20SS06

Hello guys,

So I'm new here and this is my very first post. I just got a new Impala ss 06 back in December 09.
It really is a beast, I was pretty sure it was a factory freak(not to brag but I know my cars:biggrin anyways, I took it to the local DYNO shop, and made 3 pulls and the best one out of them 3 was 226HP to the wheels !!
I always see other guys online pullin 245+ HP bone stock.
He showed me one of the graphs on HPtuners suite(which he uses to tune)
that there is a lot of knock retardation even when I was in park!! when I floored it, it reach to an amazing KR# of 9.4+!!
can you imagine that? I think thats the main reason the DYNO reading wasn't accurate, as the engine would pull timing back decreasing the power when a knock is detected...he also told me that it might also be a torque management issue, and it might be from the spark plugs(frankly speaking I never even bothered to check them ever since I bought the car..I was too busy to)..
anyways guys thanks and sorry for making you read all this.
What do you guys think might be causing the problem?
Any ideas would be greatly appreciated.
P.S. My mods are a K&N CAI and Flowmasters super 44s and 3 inch magnaflow tips.

06 SS

sounds like the dyno is accurate, your car is just hurting, and a basic oil change/tune-up is the first thing I do on a used car, but I guess I don't know cars as well as you do...so, take it with a grain of salt; KR is waaay more likely to be fuel based (aka lean) instead of ignition based. I would look to making sure the MAF is not covered in K&N oil first, KR with essentially zero load (in park) is very bad. Check for vacuum leaks, crazy non-stock tune, plugs (to ensure that you don't have a broken tip flying around a cylinder), then scan to make sure that you are getting good temp sensor readings (aka no dead/unplugged sensors)

20SS06

Thanks for the reply!
LoL about me knowing cars more than you do haha
I have checked the MAF sensor and there is no oil, I'm gonna check the spark plugs tomorrow and probably do an oil change.
This is really frustrating though

Rossko85

iTrader: (11)

I would say keep on to what 06 said....if no avail...take a look at your O2 sensor as well....like he said, just plug into your sesnsor bank with a scanner...visually check it as well....dont get too discouraged, i was at 221whp on my run before my tune....and just another though...the LS4 has external knock sensors as well....they are outside the valley...so you could have once again, a sensor out or going bad....but I have had to tone down the KR sensors with my tuner just to get some practical numbers....and also, I know my car is this way but, mine was the last year they did the LS4 in the GXP and the GXP period and the first year they changed the ECU...its an E67 where as you guys have the E38...but, back to my point...the torque management is a very tricky animal for these cars cause it works in combo with ignition advance to pull that TERRIBLE TIMING ive come to call it with these cars....its a big factory pillow...so, if you cant determine that it has a BAD TUNE from the last owner, or a senor(s), or your plugs, maf, etc...then I would look at looking up a tuner and having them plug in either HP or EFI LIVE and take a look at your ECU....you might just need to pull down that KR with timing...BETA is the secret from what Ive experienced with mine and the timing world...my car pulls it up top and we cut out and my tuner cant see it...its invisible...so imagine fighting what you can feel but now see...LOL...

AND DONT WORRY ABOUT BEING LONG WINDED....I HAVE THE BOARD COVERED ON THAT...ASK ANY OF OUR GUYS!! LMAO...WELCOME THOUGH...WE ARE GLAD YOUR HERE...WE HAVE A GREAT BUNCH OF GUYS...WE ARE THE UNIQUE ONES THATS FOR SURE...!

20SS06

Thanks for the great reply!
I have made a checklist on the things you specified and I am taking it tomorrow to the garage and have em check it out.
I will definitely keep you posted
Thanks again

Pauls325

iTrader: (1)

could be cat overtemp protection too

Mike@Diablosport

iTrader: (2)

I didn't see anyone ask, so I will....what was in the tank?

LS4SPEED

iTrader: (3)

I'm guessing gasoline! LOL, but don't know what octane, prolly just RUG.

20SS06

not sure what you mean by what was in the tank... but I always use premium gas (which is 91 octane over here)

06MonteSS

not Shell I hope... heh...

20SS06

Guess what?!!
the day i took it to the DYNO I filled it at SHELL!
and that was my third time filling up there....after seeing and reading how their new nitrogen technology cleans up gunk and stuff I thought that was the best gas out there?!

Sittingmongoose

iTrader: (1)

Well thats causing your knock....or at least some of it. I did the same thing and when i first went on the dyno i had a LOT of knock as well. The gas i am sure was contributing to it. If i were you i would do a basic tune up. Oil and oil filter i would use royal purple. Change spark plugs to a little nicer ones. Than fill up on nicer fuel like sonoco or Exxon. That should bring you closer to 235ish. Also dont forget that you dont have an after market exhaust. If you did a full exhaust, it would help.

heavyft

Run a few gallons of e-85 mixed 50/50 with premium. It'll clean the fuel system and boost the octane. Plus it smells sweeet!

06 SS

If he is showing knock in park, which he claims, that means no load on the engine. It is not the Octane of the fuel. There is something wrong mechanically or with his tune.

Brian396

iTrader: (3)

50/50 mix on a stock tune would be way lean.

Panther427

Shells nitrogen gasoline is funny to me when all the newest emmions is to eliminate nitrates lol

BadA$$

iTrader: (4)

220 hp on a run sounds CRAZY low. I did 205hp at 7250 ft above sea level.