Z BomB

Hi guys, I'm new to this forum and still learning about the "performance" aspects of the 300ZX. I understand that an engine equipped with long intake runners (which I know the 300ZX possesses) helps to yield a good low end torque, but at the sacrafice of high end horsepower. But after looking at the specs of the 300ZX n/a (VG30DE), I noticed that not only does it have good low end torque, but also high end horsepower. Can someone please explain to me how this is possible? Any help will be highly appreciated. Thanks guys in advance.

hoov100

because of the extra two turbo, the lower C/R the different ECU tuning and different conditions where the two cars where dynoe'd..

KasbeKZ

hoov's a beast!

hoov100

KasbeKZ

lol just a spur of the moment thing.

hoov100

O_o




msglngth

ZLover4Life

Short version: Nissan knows how to engineer a proper engine

hoov, he asked about NA's. lol

But hoov is almost right... the *higher* compression ratio of the VG30DE in addition to the bore width and stroke lengths have a huge play in how a car produces hosepower and torque. Generally speaking, larger bore makes more horsepower, and the VG30DE has a good bore width for its stroke length, thus making a well balanced engine, power-wise. And that's just being basic... there's also the cylinder head design and the VTC system that I haven't gone into, all of which are a HUGE reason why the Z32 can make incredible power at all RPM.

CanyonCarver

There used to be a web page with a very good article on what the nissan designers went through to develop the VG30DE motor. It covered alot of the design considerations. Anyways, I can't find that link anymore. I think it was on the old AMZ website.

Here is a different link with some similar info:

http://autospeed.com/cms/A_109870/article.html

hoov100

i still dont like the long runners and all the lines that should have been made of metal in the first place, i mean why couldnt they just make a set of ITB's with like velocity stacks or something?

ZLover4Life

1. $$$

Far cheaper to cast 1 plenum and 2 throttle bodies than 6 throttle bodies and their corresponding tubing.


2. There's no big benefit for doing it that way. Lamborghini and Ferrari both use the exact same setup the Z32 does - 2 throttle bodies and a nice big plenum. There must be a great reason they do it that way, because they don't cut corners. I'm not a mechanical engineer, so I don't know all of the physics behind it, but I'll trust Ferrari and Lamborghini when they use it on their cars.

bardabe

not only that the only reason nissan has ever used ITB's was to get the car to Idle right with such high cam durations (RB26)

Z BomB

First of all, I would like to thank everyone for their replies and help, I truely do appreciate it. So basically, the long runners help to produce the torque,while factors like C/R, the bore size, head design and the vtc help with horsepower side. If it isn't too much to ask, can you please go a lil in depth with the factors. I am actually understanding it and hopefully a lil more will put the icing on the cake. Thanks once again guys and again I do appreciate the help.

ZLover4Life

Dude, it would take SO LONG to explain it all that you'll be hard pressed to find someone on a forum willing to devote the time (sorry, but I certainly am not... I've got my own obligations). My advice is to grab a book (there are entire books written on how to make performance engines) or start searching online. Once you have an understanding of how power is made, look at the VG30DE and you'll be able to understand which methods Nissan used to accomplish it.

Again, a short version: higher compression ratio means you're compressing more air and fuel in the cylinder. More air and fuel = more horsepower. VTC adjusts the cam timing to optimize the airflow into the cylinders so that the engine breathes better at different RPM's... again, better breathing = more power (getting the additional fuel is easy). It ALL comes down to getting more air and fuel into the cylinders and the many methods of doing that. So start searching.

The internet is like a library... you don't go into the library shouting your questions hoping someone has read the books and can answer them... you go to the library and look in the books yourself.

Z BomB

Oh no, I wasn't looking looking for the entine rundown on the subject. You actually provided me with a very good understanding in your last post, something short and to the point. I know how great the internet is in providing information, but for some reason I wasn't finding no answer what so ever regarding that subject (and trust me, I tried a lot). But I now having a way better understanding of it now than before. Thank you very much again for taking the time to help me out.

hoov100

basically, the longer runners are great, but they are absolutely horrid when trying to work on the car and are such a pain in the *** to remove.

ZLover4Life

EGR Elimination + Coolant Bypass = 10 minute plenum pulls

hoov100

yeah, thats true but its still a bitch, can you eliminate all that ACC valve crap on the back of the plenum and still have it run right,..

ZLover4Life

You can't eliminate the mechanical bits on the back, those all serve a purpose. But those are just connections and tubing and they're on the top (for the most part)... so they're not the hard part of a plenum pull. Once the EGR is gone (eliminating the need to get those 4 bolts on the underside of the plenum) and the coolant bypass is done (eliminating the need to detatch hoses from under the plenum), it's a breeze... hardest part becomes the AIV's, which you can simply unclamp and slide off when the plenum is coming out.

Z BomB

I know that the z31 came with intake secondaries (or at least that's what I read). Are the VG in the z32 equipped with some type of secondaries as well?

ZLover4Life

I have no idea wth you're talking about.

Z BomB

I was talking about secondary runners in the intake plenum. After doing a lil research I think they don't. But please correct me if I'm wrong.