V2Rocket

because theres nothing really to clean up with a port job on the head. its pretty much ideally shaped from the factory. the only real way to improve it would be basically to make the ports simply larger and match the valves accordingly. the manifold basically is port matched.

it is debateable whether a MAF will work with the stock computer, some people say technically no but some have had success basically tricking the dme into working with it. for something that truly understands maf output (entirely different than AFM output) it is over $1000 for a maf setup.

as has been discussed before, higher compression isnt the end-all to horsepower. yes it makes the engine more thermally efficient which allows for more hp to be sent to the crank and wheels than out the exhaust, but more HP is not possible without more air and fuel. this is where a higher lift, later coming-on cam is useful and probably the most advantageous part of a build like this. a good chip will work well if it is programmed to match the cam.

a cam is about $700. a chip is about $300 + all kinds of time to develop. 1000+ for a maf setup. custom high-cr pistons about 800 (from JE). add probably another $500-1000 for machine work on enlarging ports and new valves and working the manifold.

if there were a simple solution for under $2000, we all would have done it and this thread would say "the magic 300HP for NA?" and no one would buy a turbo for a daily car

86 951 Driver

Why is the machine work so expensive on this car? Is it because of the nickasil block or what? It seems like our cars are much more expensive to work on engine internals wise than a 911. Its just redicilous. Could a local machine shop do the rods and crank to balance it. Where do custom pistons come from? There has to be a cheaper source out there. If our ports are already maxed out then why don't people just put a bigger cam in stock then get the 944 hpmax kit for a chip and tune it? I think the problem has and always will be is that people are scared to try to max out this motor. Use some american engineering on an already maxed out engine. More cam, more fuel, a lopey idle, and bigger spark. Has anyone looked into web cams for our cars. I know Acura Legend guys use them and have had great success. Would ITB's be out of the question? Is the fuel management the big limiting factor or is the expensive machine or is the valvetrain holding us back?

Lorax

the balance shaft is due to an inherent imbalance in the design of any inline 4 engine, not because of unbalanced components.

You also aren't going to want to try and build an ultra high performance engine using nothing but ECU reflashes. At the least you will need a quality MAF conversion with piggyback from someone like vitesse. As far as being more expensive than 911 motors.... wha?? You gotta be kidding me... have you ever priced out just a stock rebuild of a 911 motor? Not to mention the motors start around $5000, where as a 944NA motor goes for like $500. The alumisil only becomes expensive if you start to bore or sleeve the motor. Custom rods and pistons running about 1k a piece is totally normal and no different than the prices for any other motor. Heavy machine work is espensive for any motor, personally I'd rather not have billybob's plumbing and machine shop be working on my car with a hand hone.

Lorax

Yes more HP is possibly without more air/fuel. That is the whole idea of raising CR. You will get more thermal efficiency, therefore more overall efficiency and thus more power using the same amount of air and fuel.

You guys are also ignoring ignition timing. Much more aggressive timing can be used.

V2Rocket

there are some crazy people out there and on this forum, its not really logical to assume they are afraid to build the motor because if they nuke it they can start over for like $300 with another engine.

machine work on this car wouldnt really be any different than any other car getting larger ports and valves, there's nothing special about the aluminum in the NA head. the blocks are a different story because if you modify the cylinders you will 9 times out of ten need to put sleeves in it or find someplace that can redo nikasil.

the problem with all these parts that are readily available for 944s is that the market is so small that large enough quantities are not able to be made to lower prices. something like 110,000 944 NAs were made between 1982-1989 worldwide. say half of those came to the US. and say a quarter of those are totalled, non-running, or just worthless. suddenly youre left with a potential market of under 40,000 units and the vast majority of those units are owned by people who couldnt care less about performance.

the 911 has been in production since 1964. lots of people have had the time to develop an expertise on developing those cars. and the new 996 and 997s are mechanical wonders because they use technology that wasnt even dreamed of 30 years ago when the 944 was starting to be designed.

also keep in mind the 944 engine was designed to be a mixture of performance and civility. the car, like almost all others, was designed with compromise in mind. it was supposed to be a quick, fast acceleration car with amazing handling able to go tear up a track event. however at the same time it was designed to be able to be used every day, with a cam and head design optimized for mid-range torque rather than top-end power. next time you get in your 924S get in maybe 3rd gear at 25mph. roll on the throttle and it will feel kinda sluggish, sluggish, picking up, and then once you pass about 3400RPM it really starts to come to life. this is so you can pass people with ease on the highway without really straining the car. horsepower peak is 5800 RPM on the 82-87 8v cars. this is also why the car has balance shafts and (HEAVY) hydraulic lifters. they are designed to keep noise and vibration down.

you could find a great cam or have one made that the powerband starts at 4000RPM and goes all the way to 7000. but to do that i wouldnt want to run hydraulic lifters, id go get a set of lindsey solid lifters that are a fraction of the weight and wouldnt collapse. and then youd probably want to put at the least stiffer 951 valve springs on your new larger valves to ensure that they are closing properly. and then call or email russell berry (944max guy, who actually has recently come under alot of personal problems and may not be available for some time, for everyones information) and see if he can set you up with a chip to match your cam and new airflow/fuel requirements, probably including (for ~200HP) about 30lb/hr injectors. and with all this you will sacrifice some of the ease of driveability although you could still live with it.

most people on this forum would love to get alot more power out of their NA. this topic has been covered a thousand times before. its not a question of fear, just money in relation to the small market. 944 guys generally arent as well off as 997 guys either. certainly there are people on here pulling 6 figures and driving an 84 NA with ripped seats and stuff but overall were shorter on money.


or weve learned to love and enjoy the car for what it is.





or weve come to realize that going NA isn't the way to go with 8v power builds....

V2Rocket

i think what i was trying to say was that higher CR is a way of salvaging some HP the engine already produced before but was just dumping out the exhaust pipe from thermal inefficiency. by raising TE that power is more able to be sent into the crank rather than out the pipe.

Lorax

The major point here is that while yes it is possible with a bit of forward thinking and a lot of money.


BUT - It's absolutely stupid unless you

a: have something to prove

b: are doing it to stay within some kind of class regulation


For all other circumstance, buy a friggen turbo or at least a 16v engine

V2Rocket

build an all bore high CR 2.8L na and rev it to 8000

DarylJ

I'm not sure there is any way to respond to that kind of logic.

V2Rocket

i believe what hes trying to say is...

"this engine was designed with almost no free tolerances from the factory as a completely worked package, but in reality i believe that it can still be improved upon"

Alxx Nova

Just a thought and I wouldn't bother to do this unless I needed to open the motor up so it would be a case of... well... while it's apart... why not. I do need to change my oil pan gasket soon and might be looking at a cam tower gasket (but that's another story for another post).

I was thinking that since I have a 89 2.7 and that the only difference in size between a 2.7 and a 3.0 is the stroke. So if the engine had to be opened up couldn't I add the crank and rods off a S2 or a 968 and bump my motor up to a 3.0 by stroking it the way the factory did. Then maybe one of those after market cams, but nothing to radical since I'd only like to add a little more passing power. Wouldn't that be worth some extra hp without to much trouble? Provided I was already in there working on the motor anyway.

Also I was wondering. I've heard that the 944S 16V head can not be used on a 2.5, but the S2 16V head can be used on the 2.7 (along with the proper 16V pistons and computer). So does anyone know for sure if the S2 head works on the 2.7?

Although I would much rather just drop in a complete 3.0 and computer and be done with it.

-----------------------------------------------------
Alex Portanova
1989 944 N/A
1999 Chrysler 300M
1992 Harley FXSTC

DarylJ

I think everyone knows that. Obviously more can be had from these motors. I don't ever recall anyone saying anything to the contrary.

All it takes is money. You can spend $1500 on a Chebby motor and pull out an amount of HP equal to the entire HP of one of these motors. You can spend $15,000 and pull out 50% more HP out of one of these motors.

Why? Simple: Chebbys aren't "built" from the factory, and 944 N/As have a much smaller aftermarket parts pool. That translates into only the more expensive modifications being left to do (same things you can do on the Chebby to get even more HP out of it), and almost no readily available aftermarket parts left to do them with.

I'd love to see this happen. I'd love to see it become something, so aftermarket manufacturers take notice and start producing things. Is it ever going to happen on a 20 year old dead platform? Highly unlikely.

V2Rocket

944S head will bolt onto any 2.5l block but will not work right away because the pistons on the 8v engine dont have reliefs for the extra 2 valves

S2 head bolts on to 2.7 block but needs valve reliefs still.

2.7 head bolts onto S2 block. this is how many of the 3.0L turbo guys do it

944S2NUT

Burned rubber thru 3 gears on a early 928?! That is pretty impressive.

V2Rocket

there is a 928 out there with over 800Hp. he probably has problems with traction at over 100mph