Osiris from Uprev
02-01-2008, 04:46 PM
#684
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i have read all the posts and is something that i do not understand
1) so after 4000 rpm or so , VQ35DE will run blind from the Knock detection point of view, so if knock will start to occur big time on the rev range where is most dangerous 4000-7000 rpm, the ECU will not do a thing and will let the engine blow ?
2) there will be any after market knock detection system supported by the RTT EU version of Osiris ? because if the ECU cannot detect the knock in the higher part of the rev range,in my opinion there is a need that other system should be used in order, to create a safe tune (using a stethoscope may be still a good option but i never tried it on a V6 engine only on L4 engines where is very eficeint)
thanks
1) so after 4000 rpm or so , VQ35DE will run blind from the Knock detection point of view, so if knock will start to occur big time on the rev range where is most dangerous 4000-7000 rpm, the ECU will not do a thing and will let the engine blow ?
2) there will be any after market knock detection system supported by the RTT EU version of Osiris ? because if the ECU cannot detect the knock in the higher part of the rev range,in my opinion there is a need that other system should be used in order, to create a safe tune (using a stethoscope may be still a good option but i never tried it on a V6 engine only on L4 engines where is very eficeint)
thanks
Last edited by ByReaL; 02-02-2008 at 01:53 PM.
02-02-2008, 04:32 AM
#685
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Originally Posted by ByReaL
1) so after 4000 rpm or so , VG35DE will run blind from the Knock detection point of view, so if knock will start to occur big time on the rev range where is most dangerous 4000-7000 rpm, the ECU will not do a thing and will let the engine blow ?
It doesn't really makes any sense at all.
02-02-2008, 12:32 PM
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I just noticed ByReaL was speaking about a VG35DE - so he was not refering to the 350Z's engine (which is VQ35xx) - and in this case my questioning is obsolete. He must have been refering to a side topic I missed.
02-02-2008, 01:55 PM
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Originally Posted by Silo
I just noticed ByReaL was speaking about a VG35DE - so he was not refering to the 350Z's engine (which is VQ35xx) - and in this case my questioning is obsolete. He must have been refering to a side topic I missed.
later edit:
done i found it
https://my350z.com/forum/showpost.ph...&postcount=395
Originally Posted by PunKidd
The ECU only monitors the knock sensor in a very limited RPM & Load range. Our development Z for instance only monitors knock above 7.29BFS (Load) and between 800 - 4800RPMs. Above 4800 it won't pull timing based on knock, so it is critical that the ECU not be tuned too aggressively above 4800RPM. It's lame, I know, but the DSP filters in these ECUs just aren't good enough to filter out noise at high RPMs. Hopefully it gets better on the HR ECU, but that is yet to be seen.
The only way to know for sure that you are OK w/ the extra 2 degrees is to get on a dyno and verify that it's making more power throughout the RPMs w/ the extra timing. If it's not, then there's no point in leaving it raised.
Another way to verify would be to make sure you don't have any audible knock or ping at high RPMs. Then try to make some consistent 0-60 pulls (consistent means your coolant temps are the same
). Do a few w/ the 0 advance then run a couple more w/ the 2 deg. If the 2 deg. pulls actually run the extra timing in the knock window I described earlier, then you are probably alright. If pulls a bunch of timing anywhere in that window, then it's too aggressive and the closed loop knock control is pulling timing (and you are loosing power).
-Jared.
The only way to know for sure that you are OK w/ the extra 2 degrees is to get on a dyno and verify that it's making more power throughout the RPMs w/ the extra timing. If it's not, then there's no point in leaving it raised.
Another way to verify would be to make sure you don't have any audible knock or ping at high RPMs. Then try to make some consistent 0-60 pulls (consistent means your coolant temps are the same
). Do a few w/ the 0 advance then run a couple more w/ the 2 deg. If the 2 deg. pulls actually run the extra timing in the knock window I described earlier, then you are probably alright. If pulls a bunch of timing anywhere in that window, then it's too aggressive and the closed loop knock control is pulling timing (and you are loosing power).-Jared.
from the user manual:
The knock sensor retard system is designed only for emergencies. The basic ignition timing is programmed
within the anti-knocking zone, if recommended fuel is used under dry conditions. The retard system does not
operate under normal driving conditions. If engine knocking occurs, the knock sensor monitors the condition.
The signal is transmitted to the ECM. The ECM retards the ignition timing to eliminate the knocking condition.
within the anti-knocking zone, if recommended fuel is used under dry conditions. The retard system does not
operate under normal driving conditions. If engine knocking occurs, the knock sensor monitors the condition.
The signal is transmitted to the ECM. The ECM retards the ignition timing to eliminate the knocking condition.
response to the post below:
in my opinion when you start hearing knock may already be to late, on my CA18DET i use e stethoscope attached to the engine block, and using it i can detect knock pretty good, and on CA18DET even if it has a knock sensor from factory it seams it does not work at all, i was just hoping VQ35DE witch is 14 years newer will have no problems in knock detection and i will not have to use again that stethoscope method (i look kinda funny with that device in my ears)
basically when you tune the engine you can enable or disable the knock monitor flag for each cell in the ignition table, so theoretically it will not be a problem to enable the knock detection from 0 to 7000rpm, but it will work or not (from the post above i understand it will not work)
this knock detection problem is more like a hardware problem, or anyone believe it could be fixed by a firmware upgrade (not necessary an official one) where knock detection is set to work properly in the higher rev range and not on the lower one
anyway as many details regarding Osiris / VQ35DE / Knock detection / knock logging / engine protection routines based on Knocks ...... will be highly appreciated
Last edited by ByReaL; 02-02-2008 at 02:55 PM.
02-02-2008, 02:10 PM
#690
Originally Posted by ByReaL
corrected my post, i was referring to 350Z engine, and the info about that knock stuff can be found somewhere on the last 34 pages, i'll start to search the post and put a link to it
02-02-2008, 05:30 PM
#691
Knock on an NA car is only needed at peak torque. That is when the cylinder pressures are the highest. Knock is used for differences in gas and fluctuations in octane. Knock should not be used as a tuning device or safety feature. I noticed knock on my tune from uprev and they are going to get is taken care of via etune. This happen between 6200-7000.
My experience with factory computers they only take out about 2 degrees of timing when sensing knock.
My experience with factory computers they only take out about 2 degrees of timing when sensing knock.
02-03-2008, 08:05 AM
#695
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I posted review, but never dyno… here it is: AT sedan… I took it back to Shawn after this to dial in off idle-low RMP range (not able to register on dyno)… because he dyno tuned originally it was a slug off idle to 3K – Shawn street tuned for the low rmps and it made a huge difference (not shown on dyno chart of course).
Edit to resize:
Edit to resize:
Last edited by OCG35; 02-03-2008 at 08:22 AM.
02-03-2008, 09:16 PM
#698
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Originally Posted by Cloud
what mods do you have?
02-03-2008, 09:31 PM
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I see, nice hp. I wonder if shawn incorporated the "power down low" tune in my tune. It does feel a little bit sluggish at 2-3k rpm.
I wonder if my hp is proper for my mods. I only have a blitz intake, MREV2 & 5/16 spacer. Lightened flywheel too but i don't think that matters.
I wonder if my hp is proper for my mods. I only have a blitz intake, MREV2 & 5/16 spacer. Lightened flywheel too but i don't think that matters.
02-03-2008, 09:47 PM
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Originally Posted by Cloud
I see, nice hp. I wonder if shawn incorporated the "power down low" tune in my tune. It does feel a little bit sluggish at 2-3k rpm.
I wonder if my hp is proper for my mods. I only have a blitz intake, MREV2 & 5/16 spacer. Lightened flywheel too but i don't think that matters.
I wonder if my hp is proper for my mods. I only have a blitz intake, MREV2 & 5/16 spacer. Lightened flywheel too but i don't think that matters.