Modern Art and Performance (a local shop) had a free dyno session the other day. My S4 NA was lucky enough to get a turn, but only pulled about 116 HP. Its mostly stock except for hollowed cats and an HKS catback. It has no problem starting up hot or cold, and pulls pretty well throughout the whole rpm range. The only thing i can think of is that the aux ports were stuck closed at the time. (they have since been wired open). Would the aux ports not opening really take away that much power? Or are there other things i should do to trouble shoot?
THanks!
~Alex

 

you should notice a difference with the aux ports open vs closed, more air in and out means more power.

 

damn 120 hp? That's no good, I'm guessing that aux ports being stuck closed would cause that.

 

Not bad actually. Most stock N/A's I've seen on the dyno pull in the 130 range.

A few S5's I've seen creep toward 160whp, but very few and far between.

 

I dunno, 116 rwhp sounds about right.. you said you're mostly stock. Assuming 20% drivetrain loss on a stock 146hp engine.. that's right around 116 rwhp. You've done exhaust work but perhaps the engine's age is counteracting that. I remember seeing another stock s4 n/a dyno with stuck aux. ports and it was putting down around 106 rwhp. If they were functioning properly, he probably would have seen numbers like yours. So..


Bad news: these cars just don't put out much power.

Good news: it appears you have a healthy motor. Do some suspension mods and have fun; that's where these cars really shine

 

I pulled 140hp (Mustang dyno) on my S4 NA, but the aux ports were working, with Pineapple sleeves, I had no cats (Racing Beat presilencer/cat replacement pipe), and a SAFC-II leaning it out up high.

-=Russ=-