T,

Do you have a log of the 8 counts? 4 is pretty standard for normal acceleration with transit into boost to be perfectly honest. I know what you mean though because that stumble really isnt fun when it happens. I would tend to think of mechanical changes that have happened since the turbo swap. Downpipe is maybe a little closer than it was to cross bars or its not quite tight enough and its rattling, etc. I dont think there is honestly any other explanation since it didnt do this prior. Of course like grampa always said never deal in absolutes, so I would think there is a chance of it being something electronic but I dont have faith in that.

 

that wouldmake sense since it isn't happening all the time, u would think that if sometimes u get knock and sometimes u don't its probably false knock ...also if ur knocking at 3psi it seems like when u roll into wot the knock stays and thus lowers ur octane flag ...so even if it is false k ick the car isn't running as strong as it could be

 

tkman

I'm thinking you have an interference issue with something under the hood. The engine is moving and something is rattling.

but for a good test... put some race gas in it to see if the knock goes away. the fact that removing timing doesn't help makes it a mechanical issue in my mind.

 

steexz is having the same problem and hes running 100 hes going to look at some stuff under the hood tomorrow.

 

Yeah, I think this weekend I am going to get under the car with a few wrenches and make sure everything is nice and tight. I made sure everything up top was tight because its easy to get to. I wonder if there is a natural resonance in my set-up that causes something to vibrate right in that spot.

Last night, 20psiMR, I was comparing my map to a stock map in the areas of trouble, and decided to put a ton of timing back into the map, some areas up to 12*, and tool her for a late night spin. Woah, that made a huge difference in the stumbling and the car seems to pull away smoother now. It seems really weird to rid knock by actually adding timing back in, but in this case, kind of makes sense.

I am going to contie in my adding of timing back in to these areas, but slowly, until the timing is back up into the stock areas. I am wondering how much the car will be able to handle with the turo putting out a couple of psi in these areas though.

 

Ya it seems to help. It looks like the car just wants some serious timing during spool. Steexz's car is running 29psi and boost comes on REALLY strong, so could be why the knock is similar. We added a bunch of timing in the 80 to 100 load cells, and that seemed to fix it. Now the car is throwing knock when the guage hits 3-5 psi so I increased more timing through 120-140 load as well. If timing fixes the problem, it definitely is real knock unfortunately. Just weird that it would happen in an area we dont normally play with at all. Ive noticed that cosi cams are usually really picky on timing during cruise when on 91, but this is the first time I had cosi's flip out on 100 octane. Im running same mods in my car, same mivec map, pretty much same setup and have no problems.

Im still waiting for Steexz to call me today and let me know if its about gone. I have him running with the tephramod knock light set to 5 counts from 10 load on, and I want to see if my changes to the 120-140 load cells took care of it. Will let ya know.

 

adding timing in the load range 20pimr didn't change anything. Im assuming there will come a time when adding timing will start to cause knock that was not there before. so i dont know, im gonna have to start looking to see if anything is loose in the engine bay. Also i am going to turn the boost down to about 27psi. 20psi also said something that may be causing problems as well is possible maf disruption.. but i dunno. Im hoping that the knock is being cause by the clutch....

 

So, I added even more timing, and the car isn't increasing knock at all. Its getting smoother too. I haven't changed my Accel Enrichment back to stock, so that might be helping. I only added a few % (0.10) in the areas I was having problems, and just before where it started. It seems to be getting much better.

Also, the car had a CEL this morning. P0401, sure a poop, the damn EGR hose was off. Does this hose blow boost? If it does, then maybe that's a lot of the reason the car was running like poop. Feels much better now though pulling away from a light..

 

Might have to add to his accell enrich then. I had earlier open loop settings in there but took it out when we were trying to troubleshoot the problem. Ive seen before where the car just does NOT want to spool rich, and knocks like a pig. Could be the same thing, at the onset of boost it wants timing. But like Steexz said, add too much and that can start causing the knock too so its a pain in the *** to diagnose and fix. Fak I dunno anymore. His car spools up SOOOOO much faster then mine, and hits boost extremely hard. Maybe its just too frickin hard and its causing knock. If you roll into it though I get 1-2 counts (what he wanted, he likes ragged edge tune hehe) all the way through the pull. Its just that initial slam of boost while cruising that causes the knock every time. His spikes really crazy though, will tag 17 counts then go away. Hit gas again, tag a couple 35 counts then its gone. Frickin weird.

 

yea ur telling me.....one thing i noticed is that on the drive home i was ding freeway pulls, and i never really felt a loss of power from when i would pull when it started to knock before the pull as to when it was not knocking at all.

 

So, I added all timing back to where the stock values were prior, and even a little more, and just took it for a spin to Starbucks.. The car really takes off now, and wasn't knocking with the knock light set to 6. I am going to really concentrate on the part throttle now, I find it's making the car a blast to drive, even when below 15psi..

Hmm, adding timing to get rid of knock. Interesting...

 

so you added all the timing back to the load areas of like 80-120 right? knock hasn't gone away though? im just confused... im wondering how many people actually have this problem but just do not know it....

 

yes, please post results.

Also... am I the only one interested in your "sneaky" porting? Wanna let in on your secret?

 

Yeah, I addd it all back in, and the knock for the most part went away. It only does it about once every 8 starts now. Most of the reason I had a little problem with the timing taken out was because when I rescaled the maps, I did both load and RPM, I don't have 750, 1000, 1250, 1750 rpm's defined anymore, so I had to really change the timing map around.

The load areas of 80 through 120 all were changed from 1500-3500 areas. The timing in those areas now is between 12-24* now, almost like stock...

Knock hasn't gone away 100%, but then again, I don't think it ever will go away 100%.

 

would u mind posting your timing table? u are running 93 oct right?