Before the SAFC and on S1 injectors the car had zero knock at 17psi spike. Installed the SAFC and drove around for a few weeks on 0 setting. I added S2 injectors over the weekend and raised the boost to 22psi spike. Well I tuned the car on the highway doing 3rd and 4th gear pulls with my cut-out opened. Got it around 11.8-12.0 and its around 10.8 at redline. At that setting I saw as high as 4.5-5.0 kr on my Aeroforce Scangauge... this was around 4500-5000 rpms. With the cutout closed at one point I saw 6.0 kr. So I went ahead and added some fuel. That reduced the knock count to around 2.5-3. So then I went ahead and lowered the boost (spike) to 20. Still getting kr around 2.5-4.0. If I add fuel around the 4500-5000 range the wideband reads 10.0 with 2 kr. My spark plugs are NGK 4306 gapped at .032 and are only a day old. This is stock turbo with S1 and bolt-ons. Its around 93 degrees outside or a little under now. Timing might be an issue I would imagine so, didn't pay mind to it on the Scangauge. Any recommendations? I might go back to the s1 injectors drop the boost down to 17 and tune there. But I was hoping to run more boost and be okay but the s2 seems to be giving me kr. This car was mapclamp tuned long time ago at 21psi spike with S1 injectors and showed no knock back then (if I remember correctly).
Bump boost down to around a 20 spike and swap in your STG1 injectors. See if KR goes away. Your gap probably could use to be a slightly tighter around the .025-.028 range at those boost levels.
Thanks for the advice Jason! I ended up throwing the S1 injectors back in, zeroing out the SAFC, resetting my pcm, and lowering the boost down spiking 16psi. Its at 10.0-10.1 afr's with zero knock. So I should spike around 20... and also gap my plugs maybe say .028... the re-tune? I figured .032 would be fine since there was no spark blow out. Being that its S1 injectors I've been reading not to bother tuning the LO and just tune the HI.
You shouldn't need to piddle with the LOW setting much, keep an eye at part throttle though. Honestly you shouldn't need to pull much up top, 10-15% tops I think. Meh I've never found the point of going over 20PSI with the stocker, your well past it's efficiency range over 20 PSI anyhow. A nice 20 spike/17-18 hold should do nicely. As far as the plugs go, if your not seeing any blowout you should be fine. However I think once you get it leaned out up top you might start seeing some blowout. Let me know how it turns out for ya. OH and be SURE to do a boost leak test before you set the final tune!!! You'd be amazed at how much one little leak can throw things out of whack!!
Thats what I thought, that anything past 20 it would just be bringing hot air and not beneficial. Figured I try it since another friend of mine is spiking 22psi with s2 injectors and a tune. I did warn him of my knock readings... since he doesn't have a Scangauge. Too much fuel, too much timing, and possibly high EGT's is what I'm thinking was my problem. So I began by tuning the AGP wga this morning. I got it spiking 18. Decided to keep it there for now. Went home, opened the downpipe and went on the highway to tune. Got AFR's around 12.0 on initial WOT (4th gear) leveling off to 11.0-10.8 redline. Needs some fine tuning towards the top end but decided to call it quits due to amount of traffic on the road and the amount of highway patrols. No knock... stayed at 0 throughout the band. My LO Map is 0 all the way. My HI Map which I just consider my base tune (till I can fine tune it) is: 1000 rpms (0%) 2000 rpms (-5%) 3000 rpms (-8%) 3500 rpms (-8%) 4000 rpms (-8%) 5000 rpms (-8%) 6000 rpms (-5%) 6500 rpms (-5%) Only have 8pts of tuning since I'm using an SAFC I. I didn't do a boost leak test because I need a new coupler on my tester. As soon as I get one I'll do one. I did do a boost leak test about 3 weeks to a month ago and had zero leaks.
Good! Bump boost up a few more PSI and get redline leaned out to around 11.5-12.0 and you'll be golden. Correct to much injector will add to much timing Watch your injector duties, you may be running out of injector at 20 PSI though. I ran STG2 injectors on my full bolt on stocker, but my set up was maxxed out 300HP/365ft/lbs TQ. SAFCII works PERFECT, my favorite piggyback for the NSRT. Reliable and cheap:thumb2:
Just went out for another tuning session. Bumped it up to around 19 spike, took around 10% of fuel out from 3k-6k and got knock up to 3-4 counts. Guess I'll bring it back down to 18 and fine tune it there. Seems anything past 18 shows knock. Cut-out on downpipe is open. I'm going to check the torque on my knock sensor as well. Letting the car cool off. Had to get off the highway before someone calls the cops lol.
Something else to keep in mind is that the ECU is predictive when it comes to knock. It looks at IAT,ambient temps, boost levels and then pulls timing accordingly. typically it is going to pull timing between 4800 and 5200 rpms since that is the most likely place it could detonate. Typically it will put it right back in after it passes that point if the knock sensor is being quiet. Something else to watch would be the knock voltage to see if it is the ECu being cautious or if you actually have knock.
Its 90 degrees currently outside so that definately has a play in this. Viewing the knock voltage. What range would I be looking at? Car pulls nice but this knock thing is driving me nuts lol.
What I would do is look at kock voltage vs knock retard. If you have a bunch of kr but barely any voltage that would point to the ECU being cautious IMHO. With my setup I'm spiking around 20-21 psi gauge (map is seeing about 16.8 to 17.1 psi, AFR's are around 11.6 on the spike dropping to 10 by redline). From about 3k to 4800 I have about 0 to 1.5 kr then at 4800 it jumps to between 3 and 4* (sometimes more if my IAT's are getting hot fuel temp can play a part as well) and then at about 5200 it is back to the 0-1.5 range. Just FYI my setup is, S1 ECU, s1 injectors, AGP wga, agp hard pipes with HKS bov, thermal o2 back exhaust, mopar CAI with AEM dry flow filter. Diagnostics i have are a scan gauge and an AEM Uego wideband.
I do have a question. How do you know what psi your Map sensor is seeing? I pretty much have what you have minus I don't have a 3" O2 and instead of full exhaust I have the Needswings DP with just a few added things like fuel pump re-wire, Walbro 255, other then that its just a S1/S1 injectors with AGP wga and basic bolt-ons. My wife S3 car on the tune I did for her she shows anywhere from .5 to 4.5. Its on what I would call a "safe" tune. Maybe I'm just a bit too worried with my car and if that's the case seeing knock below 5 shouldn't be a problem or too much of a concern? If so, I'll raise it till 20psi spike and tune. Just trying to be more conservative I guess lol. I just checked the knock sensor and its tq properly. I'll take her for another round and pay attention to both knock voltage and knock retard.
The scan gauge will tell you what the map is seeing. I have a 3" exhaust right up to the o2 housing since that mo fugger is such a bitch to remove. To just give an arbitrary number to the "right" amount of knock I think could be dangerous. Just look at what it is doing if it is constant then I would say you need to back off if it is relatively low with a small spike then I would say you are probably ok. The approach I took is I looked at the stock EGT's on the scan gauge (yes I know they are calculated but it is a relative measurement anyway) and then look at the knock retard, and the AFR's. As long as I am below 1700* on the egt's, below 12:1 on the AFR's and my knock is relatively low with only that slight increase I call it good. I was driving myself nuts with the whole knock thing. If you are that worried about knock i would get a water/alky kit then you shouldn't have to worry about knock at all. :grin:
Thanks Nate for all the help! I'm back with an update. I dropped the boost back down to 17.5-18psi spike. Ambient Air and Intake Temp on the Highway (after doing numerous runs I checked it) were around 105 degrees. Timing Advance on initial WOT in 4th gear at 3k was 23.5. I got the AFR's at intial WOT 12.0 and ranging from 11.6 to 11.8 throughout the powerband until redline. 0 knock
Thats weird, because mine behaves nothing like that. This was on an old setup but boost levels were similar. Your's sounds alot like nevins his bounced around alot.
Just some FYI, I've compared Scanguage EGT with a true EGT gauge and the Scangauge EGT reads about 100 degrees high. It is actually fairly accurate. Figs what is your timing advance at WOT? Your final tune, looks pretty good. Have you tried running with the dump closed? Honestly I feel you'll have a stronger powerband with the dump closed. You'll sacrafice a bit of upper RPM HP for a stronger lower/mid RPM TQ curve. Here is a dyno scan of my stock turbo set-up: Here
I remember someone saying it read about 100* high. Kinda gives me a cushion if my scan gauge EGT's are reading 1700 then I know I'm actually not at the temp limit for the turbo seals. :grin: I should be getting a couple dyno pull this weekend with the new setup I'll post it up.
