944obscene

The head is an 8 valve design. Most any 4 cylinder that is offered in 8 and 16 valve design sees big hp differences between the two.

the 4A from Toyota. The GE head (higher performance) was the secret. Porsche 2.5 making 160? The 1.6 4age made about 120 NA. hp per liter was amazing. The 4afe (economy more or less) was a joke however with sub 100hp numbers.

The Saturn 1.9 in the S series is another good example. The blocks are identical with different pistons designed to accommodate the number of valves per cylinder. The head was the only real difference. With an 8 valve head, the motor makes around 90-95 hp... at the crank. The "twin cam" 16 valve head allows the motor to produce 124 crank hp. Big difference with only head design.

The 8 valve 944 NA's just have a low peak due to head design. Its well known that for optimum VE and burn characteristics in a cylinder, the valve and port design are the end-all make-all factors. You need to be able to flow a certain amount of air to make a certain amount of hp. Likewise, the valve area and angle (angle between intake and exhaust valves) of the head changes the way the head can breathe (overlap and other conditions in mind). The squish area needs to be designed to allow optimal burn as well. An 8 valve head doesn't take advantage of some of these things, while a 16valve head can.

One note. The SB Chevy V8 does NOT flow very well, but does make good power due to shear size. However, a company developed a 4valve per cylinder head to be used on OEM style valve components (cam, lifters and pushrods... yes all unaltered). This yielded a power increase of over 100 hp on top of a cam and a couple other things (already installed and dyno'd with regular heads). This was due to the larger valve area and better squish area as well as superior flow characteristics.

I can see great potential with the 16valve Porsche head, but not so much with the 8v. (speculation)

944obscene

I'm not trying to bash. Just trying to make sense of thins. It would take an awful lot to make almost (if not more than) 200hp on that motor. Not sure where you'd get an extra 40 brake hp.

Olli Snellman

This car is built for the local "low cost" endurance series, so there are quite strict rules what modifications can be made. There are a lot of E30 bodied 325I BMW's in that series. These cars (euro version) originally had 170 hp. They take over 200hp's easily from these. The engine size is the same as 944's have and also two valves per cylinder. So if it can be done with BMW's why not with 944 N/A.
For me it does not make any difference. I do not own a 944 N/A, i am 951 owner.

xsboost90

i think the higher compression euro pistons are the key.

944obscene

+1 im not discounting the claim.im just curious about the engine aside from the head. the 8v head can only be so good but its not always the amount of air you get but what you do with it. compression numbers?

TedA

I had a 2.5 race motor rebuilt due to failure shortly after I bought the car. Many $$$$, sleeve kit, custom pistons, head work, valve work, etc., etc. etc.....Oh and a dyno sheet. Most here would not be impressed. I believe I am easily within 10% of peak HP possible without spending a butt load of cash. Some of you have seen the dyno sheet feel free to comment.

Low end torque pulls great out of the corners and keeps up with most until the straits. It ain't a GT3 but it serve its' purpose.

V2Rocket

do you know off the top of your head what kind of numbers it put down?

TedA

Just a hair shy of 160 rwhp, peak at approx 6000rpm, torque approx equal in ft-lbs. at I forget what rpm, I can report back tomorrow if interested.

V2Rocket

if its no trouble then id appreciate it

TedA

Shoot me a pm with an e-mail address and I'll forward you the dyno chart in the a.m.

porshaowner

What camshaft was used? What was the reason for sleeving it? what was the static compression ratio? whose exhaust- header and rest of system? whose computer program? What pound fuel injectors? that should cover the questions.

Cone_eater

A little OT... but
Can a 16-valve head be fitted on a 8-valve 2.5 motor?

Raceboy

On race configurations we have Formula Baltic where they use 8valve 1.6liter VW engines that even don't have cross-flow heads and still make 200+ rwhp.

On 944 200hp is possible: get a good cam (Milledge), run Euro engine (not US that has *****-CR pistons in it), use ITB's from GSXR1000 or Hayabusa and standalone EMS.

And for those who can't see further than one's nose and/or don't know engines elementary, I built fredisGT 924 Gulf 2.0 NA engine (EFI, standalone, 931 head, raised CR, stock cam), and ITB's weren't allowed, we made 120 rwhp on the dyno (he can provide a dyno-sheet). 120 rwhp is pretty good for 924 NA engine.
Beats me how some people here think that 163 hp is max that this engine can make and that factory already maximised it's potential and also sort of think that this engine is one of a kind (in not capable of making power if done properly).

Peace

Mongo

Milledge isn't the only best camshaft maker out there. Webcam is good too and have cloned the specs on Milledge cams for customers. They also save you money compared to what Milledge has to offer.

As far as breathability goes for the 8-valve 944, if you look at the port sizes, they are matched to the valves. This means the ONLY way to get more into that motor is to get bigger valves and bore those port sizes up. With that comes the need for more fuel.

TedA

Motor was torn down due to blown head gasket. The deeper we got into it the more problem were discovered.

Webcam camshaft. Motor sleeved due to the bores being found out of round....Darton sleeve kit, bored to 102mm (technically now 2.6 liter). JE custom pistons CR<11 to 1. Header and custom exhaust, can be run open or capped off. Back pressure of the muffler (glorified glass pack) actually helps torque. Electromotive crankfire ignition. I believe the chip and injectors to be stock, but is does have an adjustable FPR. Those smarter than me here on the boar that have seen the dyno chart that there is likely a little more to be gained by getting the AFR adjusted through certain RPM ranges.