8000 - 9000 rpm VQ30DE valve train.
10-21-2004, 12:15 PM
#1
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8000 - 9000 rpm VQ30DE valve train.
Is there any aftermarket parts besides the jwt cams that can make this as safe as possible I read a post about using titanium 2jz retainers and springs. Lets clarify this now. what are the best valve stems, springs, retainers, and cams for a 8,000 - 9,000 rpm VQ30DE?
10-21-2004, 12:26 PM
#2
Cams only open/close the valves. They don't do anything to make the engine any safer to rev. Valvetrain items like stronger springs might help prevent valvefloat. Lightweight valvetrain items might will reduce the amount of mass the engine has to overcome.
But you are ignoring the entire lower end of the engine. If you REALLY want to get into the 9,000 rpm range. You had better tear the entire engine down, get the block magnafluxed and maybe alignbored. Get the crank checked and balanced to a tighter tolerance. Get stronger rods and maybe pistons. Also invest in quality bolt hardware. Once you have all the parts, you're going to have all the rotating parts balanced and assembled at once. ie.. shortblock/flywheel/clutch and maybe the crankpulley etc....
I'm not even sure there is enough aftermarket stuff out there that would allow the VQ30 to even make any power at 9,000 rpm. You can rev the stock engine to 9,000 I guess. But making it last for any reasonable amount of time is the trick.
But you are ignoring the entire lower end of the engine. If you REALLY want to get into the 9,000 rpm range. You had better tear the entire engine down, get the block magnafluxed and maybe alignbored. Get the crank checked and balanced to a tighter tolerance. Get stronger rods and maybe pistons. Also invest in quality bolt hardware. Once you have all the parts, you're going to have all the rotating parts balanced and assembled at once. ie.. shortblock/flywheel/clutch and maybe the crankpulley etc....
I'm not even sure there is enough aftermarket stuff out there that would allow the VQ30 to even make any power at 9,000 rpm. You can rev the stock engine to 9,000 I guess. But making it last for any reasonable amount of time is the trick.
10-21-2004, 12:33 PM
#3
Yeah, even with a VI of some sort, I can't see revving to 9,000 being beneficial at all. I just think the power would drop off before that. Krismax has gone to 8,000, but I don't think he ever did a dyno to see what kind of power it was making up there, did he?
10-21-2004, 01:02 PM
#4
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if not 9000 rpm 8,000 is fine. im doing a DEK IM swap and i have forged pistons and the block will be balanced and checked. i know im pushing the stock rods .....(and so what) they can hold what ever hal is doing to them. im gonna do this engine right, belive me. I just want to know if there are titanium components that we can use for 4th gen heads.
10-21-2004, 01:03 PM
#5
Um VI won't make the difference. You need to consider valve size, port size, cam profile, yes intake manifold design, TB size, maf size etc.....
Originally Posted by Tatanko
Yeah, even with a VI of some sort, I can't see revving to 9,000 being beneficial at all. I just think the power would drop off before that. Krismax has gone to 8,000, but I don't think he ever did a dyno to see what kind of power it was making up there, did he?
10-21-2004, 01:26 PM
#9
Originally Posted by Jeff92se
I think recipocating stresses are different than stresses from boost. So if hal is getting 500hp out his motor from boost, doesn't mean you can spin the engine to xxxx rpm to get 500hp to match.
10-21-2004, 01:37 PM
#10
Originally Posted by Jeff92se
Um VI won't make the difference. You need to consider valve size, port size, cam profile, yes intake manifold design, TB size, maf size etc.....
10-21-2004, 03:32 PM
#11
Originally Posted by Stephen Max
That's right. In fact, boost pressure helps to lower rod and rod bolt stresses since it acts against the tensile load seen by the rods at TDC when they are reversing direction.
Mass is the enemy of high rpm operation. Lighter components in both the valvetrain and the bottom end are necessary.
10-21-2004, 03:42 PM
#12
With boost you don't need/use 9000rpm Neal.
Comparing a NA engine at 9000rpm vs. a boosted engine at 7000rpm producing the same output, the tensile stress exceeds the power/compressive stress of boost by SEVERAL multiples.
Comparing a NA engine at 9000rpm vs. a boosted engine at 7000rpm producing the same output, the tensile stress exceeds the power/compressive stress of boost by SEVERAL multiples.
10-21-2004, 04:20 PM
#14
Originally Posted by IceY2K1
With boost you don't need/use 9000rpm Neal.
Comparing a NA engine at 9000rpm vs. a boosted engine at 7000rpm producing the same output, the tensile stress exceeds the power/compressive stress of boost by SEVERAL multiples.
Comparing a NA engine at 9000rpm vs. a boosted engine at 7000rpm producing the same output, the tensile stress exceeds the power/compressive stress of boost by SEVERAL multiples.
I didn't say you would or should. I was responding to what stephen max said about the extra cylinder pressure counteracting the tensile stress on the rods and rod bolts on a boosted engine running those kinds of revs, which is true until one lets off the gas like at the end of a 1/4 mile run.
10-21-2004, 04:26 PM
#15
And I'm saying that StephenMax wasn't comparing a boosted engine at 9000rpm, but a NA engine at 9000rpm and a boosted engine at stock/slightly raised rev-limit.
I know the quote he's referring too in Corky Bells' "Maximum Boost". It's a ratio of like 20%(boost) vs. 120%(1200rpm more) IIRC.
I know the quote he's referring too in Corky Bells' "Maximum Boost". It's a ratio of like 20%(boost) vs. 120%(1200rpm more) IIRC.
Originally Posted by Nealoc187
I didn't say you would or should. I was responding to what stephen max said about the extra cylinder pressure counteracting the tensile stress on the rods and rod bolts on a boosted engine running those kinds of revs, which is true until one lets off the gas like at the end of a 1/4 mile run.
10-21-2004, 04:29 PM
#16
Originally Posted by Nealoc187
I didn't say you would or should. I was responding to what stephen max said about the extra cylinder pressure counteracting the tensile stress on the rods and rod bolts on a boosted engine running those kinds of revs, which is true until one lets off the gas like at the end of a 1/4 mile run.
Make sure to check your oil
10-21-2004, 05:01 PM
#18
Jeff and SM both said boost *VS* over-reving aren't apples-to-apples rod stress wise when looking at the same output level. SM just clarified why.
I agree on your point though...I'm glad you said it, since I hadn't considered it. Although, I wouldn't push over 7000rpm *IF* boosted, so it's not a concern.
I agree on your point though...I'm glad you said it, since I hadn't considered it. Although, I wouldn't push over 7000rpm *IF* boosted, so it's not a concern.
10-21-2004, 05:15 PM
#20
In that case yes I agree the stresses on the internals are not in any way the same when comparing a 7000rpm high HP engine vs a 9000rpm high revving engine. Tensile stress vs compression stress. I must have just misread somewhere in this thread because I'm at work right now trying to post on here and listen to these idiots I have to call on the phone.
10-21-2004, 05:23 PM
#21
In the high revving situation, the stress I'm referring to is the the "stretching" stress that is put on the rod as the rod has to deal with the mass of the piston moving up at such a high rate of speed, sortof like a rubber band stretching. Such a stress shouldn't be subject to engine load. Regardless of whether or not the engine is under load or not, the piston and rod are moving at a fixed speed at any given RPM and the rod has to "hold on" to the piston.
10-21-2004, 09:36 PM
#22
It usually isn't the rods that are first to fail during an over rev. The rod bolts are more or less the fuses in this case. The VQ35 rod bolts only allow for a constant 7200rpm wheras the Nismo rod bolts allow for 7500+.
The valvetrain can be made to handle a 4500rpm cam speed but that will get costly. I have mentioned in other threads before that the VK45 Ti valves will work in the VQ30 heads but the lenghts are a little shorter and will require different shims (on top of the lifters). You can also switch to Ti retainers but the mass savings is so minute it isn't even worth the cost. The most important part of this valvetrain would be the valve springs. Something with about 150 lbs. @ 27.8mm (stock is about 100 lbs. @ 27.8mm)should do the trick but that extra valvetrain load is going to hurt your low end torque.
The valvetrain can be made to handle a 4500rpm cam speed but that will get costly. I have mentioned in other threads before that the VK45 Ti valves will work in the VQ30 heads but the lenghts are a little shorter and will require different shims (on top of the lifters). You can also switch to Ti retainers but the mass savings is so minute it isn't even worth the cost. The most important part of this valvetrain would be the valve springs. Something with about 150 lbs. @ 27.8mm (stock is about 100 lbs. @ 27.8mm)should do the trick but that extra valvetrain load is going to hurt your low end torque.
10-22-2004, 11:05 AM
#24
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Originally Posted by IceY2K1
And I'm saying that StephenMax wasn't comparing a boosted engine at 9000rpm, but a NA engine at 9000rpm and a boosted engine at stock/slightly raised rev-limit.
I know the quote he's referring too in Corky Bells' "Maximum Boost". It's a ratio of like 20%(boost) vs. 120%(1200rpm more) IIRC.
I know the quote he's referring too in Corky Bells' "Maximum Boost". It's a ratio of like 20%(boost) vs. 120%(1200rpm more) IIRC.
10-22-2004, 11:47 AM
#25
Yeah, I'm jumping around in Jeff Hartmans', it gets boring if I don't.
I've pretty much read all Corkey Bells' except the carb and some other stuff I didn't care about. Easy and worthwhile read.
I've pretty much read all Corkey Bells' except the carb and some other stuff I didn't care about. Easy and worthwhile read.
Originally Posted by pawnstar12
i guess i should read that book since i have it. im still trying to take in jeff hartmans, how to tune and modify ems
11-04-2004, 05:22 AM
#29
Originally Posted by pawnstar12
hey what is the part # for the nismo rod bolts because i went to the nissan dealer and they said they dont make them for the VQ30
9000 rpm for a n/a setup wouldn't be bad. You would need individual throttlebodies and a ligtened valvetrain and a balanced upgraded lower end. Like nissanperformancemag.com 350z guy with the VQ30 and vustom transmission in his car that revs to 8500 rpm or higher.
11-04-2004, 07:28 AM
#31
okay, im not engine PRO with the vq30 or any othe rengine, but after reading this i am curious to know what would prolly be the maxima rpm the vq30de-k would make horsepower before it dropped. I ask this because of the technosquare ECu which raises the revlimiter to 7100 rpms. Is the increased limiter enough to take full advantage or could our engiens go even further than that and make more power (say 7500 rpm or even 8000 rpm). Or has this pretty much not proven (lack of dynos or what not)
Eugene.
Eugene.
11-04-2004, 04:19 PM
#36
I'd agree, since VQ35s are moving a lot more air, however the first wall/limit will be our cams not heads/valves.
Slap on a set of VQ35 heads/intake manifold/Tomei cams/TC and call it a day IMO.
Slap on a set of VQ35 heads/intake manifold/Tomei cams/TC and call it a day IMO.
11-04-2004, 07:53 PM
#38
Originally Posted by Larrio
doesn't the vq35 heads on the 3.0 block supposedly lower compression? So you'll need custom high comp pistons to go NA?
my brain isn't working right now, whats TC?
my brain isn't working right now, whats TC?
