upcruiser

So, I've think I've got a good feel for the direction I want to go with my '83 944 in the suspension department. Now, for hp. I'm understand the general sentiment that extracting more power out of a 944 NA is expensive and doesn't yield much. My uses for the car will be primarily autocross and HPDE events, but I want to keep it licensed for the street. However I have questions on the following.... (I've searched these too, but haven't had luck finding specific answers)

exhaust- Are there any header setups that you guys have good experience with? Sounds like its easy to put a custom exhaust on that actually reduces power (ie. too large of diameter), what is the general consensus with regards to pipe diameter? I'm planning on removing the cat, was thinking of pulling off the muffler too and replacing it with a less restrictive resonator. Not sure how loud that would be though. I realize any gains here will be minimal if at all.

intake- Currently I have the stock airbox with a K&N. From what I've read, it seems to be that the cone filters, without some sort of shielding for cool air, actually hurt more then help. Is the standard box the way to go?

cams- Any good aftermarket cams out there that could aid?

I'm not looking to go any more hardcore other then those areas really. I am planning on doing all of the obvious upkeep items on a high mileage car such as mine like plugs, wires, rotor, etc in the spring as well.

I think I'm really trying to optimize more so then make additional power but any easy tips would be appreciated.

MPD47

Webcam. I dont know what kind of ecu mods you're going to have to do to take advantage of parts on the NA though as I dont have the stock ecu. I'm sticking with stock headers.

Techno Duck

You can try JME for cams also.. http://jmengines.com/index.htm

ubercooper

porsche headers are as good as you will get.

if you want more hp, get a turbo. You will not get more than 20hp from any upgrades under $3000.

porcho heat

Lose some weight and appreciate.

jgporsche

I gained 10.9HP and 11TQ at the wheels with a Speedforce Racing exhaust. The exhaust was from the headers back. It was a full 2.5" stainless steel system. It has a high flow cat, bullet muffler and 4" tip. My opinion about exhausts on these cars, is that you DO need some kind of restriction in the system, too much free exhaust will inder your performance. This is why I have both the muffler and high flow cat.

The stock intake manifold, t-body, and air intake is terrible. The intake doesn't flow enough for the head, the t-body is too small to make any power. Check out www.customengineeredperformance.com they do intake and t-body mods. I will be sending my parts to them soon.

as far as cams go... i would go with jon milledge as was suggested.

Also another thing to remember is that your car needs to be retuned after each upgrade. so get something like the Maxtronic, so you can take car of tuning.

82-T/A

I haven't seen anyone mention it at all yet, but I am really wondering what the logistics would be of swapping in a SHOC 2.7 into your 83-944.

I have a 1984/944 and that's one of the things I'm considering as well. It would seem to me (just looking at pictures) that it's an identical motor all around, with just a slightly larger bore. Can anyone confirm or deny that?

If that was the case, and you weren't concerned with keeping the car numbers matching... you could look into getting a 2.7 out of a wrecked 944, and then upgrade that motor.

The 944 was certainly a MASS produced Porsche. Granted, the car is far more refined all over than any of my other vehicles... but it still is a mass produced vehicle. That said, the following would probably greatly improve performance:


1 - A good port & polish of the cyl head.
2 - Port matching of the intake to the cyl heads, and the cyl head to the exhaust.
3 - A tubular header system. I've seen cast iron manifolds on some stock 944s, and then I've seen tubular manifolds on other stock 944s? What's the deal with this?
4 - A hi-flow catalytic converter (if you still have the stock one on)
5 - FULL maintenance on everything to ensure that it's working at LEAST like new.
6 - Hotter ignition coil. (you can go with a 40,000 volt and will definitely improve the performance of the motor in the upper rpms). Accel sells a direct drop-in.
7 - Low impedence spark plugs instead of the chincy 7mm ones.
8 - Ceramic coating of your exhaust manifolds (if we can use those tubular ones). I think I'm going to make a post about this... I'm curious...


Not sure if these are available for our vehicles, but maybe a larger throttle body or an improved intake manifold? I'd be skeptical in doing this though, as Porsche might have done their homework in terms of incoming air volumne, and it might already be optimized. That said... the 944 is not a 911, and didn't get the treatment that the realy expensive Porsches did (at least not the early NA 944s like you and I have).


Hope that helps?

MPD47

I've never seen a cast log style manifold for a 944..... every one I've seen has been the standard 1-4 2-3 tube ones. (Other than aftermarket ones like Tim @ SpeedForce).

82-T/A

I'll have to take a really good look at what I've got on my 944 then... because I had thought they were cast (looked identical to some old small block chevy cast manifolds). I didn't see any tubes at all.

They might just be really rusted!


Either way, I think I'll have the spare set I ordered off eBay, ceramic coated to help dissipate heat and send it to the cat. I did this with an aftermarket header on my Solstice... made a huge difference. I can literally put my hand within an inch from the manifold and I don't even feel the heat. The engine bay doesn't even get hot!!!


UPDATE! I just went out and looked. What's on my car now are DEFINITELY cast manifolds. I'll make a post in a bit with some pictures.

jgporsche

most 944s came with the cast iron exhaust manifolds. My 944S has them.

Der Cupmeister

Be advised by someone who has intimate knowledge ..... The 2.7L na from the '89s has very specific and much more exspensive engine parts and fuel injection components than the 2.5's. There is az lot more to it than just a larger bore..

knfeparty

The 2.7 is nothing to write home about. Doesn't it, according to Clark's documentation, only have 4 more hp and identical torque?

FRporscheman

Yeah I've heard the 2.7L engine produces a negligible amount more power (I think it was like 163hp). They're just expensive to fix, rare, and have that coveted cylinder head everyone wants.

TheRealLefty

This a familiar, but always interesting discussion. Short of an old school bullet proof $30K-40K full race build with custom internals and massive upper end redesign (read JME SCCA motor) significant NA horsepower gains are hard to come by and very expensive when measured by "dollars per pony."

Lacking the proven combination of engine management and WG mods that can instantly ramp up a healthy 2.5 Turbo by 50-100 HP, gains with NA's are measured in 2-3 HP improvements.

I have a JME Stage One cam, cone filter, throttle cam, fresh Turbo valve springs, adjustable FPR and a custom low restriction header-back exhaust with only a Flowmaster 40 muffler and I don't think I've gained 10 HP over stock, if that.

FWIW, scuttlebutt suggests that a Jere Stahl header is just about the only NA bolt-on that makes a big difference, but like the JME cam it's a $700+ hit for a couple of ponies. Word is that the real deal killer in all of this is not intake or exhaust breathing but rather the head itself. The valves are big, they move a long distance and there's a lot of flow disturbance in their wake and therein lies the rub, apparently.

As advised above, best advice for NA performance is to take out weight, keep up your momentum and enjoy one of the best handling cars ever produced.

upcruiser

Great responses so far thanks everyone. I remembered an old thread on here posted by a guy looking to build his na into a 300hp streetable car from a couple of years back and went back and looked it up. It turned into a 14 page discussion in thermodynamics and covered alot of the engines limitations. Though alot of it was over my head, it seemed like some good progress can be made with headwork but really the valve layout was the main limiting factor, closely followed by some heavy internal components that prevent the motor from revving high.

Its all a bit discouraging, but at the same time there seems to be a lack of someone really trying to push the envelope with what can be done. I'm not going to go nuts on mine right now for sure, but if I could perhaps source another 2.5 it might be a fun project to work on without having to pull my motor and then rushing through rebuilding it.

With regards to my car, I've already taken some steps for weight saving as a couple of people have mentioned. It's an '83 with the manual rack so right off the bat its not bad. I removed the carpeting, sound insulation, the back seat, wind shield washer resevoir, and pretty much every interior piece othere then the headliner, front seats, dash, and center stack. When I get some time to work on it again, I'm planning on pulling the fog lights, removing the ac, and mounting up some R compounds on the cookie cutters versus my current Cup II's. I've been toying with the thought of doing lexan for the hatch but that might be a bit extreme at this point. Not sure what the weight is down to at this point.

I'm running the stock early 944 ECU still. I was considering sending it away to be reworked. Some companies claim up to 15hp but I bet, like most claims, thats being a bit optimistic. I'll have to research the Maxtronic a bit as suggested.

With regards to cams, from what I understand, to really take advantage of them, you need to free up the flow a bit on the induction and exhaust side of the equation, no? Does extrude honing the intake plenums make any noticeable difference on these cars?

Jgporsche, a 10hp increase from exhaust sounds promising. I've had a local (relatively speaking, 5 hours away, I live in the middle of nowhere) offer to fab me up a full custom stainless exhaust system from the header back for around $700. The guy does incredible work from what I've seen on my buddies old 500hp UR Quattro coupe but I just fear it not making any gains, or worse, being less effective then stock. I'm wondering how much of a difference, just removing the cat on the stock system would make. Besides a small crack on the top of my cat, the rest of the exhaust system is in great condition given the mileage. As also mentioned, trying to reduce heat in the engine compartment, I was thinking about using that exhaust wrap to encapsulate the maifold down to the confluence of the single pipe. I'm not sure whether I have the cast or tubular headers. I could have sworn I had individual tubes, but it sounds like these came on the later cars and I imagine that everything on mine is original. Unfortunately, I store my cars about 5 hours from where I live, which isn't all that convenient and prevents me from running out and checking. Does anyone have a couple of pictures showing the cast versus tubulars?