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lost 20 whp.. what could have been the problem?

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Old 07-17-2012, 06:57 AM
  #41  
djamps
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I doubt weather/dyno variance is much if any factor here. You can see the dyno uses STD corrections which accounts for temp/humidity plus it's a fixed-mass inertial dyno not subject to the huge variances brake based dynos are known for. The gains/losses of his mods should be greater than the dyno variance in any case.

I would take a look at the timing curves before/after the mods. I am definitely seeing some knock retard on those plots. Cams can induce some phantom knock if they are noisey. Try shutting knock control off completely and setting hi and low det maps equal. Also make sure you have a solid 12.5 a/f thru out the pull.

Last edited by djamps; 07-17-2012 at 07:00 AM.
Old 07-17-2012, 04:25 PM
  #42  
F2CMaDMaXX
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Did i just read that you're swapping out the MREV2 because you lost 2 HP at peak and gained torque all through the curve?

Not complaining, just trying to be clear there? Chances are, with cams, you might make more power with the complete intake revision you're ordering, i assume you're after just peak numbers?
Old 07-17-2012, 08:57 PM
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Resmarted
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Originally Posted by djamps

I would take a look at the timing curves before/after the mods. I am definitely seeing some knock retard on those plots. Cams can induce some phantom knock if they are noisey.
I'm guessing you mean improperly lashed, maybe a bit loose?

Curious as this is the first time i've heard any stories about phanom knock on our vq's...
A friend's built sti engine has phantom knock like a ****... I don't want to deal with that at all.
Old 07-18-2012, 05:15 AM
  #44  
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Originally Posted by Resmarted
Curious as this is the first time i've heard any stories about phanom knock on our vq's...
A friend's built sti engine has phantom knock like a ****... I don't want to deal with that at all.
Just being F/I on a stock block will induce phantom knock. I know because I have it . Ended up shutting down knock control completely on my track map and got an extra 4mph. It doesn't get talked about too much because uprev F/I has only recently started to take off in popularity and nobody really pushes the limits quite yet.

Last edited by djamps; 07-18-2012 at 05:17 AM.
Old 07-18-2012, 05:28 AM
  #45  
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Originally Posted by djamps
Just being F/I on a stock block will induce phantom knock. I know because I have it . Ended up shutting down knock control completely on my track map and got an extra 4mph. It doesn't get talked about too much because uprev F/I has only recently started to take off in popularity and nobody really pushes the limits quite yet.
Sweet another thing to worry about.
"fuuuuuuuuuuuuuuuuuu"
Old 07-18-2012, 07:32 AM
  #46  
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depending your goals I wouldn't jump straight into boost. If you are wanting an extra 100-150 hp then go for it but if you just want to be up at 300hp I would stay NA for sure.

Have you thought about going to a different fuel? E85 has proven great results for some imports that are NA. You can get the extra cooling from the fuel and then push the timing limits from the octane.

Increased compression would be nice like you said but requires a tear down of the engine which sucks. If you do up the compression then I would for sure use e85.
Old 07-18-2012, 07:39 AM
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Originally Posted by Resmarted
I'm guessing you mean improperly lashed, maybe a bit loose?

Curious as this is the first time i've heard any stories about phanom knock on our vq's...
A friend's built sti engine has phantom knock like a ****... I don't want to deal with that at all.
I got da phantom knock! Ya, I'm not sure if it's the knock sensor or the oem knock map but our engines show tons of knock for no reason. My built engine is pretty noisy as well (on a knock sensor, not audible). I had to tweak the haltech knock map a bunch due to random strange noisy areas.
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Old 07-18-2012, 08:05 AM
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I think even the Nissan engineers got fed up with it, which could explain why the stock map has knock control disabled below 2k rpm and above 5k rpm or so.
Old 07-18-2012, 08:36 AM
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Ask the tuner to look up a RECENT base Z33 run and see what the numbers are. My guess is the dyno is just not set up the same. The key is get a recent output from the dyno under similar factors.

Otherwise, you may have an issue. Although cams don't add monster power on their own they normally give a pretty health bump once tuned.
Old 08-30-2012, 05:29 AM
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did you ever check the old dyno sheet? this one is showing smoothing of 5 which is going to cut your numbers down more than a lower smoothing amount.
Old 09-05-2012, 05:59 AM
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Originally Posted by tonyzS/C03
thats the funny thing about this game, some times 1+1 doesnt always equal 2...

looking at the cam profile, it could be that you dont have the right suppoting mods to run that cam. There is a lot more to choosing a cam other than just the duration and max lift. You have to take into account that because of the larger lift and longer duration and no intake/plenum tuning that the speed at which air enters your motor has actually decresed, there is a good possiblity that you are getting LESS air in, thus less air out, all combined for less HP in the end...
Hit this one on the nail man, We are dealing with an unhappy customer right now because he put the wrong cams in his Titan and he's trying to say we didn't tune it correctly. I always recommend always doing a little head work with cams. Good luck !

Last edited by RDZMotorsports; 09-05-2012 at 06:00 AM.
Old 09-05-2012, 09:18 AM
  #52  
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I too have the mysterious phantom knock....I have Osiris so I have a tune w/ knock sensor on and knock sensor off; I think I'll get rid of the knock sensor on tune....

I wonder if there's anyone out there FI/built engine that runs with their knock sensors on?

Originally Posted by djamps
I think even the Nissan engineers got fed up with
it, which could explain why the stock map has knock control disabled below 2k rpm and above 5k rpm or so.
Old 09-05-2012, 09:24 AM
  #53  
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I doubt anyone making serious power is tuned with the knock control on, at least above 4500rpm. It's just too sensitive.

Ever notice how almost every VQ35DE N/A dyno chart has a slight dip around 5k or so?

Last edited by djamps; 09-05-2012 at 09:26 AM.
Old 09-08-2012, 04:52 PM
  #54  
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Originally Posted by 350z006
I too have the mysterious phantom knock....I have Osiris so I have a tune w/ knock sensor on and knock sensor off; I think I'll get rid of the knock sensor on tune....

I wonder if there's anyone out there FI/built engine that runs with their knock sensors on?
Originally Posted by djamps
I doubt anyone making serious power is tuned with the knock control on, at least above 4500rpm. It's just too sensitive.

Ever notice how almost every VQ35DE N/A dyno chart has a slight dip around 5k or so?
seriously? all of us making big power do. Of course with the limited software provided by osiris you can't tune the knock threshold so you will have to invest in a better tuning solution like proEFI or haltech. I honestly can't think of someone putting down high HP that DOESN'T have knock control enabled on their car.

On that note, it's impossible to have a generic knock map for any built engine. Every engine has unique sounds and needs to be setup properly in order to work. That goes with any car on the market. It's really not THAT hard to tune a knock map as long a the tuning solution used has that freedom.
Old 09-08-2012, 06:02 PM
  #55  
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Originally Posted by binder
seriously? all of us making big power do. ...
I was speaking specifically of uprev, not other systems. Uprev knock control seriously sucks ***** as I was trying to explain.
Old 09-09-2012, 03:26 PM
  #56  
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Originally Posted by djamps
I was speaking specifically of uprev, not other systems. Uprev knock control seriously sucks ***** as I was trying to explain.
oOo, yes it does. I'm not sure why they couldn't program a map to adjust the sensitivity like other platforms that use the OEM ecu. Seems like osiris is horribly limited compared to other oem ecu flash programs (for other cars of course).
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