some headers and a chip...Oh. And my favorite...a throttle cam to make it feel more responsive for about *$3k and about 15hp. Not enough for the money. NO2...No Thanks...Its a road car not a rice racer. Anybody else fed up with the fact that the web is clogged by people wanting to sell us air filters? Found these at every site and little else no matter what I typed into the search. Help before I buy a Vette....
Brian on October 24, 2008 at 04:53 PM
I think that the best thing you can do is to install a 16 valve head on an originally 8 valve engine ;)
Duende on November 29, 2008 at 06:48 PM
Well, the BEST thing you can do is put a LS1 in there.
manohar nagrani on March 03, 2009 at 03:10 AM
thnks this is fantstic car,
i mlooking for the computer ingnition parts which controls the electric system of the car,
where i can find out, used one,
pls inform me ,
005076656 3555
msn manoharnagrani@hotmail.com
skype mikemike950
my work 507 4412525 , 4414965
thnks,
manohar nagrani on March 03, 2009 at 03:16 AM
some body robbed my computer car parts,,,
ignition compueter which control the whole elctrical system,
pls inform me the best, way how to ge t which web site for 944turbo
few more parts i need,
motor, glass of electrical window up down,
vipers of the front and back,
seats
never give again to any paint shop, porsche
most of the decoration sides are really paint shops r not serious people in panama here thnk,
manohar nagrani,
panama .
0057 6656 3555
paul d on April 18, 2010 at 07:06 AM
i just got a 85 944 pre turbo, i too grew up looking at these cars and thinking so what, its not a 911, but now that im 38 and own one and drive it around when i can, wow what a car, not the fastest from 0-60, but one of the fastest from 0-60 around a hair-pin. talk about a fun car, i have had a lot of classics in the past but none of them as cool and fun as this thing, it looks good, and you can literally have a conversation in it while sliding it sideways around a corner, and yes i have done that. it is an amazing handling machine. i got lucky when i picked this one up, it only has 87000 on it, but it needs paint, and ill get to that. i am planing on having this car for a long while, until i can pick up a boxter.
ThePorscheGuys on August 08, 2010 at 11:56 PM
I have a 1983 Porsche 944 that has been a great car for me. It isn't incredibly slow, but won't blow away most newer sports cars. Mine has had a bit of weight reduction, so it is a bit quicker off the line, but at best it can get 0-60 in 7 seconds with about 200lbs of weight reduction (all non rotational sprung weight, so I have more weight reduction to do). Even though it isn't very fast in a straight line, it can beat almost anything in the corners and that is why they do very well in Autocross.