Markkonschak Posted February 17, 2010 Share Posted February 17, 2010 i'm am currently running msII v3.0 with edis 6. every map i load start to ping at higher rpms. at first i thought i just had a rattle but after retarding car it ran so much better. right now i am running l26 with n42 head. new turbo injectors and 240sx throttle body. just installed stock turbo with 3inch downpipe. i would ready like to know why this is happening before i blow another engine. i dont know my compression ratio i believe it would be somewhere in the neighborhood of 8.5 it is the stock l26 bottom end with flat top pistons. head is a n42. i am running stock boost which hits 7 psi with huge 28"x 12 front mount intercooler. intake temperatures stay around 70 degrees. fuel pressure is 30 psi, afr is low 12's under boost. using LC-1. when this engine was N/A i was getting ping and had to retard to 26 degrees under full throttle. ping has always starting at 4000 rpms and carried to 6500rpm (that's the highest i have taken it). right now my advanced is 22 degrees at 150 KPa, 23-140KPa, 24-130KPa, 28-120Kpa, 32-110KPa, 35-100KPa Quote Link to comment Share on other sites More sharing options...
Markkonschak Posted February 17, 2010 Author Share Posted February 17, 2010 just tried 16 degrees at 150KPa and i am still getting a very slight ping at 4000-5000 rpms. i dont know if it keeps doing it after that i start letting off because i cant hear if its pinging on not. Quote Link to comment Share on other sites More sharing options...
kolonelklink87 Posted February 17, 2010 Share Posted February 17, 2010 i'm am currently running msII v3.0 with edis 6. every map i load start to ping at higher rpms. at first i thought i just had a rattle but after retarding car it ran so much better. right now i am running l26 with n42 head. new turbo injectors and 240sx throttle body. just installed stock turbo with 3inch downpipe. i would ready like to know why this is happening before i blow another engine. i dont know my compression ratio i believe it would be somewhere in the neighborhood of 8.5 it is the stock l26 bottom end with flat top pistons. head is a n42. i am running stock boost which hits 7 psi with huge 28"x 12 front mount intercooler. intake temperatures stay around 70 degrees. fuel pressure is 30 psi, afr is low 12's under boost. using LC-1. when this engine was N/A i was getting ping and had to retard to 26 degrees under full throttle. ping has always starting at 4000 rpms and carried to 6500rpm (that's the highest i have taken it). right now my advanced is 22 degrees at 150 KPa, 23-140KPa, 24-130KPa, 28-120Kpa, 32-110KPa, 35-100KPa I'd be suspicious your comp. ratio is significantly higher than you beleive (ozdat puts it at ~9.25) Previously i've run an l26 w/shaved ported OS valve etc e88 and flatops. I was running N/A and even so It took me a while to dial in the detonation issue (by the looks of 5/6 chambers so had the PO ) I eventually conquered it by a combination approach of tinkering with slightly richers AFRs and bringing down my MAT's with creative pipework. I was able to run full 38* adv. However, that was N/A... You have colder weather going for you but i think its still an uphill battle - considered dished pistons? there are 2&3mm steel HGs available in japan which may also solve problems of a compression-related aetiology I think if detonation was an issue N/A you might have real problems under boost.... Quote Link to comment Share on other sites More sharing options...
Markkonschak Posted February 17, 2010 Author Share Posted February 17, 2010 could that be true i only have 150psi per cylinder. Quote Link to comment Share on other sites More sharing options...
Markkonschak Posted February 17, 2010 Author Share Posted February 17, 2010 i just looked it up on hybrid z the stock e88 head should of had a 47cc combustion chamber as well as my current n42 head. if this is correct i should be at stock compression which is 8.3 Quote Link to comment Share on other sites More sharing options...
Xnke Posted February 17, 2010 Share Posted February 17, 2010 Try again; stock N42 head chamber size is 44.6cc, as is the open chamber E88. On a stock L26 flat-top block, that would put you at 9.4:1 compression, so it's not surprising that you're pinging. I'm running a 42cc chamber, 10cc dish pistons, and 88mm bores in an L28 and am sitting about 9:1 CR. Due to the cam I'm running, my cranking pressures for a compression check are only 100PSI. Exactly 100PSI on every cylinder, but still, much lower than you'd think for a 9:1 compression motor. Compression tests will give you an idea of pressure, and will tell you if you've got an inconsistant cylinder; but they won't tell you your compression ratio. What grade of fuel are you running? Quote Link to comment Share on other sites More sharing options...
z-ya Posted February 17, 2010 Share Posted February 17, 2010 Lengine calculates the CR to be ~9.3:1. First of all, this is much too high for a turbo motor with an N or E series head. I'd only attempt that CR with a P series head, and even then, the static CR is probably too high. 8.5:1 max. Also, did you calibrate your ignition system? For example, is 20BTC really 20BTC? Pete Quote Link to comment Share on other sites More sharing options...
Markkonschak Posted February 18, 2010 Author Share Posted February 18, 2010 yeah i screwed up. for some reason i was thinking edis which is a wasted spark system would fire twice as many times so my degrees would be twice as many. 10-20. so when my car was at 10 degrees i set my trigger wizard at 20. anyways i feel really stupid. Quote Link to comment Share on other sites More sharing options...
z-ya Posted February 18, 2010 Share Posted February 18, 2010 yeah i screwed up. for some reason i was thinking edis which is a wasted spark system would fire twice as many times so my degrees would be twice as many. 10-20. so when my car was at 10 degrees i set my trigger wizard at 20. anyways i feel really stupid. Verify the timing with a timing, it's the only way to be sure it's calibrated. It is amazing how many people make this assumption. Live an learn, right? Quote Link to comment Share on other sites More sharing options...
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