theking

iTrader: (3)

Please explain how rod ratio doesn't effect rev ability? You talk about ditching the CVTCC and then in the same breathe the better breathing of the VQ35. With the new options available(EU and Utec) having a flashed ecu by JWT is no longer such and asset. Not trying to be a jerk, but please explain how you can get the VQ35 heads and VQ30 cover with no Variable timing. Thanks in advance.

Larrio

I thought it was because the timing chain cover between the vq30 and vq35 are interchangable.

Hence if you used vq35 heads but disabled the CVTCS and slapped on a VQ30 timing chain cover, you have a working engine. This is what Tilley99 has done on a few VQ's

tilleys99

iTrader: (3)

IMHO if you got vtcs why ditch them. I have dynos of a 3.5 without VTCS with a few blot ons and compared to a 3.5 with vtcs i lost about 20tq in the low end.

blubyu

iTrader: (1)

go away troll

Resolute

iTrader: (2)

I never said it doesn't affect rev ability, only that it isn't very important. And it's not. Virtually everything else is more important than the rod/stroke ratio in getting this motor to rev safely. If we were building a motor from scratch to rev like a sport bike, then by all means we would take the rod/stroke into account. But we aren't. We are talking about swapping VQ30 parts and the minor difference in piston speed will not be a limiting factor. People seem to think that this rod/stroke value is the key to revving high, but how high? 8000rpm? stock rod/stroke is fine for that, but nevermind that you would need lighter pistons and conrods to do it well, or cams that don't exist to breathe at that rpm. 10,000rpm? Now the ratio becomes more important, but still not more so than the ability of the heads to move that amount of air, or again cams that don't exist, or in both cases conrods strong and light enough not to get destroyed since the inertial forces alone are many times more destructive than high boost levels. Or that the stock cam on bucket probably won't work well above 8,000 rpm. Sure the system is light, but most high-reving engines, including Nissan's formula VQ, 8500rpm 197hp SR16VE N1, RB26, every high revving Honda, etc.. all use some form of hydraulic lash controlled roller followers because a cam on bucket doesn't usually provide enough wiping pad for aggresive ramp on high profile cams. Again, just about everything else on the engine is more important for high rpm use than the rod/stroke ratio.
The head's ability to breathe is a function of port size, smoothness, angle of entry, valve diameter and position, etc.. not the CVTCC system. The CVTCC is nice for varying valve timing to help keep a smooth idle with aggressive cams, and then introduce some overlap at higher rpm, but it is not a function of the head's ability to move air, but at what time the air is to be introduced into the cc.
I mentioned removing the CVTCC strictly for the ability to use a JWT ECU, as a sound, and probably cheaper, alternative to piggybacks and stand-alones. Not as an altogether performance modification.
And I don't think you're sounding like a jerk, it's cool. This post could have some useful ideas on building a VQ for boost and better management, but has become a VQ30 vs. VQ35 bash, a Maxima vs. Z bash, etc. I was only trying to straighten out, and maybe clarify, the useful information of this post.
Will

tilleys99

iTrader: (3)

I know i was just stating the fact you would lose low end tq. BTW thanks for taking my ideas the way i was intending. Too many haters out there dont wanna hear anything other then what everone else is doing.

Resolute

iTrader: (2)

The NISMO VQ30DETT makes its power at a peak of 5600rpm. If I recall, it doesn't actually rev past 6500 rpm. The motor also makes more torque than hp.. it's about as opposite a motor as most people here would probably want to build, but obviously suits the needs of NISMO in a light car with tons of grip in a series that limits hp, but not tq. The lower rpm increases life expectancy of the motor with that much boost. The NA VQ35DE built by NISMO makes its most power in the Dakar Rally trucks, unrestricted it makes almost 450hp, at about 7500 rpm. I would consider anything over 8000rpm to be a high-revving motor, and personally 7000-7500 more practical for a street driven sports car without any type of cam phasing, and entirely doable without changing discplacement on the VQ35.
Will

mojo powered

iTrader: (2)

Will.. I personally would like to thank you for your valuable and constructive comments, unfortunately among the very few on this thread as you mentioned earlier.

I also would like to bring to the table the issue of transmission and rear end ratios. What makes a car fast is not only the engine, but also many other factors. So for a torquey engine that doesn't rev very high like the nismo vq30dett you mentioned, you could play with gear ratios to make all that power and torque useable for whatever application you want, street, strip or race track. Remember that high revving cars like the S2000 have higher ratios to allow that much revving, and go fast in the same time where as a car like the Z has much lower rear end ratios.

So yes, high revving could be an advantage but what other factors are we talking about? You don't need high revving for all applications and let's please not take what one driver in a japanese video said about the VQ as a rule. Everything is relative. Yes, the VQ doesn't rev as much as some other cars, but then it does not need to given the other factors that I just talked about.

Resolute

iTrader: (2)

Well put,
In regards to the VQ30DETT, taller gearing will certainly make the torque curve more manageable and useable, but also taller gears are stronger (due to fewer gear teeth) and therefore more durable.
On the flipside, when displacement is limited, higher revs will gain more hp, and the loss of torque can be easily compensated with shorter gearing, as is the case for the S2000 you mentioned. Personally, the s2000 is a hoot on the track, but I prefer my Z for a good ride in both worlds, and exactly why in my own personal case, a NA VQ35 with good power up to a 7500rpm limit and the 3.9 gearing strikes me as ideal. If I wanted to boost, I wouldn't even bother with shorter gears, but maybe the other way around with so much torque. Similiar to the VQ30DETT... in any case, I don't see this crank and rod swap as a real benefit for the NA crowd, by the time the better rod/stroke came into play, you're well outside the feasibility of a street car. For the pressurized guys this might be worth looking into.
Thanks for the compliment, but it's all speculative and theoretical on my part. Whether people agree with this swap or not, guys like Tilley are the one's actually getting down to the grit and finding out what works, and providing the solid information on what's possible.
Will

theking

iTrader: (3)

Resolute, thanks for the informative replys. I didn't even think about the cam on bucket issue, good point. I am more excited about the big end size being different and having more options for better bearings. This is a cool option for under 2grand for having a motor that can make 500whp+. I hear what you say about the NA being no benefit but this is the FI forum, lol. J/K. Just poking a little fun. In all honesty, thanks for your input.

Larrio

mojo: point taken. I brought up the few examples I knew as a point for conversion and not as a basis that the VQ35 is inferior in comparison in high rev ability.

kaos1

iTrader: (1)

lmao people are still posting on this shiiiittt

mojo powered

iTrader: (2)

Larrio.. you're actually one of the few that were constructive so I thank you for that. I was talking about the hijacking comments comparing a maxima to a Z and who's got heritage pissing contest whereas the topic is about the VQ.

And to those who cannot believe that this thread is still going.. this could actually be one of the best threads in this forum since tilley's is exploring a path no one has ever tried before. But if you'd rather talk about how your nismo carbonfiber b-pillar cover looks, than you're in the wrong forum and thread to begin with. Unfortunately, most comments were about a pissing contest that has nothing to do with the topic and turned people off, people that actually had a constructive comment.

tilleys99

iTrader: (3)

good call

down_shift

iTrader: (12)

From what I read on the first page, Tiley knows what he's talking about. It totally makes sense to go back to the 30 for his purposes.

No need to point fingers, but Taur had a nice outburst for some reason lol

I wouldn't mind losing a little torque if I can have some highend.. I didn't even know the 30's internals would fit in a 35! Shed more light to us here. Also how will the room affect the gearing of your 6spd tranny?

mojo powered

iTrader: (2)

Hey Tilleys.. are you planning forced induction any time soon? If you are, what boost are you planning on running? Also, a cost estimate for your setup compared to -let's say- a built and installed VQ block (with pauter/arias for example) would be interesting to look at.

Remember that we have to take into account putting in a new crank, whereas a pauter/arias setup with 8.5 to 1 would keep the existing.

tilleys99

iTrader: (3)

It is boosted, i am currently redoing my piping but it will be back soon. I was running 13psi before i decided too redo a few things.

mojo powered

iTrader: (2)

oh sweet! ok so let me get this straight.. so sorry if this has been covered before.

You have a vq35 block, vq30 internals and crank (~3.2L, 8.5 to 1), JWT bumpsticks and JWT ecu with disabled variable cam timing?

did you get to hit the dyno at 13psi?

on and also, was it a custom turbo kit you made or a kit?

tilleys99

iTrader: (3)

Its a custom kit with a T04r on my new setup. Vq35 block/pistons vq30 crank and rods, and alot of other goodies. No dyno times yet my primarys were too small so i decided too upgrade them for better flow, no more cast manifolds

mojo powered

iTrader: (2)

sounds nasty I guess your engine is mounted transverse so your setup is quite a bit different than the Z's engine bay. Where is the turbo mounted?

I guess I should do to the maxima forums to educate myself first. Sorry for the noob questions, I never saw a turboed maxima engine bay.