porshaowner

What is the maximium rpm a 2.5na 944 race motor can sustain? Is an 8000 rpm or higher limit possible? If so will it be reliable for a season? What should be done to achieve this dream of an engine? I can't afford to build it, but talking about it and sharing ideas will be fun.

sharky47

Maybe we could turbo a NA engine, shouldn't take much.......




Just kidding - it would be nice to see some ideas kicked around.

nine-44

It's been kinda talked about in a bunch of other posts.. There would be little to no merit to this, the HP already drops off before the stock redline.

In order to get it there(off the top of the head) heavy valve springs, solid lifters, kickass connecting rods like Carrillo or Pauter, prolly go dry sump oiling, lightened valve trane(valves, cam followers, retainers), 4-1 header(tuned length runners, a nice tuned cam(prolly throw some overlap in there to promote flow up in the revs) a better- tuned intake with a "loop" runner off the back of the plenum to help balance flow(like the 968 design) etc etc etc, then off to the dyno to find that you need to make 4 more exhaust header designs, 10 more intake designs and cut a half dozen cams then go to the dyno to see what the motor really likes and in what combinations. That's my thoughts, along with this is a plan for a really bored person that just won the lottery and will only build a 944, lol. Like me!, well minus the lottery part.

nine-44

OOOO, OOOOOooh, or, oorrr, NA a turbo motor!

porshaowner

[QUOTE=nine-44]It's been kinda talked about in a bunch of other posts.. There would be little to no merit to this, the HP already drops off before the stock redline.

Thats because the stock cam was made for mid range torque not high rpm horsepower.

nine-44

I agree, but you are more than a cam away from 8K or alot of HP. Check out John Milledge. There's not a cam on that site for an NA that gains more than 25 HP or there abouts.

tod84944

Andy,
Post the link to John Millege site.

Kurt R

Here you go http://www.jmengines.com/

Anybody here say we have to stick with 2 valves, or can we use 4?

M758

It would take alot of work to get to 8000 RPM.

Two things are needed. One is adjust the air flow to actually make power at 8000 RPM and the second is to build it sustain spinning at 8000 RPM.

Lots and losts of work.

porshaowner

So besides the ludicris amount of money it would take, 8000 rpm is possable? Is the main block structure strong enough to handle this?

M758

bottom is not what gets torn up from high RPM. It is the top end.

What is a concern on the bottom end is proper oiling for those RPMs.

Even so this excecise is pointless unless you can get power from those RPMs.

porshaowner

So all the magic is in the cylinder head. With proper porting, larger valves, and a cam that works, 8000rpm is a reachable goal. Will both of the timing belts withstand this type of rpm? or is that not an issue? Since this wouldn't be a throwaway motor I think I would keep the balance shafts. Other than the weight would there be a draw back to keeping them?

Campeck

8k rpm might break rods. and rod pins or whatever they are called.

i heard somewhere someone had a 9k revving 968?

mark944turbo

"8k rpm might break rods. and rod pins or whatever they are called.

i heard somewhere someone had a 9k revving 968?"

They are full of ****. The stock crank fails at sustained 8k, that is one of several reasons why the 944gtr had a new crankshaft.

What is the ASSumption about breaking rods based on Campeck?

Campeck

which is why i said i think i heard.

so the crank fails before the rods? you going to tell me that rods will never break because of rpm?
you sure like following me around and saying *** alot.

what happened? turbo guys kick you out?