Has anyone had this problem when taking there car to dyno??? I took my car to dyno for the first time and got severe spark knock and pre detonation in 4th gear pull at 3800 rpm's and worse at higher rpm's.. Whats weird is the car never does it around town or when I get on it hard!! wonder if its because the tune I have at the elevation i am at or because the load and lack of air flow when strapped to a dyno?? not sure.... anyone get this ever?? disappointing could not even get one pull out of it


Mods: Aem intake, hahn catback and downpipe, hahn/bsr ppc tuner

 

Did you turn off the esc? You know, press and hold the traction button in for 5secs or however long it takes.!

 

I was under the impression when you turn traction control off and select competition mode it turned off esc??? did not hold button for five seconds just pressed it twice

even with that if the esc on would that cause this issue?? I thought it only controled braking and abs?? when I took the car back to my dealership and scanned the ecm I had misfires on 3 out of the 4 cyl.

 

You shouldnt have an issue with the hahn tune, not to agressive. Im thinking its because you didnt turn the ESC off and it fucked with everything. Where in Utah? I used to live in Ogden

 

Even in competitive mode the esc monitors how fast the wheels are spinning if there is too big of a difference it retards timing etc, and will also apply the brakes. (I have the esc active coming up all the time in competitive mode) So on the dyno, frontwheels spinning away, rears are not and you get what happened to you unfortunately

 

I believe its 10 secs

 

the car MUST be in ESC OFF mode to dyno

 

The dyno runs your car alot harder then you do arround town.
If you went full throttle uphill at 3800 rpms in 4th gear, it would
proably spark/ knock. Did the dyno guy put a fan over blowing air
at your radiator? Normaly driving arround you have the air going over it
from moving forward that you don't have in a dyno.

 

yep! the car thinks its doing its launch control thing, and is trying to hold the engine rpm's to about 3800 or so despite it being in 4th gear. hold that traction control button in for ten seconds untill the DIC says "ESC off" then go for another dyno pull!

 

Or do not put it into competitive mode

 

Most of your common inertia-style Dynojets do not load the car as much as you would out on the street. That's why on many other cars that only have a narrowband O2 feedback which can't be used at wide-open throttle (WOT) they'll run leaner out on the road than they will on a dyno.

Besides making sure you have stability control fully disabled, another thing you might watch for is dynoing your car in fourth gear. Many shops will do this as it places a higher load on the engine which on some turbocharged applications such as cars with massive aftermarket turbochargers can decrease spool time and give slightly higher numbers. Down side is that because you're in fourth gear it takes longer for the car to rev to redline and even with the biggest commercial fan placed in front of the car it doesn't come anywhere near simulating the amount of air flow you'll get out on the road at speed.

I'd suggest if you take it back to the same place to have them dyno the car in third gear. Many shops will say they should use the gear ratio closest to 1:1 and should use fourth gear but nearly every dyno calculates and compensates for gearing (since they know engine rpms and roller speed). I've done back-to-back dynos and there shouldn't be any significant difference. Since you mentioned having an aftermarket tune, if it is over-spinning the stock turbo and creating more heat you may benefit more from the shorter third gear pull with a cool down period between pulls.


Also as a technical note, there isn't such a thing as pre-detonation. Detonation, spark knock, and knock are normally interchangeable terms for the event where the air/fuel mixture starts to ignite and the flame front propagates before the piston has reached top dead center (TDC) causing the characteristic rattling/knocking sound which is picked up by the knock sensor. There is such a thing as pre-ignition where something like a hot point in the combustion chamber lights off the mixture before the compression stroke starts, but if this were happening you'd more than likely have a hole in your pistons. It's also not very likely as the direct injection doesn't spray the fuel into just before the ignition system lights it off to burn.

 

I live in clearfield right now but have lived all around ogden area most my life, I work in ogden

Thanks for all the info everyone!!!! going to dyno again this week, will see how it goes!!! lol, I was so pissed after the dyno I went to wendover to gamble and win money to pay for new tune!! lost my ******* ass- could have had a tune and then some if just stayed home- oh well