PDX-944

I bought the car a month ago, and ive been thinking "wow, ive never revved above 4k, because around 4k the power curve seems to dip off..." i thought all my power was 2-3k, and its plenty quick - its not a running issue. But after watching a few youtube vids of other 944 n/a tachs, ive determined my needle doesnt have near as much movement as those, and when im hitting 4k on my tach, im positive its much higher.
the needle moves right as i start, so its not a needle placement issue im guessing. it moves smooth. thats why i thought it was accurate this long. it looks like it should, just not calibrated correctly.
what could cause this? thanks!

Fara

What year is the car?

It's possible you have a gauge problem, but they are normally pretty easy to swap.

PDX-944

84, in the title haha
i drove it again tonight, and im not completely convinced now that its off - but i still have a concern then:
i autocross, and i have revved/ran cars to the redline many many times. in the 944 when i hit 4-4200, the engine sound just doesnt make me comfortable pushing it higher. it runs well, its got a slight ticking, but after about 3500 i feel like the revs are useless. so i shift, and at about 2400 i have a good amount of torque again. ive looked at stock n/a dyno sheets on google, and it doesnt look like theres a typical drop off at 3500. it seems like its running fine, but i cant imagine revving it past 4200 for any reason, and the engine is screaming at that rpm as is, so i wouldnt want to anyways!
is this normal at all for this?

i can try to get a video, but i doubt the audio would be good enough to help.
basically, i feel like shifting at 3750 is where i get the best power. and im curious if thats typical

Fara

Well I can say that my car definately doesn't feel like it needs to shift, nor do I notice a drop in power after 4k.
I've run it to 6k many times and It doesn't sound like it's about to fail or anything, so it sounds like something may be hinkey.

Maby grab a multimeter with RPM measurement and confirm it that way?

PDX-944

any link to how to do that?
my 944 DOES have 223k on it, so its not out of the realm of possibility. but it still pulls nicely.

Fara

depends on the multimeter - Mine just clamps over a spark plug lead and you set it to 4Cyl then it lists your RPM as either a number or on a dial.

Confirms your numbers very quickly and easily.

ZR8ED

Mine is chipped with a Wilk chip with a 7k redline. It does get rowdy sounding approaching 7k. 5-6k sounds like it is safe, but snarling nicely...by 7 it sounds down right angry. I shift a 4k on city streets, and I'm not driving around like some insane a$$ when I do it...feels very slightly spirited, definately NOT dangerous.

PDX-944

i need to find someone local with a 944 to drive mine and tell me im either crazy, or that my engine is noisier than it should be. it would go right along with my extremely whiney transmission (which shifts great)

Kurt R

Tell us what RPM is indicated at 60mph, and what gear you are in, and we can tell you if your tach is correct or not.

PDX-944

that makes sense, smart you are! haha, ill check when i leave here in a bit.

flagtie

Yeah, that is smart. There's also the graph in the back of the manual too.

PDX-944

bah, wish i had the manual. im guessing theres a copy online somewhere?

im positive my speedo is off. unless suddenly everyone drives 80. im guessing my 65 is close to 60.
when mine says 65 (should be around 60) im at 2500 in 5th. when mine reads 60 (probably 55) its at 2250. that at least about right?

the thing that makes me think its correct is the idle rpms seem right. it reads idle as 1000-1500, which is high, but it truly is idling high, and about that. is a little valvetrain noise pretty normal with this many miles? it pulls quite strong, oil pressure reads good (when the gauge is working). i just still dont see myself shifting above 4500 with the way it feels and sounds. shifting any higher would be wasting revvs it feels like.
i really should get a video...

Kurt R

There's a gear ratio chart at 924.org. If you put in the stock tire size of 215/60/15 and an rpm of 2250, you get 60mph in 5th. Put in 2500, you get 66mph. So it sounds like your tach is right, or you speedo and tach are off by a similar amount.

So now the question is why your car won't pull to redline. Could be a number of things: Plugged cat, dirty fuel filter, dirty air filter, failing fuel pump, bad plugs or plug wires, cam timing is off. It might take some time, but you'll figure it out.

PDX-944

i do know 2 things so far - my iacv needs cleaning, and i have a leak in one runner on my intake mani. ill be doing both next week.
the leak isnt so bad that i would expect that kind of effect, but its possible maybe? the iacv wouldnt cause that i dont think.
when i push in the clutch i get an idle dip. and when warm i idle at 1500. cold is at 1000.
again those dont seem like issues that would cause this. how should i go about diagnosing this? fuel filter is simple enough, and i suppose could cause my idle dip, no? i would expect the iacv more though.

i do have maintenance records. in 2006 the PO complained that the cat was rattling, but didnt have it fixed. in 08 the plugs, cap/rotor, and wires were replaced. that was 17k ago. then in 2010 the plugs and fuel filter were replaced again which was 14k ago.

the cat rattle is suspicious. i havent looked, is there a flange before it i can unbolt and pull aside and go for a drive, see how it feels?

flagtie

Here's the chart from the manual.