KNOCK @ Low RPM, St205 - PowerFC - Knock Options

[83841]

I am in need for some expert advice. Currently I purchased a used PowerFC for my ST205 and brought my car into a shop for a safe tune (not aggressive). My issue is my Check engine light flickers on and off, I noticed that knock starts to report at low RPM range. 2600RPM - 3000RPM. I dont hear any knock and Im hoping that its phantom knock. I have added my logs from datalogit f anyone can provide any advice it would be appreciated.

my current mods are basic:
HKS Intake
Exhaust
manual boost controller set at only 15-16 lbs.
and Berk Downpipe.


HighKnockLogs

[lagos]

Thats a really common area for knock. I've seen the same issue on my JS knock guard.

Post up a screen shot of your ignition timing map.

[Syaoran]

Try stepping on it after 3000rpm instead of at lower RPM.
Sounds like an issue some newer turbo cars have where they knock down low because they make too much torque at low RPM.

[lagos]

Try stepping on it after 3000rpm instead of at lower RPM.
Sounds like an issue some newer turbo cars have where they knock down low because they make too much torque at low RPM.

Its all part of how the timing map is setup for that range. Its not normal and shouldn't happen.
This is also a very common area to hit if just daily driving up a hill.

[Syaoran]

Try stepping on it after 3000rpm instead of at lower RPM.
Sounds like an issue some newer turbo cars have where they knock down low because they make too much torque at low RPM.

Its all part of how the timing map is setup for that range. Its not normal and shouldn't happen.
This is also a very common area to hit if just daily driving up a hill.

Definitely not a good thing. It's a common thing for cars with too small of a turbo apparently.

[cardshark525]

Try stepping on it after 3000rpm instead of at lower RPM.
Sounds like an issue some newer turbo cars have where they knock down low because they make too much torque at low RPM.

Its all part of how the timing map is setup for that range. Its not normal and shouldn't happen.
This is also a very common area to hit if just daily driving up a hill.

Definitely not a good thing. It's a common thing for cars with too small of a turbo apparently.

Well there is an easy way to fix the problem of "my turbo's too small"..... lol

[Syaoran]

It's not as easy as it seems though

[cardshark525]

Oh I know. Just pointing out kind of a funny issue...

"Your car has a knock..."
"Yeah I know my turbos too small."

Agree with Lagos though the tuning map needs to be looked at.

[lagos]

The basic trick to fixing this is to massively drop timing in the 2-3000 RPM range at 100+kpa (0psi and above). This is the area where the turbo is just starting to spool, and the reduction of timing is going to actually help the turbo spool faster.

Here is part of a 3sgte ignition basemap. Notice how much timing there is between 2-3k around 100kpa. With this much timing, I would see some knock when going up hills.



Now here is a much better tuned map. See how much less timing there is in that area? With setup, I saw no knock in that same range.

[83841]

Just got back from the tuner and it looks like the timing needed to be pulled back in a couple of cells mostly in n06-n08 range (low RPM range on the powerfc datalogit). We ended up road tuning as they said it was not necessary to put it back on the dyno based on the logs that Ive captured. The tuner sat in the passenger side with my laptop watching the datalogit/logs while I was driving to replicate the issue. Now my knock went from high 80s-90s to low 40's and below. NO MORE CHECK ENGINE LIGHTS!!! WHOO HOO!!! Was done all within an hour... I love driving my car again!!!!

[lagos]

Just got back from the tuner and it looks like the timing needed to be pulled back in a couple of cells mostly in n06-n08 range (low RPM range on the powerfc datalogit). We ended up road tuning as they said it was not necessary to put it back on the dyno based on the logs that Ive captured. The tuner sat in the passenger side with my laptop watching the datalogit/logs while I was driving to replicate the issue. Now my knock went from high 80s-90s to low 40's and below. NO MORE CHECK ENGINE LIGHTS!!! WHOO HOO!!! Was done all within an hour... I love driving my car again!!!!

What type of dyno was this originally tuned on?
These types of problems tend to pop up when you tune on something like a dynojet that can only do WOT pulls and can't hold the engine under load at specific points.

[83841]

Just got back from the tuner and it looks like the timing needed to be pulled back in a couple of cells mostly in n06-n08 range (low RPM range on the powerfc datalogit). We ended up road tuning as they said it was not necessary to put it back on the dyno based on the logs that Ive captured. The tuner sat in the passenger side with my laptop watching the datalogit/logs while I was driving to replicate the issue. Now my knock went from high 80s-90s to low 40's and below. NO MORE CHECK ENGINE LIGHTS!!! WHOO HOO!!! Was done all within an hour... I love driving my car again!!!!

What type of dyno was this originally tuned on?
These types of problems tend to pop up when you tune on something like a dynojet that can only do WOT pulls and can't hold the engine under load at specific points.

I dont know what dyno was used by the previous owner, but the tuner I took it too uses a Dynapack 4-wheel Chassis Dynamometer. I think they just tuned WOT as I know the dyno they use can do POT and they just missed it.

[PETE]

That area of the map is very common for knock on the standard PowerFC tune. Remember that the Base PowerFC maps were originally designed for at least 100Oct Fuel, not the 98 Oct fuel we are using.

[jbod]

You can use the map tracer with the FC datalogit. Watch what cells get knock and then remove ignition timing from the cell or row. I have thought anything over 40 Is detonation. One of my friends 205s is 290kw and never sees more than 35 on the knock, it is also high compression (320psi per Cylinder under boost). Another friend making 260kw sees 60ish which to me seems alarming, i dont think he really cares..
I usually have sub 40. 30-35. However on the track after awhile have seen it get up to 45-50-55. Which i would say would be knock. Tunning the car on the dyno and then taking it around the track are two different enviroments, the dyno is a major amount less work.

You can set the knock warning to come on between 0-99.. I have seen tuners set the warning at 40.. And some at 50 and some at 60. So what is right? At what point are you really getting detonation. I have thought of using knock headphones however i cant be sure where i could put a knock sesnor in a easy access place that is accurate...?

Id be interested to see what other 205s are getting around the track detonation wise. Mine is standards just exhaust downpipe etc etc amd power fc