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Thread: How high can the stock SR20VE Rev to?

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Posts: 21-30 of 37
2012-04-03 01:05:00
#21
When i had my stock VE i would rev it to about 8-8200 in 1st and 8k in 2nd, 7800 in 3rd and 4th. I didnt have a rev limiter set and there was a couple times when I was racing it that i tried doing my normal flat shifting into 2nd and missed 2nd and saw the tach hit the stop peg past 9k. Probably over 10-11k. I got away with it a couple times with no damage. However did it again but even worse, maybe saw past 11k and floated the valves into the piston breaking he heads off 2 valves. The rest of the cylinders had nicks on them from the valves slightly hitting as well but didnt bend or break the valves. Just on #3.

Like they said the valves will have started to float past 8k rpm for sure. Higher you go on them the worse it will get and yes could eventually hit valves. I guess i got lucky the several times it saw past 9k on mis shifts.

N1 cams, different story. Rev to 9k all day long without issues at all with valve float.
2012-04-03 13:32:24
#22
Originally Posted by eggman
If it makes you feel better,I bet your factory tach is off by around 500(reads high) at those RPM in most cases,so you MIGHT get lucky.
does the motor run ok still?


Ya, engine sounds normal. When i rev it, Pers like a kitty.. it might be off a bit because when i hooked up the MSD window switch and i activated the VVL to come on @ 4800, on my tach it activates at around 5200.
2012-04-03 13:34:13
#23
Originally Posted by ashtonsser
When i had my stock VE i would rev it to about 8-8200 in 1st and 8k in 2nd, 7800 in 3rd and 4th. I didnt have a rev limiter set and there was a couple times when I was racing it that i tried doing my normal flat shifting into 2nd and missed 2nd and saw the tach hit the stop peg past 9k. Probably over 10-11k. I got away with it a couple times with no damage. However did it again but even worse, maybe saw past 11k and floated the valves into the piston breaking he heads off 2 valves. The rest of the cylinders had nicks on them from the valves slightly hitting as well but didnt bend or break the valves. Just on #3.

Like they said the valves will have started to float past 8k rpm for sure. Higher you go on them the worse it will get and yes could eventually hit valves. I guess i got lucky the several times it saw past 9k on mis shifts.

N1 cams, different story. Rev to 9k all day long without issues at all with valve float.


Sounds like what happen to me.. Very similar stories!!
2012-04-03 13:39:10
#24
Ok guys, another question.. How is it that it's "SAFE" to shift at around 8500-9k on N1 cams, but not safe for the sr20ve cams?? I understand we need dual valve springs and titanium retainers to keep everything DOWN tightly, but don't understand how we can put N1 cams and simply that lets us shift higher safely.

I might have answered my own question. I don't think we can put N1 cams without the proper supporting valvetrain..??
2012-04-03 14:07:54
#25
Stock VE's have dual valve springs.

N1 cams have a much smoother ramp profile, lot more duration and so on to make that happen. You can literally look at the two cams and tell the difference.

At high rpms the ramp profile of the stock ve cam is soo sudden and ends sudden that the valve literally slams shut and at high rpms will causing the valve not to be able to shut quick enough and also bounce on the seat.
2012-04-03 14:38:36
#26
Originally Posted by P10FTW
Probably not directed towards me, but actually my tach is on point. Tried it out on the dyno, my speedo is off though. Most likely due to tire size.

But yeah anything over 7.6k is justmaking mostly noise.


On stock cams yeah, on N1's they just keep on making power. Here is my virtual dyno run (based on ecu logs). I didn't even hit 8k and it was still making power.



Originally Posted by NissanUnlimited
Ok guys, another question.. How is it that it's "SAFE" to shift at around 8500-9k on N1 cams, but not safe for the sr20ve cams?? I understand we need dual valve springs and titanium retainers to keep everything DOWN tightly, but don't understand how we can put N1 cams and simply that lets us shift higher safely.

I might have answered my own question. I don't think we can put N1 cams without the proper supporting valvetrain..??


The cam profile dictates it all as Ashton said. Looks at it this way, stock 20VE cams with big lobes and low duration essentially kick the valves, while N1 cams that have big lobes but long duration provide a smooth ram that guide the valves.

For comparison sake here are some pics.

SR20VE cams


SR16VE N1 Cams
2012-04-03 14:52:14
#27
this is good info =) good work!!
2012-04-03 14:55:30
#28
Yes, well explained.. Thanks guys!! So i guess installing some N1s will let me rev and make more top end power Safely..
2012-04-03 15:51:48
#29
Originally Posted by NissanUnlimited
Yes, well explained.. Thanks guys!! So i guess installing some N1s will let me rev and make more top end power Safely..


Yup, though N1 cams are a whole beast of their own. I actually lost power with my SSAC header and 3" exhaust when I first installed them. I had to really tune them out before they started shinning. The SSAC header is probably the biggest thing holding it back now though, I'm going turbo so I don't care to replace it with a better header
2012-04-03 16:27:41
#30
N1 cams is a must in any VE N/A setup, they got me several tuning hours but got my car from mid 14's to 13.6 trapping 104 on stock s&r
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