Getting more out of the 2.5l atm
 

I am looking at buying a 1986 944 but the 155HP of the atmospheric 2.5l seems a little under powered. Does anyone ever tried to give it a little more power.

If you have suggestions I would appreciate. If there are no possibilities of getting more than the 155HP I will look into a turbo but I don't like the lost of reliability.

Tanks,

Philippe.

The common answer is that "Porsche extracted all they could from this engine, don't mess with it". While I do believe Porsche makes good engines, I think it highly unlikely that they made the end all, be all, 2.5L. There's just too many other factors in there to restrain them from that.

Here's my wish list for my motor:

FRWilk Chip
Forged rods
Forged JE Pistons, maybe 10.5:1
Lightened crank (Huntley Racing advertised they could take up to 17# off!!!!)
Web or Comp Cam, with a grind that makes power in the low to mid range, who needs a ton of power at 5.5K+ on the street?
Bigger injectors
Turbo valves (or hell, just new ones..)
Head work/valve job
Custom Torque Tube (way less rotating mass)
Lighter clutch/flywheel
Bursch exhaust/header

Honestly, I have no idea what kinda power it would make, but with so much less rotating mass, it would rev like hell and be a heck of a car, albeit a large pain in the neck in traffic. Oh yea, it cost you an arm, leg, kidney, bank account, and a pint of virgin blood. If I had more money than I knew what to do with, I'd so build that motor.

I don't care whose name is on the valve cover, there is ALWAYS room for improvement. The cost to play might be higher, but to each his own.

Also, I wouldn't waste the time slapping a turbo on there. Although, it would be interesting to do it 968 style, where a lot of guys run low boost (5psi) and no intercooler, and hence almost no turbo lag. But then I'm not really a turbo motor fan.

Finally, these motors actually aren't too bad. It ain't the fastest thing around, but they do scoot along pretty good once you hit about 3 grand. 155hp doesn't seem like a lot (and it isn't, really) but remember, these cars weigh in the neighborhood of 2700#.

I really wish someone with a ton of money would build a moster 2.5L, just to see what it'll really do. Maybe if I can get rich...

A turbocharger itself is a very simple mechanical device. The "loss of reliability" doesn't have to be there, it's all about the stuff that acompanies the turbo. Handling the heat is the second biggie. Still though the amount of power a turbo makes, and the potential for more is simply in a different class. If you're looking for up to 200ish hp, you ought to look at an S2. If you're looking for more, go with the turbo. The other alternatives are simply not cost effective.

HOWEVER, an NA 2.5liter can still be lots of fun. The 8v NA cars are amongst the lightest front engined Porsches, they're very agile and fun to drive with world class handling and great road manners.
Ahmet

the normally aspirated 944 is a fine machine. Many cars are built for speed, but few are built as durable as the 944. The engine is a masterpiece. The block, bottom end, cylinder head, everything, just a beautiful piece of conceptual design and exquisite castings and fine execution. So what if it doesn't have as much power as some of the newer cars. Show me one of those cars with 160,000 miles that will sound and drive like a sewing machine like my '84.

The 944 is and always will be a balance machine that is one of the best surgical tools for carving up the rural countryside. It also can run with just about anything on the super highways.

I have two other Porsches that are faster, but I still appreciate and greatly enjoy every drive I take in that normally aspirated 944. Once you understand the car, you'll see the horsepower is only one part of the equation. Remember, this is the car that beat out Ferrari and Corvette in a head to head test in 1984, and both of those cars had more power. Oh yes, we don't need to forget it also beat out the 928 (but by only one point).

On an acceleration run from a dead stop, the car will outrun a six cylinder 240-Z, which used to be an enviable standard. At speed is where the car really comes into it's own. The transmission and power band will allow the moderate power of this car to stay with cars that have considerably more power, and when the road turns bad or twisted, the 944 becomes the superior weapon due to superior balance.

PSmileWavy

yes, the HP numbers aren't very high, but keep in mind that these cars weigh only 2680-2800 lbs (depending on model). The low-end torque isn't much, but once the engine starts singing, it seems like the accelleration doesn't slow down at all until well over the 100 mph mark.

If I remember correctly, when tested in the mid-80s, the 944 had the slowest 0-60 time of other cars in a group test, but the 2nd best 60-100 (i think it was the 3.2 Carrera or 928S that beat it)...

Not only that, but the 944's road manners, excellent braking, and absolutely exceptional handling characteristics mean that it can travel at a higher rate of speed than other sports cars. I have left many "faster" cars behind on twisty back roads.

Even though it was less powerful, less accellerative than a 911SC, when GRASSROOTS MOTORSPORTS tested a 1983 944 vs. a 1983 911SC (both stock), the fastest lap time of the day was put up by the 944!

Before this turns into the typical monthly pissing match let me point out that I don't think anyone ever said you can't make more horsepower with the 2.5 N/A. The ranting is usually started by a high school/collage student who starts a post asking how do I CHEAPLY get another 50 HP out of my car and when the mechanics on the board calmly suggest it can only be done by spending lots of money the rebels jump out of the woodwork screaming... "YOU BUNCH OF PORSCHE SNOBS ANY CAR CAN BE BUILT UP... IT'S JUST A CAR YOU *********S!).

Anyway Slow Toady list is a good place to start, the chip is relatively cheap and people on this board have given it great reviews.

From what I could gather in a few days the only difference between a 944 and a 944S motor is the head. The 944 S as a 16 valves head, maybe it would be a perfect replacement for the 8 valve head. This would get about 30HP more out of the engine, the question is were do you find the 16 valves head? I am sure that with a little patience it can be found.

Thanks for the info, from the positive feed back you guys gave me on the 944 with 155HP I think I will give it a try and if it isn't enough I’ll find a way to get more out of it.

Philippe.

By the way any suggestion on good technical literature on the 944 (Wayne didn't write ''101 project for your Porsche 944'' or ''how to rebuild and modify your Porsche 944 engine'', until he does there is probably some acceptable reference for that car and it's engine?

About the chip...i think i have some evidence that it doesn't do much AT ALL. http://members.rennlist.com/m758/944SpecDynoCharts.htm

The 944 n/a engines are hard to tune without spending thousands. Most aftermarket performance products are aimed at the 951. Very little is available for the n/a. Unless your n/a is in pristine condition with 50k miles, and youre gonna keep it for years, i suggest you buy another car. Maybe a 944 s2?

Btw, dont get a cone filter. I woulnd be surprised if it actually decreases performance due to all the hot air it sucks in. The intake box is very good on the 944, so keep it stock.

I don't know if just swapping heads is enough - you'd have to get a new chip & possibly some other things too to maximize the use of it. Are the S2 16 valve heads belt driven or what? Could they be made to work with the earlier engines' belt / roller setup?

They are belt driven...but it wont be much of an upgrade. Theyre designed for a higher displacement engine....and theres no way theyll fit.

A fool and his money are soon parted.

Kind of figured if there were an easy, cheap, "bolt-on" kind of solution like that I'd have heard about it by now. . .

I suppose there's always head porting & polishing, but that's sort of expensive and won't give THAT much HP gain (maybe a few)

I have seen N/A 8v 944's making over 200hp at the wheels, but this is a costly endeavor. You'd pay 3x over what you paid for your car to begin with to get these results.

There is a supercharger kit running around somewhere, though that will end up being quite a few thousand as well.

The biggest improvements as far as HP for that motor are probably going to be in the cyl. head. Have it ported and maybe try to find a decent cam for it if you have the money.

Otherwise...a good intake setup, maybe a chip, throttle response cam, exhaust...all the basic stuff might net you ~10hp or so put together. That's enough to feel anyway.

I'd concentrate on the suspension, as that's where this car really shines. So what if some riceboy can beat you off the line? Set up your suspension and spank him in the turns. ;)

Plus, which is really the car people are going to "wow" over? Some Honda civic with a bunch of junk tacked all over it or a Porsche? Let's be serious here. . .

How did Honda's and rice get in here? The thread starter asked about extracting more power from the 2.5, not how to make super cheap power super quick so he can run with the Honda's. The guy didn't even ask how to get it cheaply.

Phil, if you have the money, go for it. What have you got to loose? Some Bens and you might hash a motor? Not exactly the end of the world. Remember that while good technology, it is still 17 year old technology. Anyone care to weigh a new, forged, JE piston against a stock piston? I'm willing to wager the tolerances are more precise as well. When you're talking about parts that are moving very quickly, a little weight difference can make a nice difference.

I dunno man, if I had a lot of spare money and I could afford the down time, I'd try and build a killer 2.5/2.7. Also, remember that numbers aren't everything. Take the S2000 for example, yea it makes a good amount of HP, but where is it? Somewhere like 5 or 6 grand. Yea, REAL useful in a street motor. Err, not. If could change up the powerband, and add some power while you're at it, I bet you'll get on just fine with the 944.

Ok I got the message and if the car pass the inspection I might be able to add ''1987 Porsche 944S" by the end of the week.

Thanks again for the input,

Philippe.

PS I don't plan to buy this car to run with Honda's, it's just that a car that as a good handling is better with a little more than 160HP.

I dont know about hp increase, but after my catalytic cracked, i welded on a straight pipe. You can definitely feel the power difference after doing a 1st to 2nd shift at 5k rpm. Btw, im going to put it on ebay pretty soon, or if anyone here wants it in about a week. Good condition with good threads and clean welds. This is because im tired of fixing header cracks and ordered a set of bursch.

the normally aspirated 944 is a fine machine. Many cars are built for speed, but few are built as durable as the 944. The engine is a masterpiece. The block, bottom end, cylinder head, everything, just a beautiful piece of conceptual design and exquisite castings and fine execution. So what if it doesn't have as much power as some of the newer cars. Show me one of those cars with 160,000 miles that will sound and drive like a sewing machine like my '84.

The 944 is and always will be a balance machine that is one of the best surgical tools for carving up the rural countryside. It also can run with just about anything on the super highways.

I have two other Porsches that are faster, but I still appreciate and greatly enjoy every drive I take in that normally aspirated 944. Once you understand the car, you'll see the horsepower is only one part of the equation. Remember, this is the car that beat out Ferrari and Corvette in a head to head test in 1984, and both of those cars had more power. Oh yes, we don't need to forget it also beat out the 928 (but by only one point).

On an acceleration run from a dead stop, the car will outrun a six cylinder 240-Z, which used to be an enviable standard. At speed is where the car really comes into it's own. The transmission and power band will allow the moderate power of this car to stay with cars that have considerably more power, and when the road turns bad or twisted, the 944 becomes the superior weapon due to superior balance.


Wow! that's great!
Just put a set of the very best tires you can find on it instead of the HP increase...

There is no one single bolt on that will give you lots of HP, its the combonation of performance parts that will start to show some HP, a little here a little there starts to add up to a good amount, I need to get my ride Dyno'd just for fun