How to increase power on 2.5 8v
 

I am the proud owner of a 1988 944 n/a . At just 15 years old, I need to make more power out of this car because 158hp is terrible. Any cheap ways to make more power?

Real power that you can measure easily and and maybe even break transaxles with, or milktoast power that robs your wallet with no significant measurable improvement in performance?

Real: Drop in a fresh-tuned 951 motor or LS3.
Milktoast: Try and get there with low cost aftermarket bolt-ons.

A 944 is a great car for what it is but it's no tuners paradise.

Unfortunately no easy & cheap ways to get noticeable power increase with bolt-on mods. You can spend thou$ands and get 10-15hp increase. Best $-to-HP value is from the inside out:

- hybrid stroker crank for 2.8-2.9l
- Eagle 4G63 rods
- sleeve block for oversized Chevy pistons
- higher compression 10.0-10.5:1 like the Euro cars
- Rogue NA-tune for dyno tuning

Now you're looking at +60-70hp easily with substantial increase in torque. Gives you 944 Turbo performance for less than the cost of selling your 944 and buying a 951.

Learn to drive safely first. 158BHP is plenty , more than enough to accelarate the car up very steep hills. These cars are about balance, and roadholding, and very high cruising speeds(don't try this-guaranteed you wont like jail). If you want high horsepower just buy some Detroit iron, but it will be comparatively a pig to drive around corners

When I was 15 years old, I wanted more power, too.

Some time later (much), I want reliability, cornering, and good brakes.

There are no cheap power upgrades for an NA 944. I know an engine builder who will build you a 190 bhp race engine for $15K. Freshening of the engine, done once a year, is only $8K.

You want power... try a turbo, but don't expect reliabilty or economy.

At 15 I'd say if you want power on a budget get a Mustang five point oh and build that. They have pretty good power stock and it's easy to get more, and cheap used go-fast parts are plentiful.

If the badge is more important then live with the HP until you can at least afford an S2, they have good power and are not bad to own on a budget if you can wrench (and brain).

at 15 i would say you need to learn to drive first. i would be willing to bet that you already have more power than skill to use it. take the car out to a DE with an instructor, and you will find that out in a hurry.

To answer your question in an honest manner, there are several things you can do to improve the drivability, and response of the motor without too much $$. I really like the replacement Weltermeister throttle cam (it improves throttle response, and livens the car up a bit). I also have a "Wilks" computer chip in my 85 944 N/A, and it made a world of difference in the smoothness, revability, and top end performance of my stock motor. I also have a full stainless "Magnaflow" exhaust system on my car, which gives it a small boost, but also makes it sound SO MUCH better.

There is no one modification that can be done to get 50 HP without going crazy.

just as a point of realism, typically, on a normally aspirated engine, without getting into the engine itself to do things like compression bumping, cam work, etc, you are limited to about 10% in what "bolt-on" mods can do in terms of horsepower. it is not a cumulative effect either. it is erroneous, albeit common, to think that if a header does "X", and a chip does "Y", that you can sum them up. you cannot. there is a diminishing return on these. basically the rule of thumb is that you will get 100% of the what the first mod will do, 50% of what the second mod would do if by itself, 25% of the third mod, etc.

even if you do get inside the engine, if you stay normally aspirated, you will not get past a 25% bump.

raw power is not what these cars are about. if you are looking for 0-60 times and such, you chose the wrong car. almost every sporty car out there today will outrun any 944 in a straight line, no matter what you do to its normally aspirated engine.

none of that though means that you can't enjoy the car

1) make sure the engine is in good running shape and take care of basic maintenance. ($????)
2) get a Weltmeister or equivalent "throttle response cam", no more power but sure feels better ($20)
3) get the offset camshaft woodruff key, set the camshaft to 4 degrees advanced ($24)
4) get a Lindsey Racing NA-tune MAF kit ($650)

That combination got me a ~12% gain in peak power and ~20% more peak torque, with much more responsiveness across the RPM range. Car was great fun to drive with this combination.

How much do you want to spend?

also realize that any significant increases in power from tuning (i.e. a chip, advance key, or aftermarket ECU) frequently comes as a result largely of timing advance. this requires a higher octane fuel in order to achieve those gains. at a minimum you will have to run 91.

another thing to consider is that due to the timing advance of the above, if you have carbon buildup in the engine, the compression will go up. that means an increased likelihood of detonation.

forced induction is really the only way to get any real power out of a 944, and even then, it is limited with regards to what you can actually use, as it would mean a lot of other upgrades across the car having to be done

better to make sure everything is up to snuff, and then spend some serious seat time with an instructor on a track. then you will be able to appreciate what the 944 can do.

IMO it's pretty reasonable to want more power even if one is not that interested in driving skill, technique, etc. Plus young people nowadays might have lots of seat time in a Kart and already have it pretty wired. Imagine getting up a mountain or passing an RV with what amounts to base-model Civic performance. If instead someone wants Accord V6 level performance that seems pretty reasonable to me, I'm not one to say they should go to Skip Barber before braving the Accord EX Touring.

-Joel.

Step one: remove radiator cap and suspend in air
Step two: place 944S2 or Turbo under cap
Step three: reinstall cap as normal
Step four: Enjoy :)
Seriously learn to drive it first. This car will reward you with more joy on a twisty road than you think 158 HP could. Just adding a throttle cam on it will make it feel more responsive. A chip will gain you a few ponies and doing the cam offset key trick is as cheap as you can get. Forget the racy looking cone air filters that do away with the factory cold air set up and suck up hot engine compartment air actually taking away horsepower.

lol - i was going to suggest that, though i would have chosen a 968

If you want hi hp, sell your Porsche and buy something else. If you want a car that will play with ill driven GT3s at the track, keep your car and add the following:

Aero, front splitter and rear tail
FABCAR A arms
Aggressive wheel alignment for the track
Remove everything from the interior
Change the front windshield and rear hatch to plexiglass
Remove the sunroof and put in fiberglass patch

Oh sorry I'm building a race car.

Keep your car bone stock and put some nice Hoosier rubber on it, good brake pads, stainless steel brake lines and remove the CAT. Rock in roll.

In all seriousness, modifying the 2.5 NA engine for more HP is an expensive proposition. Be happy with what you have and make small changes to the suspension that will still keep it road worthy, then flog it at the track. I'm a PCA instructor and you wouldn't believe the number of A students I have that drive stock 944s (with a few suspension tweeks and R compound rubber) like they have 250 HP under the hood.

Fellow youngster here. You're not going to win drag races or spin your tires in anything other than 1st, so enjoy it! I've got an 89 NA and on a budget these will give you the best driving experience possible! .
Throttle response Cam $30
Racing chip $200-400
Sticky Tires $600
Short throw shifter $100

Realistically these are what you'll want from your car to push it on an open road. Enjoy it, maintain it, and when it blows up put a ls1 in there.
Cheers
Alec

You're allowed to drive at 15 in the US?? Waay too young. Madness.

Only in a couple states and even they have a lot of restrictions.