944 Dyno testing

[Jad]

There's only so much you can do with a 944 as far as power goes....the manifolds you could fix,(throw away and start over) and the ports could be welded to decrease their "too big for velocity" size, but the combustion chamber design is terrible. Seriously high compression ratio without severly masking the valves isn't possible with the existing configuration, and you can't alter the intake/exhaust cam timing independantly on the dyno without having a bunch of custom ground cams in your pocket to experiment with.
Engine development would be very expensive for what you get. 400+ hp is hiding in that block, but.....
I'm willing to bet a BUNCH more power could be made fairly easily if you started with an S2 head however. It's far more modern/tuner friendly in design.

It is called a 944S and it got 179 HP as I recall...no low end torque whatsoever, but definitely more HP.

[LUCKY DAVE]

If our 944 engines had undergone an original engine development cycle typical of sporting street motorcycles, they would be docile, quiet, reliable, have a wide spread of torque, get good fuel economy on cheap unleaded, and make 500+ horsepower @12,000 rpm.
Hell, even the NASCAR tuners get 450 horsepower out of 4 cylinders about the same bore/stroke ratio and displacement as a 944 with pushrods, 2 valves per cylinder, small carburetors, and RESTRICTOR PLATES in the intake tract.

While all of that is true, the fact remains that it's the DRIVER that's the most important. Always has been, always will be.

[cam]

Always remember...Dynos LIE!! ( or should I say vary dramatically) You can play with the numbers and get them to say almost anything you want.
Sometimes with the Supertrapp on a stock motor the backpressure is necessary for bottom end to work right.

[LUCKY DAVE]

Always remember...Dynos LIE!! ( or should I say vary dramatically) You can play with the numbers and get them to say almost anything you want.

That's absolutely true.
Most dyno operators are in the buisness of making heroes out of shade tree mechanics, and do everything but run a different car to produce "higher than a hippy" numbers.
In addition, inertial dynos don't read actual power, rather they indicate accleration. Install lighter wheels and you get higher horsepower readings. BS!
Only an eddy current dyno will give true torque/rpm numbers. These work by loading the engine at steady rpm instead of measuring wheel acceleration. The nearest one I know of is in San Jose.

[Dan Chambers]

The HP is/was never an issue for me. It was dyno tested as part of a project my son was doing for his High School auto shop. I am quite proud that my car cost me $700. out of pocket as it sits. Competition and placing is completely irrelevant to me, I am not looking to be the next McLaren driver. Just to have fun in the car I built from the ground up.
I just found it interesting how much (in percentage terms) changing the exhaust diffusers on the resonator turned out to be compared to what the marketing claims were. To a lessor extent, that I am down on HP most likely due to a tired engine.
As a result of my son welding the #2 main bearing on his 944 while doing his own experiment (how long can a 944 go without oil), we now have 2 motors I will freshen up and merge into 1 in the fall.
So in the end, I will drive it til she blows or the rest of this year, whichever comes first. Oh and the answer to my sons experiment? Three days of school commuting plus several extraneous trips totaling about 65 miles !

Ahah! The mystery is solved. Well, I find the supertrapp experiment very interesting, too. I hope your son had a good time with the case (crankcase ) study.

One comment: if you decide to "drive it til she blows" do us all a favor and drive it 'off-line' when you start hearing the rods knock or the bearings sing. I don't want to drive through your oil spill like the last 944 that threw a rod.

[Irksome]

Always remember...Dynos LIE!! ( or should I say vary dramatically) You can play with the numbers and get them to say almost anything you want.

That's absolutely true.
Most dyno operators are in the buisness of making heroes out of shade tree mechanics, and do everything but run a different car to produce "higher than a hippy" numbers.
In addition, inertial dynos don't read actual power, rather they indicate accleration. Install lighter wheels and you get higher horsepower readings. BS!
Only an eddy current dyno will give true torque/rpm numbers. These work by loading the engine at steady rpm instead of measuring wheel acceleration. The nearest one I know of is in San Jose.

I believe that JMC Motorsports' dyno is one of the cool ones. When I had my car dyno'd there, we used the straight up pull, but they claimed the ability to go up, down, hold, etc. It is definitely a magnetic resistance, not the typical big drum. I've done dynos at three locations in my life, two were the typical big drum, and JMC has something much better.

They are located in Kearny Mesa, just south of Clairemont Mesa and just west of Convoy.

[harnishclan]

Dan,

You know what's funny (at least to me) about the last 944 oil slick? I was pitted next to Sean and he came in early because the car was making an odd noise during his run. In the pits, the noise went away. Next run session, the motor let go. So now in the last 60 days I have had the "honor" of hearing that #2 rod bearing failure twice now. As for my son's experiment-it sucked! Had to find a new motor (Thanks Autobahn). Then spend a weekend putting it in. Though I let him make the usual rookie mistakes of engine removal and subsequent wrestling with vac lines that he didn't bother to mark their origins.

[gulf911]

To make the car faster I removed weight. Thats the secret to 944 speed.

Actually, its no secret. And it applies to any car. "To add speed, add lightness" Colin Chapman.

[Tim Comeau]

Brian,
I imagine you might have had more dramatic results on an engine other than a Porsche. I've seen lots of claims from "add on" products. Here's the test that separates the BS from the products that actually work. Tell the company that you're ordering a part from that you're going to test their product on a dyno. If it fails to make the claimed power, they have to buy it back and pay for shipping. Chips and headers are the worst at making the big claims. Your typical Joe six-pack doesn't have a dyno near him to prove other wise. Ask me about cold air intakes and air filters sometime.
The typical HP/TQ rating for a 944 Spec car is 132-135 (both HP and TQ). See published dyno charts on the 944 spec.org website. When I was doing well with the Zebra car, it was rated at 133HP, and 134TQ. That was with stock headers and a chip burned on the dyno at Vision Motorsports. After a couple years of hard running, I could tell the engine was getting tired. We replaced the rod bearings and put a fresh head on. All the power was back and I cut a 1:35.5 at Willow.
The stock cam HP peaks around 6,000 rpm. However, the torque maxes out at 2,500 rpm and holds till about 5,800, at which point it drops fast.
Our engines need more air to make more power.
And yes, though not MOST important, weight is important. Our black 944 came across the scales at 2607 at the big 944 Spec event at Miller Motorsports Park this past June. Class minimum is 2600 with the driver.
Here's my take on order of importance:
1. Driver
2. Suspension alignment/corner balance
3. Power
4. Weight

The beauty of the 944 Spec class is that you don't have to worry so much about power. Our rules are written to dial out that variable and it's associated costs. Many of us know lots of speed secrets to make the 944 engines more powerful, but they all cost money.