ok. i went and did 2 free dyno runs today and the results were disappointing to say the least. i was under the impression that my auxilary ports were working, but in the dyno sheet it looks like they are not. the VDI obviously kicks in and my horsepower just levels out from there to 7500. is that just my auxilary ports or is something else probably wrong too? there are no mods done to the car except a stock replacement filter and some additional ground wires.

 

here's a little zoom

 

clogged cats...get a header and catback and i bet u see an instant 40 hp gain

 

my car used to not rev happily (it made mean rough noises) at 5500rpm and past. maybe even not that high of an rpm. i took off the complete exhaust and installed an RB header to custom pipe to RP catback and now my car revs all the way to 8 (even 8500..) without that strange hesitation. big difference. but i do recommend having a cat. its not a big horsepower robber and your car will run cleaner. might even pass emissions.

 

I agree. looks like it's tapering off at the higher RPM's where flow is vital.

Good luck!
-Ross

 

the car had emmisions taken 3 months ago and i passed with flying colors.... so i'm not so sure it's the cat. it could be the mufflers, they are broken/rusty.. but they should still flow just about as good as stock, if anything they are more free flowing i think.... maybe i should go again tomorrow if they'll let me for free still with my ports wired open and see if i get a change

 

WHAT only 100hp thats just not roight!! myswell buy a geo metro or some thing in that nature!! damn man i feel fer u, get an exhuast system and intake u will instantly feel the diff in most ways!! i dont think the ports r cosing that useless u have that dreeded hesitation at 3000-4000 RPMage otherwise they should be workin'

 

At least you can learn where to shift

JAmes

 

yeah, i'll just shift at who gives a crap because i only have 100HP :P bah. this will be fixed, this injustice will not stand!

 

are your aux ports stuck shut? it looks like you have a little bump of power that starts right at 4000 or so (aux ports come on around 4k) so im guessing they're working. the VDI system also appears to be working (comes on around 5500) and on your graph it looks like the VDI came online and tried to bump the power back up a bit.
there is obviously a HUGE restriction somewhere whether it be intake (unlikely, go buy an autozone cone filter for the hell of it) or exhaust (my vote is for exhaust)
check that out and hit up the dyno again.

 

Remember, you have 100 HP at the Wheels in a car that spec'd at 146 HP at the crank from the factory.

Take into consideration your car is stock and has CATS, and factor in as much as 20% drive-line loss due to the age of the components, you are not that far off.

Pure stock S4 NA's don't put out much more

 

His car is actually rated at 160HP from the factory.

 

Ah S5, ok...

 

Wow, I think that's the worst dyno I've ever seen. But anyway you didn't ask about that. I'd say check out the exhaust system whether it be a clogged cat or a leak somewhere. Something is terribly wrong, I know the S4 makes more TQ overall (less peaky) but damn man. I think once you do some exhaust work whatever is wrong (O2 sensor maybe???) will smooth itself up and you'll be a very happy man. Good luck with whatever is trying to hold her down...wow

 

You wouldn't happen to have a graph of the A/F ratio also would you??? How many miles do you have on the car, and what kinda condition is she in (we can see the numbers but I mean how does she drive to you...).

 

if the exhaust is stock thats not too bad a chart...losing about 15 hp likely due to the exhaust being OLD and slightly clogged as well as reg. tune up duties. as i said, a minor tune-up and full exhaust from the motor back (racing beat etc...) and you will see +40 hp

 

here is the dino sheet from my s5 n/a, with 80,000 strait pipes and intake. gives you something to compare to since mine looks like its runnying right

 

Holy **** that's a mint dyno almost too perfectly flat of a curve

 

hahaha, yeah i kind of thought it was clean..... you can notice very well where my 5/6 ports open... and when the vdi opens or whatever that is... i thought one of marks them were secondarys...

I was kind of pissed cuase is doesnt show torqe nor my rpms....