Add on power

Kirby2 · 05-30-2003, 03:29 PM

I have discovered the availability of a Mass Air setup that would allow much more air into a choked down N/A 944. Has anyone tried this mod with the appropriate custom DME chip? Seems like it might be the answer to another 15 to 20 HP if true.

Roastin944 · 05-30-2003, 03:49 PM

If so i am interested, maybe FR WILK could custom make a chip to work with the setup.

will944 · will944's Garage

Where did you find this?????

I am extremely interested as well!!!!

AaronM · 05-30-2003, 06:31 PM

Much more air? I was under the impression that the main restriction on a 944/924S was the head itself and not the intake (especially on the 8-valve cars). I could very well be wrong, but the stock intake tract sure seems to be one of the least restrictive stock setups I've seen and I seriously doubt that there are 15-20 horsepower to be gained simply from a free-er breathing intake tract. I mean, if there were a cheap way to pick up another 15-20 horsepower don't you think that Porsche would have done it?

Aaron

todwic · todwic's Garage

does the throttle body grow?

Moneyguy1 · 05-31-2003, 12:32 AM

"If there were a cheap way to pick up 15-20 horsepower, don't you think Porsche would have done it?"

Not necessarily. Porsche usually chooses the most difficult and arcane way to increase power of any auto manufacturer. Why doesn't the 944 include a different chip? Looks like aftermarket units add a few HP at a relatively low cost. Also, considering the displacement, the HP per liter is nowhere near their boxer engines of the same era. Only my opinion, but I don't think a whole lot of effort went into the 944 engine design....

Nomex skivvies on......

CJFusco · CJFusco's Garage

"Only my opinion, but I don't think a whole lot of effort went into the 944 engine design.... "

The 944 engine is basically one-half of a 928 V8; and a LOT of effort went into THAT engine.

Moneyguy1 · 05-31-2003, 10:47 AM

The story is that the 944 is half of a 928, but only a handful of parts are interchangable. (can't count things hung on to the engine like oil coolers and accessories..we're talking block and interior mechanics here...)And that can be said for any auto manufacturer when they design a family of engines.... Heck, back in the 60s, Pontiac "cut" a V8 in half to create the Tempest 4 which also had the transmission in the rear. The 944 has some unique reliability problems that almost seem designed into the engine, as well as some maintenance procedures that make it an extremely difficult car to work on. I have rebuilt 356, 912, and early 911 engines and getting them out of the car and on a stand to work on them is an hour at the most with a helper. I even had a three wheeled "cart" made of industrial casters and 2 x 6 lumber for the purpose. Changing a clutch was simple and straightforward, I assume in part because the layout was so close to the VW Bug which was designed to be simple to work on. As a whole bunch of us will testify to, changing a clutch on a '44 is not for the faint of heart.

Please do not misunderstand me. I am not trying to say that the 944 is a terrible car. I enjoy mine and within reason I enjoy working on it. (like driving it the best) I am simply saying that the design of the Porsche engine and drivetrain was not the best work Porsche ever did. I am certain that, taken individually, most parts of the 944 engine are built to extreme tolerances and specifications. Too bad the various designers didn't talk to each other before the entire drive assembly got mated with the rest of this fine (still beautiful) body assembly!!

Cheers!!!

Kirby2 · 05-31-2003, 04:34 PM

Here is my discovery...A true Mass air flow with cone air filter for around $700(I'm NOT selling these things); The chip mfgrs say 10-15HP stand alone; with the addition of a mild cam for $500, you should have significant added HP.

I really don't want so much extra HP that I begin to find the weak points in the rods, crank, the transmission etc, BUT an extra 15 to 20 HP would do me just fine for passing power, or that extra boost in the twisty backroads.
I know that the stock vane air flow meter is by far the smallest orfice in the system (check it out next filter change)... imagine that tiny square opening with a vane blocking the passage most of the time.

Kirby2 · 05-31-2003, 04:40 PM

Check out: www.pro-flow.com/Import%20front.htm

AaronM · 05-31-2003, 05:51 PM

Quote:

Originally posted by Moneyguy1
"If there were a cheap way to pick up 15-20 horsepower, don't you think Porsche would have done it?"

Not necessarily. Porsche usually chooses the most difficult and arcane way to increase power of any auto manufacturer. Why doesn't the 944 include a different chip? Looks like aftermarket units add a few HP at a relatively low cost. Also, considering the displacement, the HP per liter is nowhere near their boxer engines of the same era. Only my opinion, but I don't think a whole lot of effort went into the 944 engine design....

Nomex skivvies on......

You're right that the boxers have more specific output, but you can't compare engines with different configurations. Boxer engines are inherently balanced and as a result do not need to drive balance shafts. The boxer engines also had many more years of development work and went into cars that were more expensive, which means that the boxer engines benefitted from more expensive technology. The boxer engines were also in the rear of a car, which means a shorter exaust with a potentially more direct routing path.

It is also worth noting that the aftermarket chips either by-pass the O2 sensor or do other things that were not a viable option for Porsche. Also, while chips tend to change the character of an engine, simply boring out the intake tract would give improvement throughout the engine's range (assuming that the head itself is not the bottle-kneck, if the head is the bottle-kneck then all a bored-out intake tract does is decrease the velocity of the incoming air and actually hurt low-RPM performance).

Aaron

AaronM · 05-31-2003, 05:59 PM

"I know that the stock vane air flow meter is by far the smallest orfice in the system (check it out next filter change)... imagine that tiny square opening with a vane blocking the passage most of the time."

As long as the AFM can flow more air than the cylinder head (or, really, as long as it can flow an equal amount of air to the cylinder head) then it's not a bottle-kneck. I don't know the specifics of the 924S/944 intake tract but I still say that there is no way that it's so incredibly restrictive that it cuts 15-20 HP. The engine would almost have to have been intentionally restricted from the factory to have that sort of improvment from what is essentially a bolt-on part.

Aaron

pearldrum · 05-31-2003, 06:42 PM

Quote:

Originally posted by FR Wilk
You have already put one chip in backwards. Destroying it. You'll just put this one in backwards too.....

lol!

Kirby2 · 05-31-2003, 07:12 PM

If the bottleneck is the head, then a slight change in the cam should help immensely, along with port matching.

Remember at this time (early 80s) vane type metering was state of the art.

Some people are so pesemistic about any attempt to modify what St. Porsce originally created.

Kirby2 · 05-31-2003, 07:28 PM

At the outset you can see that Porsche was attempting to create air turbulance for a cleaner burn....look in the intake venturis...you will see a VERY intentionally rough surface. School of thought at that time was to get the most turbulance for a better air/fuel vaporization and a cleaner burn. Current state of the art automotive engineering has taken all of the surfaces and made them mirror finish for increased air flow.

Hone the intake,
flow the head,
match the ports,
Mass air intake,
Increase the fuel pressure,
dyno a chip to match the mods.

Remember the equasion: more air + more fuel = more HP.

carsontc · 05-31-2003, 07:40 PM

Quote:

Originally posted by Kirby2
Current state of the art automotive engineering has taken all of the surfaces and made them mirror finish for increased air flow.

Hone the intake,
flow the head,
match the ports,
Mass air intake,
Increase the fuel pressure,
dyno a chip to match the mods.

Remember the equasion: more air + more fuel = more HP.

current state of the art hasn't changed much then...in a long time

AaronM · 06-01-2003, 09:02 AM

"Some people are so pesemistic about any attempt to modify what St. Porsce originally created."

No, I've just seen plenty of "15-20 hp" modifications that yield 3-4 hp (at best) in actual testing.

Aaron

Roger Hall · 06-01-2003, 01:16 PM

It should work if done properly. Many 924 owners say that a larger throttle body is a worthwile upgrade. More air/fuel = more hp, but realisticly I would say more like 3-5 hp increase. I would be suprised if you get 15 hp. $700 dollars is alot to pay for 3-5 hp. You might notice improved throttle response too.

Kirby2 · 06-01-2003, 06:45 PM

The way I look at it, My business car is much less enjoyable to drive and I spend $600 a month on a car payment.

If I invest the $700 and it doesn't pan out, I have just taken the first necessary step to supercharging.

Ebay has superchargers for as little as $500; add a fabricated bracket and pulleys... there will be at least another 50hp available.

Honestly though, I would be satisfied with the 15 or 20.

Roger Hall · 06-01-2003, 06:57 PM

Talk to Scott R about supercharging. Its goning to cost alot more than $500.