Jump to content
SAU Community

Recommended Posts

Hi Guys,

I got a Cobb and have been using Stage 2 & LC5 for my ADM2009 on the road since. Great burst of power and improved drivability.

(I'm on 98RON Shell vPower, HKS res midpipe, K&N air filter element)

I took it to Phillip Is (18 deg C) and Sandown yesterday (23 deg C).

I noticed flashing of the boost gauge - which I think means that there is "knocking". This usually happens after the 3rd or 4th lap, especially if I hit the rev limiter. Sometimes it occurs even at 5000rpm in 2nd gear and tends to linger for about 5 to 10 seconds. I feel the car is not as fast as it normally is.

How do I fix this?

Is this BAD for the engine?

Thanks in advance.

Link to comment
https://www.sau.com.au/forums/topic/411598-knocking-with-stage-2-cobb/
Share on other sites

Thing is, it doesn't do it when I drive on the road.

The Stage 2 is the Off-the-shelf map that came with the Cobb, which I thought was conservative.

What parameters should I log?

Thanks for the reply, Martin. I received your Trans Fluid 35TML last week and filled it up before Sandown. Goes nicely.

Sounds just like the tune is street conservative, but not track conservative (3-4 laps heat++ etc) - they are two totally different scenarios really.

Good news is it's not a major fix required, but certainly shouldn't keep trying to replicate it! Knock = bad.

So maybe after 2 laps have an easy 1 rather than going for 3-4 (until its fixed) :)

Does that meant if I get a track-oriented tune, it would generate less power? Because it would have to dial down the timing or boost to cope with heat.

Would larger injectors to fix this?

No point in speculating about it, you need to generate a log of some third and fourth gear pulls and then let me have a look through it. Either that or get the right map for your car running Aussie 98 fuel - such as the tune we supplied for Duncan Forrests GTR that won the NSW Supersprint championship two years in a row. No knocking, plenty of power.

OTS Cobb maps are ok, but they tend to not be a bit sketchy when pushing the limits of our 98 fuel - as they simply dont calibrate on it in the US. Regardless of what you do, that flashing engine ligh it something to take note of, and try to avoid if the idea of rebuilding an engine scares you even just a little bit :)

If you want someone local (Bayswater-Vic) the guys at Racepace can put it on the dyno for you and they have the Cobb tuning software.

9762 9421

But I've seen a few R35's knock at Sandown and PI as they have a lot of engine load at those tracks.

Ok maxzugkraft I have had a chance to have a look at a few of your looks. Looks like the tune is working really really nicely, the only time there was any indicated knock (false knock) was when you shifted on the rev limiter. The yellow line in the picture below is 'knock' and as you can see it stays on zero the whole length of the run...which is very nice :)

486666_10151212210434571_56066567_n.jpg

Thanks Martin.

I can't see your picture. There is a question mark instead.

Will this tune work for warmer weather? 25-28deg C?

Bear in mind the log was done at 15 deg C ambient temp.

Is it running too rich, as I'm getting a lot more black soot on back now.

Thanks Martin.

I can see your screenshot now.

Now I can use full power without holding back!

Can't wait to get back on the track!

Hope to see lap times plummet.

Good job. Cheers!

If you want someone local (Bayswater-Vic) the guys at Racepace can put it on the dyno for you and they have the Cobb tuning software.

9762 9421

But I've seen a few R35's knock at Sandown and PI as they have a lot of engine load at those tracks.

Would you recommend some further intercooler upgrades on top of the custom dyno tune?

Pinging at 18degC or 23degC ambient temp is pretty bad.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • My guesstimate, with no real numbers to back it up, is it won't effect it greatly at all.its not a huge change in position, and I can't see the air flow changing from in turbulence that much based on distance, and what's in front of it. Johnny and Brad may have some more numbers to share from experience though.
    • Which solenoid? Why was it changed? Again, why was this done? ...well, these wear..but ultimately, why was it changed? Did you reset the idle voltage level after fitment? I'm just a tad confused ~ the flash code doesn't allude to these items being faulty, so in my mind the only reason to change these things, would be some drive-ability issue....and if that's the case, what was the problem? Those questions aside, check if the dropping resistor is OK ...should be 11~14 ohms (TCU doesn't throw a flash code for this) ~ also, these TCU designs have full time power (to keep fault code RAM alive), and I think that'll throw a logic code (as opposed to the 10 hardware codes), if that power is missing (or the ram has gone bad in the TCU, which you can check..but that's another story here perhaps).
    • Question for people who "know stuff" I am looking at doing the new intake like the one in the picture (the pictured is designed for the OEM TB and intake plenum), this design has the filter behind the front bar, but, the filter sits where the OEM duct heads into the front bar, and the standard aperture when the OEM ducting is removed allows the filter to pulled back out of the front bar into the engine bay for servicing, a simple blanking plate is used to seal the aperture behind the filter This will require a 45° silicone hose from the TB, like the alloy pipe that is currently there, to another 45° silicone hose to get a straight run to the aperture in the front bar Question: how will it effect the tune if I move the MAF about 100-150mm forward, the red is around where my MAF is currently, and the green would be where it would end up Like this This is the hole the filter goes through  Ends up like this LOL..Cheers    
    • Despite the level up question, actually I do know what that is....it is a pressure sender wire.  So check out around the oil filter for an oil pressure sender, or maybe fuel pressure near the filter or on the engine. Possibly but less likely coolant pressure sensor because they tend to be combined temp/pressure senders if you have one. Could also be brake pressure (in a brake line somewhere pre ABS) but maybe I'm the only one that has that on a skyline.
    • Pull codes via the self-diagnosis procedure. As far as I can tell this is just a sign of transmission issues but not a code unto itself.
×
×
  • Create New...