How safe is reving to 7000rpm with a stock cylinder head/valve train????
#1
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How safe is reving to 7000rpm with a stock cylinder head/valve train????
I've searched this and ally of NA guys rev to 7.2k on the stock DE motor. I have my rev limit set at 7k with a built bottom end but a stock rebuilt cylinder heads.
I know I won be making more power due to the stock cams being out of puff.
I just wanted to know how safe you guys think it will be reving that high now and again?
I know I won be making more power due to the stock cams being out of puff.
I just wanted to know how safe you guys think it will be reving that high now and again?
#4
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who are you? what a waste of a post.
dj- Id keep it within the stock redline, there really is no point in over revving ( I know you dont do a lot of drag so ) NA guys do it a lot because they got no power lol... but FI I wont trust the stock heads so much. Power falls on its face so no point.
Get some cams on that built motor!
dj- Id keep it within the stock redline, there really is no point in over revving ( I know you dont do a lot of drag so ) NA guys do it a lot because they got no power lol... but FI I wont trust the stock heads so much. Power falls on its face so no point.
Get some cams on that built motor!
#5
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it's safe. Stock valvetrain has shown to hold up just fine to 7100 or 7200. The power might fall off, if it does no big deal because you can hold your rev longer as long as the power doesn't fall off severely.
The problem with revving high is the valve springs. I would worry about floating a valve up that high because the stock springs sack out with higher revs. So far i haven't seen any proof of **** being a problem at 7100 or so. As far as i know the rev-ups utilize the same valvesprings as the non-rev's and they are safe to 7100.
The problem with revving high is the valve springs. I would worry about floating a valve up that high because the stock springs sack out with higher revs. So far i haven't seen any proof of **** being a problem at 7100 or so. As far as i know the rev-ups utilize the same valvesprings as the non-rev's and they are safe to 7100.
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It comes down to if the car will be producing any power above the stock redline if not then revving past redline is pointless you would just be putting unwanted stress on the valves for no reason
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#13
Cranky FI Owner
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OP-only do it in 1st and 2nd gear where you truly need it and you will be fine.
This is way crazy but I know a stock valvetrain car that revs to 8300rpm's and it makes anywhere from 500-860+whp. Would I recommend that? Hell no, but just know its been done and with success, the stock valvetrain is better than you think.
Now if you were stock bottm end Id recommend sticking to the stock redline.
#15
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it does fall on its face but hey if its faster to rev that high and the results are there then i cant argue the faces. did you rev that high before your cams bert cause its all whole new ball games with your bc2's. oh and im still on the fence with cam selections, i cant seem to make up my mind between bc2's and bc3's. i initially thought bc3 but your feedback and experience has me leaning towards bc2's.,
Last edited by Nexx; 10-08-2010 at 11:00 AM.
#16
Registered User
6500rpm? Stock DE cams are done at 6200rpm....if you have every breathing mod done maybe 6500 it'll hold power but its gonna fall hard whenever it crests.
Rev'd my "old" car to 7200 at drag strip on stock heads/cams. I'm certain there was some valve float but it was just used at the strip (to keep it in 4th gear).
On street I didn't rev much passed 6500.....now with the BC Stage 3's.......rev rev rev
tom
Rev'd my "old" car to 7200 at drag strip on stock heads/cams. I'm certain there was some valve float but it was just used at the strip (to keep it in 4th gear).
On street I didn't rev much passed 6500.....now with the BC Stage 3's.......rev rev rev
tom
#17
350Z-holic
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He has a built block, etc.....don't see why it matters what I am.....I stand by the fact that revving the car to 7200rpm (in first and second in particular) will be faster than shifting at 6500. Just sayin'. My old turbo integra (455whp) always ran faster shifting after the peak power...peak was ~8800 and I shifted at 9300.
I was simply pointing out that the stock valvetrain, in my experience, has no problem with going to 7200rpm.
I was simply pointing out that the stock valvetrain, in my experience, has no problem with going to 7200rpm.
Last edited by 03threefiftyz; 10-08-2010 at 11:11 AM.
#18
Cranky FI Owner
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He has a built block, etc.....don't see why it matters what I am.....I stand by the fact that revving the car to 7200rpm (in first and second in particular) will be faster than shifting at 6500. Just sayin'. My old turbo integra (455whp) always ran faster shifting after the peak power...peak was ~8800 and I shifted at 9300.
I was simply pointing out that the stock valvetrain, in my experience, has no problem with going to 7200rpm.
I was simply pointing out that the stock valvetrain, in my experience, has no problem with going to 7200rpm.
I havent seen an NA motor starting to show signs of valve float on any dyno, but I have with FI, big differance IMO
Your shift points are still correct though
#19
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Why? FI has no effect on Valve springs RPMs are RPMs
Valve float will occur at a given rpm due to spring sag
and tension no matter if it is FI or NA on the same motor.