Getting more power from the 'S' model...

[Mike_944]

It's finally that time where I can start digging into my 944S.

I am wondering if the 16v is any different in options for gaining power than the limited 8v.

I am going to be pulling the engine and need to send out the head to be shaved etc...

[v2rocket_aka944]

heres a starter..

http://forums.rennlist.com/rennforums/924-931-944-951-968-forum/782202-944s-16valve-na-tune-dyno-results.html

[Catamax944]

also s2 intake manifold and if i'm not mistaken performance camshafts are also availible.

[JD159]

Headwork (competition valve job, larger valves, port and polish), Cams as mentioned, some sort of chip, S2 manifold, possibly an intake directed to the nose like I have, exhaust and headers.

All this with the correct tune (which I am looking to find) will give you a pretty solid improvement in overall power. Its certainly much much faster then stock. Once its tuned properly I want to get a good dyno result.

[flash968]

if there were a market for this, i'd develop a centrifugal supercharger kit for it. that kit would gain 35% in hp and torque, across the board, and be smog legal. it would go for about $6k.

but, as i suspect that nobody would be interested in spending that much on a 944, i have not pursued it.

[Lapkritis]

That may be the second worst hp return for dollar and spent that I've ever seen. Right up there with the Audi S4/R8 supercharger kits by PES... in my opinion.

[JD159]

GUILTY

Flash if you made it, I would of bought it...

[flash968]

worst hp per dollar??? have you ever tried to pump anything up? there are diminishing returns with power increase items. carol shelby used to call it "cubic dollars". the industry standard on any supercharger is 30%. that's huge. perhaps you misread it as 35hp and not 35%. on a standard 944S, it would go from 190hp and 170 lb/ft to over 250 hp and 230 lb/ft.

as for power comparisons, that puts it square in 968 engine territory.

as for cost, that is about the same as buying a used 968 engine and all that is needed to get it in there.

a ported head, headers, cams and all the stuff you could possibly bolt on won't give you half that increase, and won't run all that well. i could generate a lot more power, but at the expense of civility, and i won't do that. when i do a kit, it's transparent in operation. this amount would be straight bolt on daily driver reliable power.

a 951 swap could make more power, but there is a whole lot more involved, and in the end at a higher cost.

not sure what else you could do that would even get close in power upgrade for anywhere near that kind of money, with the same kind of results.

but as i said, most people would not do this kind of thing anyway. most 944 owners just don't have the money. so, they do stuff a little at a time, as they can afford it, and ultimately end up spending that much anyway, but not getting the power and drivability they wanted, or they sell the car and move on.

i wasn't trying to sell the idea. not sure i have the time anyway. but, rather i was saying that i would have probably done this a long time ago, if things were different.

[Lapkritis]

Sorry, meant the NA tweaking.

[flash968]

ah - i didn't see anywhere that there was an expense figure attached, so i assumed you were referring to supercharging.

i agree, tweaking a normally aspirated engine has very limited returns for your investment. it can be a step by step path though, which is why many do it. it's not so much money right out of the gate.

been there done that though. did it on the 968 too. in the end, i developed the kit, got it CARB certified, and now have 45 of them out there with many thousands of trouble free miles on them. that's what it's all about anyway, right?

i'm not sure what the truly "best" way to improve a 944S would be. it's a complicated problem. if you bump up power beyond a point, you need to bump up brakes, suspension, drivetrain, and all that. where does it stop?

another thing shelby used to ask was "how fast do you want to go?" immediately followed by "how much money do you have?"

[Mike_944]

I guess I should specify what I want out of this thing.

I want maybe 20 more hp/torque from it.

I'm gonna be upgrading all the suspension and brakes to something reputable.

[Mike_944]

Originally Posted by JD159

Headwork (competition valve job, larger valves, port and polish), Cams as mentioned, some sort of chip, S2 manifold, possibly an intake directed to the nose like I have, exhaust and headers.

All this with the correct tune (which I am looking to find) will give you a pretty solid improvement in overall power. Its certainly much much faster then stock. Once its tuned properly I want to get a good dyno result.

Have you had this done to your S?

[guru944]

Mike _944:

Its all doable. I'm there right now and pushing ~+250hp with MAF. Really surprised a white E46 M3 on the LIE going East by exit 43 Oyster Bay Road exit. Driver was in disbelief...and was Pulling away slowly up to above 5800rpm in Going into 4th Gear....
Old school is no bed wetter...
Later..

[flash968]

over 250hp from a 2.5 liter 944 engine normally aspirated??? that had to cost a pretty penny.

[v2rocket_aka944]

thems must be some big cams.

[flash968]

what? i didn't see any pics - oh - cams - not cans - roflmao

sorry - went straight from the porn site to this one, and hadn't cleared my head yet

ba dum bum

seriously though, yeah, i would expect big cams, huge ports, stiffer valve train, bigger valves, bigger intake and exhaust manifolds, a MAF, completely new programming, and probably higher compression. all in, probably at least $15k retail. could be as high as $40k

[JD159]

Mike, yes I have done all of this

Sorry flash but doing the mods I have done have definitely netted me more then half of what a supercharger kit could do. Well not all supercharger kits, just one you were referring to that would get about 250hp. I'm sure its possible to design a system that could get well over that, but maybe not quite reliably.

It was all done by Lindsey Racing. I can get the sheet on the headwork and cams to list all the stuff they did but it did cost a pretty penny. Not anywhere near 40k though. I'd say under 10k I cant quite remember

I had a dyno sheet, but the car was running very rich and much slower then it is now and STILL made 180 RWHP. So at the crank its getting up there in terms of HP. I'll see if I can track it down. I don't have the dyno sheets to prove but thats what I remember. I will be getting it dyno'd come spring so I can get the chip programmed by Russel to be more accurate because its way off right now. I'll also be adding the S2 manifold.

I kind of forgot about the dyno sheets because they had so many issues with the chip and AF, that when I got the car the FQS was cranked up to 9% or so. When I decided to investigate the rich issue and turned that switch down, (its currently at -3%), it REALLY woke up. So I'm not sure what a dyno will show now. However, when I do get it done and everything settled over the winter, I'll be sure to post a dyno sheet so nobody thinks I'm crazy!

From the bill:

Head:

Complete rebuild.
replace valve seats with 968 seat
competition valve job (5 angle)
port and polish,
968 intake valves.

Cams: Webcamshafts grind# 278/264

Valve lift:.441/.398
Duration: 244°/233°
Duration @ .050": 227°/216°

*No idea what these numbers really mean, posting for those who have more knowledge, info taken from webcam website*

Exhaust:

MSDS headers from Lindsey Racing (made for S2 but adjusted for my car)
3 inch and 2.5 inch parts to reduce noise
No Cat, just resonator and muffler.

Intake:
Cone fitted under the nose (no idea if this actually does anything, but its how I wanted it for cooler air.)

Chip:
Maxhp - Russel Berry

Misc:

Soon to be S2 intake manifold.

[flash968]

i should have qualified my comment by saying that it wouldn't be terribly streetable if you went much beyond half of what the supercharger would do. by streetable i mean mixture correct, good cold starts, not having to raise the idle, yada yada. turn key normal in operation, daily driver reliable in all weather, just as if nothing had been done.

at 180 at the wheels, you would be making about 215 at the crank. a far cry from 250+, and more like i would expect. to answer the math question, drivetrain loss is a fixed number, not a percentage like many think. were you to use the standard 15% for drivetrain loss though, you would end up at 207 from 180 at the wheels. even farther from 250+. just as a note, both of those numbers are about half of what the supercharger would do. the supercharger would push the entire curve though, and not just the right side.

the real problem with cranking things up normally aspirated is that the curve gets really spikey. horsepower numbers are pushed to the right of the curve. the thing that makes a car go fast is torque. widening the torque curve, and pushing that up is the key.

like i said, it's diminishing returns. you end up spending a lot more money trying to do it normally aspirated, and generally lose reliability in the process.

again, not selling the idea. just pointing out some realities. i've done it just about every way that can be thought of, and all of them have their own plusses and minuses.

i look forward to seeing the charts though. i'd like to know just what somebody can do, in streetable trim (not interested in race car setup).

[JD159]

Hey Flash,

Just trying to understand things properly, you have much more experience and knowledge then I do so i'm trying to wrap my head around this stuff.

However, the S dyno's at about 150 RWHP and Porsche lists it as having 190 HP at the crank

If I have 180 RWHP, I'm around 215 - 220 hp. Thats really not toooo bad for NA. It certainly wakes up the car and I would say is worth the money.

Sorry had 140 earlier, was looking at the torque numbers, Id like to say that stock its 150 RWHP. Anybody know for sure?

I may have more, I hope I don't have less :P. But i'll be finding out come spring time. It certainly is a lot quicker and more fun to drive with the stuff I have done. Yes, a far cry from selling and buying a turbo, or getting a supercharger, but its unfortunately all that is available really.

Oh, and 100% streetable. Great cold stars, idle's perfect. Reliability, well, its getting better I hope!

[flash968]

this is a common area of confusion. people read a number and then draw conclusions, often inaccurately. i see so much dyno talk out there, it's silly, and most of it has no basis in reality. i've spent about 300 hours on various dynos, and have had the opportunity to learn a lot about what they are good at and good for, and what they are not.

porsche lists the S at 190 at the crank. that is with a brand new engine in perfect running order.

if your engine only made 139 at the wheels, then i would say it was probably not in perfect running order, because you should have made about 165. if i had to guess, i would say that engine had about 100k miles on it. you will lose about 1% of your power for every 10k miles on an engine.

also, different dynos read differently. a windyn will not read the same as a mustang, which will not read the same as a dynojet, none of which will read the same as a dynapak. the differences can be as much as 10%.

further, tire pressure, strap tension, air temp, humidity, yada yada, can all be factors which can alter the numbers.

that is why the only thing that matters is the before and after, and even then, only what is at the wheels. calculating forward to the crank is mathematical masturbation.

drivetrain loss can be measured though, on an eddy current dyno (unlike a standard dynojet 248). if you do measure it, you will find that it is between 30 and 40hp on a 944/968. once measured, you can then add that to your rwhp numbers and get a real crank number.

215 is no joke though. that's a significant increase for a normally aspirated engine. that's a 13% increase.

yes, bigger numbers can be reached, but again, at the expense of how it can be driven. you could probably get close to 300 hp out of that engine, but it would idle at 1500 and only have power up over 4k rpm. not exactly fun to drive back and forth to work. such an engine would also cost you a bundle. the last 944 engine i did like that was about $25k, and that was over 20 years ago.