Does anyone have one? ive heard they nose dive at 6200 but then pick back up to 7k, just trying to see how healthy the power band is after the stcok rev limiter.
also how much timing are this cars getting? i hear the tunes available are very conservative, pfff, is any tuner out there doing any real peak performance maps?
any reason you wanted that low timing? havent tuned my new set up, but on stock turbo and meth my timing was around 30*-32*. is to compensate for the higher air volume?
any reason you wanted that low timing? havent tuned my new set up, but on stock turbo and meth my timing was around 30*-32*. is to compensate for the higher air volume?
yep. you make up power via w/ boost. big turbos + big timing =
i was running 42* of timing on my stock turbo on pump/meth.
i rather be safe trying to push 430-440hp on pump/meth than on the edge.
if its low and my KR is still 0, i could always raise it via w/ the safc2...
why does the oil pressure drop at 6200? that doesn't make any sense, the pump is still spinning faster and faster. unless there's some sort of bypass built into the pump, or if it's cavitating
Some of the dips in power have to do with head flow & cams. Also the oil pressure dropps at 6200 thus why DCR has the fix.
the dips in power im talking about were seen on cars with big turbos, built motors, using a reflash, i know the dips you talk about but the ones im referring to are not caused by physical factors, they are caused by poor/conservative tunning of the timing curve, killing timing at 6k but letting it pick up again, to stop the power from climbing further passed the stock redline but still letting the motor rev to 7K.
dont want to mention whos flash it was, but thats why i want to see if other sct's are better or do they have the same problem, that could disprove it, being tuners fault. also it could determine wich tuner i would go with.
Quote: Originally Posted by -ND4SPD-
the oil pressure dropps at 6200 thus why DCR has the fix.
actually its not oil pressure drop its quite the opposite, the oil system flows too much oil at high rpms, this creates an effect called "valve float" the valve cant move freely, so it slows it down due to the excess oil in the head at such rpms, the oil modifier just restricts the passage of the oil through the oil valley in the head so that the valve can move like it needs to by preventing the head from flooding with excess oil.
Quote:
why does the oil pressure drop at 6200?
you are right it doesnt, he understood the function of the oil flow modifier wrong.
Last edited by nightmare_rebuilt : 04-29-2008 at 11:36 AM.
actually its not oil pressure drop its quite the opposite, the oil system flows too much oil at high rpms, this creates an effect called "valve float" the valve cant move freely, so it slows it down due to the excess oil in the head at such rpms, the oil modifier just restricts the passage of the oil through the oil valley in the head so that the valve can move like it needs to by preventing the head from flooding with excess oil.
QUOTE]
Actually, this is not correct, either. What actually happens is that there is too much oil in the head, and it pumps up the lash adjusters, which will slightly overextend at these pressures and volumes. This holds the valve open, instead of letting it close all of the way, causing pumping losses. That's why the engine loses power in that regard. As for losing power at 6200rpm, timing and tune certainly affect it, but the head is simply running out of flow up there. Even with big cams, the cars are falling down in that area. They do not pick up again, torque is on a downward spiral starting by 5800rpm at the latest. Big cams seem to hold it up a little longer, but that's all. Cars with headwork, and the supporting mods to handle high rpm will make power a little later. Other than that, all you are doing is making some cool sounding noise.
Actually, this is not correct, either. What actually happens is that there is too much oil in the head, and it pumps up the lash adjusters, which will slightly overextend at these pressures and volumes. This holds the valve open, instead of letting it close all of the way, causing pumping losses. That's why the engine loses power in that regard.
well that is what i said, excess oil preventing the valve to move like needs to, holding the valve open is the effect known as valve float. i didnt take into account the lash adjusters, thank you for that info, now i remember nemo telling me about it.
Quote:
As for losing power at 6200rpm, timing and tune certainly affect it, but the head is simply running out of flow up there. Even with big cams, the cars are falling down in that area. They do not pick up again, torque is on a downward spiral starting by 5800rpm at the latest. Big cams seem to hold it up a little longer, but that's all. Cars with headwork, and the supporting mods to handle high rpm will make power a little later.
like i said this dips were seen in big turbo, built motor flashed cars, and timing was shown to be poor.
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Other than that, all you are doing is making some cool sounding noise.
so you think there are no benefits of higher redline other than the sound?
i have a built bottom end, head, and a bigger turbo, i only want to rev as high as my power curve will take me, i know after all i have done is damn sure higher than 6200 rpms.
Some of the dips in power have to do with head flow & cams. Also the oil pressure dropps at 6200 thus why DCR has the fix.
Haha... I understand the concept, I was just typing too fast before I left earlier. I was trying to say power drops due to oil pressure, that's my fake dyslexia popping up.
Quote:
so you think there are no benefits of higher redline other than the sound?
i have a built bottom end, head, and a bigger turbo, i only want to rev as high as my power curve will take me, i know after all i have done is damn sure higher than 6200 rpms.
Sure there's benefit, otherwise the honda boys wouldn't be doing it. That's the whole principle of "replacement for displacement". By having the lesser hp/tq production be streatched out over a longer period of time, you can equal or improve upon the classic hotrod approach of more hp/tq over a shorter period of time.
The problem Like myself & Neil stated above has more to do with the head/cam & not the tune. You'll need to address those issues first before you'll achieve the results you're looking for. Besides, I wouldn't trust reving out the stock valvetrain over 7K without upgrading springs/ retainers etc...
valve float is actually where you have a freak nasty big cam with an overly aggressive opening ramp and the valve actually floats over the apex of the cam. also known as "lofting" the valves to the old school hot rod guys. in nhra classes where a maximum cam lift was specified, they'd grind a super aggressive opening ramp, so the valve would gain lift as rpms went higher. i'll have to read up on the dcr oil mods. they've got a few
Haha... I understand the concept, I was just typing too fast before I left earlier. I was trying to say power drops due to oil pressure, that's my fake dyslexia popping up.
Sure there's benefit, otherwise the honda boys wouldn't be doing it. That's the whole principle of "replacement for displacement". By having the lesser hp/tq production be streatched out over a longer period of time, you can equal or improve upon the classic hotrod approach of more hp/tq over a shorter period of time.
The problem Like myself & Neil stated above has more to do with the head/cam & not the tune. You'll need to address those issues first before you'll achieve the results you're looking for. Besides, I wouldn't trust reving out the stock valvetrain over 7K without upgrading springs/ retainers etc...
we are going off topic this is about the reflashes actually holding its power to at least 7k rpms after all the physical engine week points have been addressed.
how many times do i have to say it? no one here is planning to do it to a stock motor!
both drastic and i have the valve train needed for this, as should anyone who has done it already, i asked for dyno sheets, if you dont have one, or havent done this, or dont have any first hand experience about this particular subject, please dont post.
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dyno sheet of flashed Nsrt4 reving past 6k?
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