Most Power From the NA

[PHillary]

I know most of you guys favor the turbo in terms of Hp and getting the 944 to go fast. But I was just wondering about how much Hp's you could squeeze out of an NA engine. I have an 88' 944 NA and it is supposed to be about 160 Horses at production. I've had the Head ported and polished added a new costum 3"exhaust Catback system, MSD ignition, new sparks and wires, new belts waterpump hoses the whole nine and it seems much more quick and relieable but still wanded to know what others are doing with there's and How much can I expect with added mods the only mods I haven't done are Headers and a Chip. I mean I've added so much bolt on mods, (except for the mentioned above) and even now I can't drive the car because the car is getting so much torque the Factory clutch is not holding pass 3500rpm's. don't have access to a dyno but My mech says there has been aleast a 25hp increase since he last worked with car (after I did the Head) just don't know if that's replaced hp's that was lost over the car's life span or new horses from the port job, maybe it's both. Thinking about adding Nos or some other Nitrous setup. Just not sure about the gas don't want to open a new can of engine worms.

P.S. what do ya'll think about the Centerforce clutches.

[Brando]

None of those modifications will give stellar results without a chip change. Even then, you can't tell without putting the car on a dyno.

Or a MAF conversion/chip change. Otherwise you'll make less than stock as the system tries to compensate in so many ways for running too rich, ultimately running poorly.

You also won't need a different clutch until you break the 300hp mark. The stock (TURBO) spring-centered clutch you SHOULD have (if not, replace that rubber-centered clutch with a spring-centered clutch).

If your clutch will not hold, you have other issues. Oil on the disc material? Bad hydraulic clutch system? Are you riding the clutch? Slipping it when shifting (big no-no, don't slip the clutch or ride it).

Also, 3" for a 2.5 NA is too big. You may want to go 2½ with the catback system, maybe 2¾ at most. The cars that benefit from the 3" system are the turbos, S2s and 968s. These engines are not like big-block V8s where a bigger carb and bigger exhaust will net over 80hp increase. The system in stock trim is pretty advanced and efficient for it's time.

To be completely honest your best money will be spent on the suspension first, engine last. I say that because a lot of people who alter their suspension make the car handle incredibly well, then they strive for turbo car, or a 3.0 engine from an S2 or 968, which comes with more power (and power potential) out of the box.

[PHillary]

Have my eye on a suspension but I needed to get the engine running good first Had valve issues when I brought car from previous owner they messed up the timing job and I had to get the head done so I had it ported while it was off. Had the clutch double inspected by two competent Mechs and they both told me the Clutch job was fine, I just don't understand why the clutch won't hold. passed 3500rpm's had the whole Hydraulic system replaced and it seemed fine no leaks no softness of clutch or air in new system the brakes work almost perfect!. I just don't know what's up with clutch that's why I'm thinking of Centerforce's Clutch system supposed to have 90% more holding power over the factory one.

Which 944 do you have?

[Techno Duck]

I honestly dont think your n/a is anywhere close to 25bhp over stock. My '87 had a ported head, full 2.5'' exhaust with no cat, FRWilk chip and pretty much a completley refreshed top end. The car made 136whp on only one single run. All other runs came in around 126whp. If you factor in 15% loss thats about 150bhp roughly... factory rated was 147bhp. True its a 20 year old car and may have loss some power.. but the car had good leakdown (3-4%) across the bank.

I think the only really proven methods of getting much power out of these is to swap for a more aggressive cam (dyno proven 10-15hp gain at the expense of a shifted powerband) and bumping up the compression (euro pistons).

A good stock turbo clutch is said to hold 350whp without problems. If your factory clutch is slipping (rubber center, spring center?) i think you either need to check the adjustment on the engagement or the possibility of coolant or oil soaking the disc. Make sure the clutch pedal free play is adjusted right.. my 951 clutch would slip only when at normal operating temps because of the adjustment was out of whack.

[PHillary]

I had the NA's stock clutch installed, will look into the turbo disc's swap-in, As far as I can tell there's no oil or coolant hitting the clutch disc. every thing was dry as a bone when inspected last by Mech. I think the stock NA clutch is just not up for the job of the added mods I put. Back to my orginal question? What is the most added hp these cars have seen. 136 or147 to What? is 156 or 180 reasonable hps from add ons without Nos or Supercharger and Turbos. Not changing my engine until it dies! for the most part I am pretty happy Just want to know what others have seen and how they went about it.

[Aslet]

It is a 944, go for handling, not power. Before any work, the best way to improve your car, any car, is you! Autocross and do drivers education at local tracks. Once you have a few seasons under your belt and can push your stock setup, upgrade your suspension. Once you max out your 944 with a upgraded suspension, buy a 951... If you can drive the car well, and are on a twisty track, you should be able to keep up with most higher power cars. I was just at a drivers ed and was passing 911 Turbos. Also, if you are spending only a little extra on work you need done, it is reasonable, but don't waste a lot of money on a 944 NA. I saw a fully track setup 944, it had around $70,000 in it (real sweet setup) and was talking to the owner, he said don't waste your time or money. The car is 20+ years old and is plain and simply outdated... Saying that, its a great car to start with, but you could buy a setup car for maybe 20 cents per dollar the owner put in...

P.S.- Unless you are able to port the engine out to 3.0L or something crazy, I would not say expect more than 150 hp max. So without doing major engine work, don't waste your time.

[PHillary]

will probably never buy a turbo and do all these mods again, No-way I would rather put in some Nos and run until egine dies, rebuild or swap in a ls1 V8 and mess around with it. I Just can see myself buying the same car over again just for a turbo and more hp. Because after I done, my car will have a better suspension and brakes than the factory turbo.

[Aslet]

But the turbo was built by the factory to handle all of the power... It isn't just a turbo added on, or you could just add the turbo on. Also, I don't know what you want to use the car for, but if you actually want to learn how to drive it, check club rules. I know that at least my section of PCA will NOT allow NOS. So you may want to check your local PCA and SCCA to find some guidelines about allowed items. Just my opinion, but whats the point of all these mods to drive the car on the street (or dumber yet, street race)... Like I said before, how much autocross or track time do you have? I don't care how good your car is, if you can't drive, you can't drive...

[Techno Duck]

I dont think any club will allow nitrous in the car (auto-x or race track) except for a drag strip.

[PHillary]

The 951 in my opinion is a NA with a (Turbo and Suspension upgrade) there's open arument about how much hp the NA and Turbo Transmissions can hold. After I finish upgrading my suspension to better than turbo standards I will see some Autocross and Race Track days. As fars as what am I do with it, I just want the fastest, most Handling friendly and reliable NA car this side of the earth has ever seen. Happy with just want to get the most out it. I will not however take my car to the track or Autocross it without the suspension being correct because the current 20 year old suspension that's on it might send me into a wall. It wobbles bad at 120-135 mph. And gets the angry shakes when I apply pressure to the brakes. There no-way I will let my car onto the track with those issues. As far as Nos and the PCCA? and Club events if I can't take the bottle out and Play I won't play, I will go to other events where nos is welcome.

[Aslet]

Just a heads up, not trying to kill your dreams. I would contact a local Porsche Club officer and ask if you remove the bottle is it fine... If you are not able to run anywhere (lots of tracks have the rules that all clubs have to abide by), it may not be worth it... Also, at a very fast autocross, the max you will ever reach is maybe 70mph. We have a small lot, so I never get out of second gear, so don't hold back driving cause at the cars top speed there are some issues. If you can drive it on the road/highways, it is fine. I'm not trying to be a pain, just as many people here will tell you, your car is nothing without wheel time.

[nynor]

Originally Posted by PHillary

I had the NA's stock clutch installed, will look into the turbo disc's swap-in, As far as I can tell there's no oil or coolant hitting the clutch disc. every thing was dry as a bone when inspected last by Mech. I think the stock NA clutch is just not up for the job of the added mods I put...

yeah, it is totally up to that job. absolutely. if it is slipping, there is another problem. as for the centerforce clutch, i have one and love it.

the long and short of it is you are not going to get huge gains on that motor without some serious cash, and most will involve a supercharger or turbo anyway. if that is where you are at, i'd put a turbo transmission in it and a LS1 and call it a day.

[Dantilla]

Originally Posted by PHillary

I just want the fastest, most Handling friendly and reliable NA car this side of the earth has ever seen.

Then you will need to start with the 3.0 liter from an S2 or 968. Lots of low-end torque, and a four-valve head for better breathing at high rpms.

[Aslet]

Originally Posted by Dantilla

Then you will need to start with the 3.0 liter from an S2 or 968. Lots of low-end torque, and a four-valve head for better breathing at high rpms.

More like start with a Cayman S :-P

[flash968]

not to rain on your parade, and i am a huge nut of modifications, but a good catback and porting won't give you 25 hp - maybe 10, and even that is probably high - what it will do is make the engine pull better across the band - i'm wiling to bet that the 3" cat-back actually cost you low end power, though it might have helped by 2 or 3 hp up top, and gave better throttle response - this is a common problem with exhaust systems - they get louder so they "feel" faster - same with the somewhat snappier response - it doesn't necessarily translate to horsepower though

the header and chip should add nicely, but remember that mods are not strictly cumulative - that is to say that while each mod by itself might add a certain number of ponies, you can't add them up and expect to get it all - there are diminishing returns as you go up

unless you changed the cams, or increased the compression, with bolt up stuff (header, cat-back, chip, porting) i would expect a total of about a maximum of a 20% hp increase over a 160 hp stock engine

if you want to rip it down and rework the entire engine, you can probably get that thing up to about 225 or so, though it will be very high in the rpm range, and not very streetable - it will also be very expensive

as others have said, and carroll shelby said it best, "there's no substitute for cubes" - if you want a quick jump in power, drop in a 968 engine - with a few bolt ups, you can get over 275 from one of those, with a LOT more torque, and maintain streetability

keep in mind though that power is not everything if you can't get it to the ground - a lower power engine can still make a car very fast, if it is set up right

also, the best mod you can make to the car is to tighten up the loose nut behind the wheel

seat time on a track with an instructor is going to make you drive faster for less money than anything you can do to your engine

have fun and good luck

[Schumi]

A 944 spec guy over at their forums did a back to back with original cat/no cat on the dyno (they have to dyno per rules) and saw a 8HP increase without the old cat at the rear wheels.

This is one of the single largest gains you can get for the money right there.

[Dantilla]

I have a 3" exhaust on my 944 race car. Switching from the stock diameter offered a noticable gain, but only at very high rpms. There was a corresponding noticable drop in low-end performance.

There is simply not enough velocity through the exhaust system for proper scavenging with 3" below 5000 rpm.

As yours is just a cat-back swap, you may not have the same issues, if the manifold and cat have stock diameter. In this case, a 3" is simply worth nothing, as it is no longer a choke point. The exhaust has to work as a complete system. Opening up just the tailpipe will acheive nothing unless it's 3" all the way from a properly matched header.

While I like the header/3" combo for the race car, the lack of low-end grunt would make a miserable car for street driving. It's like eternal turbo lag.

[nynor]

everyone should do a search for alina's posts. she had some great ideas. ajajajajaja!!!

[PHillary]

Why, what did she say?

[ERAU944]

Originally Posted by Schumi

A 944 spec guy over at their forums did a back to back with original cat/no cat on the dyno (they have to dyno per rules) and saw a 8HP increase without the old cat at the rear wheels.

This is one of the single largest gains you can get for the money right there.

were there any other exhaust mods or was this with a stock muffler? was there a proper test pipe or just a piece of straight pipe welded in? just curious...