M758

Kevin,
944-spec runs to NASA rules developed specificlly for 944-spec. Air intake to the stock AFM is free, headers and rest of the exhaust are free, chip is free.

Really the best way to make hp in these cars is to clean and bring back to factory spec. Really the 944 has plenty of power on the street in stock form once it is 100% running condition. I'd bet most 944 are slow since they are NOT in tip-tip shape.

Geo

Is that the kind of stuff they teach you in engineering school?

Yes indeed you can use it. The length and diameter of the tube (garden hose in this case) is important. Both the diameter and length are both important. Think of sucking soda through a straw. Easier to suck through a bigger straw. To a point. Then it can become impossible. Length is important as well. Would you rather drink through a long straw or a short one?

Diameter and length are indeed important.

It's significantly more complex than that. The filter and the muffler are minor concerns to improving VE.

No, you you conveniently are ignoring that the 944 Cup racers have actually dyno tested all the mods you claim would gain you 20hp. Your estimates are a pipe dream.

They have a very very short section to allow for movement.

Coatings are good. The Jet Hot coatings are little more than ceramic paint. They are not much of a thermal barrier.

It will only produce more power if the engine is still breathing and making power at redline. I'm pretty sure that's not true of the 944 engine. The advantage of the higher redline is to delay shifting in some cases unless the engine is making more power at redline.

Dave

Kevin, You're taking my analogy too literally. The point I was going for is that one needs to clean up the restrictions first, not that it matters weather the restriction is in the form of a filter or a screen or an venturi. I'm not anxious to go blow through my K&N but I see what you are trying to express, this doesn't take into account the surface area of the filter, with the load spread over a large filter area there is less restriction to air flow. In many applications this is where a cone filter's advantage comes from, a cone has more surface area than many OE filters so flow per sq in. is reduced. OTOH the 944 filter is quite large for the amount of air that a 944 needs so the stock filter offers minimal restriction, a flat K&N can flow more air at a given vacuum, but more air isn't needed. A cone for a 944 has only a little more surface area than a flat filter.
I'm not so sure Ohm's law is the greatest comparison, an electrical load will draw the same power (in watt) regardless of small variations in voltage. A 60w bulb will draw .5a @ 120v but the same bulb will draw .545a @ 110v.
Don't expect 200 watts of light from a 150 watt bulb just because you've run 2/0 cable to your socket.

Geo

You know, it's not sexy, but it's true. People spend a lot on mods, but simply getting an engine into a proper state of tune can increase hp more than mods.

It's too bad base timing is not adjustable in the early models. Or is it? Does someone know how to do this?

M758

Just to add more fuel to this little debate I know 944-spec racers that have got back to stock airboxes and paper filters and tossed their cone filters!

In fact one of the biggest issues with cone filter is a poor transition at the AFM. If this is not smooth it can disrupt the air and reduce HP. Think about that when you want to stick home made PVC adapter on the AFM to make your cone filter work and the car makes more noise, but no more hp!

FSAEracer03

M758, sorry about that NASA and SCCA have blended into one in my head. I attended both over last summer and the two are so similar, I forget which class belongs to which sanctioning body (except for AS vs. AI and AIX... I can always put them in place somehow). Sorry about that.

Geo, hahaha, I know that length and diameter are important... more important than the filter... but I'm talking about the filter difference all things held constant. I understand very well how cross-sectional area as well as length and routing are all key factors in intake design, don't worry. I'm just choosing to not address them right now

True, I guess my estimates are a pipe dream... I never said I was going to whip out a dynojet printout and say "SEEE?!?!" I'm comparing like modifications done to similarly powered cars. Granted these cars didn't have Porsche's R&D... but I'm still estimating gains until I see dyno charts with my mods showing me differently.

I was not trying to insinuate that the higher redline increases power... it's a commonly known fact that these little things, as well as many other engines, fall off before their stock redlines... once again, I perfectly understand the benefit of higher fuel shutoffs (I have done some auto-x'ing)!

Dave... you just showed me an example of P=IV instead of V=IR (is that Watt's law?? I can't remember anymore!)

Geo

BINGO!!

Both 9X and Broadfoot have made an attempt to address this issue, but neither is quite an effective solution. There should be a taper of about 2-3" from a round tube to the square opening of the AFM. The last thing you want is turbulence at the AFM.

Geo

Yeah, it's sad. Then again, these cars are old enough that any R&D would be 20 years old and out of date.

Two things keep the 944 from being properly developed.....

1) No shops willing to invest in a proper development program.

2) No customers willing to spend the money on an NA. (see #1)

It would seem to me that any real power from an 8v 944 would have to start with a cam. According to my buddy who is an aftermarket consultant (and has been heavily involved in a cam development program), the cams are likely the biggest impediment and I believe it. For one thing, the 944 was designed at a time when emission controls were still in their infancy. I'm sure the cams are designed to reduce emissions.

Then there is the crude (by today's standards) EFI. I'm quite sure there is power to be made. But don't look at me. My focus is limited to within the rules of SCCA IT racing. However, within those rules I'm after everything I can get.

jonnybgood

Isn't all this deva vu all over again!!??

ERAU-944

uhh... i'm sure these cars DID have porsche's R&D. after all, it IS a Porsche designed engine. i'm pretty sure all the motors were built at zuffenhausen...

-Mike-

Dave

Yup! V=IR is Watt's law (haven't had to remember that since '86, a few months after my car was built!) and I feel it's more appropriate in this case. Of course, VIR sounds like more fun!

Geo

You know what we meant. If Porsche stopped development of the 911 like they did the 944 it would never have been the car it is today.

M758

Remember also that alot of Race R&D on the 911 engine and components was started by the factory years ago. There are lot of 911 racing updates that have their roots in factory work.

Before we get too down on the 944 lets remember that the kind of factory support for racing the 911 has had over the years is really rare. Few other cars have be able to benefit from 40 years of factory racing development. The 944 Looks under developed compared to the 911, but infact is quite good as compared to most cars. The biggest probelm with 944 is the lack of engine development by the aftermarket. This is caused partically by the substantial 911 development. Since there are so many 911 parts they tuners and drivers tend to overlook the 944. The 944 Turbo really hurt the 944 NA power market since is power per dollar potential is so much greaters. Good thing is that suspension and brake tech does flow to the NA from this. Also are the two reason Geo stated. 1) Shops don't do becuse they can't make money. 2) Few/nobody willing to pay the shops to do the work.

ERAU-944

Geo - i guess deep down i did, but i wasn't tooooo sure

M - thank goodness for the suspension trickle-down! makes my 944 like a go-kart!!! almost 914-esque, without the killer turn in (or around!).

-Mike-

Stu Waterman

To bring this full circle to the original post...

The company that builds the MAF advertised on e-bay is Pro-M Racing (http://www.pro-flow.com). There is quite a bit of information on their website. A cautionary note: I'm guessing that the "M" in Pro-M stands for "Mustang"

The SRP for the vane meter replacement unit in the e-bay ad is $820.