US944 to European Spec

[CJFusco]

I just read a post on this board about bringing the US 931 up to European Horsepower with only minor modifications. Does the same go with the 944? My US 944 is rated at 143hp, but the European version has a much-beefier 160... how do I get mine to European-level power?

[1.2gees]

On the 944 NA, you'd need to change pistons, raise compression, remove cat, etc.

Not easy HP, but I think there are other things to get power from. I'm working on mine, within a few months it should be concluded, I've tried a variety of things on this car.
Ahmet

------------------
It's all the driver...

[TheStig]

There are a variety of things to do in order to get your car to european level:

1. DME brain has an adjustment knob that is accessable behind a small plug either metal or rubber depending on the year of your car. the knob is actually contolled by a tool similar to an allen wrench but a more square shape. The FAQs by KGross say to use a golf tee to adjust it but I used a flathead screwdriver to set mine. I dont remember what the throttle positions are but look up the 944 FAqs on the internet to find out.

2. Your exhaust and airbox are very restrictive, especially the catalyst. I reccomend a test pipe to replace your catalyst. Also get headers. The stock exhaust isn't that restrictive on the car since it is used by both the US and Euro versions. Look into a cone filter intake too for better airflow.

3. The ignition system is already good on both cars but I used the aftermarked Nology ignition system (profire coil, powercore spark amp, hot wires ignition wires) to obtain my dynoed 167 HP as well as my cone filter, DME adjustment, and the test pipe that i had on at the time.

4. REMEMBER YOUR CAR WILL NO LONGER BE SMOG LEGAL IF YOU WISH TO PERFORM A EUROSPEC PROJECT.

There is a lot more stuff to do on these cars to get them past european specifications. I just noticed a post about larger pulleys so i may look into that too.

Good luck 944 owner

------------------
Sorry Officer, my bag of crack fell and while trying to reach it my gun got wedged in between the gas and the brake causing me to speed insanely.

[TheStig]

Ahmet the compression on the Euros is 10.0:1 right??? If i recall i think it is....I've looked into some 10.2:1 and 11.0:1 pistons available at EBS Racing.

------------------
Sorry Officer, my bag of crack fell and while trying to reach it my gun got wedged in between the gas and the brake causing me to speed insanely.

[1.2gees]

The DME adjustments are NOT a source for power, they're there to simply compensate for bad fuel. Stock setting isn't too far from maximizing power anyway. The European cars had different programming on the DME (and KLR if on a turbo) EPROM chips (Swiss and Australian cars yet again different, and so were the California cars)!

I agree that catalytic converter is the biggest restriction in the exhaust (like the AFM is in the intake, as I will discuss later). Removing the cat is no source for free power, it'll make the car noticeably louder (but nice sounding IMO), and shoot some of the emissions up. A 944 in well state of tune (including good compression, no vacuum leaks, working oxygen sensor, etc.) WILL pass emissions without a cat. I don't recommend the Bursch unit, the construction quality is low, but even more importantly, the 2-1 piping on it is NOT tuned. The resonator is not quite free flowing as it should be either. I recommend going to a straight pipe (at local muffler shop!) instead of paying somebody for the extra piping associated with the lower part of the manifold. Good news is, as Europe noted, exhaust piping is the same for ALL early 944s, ahead of the catalytic converter, and downstream of it too. Overall the factory exhaust is very well designed tuned. I also advise against gutting the cat out, as this will introduce turbulence into exhaust gasses, creating more backpressure/heat in comparison to a simple straight pipe. There are now downsides to this mod, except if the presence of the catalytic converter is required to pass inspections. In that case, gutting is still a good upgrade in comparison to stock.

The mufflers can get gunk build up inside, and power gains with an aftermarket muffler is quite possibly, especially with the straight through designs (magnaflow, borla, etc.). I'd recommend keeping the rest of the stock cat-back, removing only the last few bends only if money is no issue/max gains are desired, and getting a shop to do some custom (mendrel) bending at these spots.

Aftermarket wires are USUALLY not as good as stock Bosch units. Exceptions are the Nology, Jacobs, etc. wires. Most aftermarket ignition units enhance throttle response, and midrange power by a surprising amount, but NOT maximum power. (not as much of an increase).

NOTE: Crank pulley is smaller in diameter, accessory pulleys are larger. The 944 uses well balanced, and comparatively light pulleys, and gains to be had aren't as big as on most other cars. Still an upgrade, but not one I'd perform. The 944 alternators output isn't known to be very high, on many cars with tired voltage regulators this will lead to undercharging problems. Powersteering boost may not be as linear as required under certain circumstances (ie: racing), as the system pressure is highly dependent on engine speed. All of the above implies for AC units as well. Since both the AC compressor (that's equipped with a clutch, that disengages the input shaft at full throttle), and powersteering pump don't use much more power than absolutely required, I don't think this is a good way to spend money. You'd be looking at MAYBE 1hp, if not much less. It would most likely let the engine rev a tad easier, when the clutch is not engaged however. This could be a benefit to a track car, in need of shifting gears/matching rpm fast. Still no justification for the $ IMO though.

Factory compression for US cars is 9.5:1, and European cars is 10.6:1 (quite a difference).
Ahmet

------------------
It's all the driver...

[This message has been edited by 1.2gees (edited 04-03-2001).]

[Racing]

Hrrmm.
Hi guys.
Iīm a european 944 owner/mechanic.(Swedish)
Comp specs for ours cars are 10.7:1.

------------------

[pschaars951]

does anybody know all of the differences between European 944s and US 944s? I am curious as to how the stock porsches differ; instead of how to upgrade a US one to have the same power output of a European one. I gather the Euro ones dont have a CAT from all of your posts, but how did they get a much higher compression? Would it be like shaving a US head? Some one mentioned changing to a cone intake? was this originally done on the Euro car too? Then what are the power differences in the end (hp, torque)?

-thanks
Pete

[Racing]

As far as iīve understood prime diff engine wise is the compression ratio.
The stock specs for my car is 163 ponies.
Add to that the hedder and modded exhaust i run as well as the K&N and a worked on fuel curve.
The L/Motronic systems are fairly easy to fool around with.
Stock exhaust at least on our spec cars here in Scandinavia was a goofy looking dual muffler setup.Quiet as hell,iīll admit to that tho.
Some of these actually ARE cat equipped.
Mark that i say SOME.
See..state laws differ a lot from country to country around here.
My car being originally sold in Sweden for instance DID have a cat.No matter that the law passed in 87 for 88 year model cars(mine is a 86 btw)
Bumperettes are the obvious difference from an estetic standpoint i believe,but apart from that.?
Beats me man!


------------------

[1.2gees]

The compression ratio was different for US cars, vs. ROW. (Rest Of the World). However there were no other compression ratios. Some ROW cars had US compression, to meet emissions. So only two different ratios, for some of the years. I'd like to find out why we're contradicting each other...

Even the cars produced for the same market(s) had differances between them. For example US cars (california vs. all other states), european cars (swiss vs. all others), Japan had cars that (I think) were same as the ROW cars (might've been same as Swiss, meaning US specs, I'm not positive). Australian cars are different too. There are subtle differences however, nothing too major, save for the compression/bumpers.

Anyway, despite all the different specs the cars were produced to, I don't think compression was different for Swedish cars, ofcourse I may be wrong. Where do you get that info from? Can you get engine codes/part #s for con rods/pistons?

Here's the compression #s with engine codes:

8v Normally aspirated engines up to 1987:

US engines with 9.5:1 compression
Manuals: M 44/02 and M 44/07
Autos: M 44/04 and M 44/08

Rest of the world engines with 10.6:1 compression
Manuals: M 44/01 and M 44/06
Autos: M 44/03 and M 44/05

Engine codes for the 8v Normally aspirated engines in 1988 (US and ROW cars have same engine codes, and compression) with 10.2:1 compression in ALL MARKETS (this marks the last year for the 2.5 liter NA engies with 8 valves):

Manuals M 44/09
Autos M 44/10

Now the normally aspirated 8v engines, in 1989, for the first time with 2.7 liters, unfortunately also the last year they were offered, with 10.9:1 in all markets:

Manuals M 44/11
Autos M 44/12

END OF 8v NATURALLY ASPIRATED ENGINES

All 16v cars had 10:9 Compression!

Engine code for 944S (2.7liters, 16 valves):
M 44/40 regardless of which market it was sold to, auto transaxle was NOT offered.

Engine code for 944 S2s (3.0 liters, 16 valves):
M 44.41, automatic transaxle was once again not available.

All cars had the same bore/stroke, and same con rods in comparison to each other (as in all 1987 model year normally aspirated 8 valve engines had the same bore/stroke, etc.). Pistons were the only things different internally. Aside from that, all the US cars had that would be worse for performance was the gearing, placement of the catalytic converter, and different programming in the DME. (Different fuel/ignition maps). Besides the running gear, different cars also came with different suspension packages, many of the options were not available in some countries, spring rates were also different. Ofcourse the mentioned bumprettes is another difference. I've heard that some colors were not available in certain countries, not positive about that one. One last thing is the tires being different between some of the places the cars were sold at.
Ahmet

------------------
It's all the driver...

[This message has been edited by 1.2gees (edited 04-03-2001).]

[Racing]

Sheez man!
Lighten up a little will ya?
Info is out of the OEM drivers manual that came with the car as well as an OEM 86 Swedish sales broshure(sp) i got laying around.
I make no claim to the spec i QUOTE being the final word.Just posted what iīve clearly read in whatīs OEM litterature.

As i happen to be an honest to god old race mech,yes..i can get ya the casting numbers of the different parts that make up for total comp ratio.Have worked on Porsches for a living for a number a years(very close friend still does-ergo..).Not so anymore tho(altho thereīs one or two of them still coming in the door).These days i build race cars-period.

[1.2gees]

I'd like to see piston part #s, as well as con rod, and engine codes.

I'm in no hurry however, nor is this something I take that seriously, just sharing some info here.

I'd see if I can find the part #s you have over here, and if they'd function in the US part identification system. (Just out of curiosity).
Ahmet

------------------
It's all the driver...

[Racing]

Kewl.
From memory on the conrod issue then.
As far as i remember that were three different ones.
One set for the early Neckarsulm built 44;s.
These had a rep of being more sturdy.
Then in 85 when Porsche took over there were some seriously bad looking ones that really LOOK cast,if memory serves me these were also prone to breaking when over revving with aftermarket chip et al.
Then again-donīt quote me on this-there was a revision back in 88 or something to a sturdier conrod again.
Iīll check the actual numbers with Peter tho(guys name).Heīs ontop of stuff like that-which iīm not anymore.

------------------

[1.2gees]

That's correct, the early conrods (part # 928 103 172 01)were stronger then the later ones (switch made during the 84 year production, would likely include a lot of 85 model cars too). Part # for the later ones is 928 103 172 02.

The later rods were used for ALL front engined 4 cylinder Porsches, including the turbos, the 16v Ses. The S2 introduced the fully forged conrods again.

PS: I talked about con-rod part #s, because I was wondering how they achieved the compression ratio of 10.6 you mention. I'd think it would be through pistons, unless it was a typo on your owners manual. I mean I don't see why they'd have THREE different sets of pistons, and different compression ratios. They already have two different compression ratios between US and ROW you know (via pistons)...
Ahmet

------------------
It's all the driver...

[TheStig]

Ahmet- I'm not saying the DME adjustments make an increase in horsepower, but if you are running a cone filter, which pushes more air into the motor, and you are running a 6% increase, you are more likely to be running a lil more power than the stock setting. Too much air will lean off the mixture causing some loss in power but not as much as a large amount of fuel increase...i saw a gain in power between 3800-4700 rpm on my dyno, the curve is higher and there is a slight presence of more midrange...Unfortunately, smog day is coming up soon and so i am testing different mixtures and putting my car closer to normal to prevent any fail signs on the smog report. Until then, it looks like i'm gonna be back to stock with the exception of my ignition..

------------------
Sorry Officer, my bag of crack fell and while trying to reach it my gun got wedged in between the gas and the brake causing me to speed insanely.

[1.2gees]

I don't think a cone filter would get you any more airflow, I explained my reasoning for this at the earlier posts in this tread.

PS: 6% is way richer than stock. The proper way to change the mixture is through the air flow meter adjustment.
Ahmet

------------------
It's all the driver...

[CJFusco]

Eeek you guys are speaking another language with all the compression ratios, etc... I am really not all that knowledgeable with mechanics, but I am learning quickly.

Now I have a few quick questions for clarifications... they are mostly to clear things up so that i completely understand what you all are talking about. Sorry if I sound retarded when it comes to this stuff, but here goes...

1)What exactly are the function of headers, and where exactly are they found?

2)When one gets a straight pipe, is that an exhaust pipe that goes ALL the way? Is the catalytic converter removed for this?

3)Is there any difference between a straight pipe and a test pipe?

4)What exactly is 'gutting the cat'? Does this apply to someone that is willing to keep the catalytic converter on the car and getting a cat-back aftermarket system?

5)Eurospec944 mentioned tinkering with the DME 'brain.' I am still somewhat unsure about where to find this (I haven't been around my car or my Haynes manual since the middle of March)... I am to understand that it is inside the passenger footwell? Where exactly?


Thanks to everyone for all their imput (and for putting up with my lack of knowledge), I really appreciate it.

[CJFusco]

One more question:

Where is the Airflow Meter, and how would I adjust it?

[hoff944]

All of the numbers Ahmet has thrown out are the same as what I have. I would get into this but an echo really isn't needed. I'll post again when I feel something needs to be brought to attention.

[Racing]

CJ
In order then.

1/A hedder is the first piece of the exhaust system.The one that bolts to the cylinder head.
On most motors(in general) these are cast iron logs in stock form.
What a high performance hedder(made out of steel tubing normally) does is that it uses the pressure pulses of the exhaust that the motor produces to a tuned lenght of respective pipe(4 in the case of a 944)into a collector to form sort of a resonance thereby adding in scavenging of each cylinder.Much like when you play an instrument and create harmonic sounding chords.
This is fairly "heavy duty" tech,and if youīre interested-and the reading kind-i can recommend two books on the issue.
First is a book titled 4 stroke performance tuning by Alexander Bell,and the second is scientific design of intake and exhaust systems by Philip Smith and John Morrison.
The latter one is the heavier reading of the two.
Effect of a hedder varies greatly with for instance state of tune of motor,and a given power increase for a given hedder is VERY hard(if not impossible) to give.

2/An offroad pipe is common nomer for a piece of exhaust tubing you put in place of a catalyst.
On the other hand exhaust systems are a source of power if you KNOW WHAT YOU`RE DOING.Likewise with the aformentioned hedder.
Most people seem to believe that a hedder is at its best when all pipes are of same lenght.This need NOT be true.It all depends on application.

3/No

4/"Gutting the cat" is basically just that!
You take the catalyst off the car and ram out whatīs inside,freeing up the innards of it.Most early cats(pre mid 90;s) are VERY restrictive.If exhaust tests are performed in your state this is a no-go to you(as it will make CO and HC levels jump beyond boundrarys)In such a case an offroad pipe is the way to go.

5/Donīt bother with it.Performance gains are VERY small on otherwise stock motors.
Remember that the ECM(electronic control module) controls the fuel and ignition curve both.Highest gains are from fiddling around with the ignition curve primarily and the fuel curve second on a mass meter controled injection.(Motronic of the 944 contains both)

6/Airflowmeter is found at the very front of the engine bay.A cast aluminium part with a black plastic lid on it.Clearly detectable by a rubber hose leading from it to the throttle housing on the intake manifold and bolted to the aircleaner housing at its other end.
Any EFI(electronic fuel injection) basically relies on several analogue inputs to determin engine load and so forth.
Airflowmeter is one of them in this case.
In short itīs a flap connected to a resistor via an arm under that plastic lid you can see.
This flap is springloaded,and resistance to movement is controlled by mentioned spring.Effect of resistor is inverted-ergo the higher the engine flow the less the resistance.
If one cares to play around with this-in your case i donīt recomend it-one takes the MAF out and carefully cut the plastic lid open with a razors edge carpet knife or similar,thereby rendering the resistor accesible to alterations.(This cut is made with the MAF inverted so that the cut is put in the silicone that keeps the lid in place.When replacing the lid just add silicone to the joint and put back in place)
What you will see is a black plastic toothed wheel with some numbers on it held in place by a funky looking spring.One marks the wheel with some paint(white for instance) and either tightens or losens up the resistance of said spring/wheel by moving it a couple of notches either way.Be careful when unloading the "stop spring" as the wheel after all is spring loaded too...
To be of ANY effect this entails having a GOOD O2 meter of some kind connected.
Otherwise youīre just fooling around in the dark,probably doing worse then the car was originally set up.

[Racing]

Oops.
Just saw 1.2gees post and yours again..
ADJUSTMENT of the MAF is done via a 5mm allen key on the MAF.
What you adjust is the total CO of the motor,in other words while adjusting you need to be connected to an exhaust analyzer.
What i described is a way of altering the fuel curve at part throttle.

[This message has been edited by Racing (edited 04-04-2001).]