944 HP Questions/Answers
 

12-11-2008: I will edit and add this post as I gather more information

I thought I would pin a sticky to the top of this forum because the #1 question asked by naturally aspirated 944 owners is "How can I get more power out of my 944." Hopefully this will help keep anyones feelings from getting hurt by responses that they do not want to hear (or that are not phrased the best, as typically it is a quick reply due to the question being asked so much). This is not a post meant to put anyones car down, it just illustrates what is possible with the car and what is not.

I have spent many hours dyno testing numerous 944 upgrades on a mustang 500SE dyno. My previous full time job was modifying Porsches for hp and performance (up to 1000hp in the 996TTs), as well as general maintenance on both Porsche street cars and race cars. Part time, I currently maintain and build 944 spec cars, and have my 951 dedicated track car, so I spend more time on the track, than off, so my experience with trying to get hp out of 944s is extensive. So, you can take my advise for what it is worth (free) and do as you choose, but I hope this guide helps to put things down on paper before you jump in and start throwing parts at the car.

The short of the question is this: You can not get hp out of a NA 944 without spending what I would consider serious money (in relation to the value of the car it is being spent on). Now I will break it down for you in the long version.

Cold Air Intakes:
Cost: $25-50 (ebay). Gains: Minimal, if not a slight loss.
Cold air intakes are all over ebay, get rid of that unsightly stock airbox with a cone filter! Unfortunately, what little gains that you will pick up from the cone filter, are immediately lost due to sucking in hot air from the placement in the engine bay. Remember, cold air makes hp, hot air decreases it. The stock airbox actually sucks in cold air from the fenderwell, and is not that bad of a system. Some will ask, what about the cone filters I see over behind the drivers side headlight. This is found on turbo cars, with an aftermarket mass air flow sensor setup. The filter is located over there, again to try and get away from the heat. A maf is a much better system than the stock AFM the 944 uses, and is much newer technology. In short, it creates enough hp, that a little heat soak still leaves you with positive gains (and yes, even over near the fender, us turbo guys still struggle with heat soak on a hot day). Can you add a MAF to the system? Read on.

Mass Air Flow Systems (MAF):
Cost: $1000-1200. Promax motorsports use to offer a kit, but I do not see it on their site anymore. IIRC it did get good reviews based on driveability. I can not remember the hp gains, maybe 10-15hp.
One of the biggest advantages of a MAF, is improvments in drivability. With a stock AFM, there are a lot of hesitation spots throughout the rpm range, specifically immediately when coming off idle. The MAF system will greatly improve the driveability of the car on the street.

Throttle Cam:
Cost: $30 Gains: None
Gains from a throttle cam (sits on top of the throttle body where the throttle cable wraps around): Increased throttle response is the purpose and result from the throttle cam. A nice little aid to daily driving.

Performance Chips:
Cost (Early): $200 est. FRWilk. Gains: 10hp
Cost (Late): $150-200 Promax Motorsports. Gains: Claimed 10hp (I have not tested a 8V chip, but have tested their S2 chip, which did not make the hp gains they claimed, in fact, there was extremely minimal difference, even when dynod on a few different occasions).
Cost (Late) $200 est. FRWilk. Gains: 10hp
DMEs differ from the early 944s (83-85.1) and the late 944s (85.5 on). The later DMEs have a removable chip which can be replaced. There are a few vendors out there that offer chip replacements for the late cars. Promax motorsports is one. FRWilk has been tuning 944 DMEs for quite some time, and really gets good reviews from his customers. Again, mostly the drive ability is improved, and power delivery. Overall gains are 10hp or less. His early chips also fix the "Shudder" issue found in the 83-85 cars.

Camshaft:
Cost: $650. Gains: 15-20bhp depending on other modifications
If I recall correctly, John Milledge use to make cams for the 944 NA cars. Last I had heard, he had moved to the west coast, and appears to still be in business. He was known for building some monster engines, both NA and turbo (also $$$$).

Exhaust Header:
Cost: $700-1000. Gains: 5hp. Racers Edge
Cost: $320. Gains: 5hp Bursch
Cost: $1200. Gains: Untested, but figure the same. Billy Boat Exhaust (B&B)
Cost: $300. Gains: Claimed minimum 14% gain. Untested: MSDS Exhausts

Exhaust Test Pipe:
Cost: $300. Gains: 5hp. Bursch
Removal of the catalytic converter (suggested for off road use only), will free up a little hp, but will also change the tone of the exhaust. Some will call it very raspy and unbearable, others have not minded it too much.

Exhaust Muffler:
Cost: $100-250. Gains: None
The stock muffler is a straight through design, and while switching it out to a different muffler will help to change the exhaust note, the hp gains will be nill if anything.

K&N Drop in Air Filter (Stock Airbox):
Cost: $50-100 IIRC
Gains: 2-3hp, a slight increase in fuel mileage
Drop in panel filters are available for the 944 lines. I have never seen a big increase in hp in either the NA cars or the turbo cars, but if the engine can breath better, it will produce more hp. With that being said though, K&N filters let a lot of microparticles through the filter and into the engine. If you smear a small dab of grease behind the filter in the intake track, and drive the car for a period of time and check it again, there will be significant dirt particles caught in the grease. Can the engine handle small particles, probably, but just for everyone's information. A stock Mahle air filter flows pretty well and does a great job of filtering.

RE: 944 HP Questions/Answers
 

Suspension Upgrades:
Cost: $1800 and upwards
This is an area that will really make the car faster on the track and in the corners on the street. With the 944s nearly 50/50 front to rear weight ratio, it will still hang with a lot of cars on the road today. With the right upgrades to the suspension, the car will outhandle most cars on the road. It is an area where you can spend a lot of money, or upgrade on more of a budget so to speak. Paragon-Products offers a spec racing kit which covers a good part of the suspension components. For about $1800, you can get new Koni shocks and struts with front coilover conversions and stiffer springs. It also includes weltmeister 28mm front and 22mm rear fully adjustable sway bars, and 30mm hollow torsion bars. This will definitely stiffen up the ride and corning ability of the car. Remember though, it is a tradeoff.....the stiffer you go for improved cornering, the rougher your daily ride will be on the street. Staying mild with a 250lb-300lb spring, and swapping in 968 M030 sway bars in place of the weltmeister bars would be a nice compromise for the daily driver. Or, maybe you just want to upgrade your worn out shocks. Do not bother putting in the stock boge/sachs replacements, upgrade to the konis, for a much better ride (and shock).
You can also spend a lot of money on the suspension if you are seriously tracking the car. Upgrading to a full coilover suspension kit can range anywhere from $2000 for a bilstein setup, to over $4000 for Motons, Penski, etc. The sky is the limit.

Forced Induction: Supercharger:
Cost: $4500-5500 Performance: 182rwhp (215 flywheel) - 222rwhp (260hp). Speedforce racing
Tim at Speedforceracing offers 2 stages of supercharger kits for the 944. The hp increases are really good, but I have not personally seen or tested his kit. He is well respected amongst the 944 community, and has a great product line, so the claims could be true. At 8psi boost on his stage II, and with the compression of an NA engine, I have to believe the motor is strung out pretty hard.

Forced Induction: Turbocharger:
Cost: Minimum $3k and upwards. I would figure a good safe number to be about $4500 plus install.
I do not know of anyone offering a bolt on turbo kit, so you have a couple of options:
#1: Buy all the components needed from a donor 944 turbo car, and install them on your motor. I figured the cost of buying used parts (I have parted many turbos, so I had an idea of what you would pay), and the parts totaled a little over $3k using all USED parts. There is a lot more needed than just the turbo. You will need all the cooling system, intercooler, headers, crossover pipe, full exhaust, coolant tank, auxillary coolant pump, DME, KLR, Manual boost controller, turbo motor mount, and the list goes on. If you do a search in this forum, you should find almost a 100% complete list I took the time to write out. Now, once the turbo is installed, you are going to only be able to run 8psi boost or so on the motor, or you will shell the internals. If you want to run the full stock boost, then you are going to have to do internal engine work to handle it (I.E. lower the compression of the engine to handle the boost).
#2: Buy a complete turbo motor and remaining accessories, and drop it in the car. This is probably the most cost effective way to do it. Buy a motor complete with the DME/KLR/Turbo, etc for $2500. Add the remaining hardware, and you are set to go (probably another $1000-1500 in parts). The other advantage of doing it this way, is that now you can modify that turbo motor with bigger turbos, chips, exhaust, etc, and REALLY bump the hp without fear of the engine shelling.

And of course.....
Lets not forget another obvious choice here: Sell the NA (or keep it), and buy a 944 Turbo. This is probably the most cost effective solution there is. Remember, that even with a higher hp engine in the NA, you still lack a lot of things the turbo cars come with standard: Bigger brakes (very important with more hp), newer style body, bigger and wider wheels, etc. A lot of people become very attached to their cars, and do not want to look down this road, and that is ok too, that is why there are at least a few options listed above that will help them out.

RE: 944 HP Questions/Answers
 

Thread is now unlocked for additional questions/comments. If you have some information that you think should be added to the guide, post it up, and I will get it in there. I still have information to add, but think there is a pretty good base going...

RE: 944 HP Questions/Answers
 

The clarity and brevity of this post is the most useful thing that I, a new 951 owner, have seen to date. How about the same post but for 951s?

RE: 944 HP Questions/Answers
 

Sure, I can put together something for the 951 as well. Just give me a few days.

RE: 944 HP Questions/Answers
 

I'm like a kid waiting for Santalooking forward to your post.

RE: 944 HP Questions/Answers
 

Hi
Thanks for all the usefull info, as it answered alot of the questions I had. Can you add anything on a K&N stock replacement (washable), and also for the suspension, polyeurethane bushings.
Thanks
Paul

RE: 944 HP Questions/Answers
 

I'll see what I can write up on the bushings. There is a lot of information on both poly and solid bushings so I had left it out, but I will try and summarize it. The short of it: Tighter suspension, a little more squeaking from the suspension.

RE: 944 HP Questions/Answers
 

I have to disagree about the design of the N/A muffler.The last time I cut one open I found it to have several tubes next to one another, not a straight through design like the 951 muffler. I was also suprised you did not mention the gains that can be achieved by shaving the cyl head and having a 4/5 angle valve job in conjuction with some of the other mods you mentioned. Many years ago I had an 86 that I built using an 83 short block, head shaved past the limit indicator, 4 angle valve job I/E, modified a idler roller to bring cam timing back around, MSDS header, fuel reg crushed to achieve 10psi over stock, custom Autothority chip, stock exhaust w/cat in place. As you may see, it was a budget build! It did make close to 190 though. You may not be able to get big numbers, but it can still be quite the performer.

RE: 944 HP Questions/Answers
 

The list is not complete yet, only a start. I haven't had much time to dedicate to it lately. I will add more stuff when I get time.