MikeZ

Are ITB's a pipe dream or they possible on a NA? I was thinking of building an NA as far as they can go(over time of course). No manufacturer that I have seen makes them (maybe Top Secretor Border Racing?), so if I do have to have someone make the it might cost upwards of 8K... plus all the Tuning/EMS
I looked for days on this subject. Anyone know anything?

snwbrderphat540

from what i know, there are very few model specific ITB kits, you gotta fab your own ****, but ITB's are a nightmare imo and rediculously expensive, but anything can be done with $$$$. but ITB's you will have to tune all 6 of them prefectly to match one another other wise you wont see much if any gain, then you need to keep them in tune of one another. ITB's can loose tune and tehn you get to do it all over again. i say not really worth it. many will agree some will not. but why do you want to build a NA using that much $$ to see, nothing spectacular in HP gains. i dont get the reasoning lol

NismoPick

Anything is possible with enough $$$. That's the answer.

snwbrderphat540

nismo... did you just steal my answer, i think you should read my UN EDITED post...

skittle

if he has the time and mula for it i say go for it. It woun't do much but you will have the "oooo" factor.

NismoPick

It doesn't take very many words to say "anything is possible with money"

ZLover4Life

Couple people on TwinTurbo.net are working on them.

It will be mostly for show though, as there isn't very much untapped potential in the VG30DE. (Sorry to break it to you, but it'd cost you more in the long run to make your NA faster than it would cost you to Twin Turbocharge it... I can understand if you want to be unique, but unique won't get you the best performance - proven solutions will.)

MikeZ

I agree ZLover. It is common knowledge that the TT is a more robust platform, no disagreement there. I know that the development of the ITB system would cost more to do an engine swap and the necessary 500+ hp upgrades on a TT. But I am very curious about the flow and structural limits of the NA platform. I would like to see it spin 10,000RPM(sunaco induced of course), without the crappy bogging that this RPM figure is associated with. I'm not really looking for low end power, and daily "drivability" can be sacrificed... alot Maybe a 13:1 cp ratio, properly built and lightened.

MikeZ

My Uncle used to race and build stock/modified muscle car engines, and is very knowledgable(?) on NASCAR class engines. I think he might be the best help, and biggest influence on me. I like the NA style, it's my in blood. If that's a good enough answer for you guys

Not to say I'd turn a TT down

NismoPick

So you want to spin 10k rpm for kicks? I suggest getting into the ricerocket honduh world & build a B18.

MikeZ

I know, I know. It does sound a little dumb to some people. But what about the C30A1 in the NSX, do you find that to be ricey?

Yeah it's a honda, but who says you can't do it nissan style, besides the all mighty dollar? It may not be as gracefull, but I believe it can be done, with time and patience and some green

NismoPick

What I find ricey is people thinking "hey! the higher the rpm, the faster I'll go, right?"

ZLover4Life

1. The NSX has an 8k rpm redline, not 10k.

2. The highest rpm anyone has done safely on a VG30 is 8k rpm.

3. We have a timing belt, VTC, DOHC, hydraulic lifters, and more moving parts than most of the cars being produced today (nearly 18 years after the 300ZX hit U.S. shores) in addition to a plenum/lower intake manifold/head design that won't be conducive to rediculously high rpms... have fun trying to get to 10k with that engine. I promise you, it won't happen.

And NismoPick is right, a higher redline will not necessarily make you faster. With the perfect gearing of the Z32's transmission, it does fine with a 7,450 rpm limiter that JWT and Ash set on their general programmed ECUs. In fact, a stock Twin Turbo will accelerate faster when shifting at closer to 6,500 rpm out of first simply because it'll hit the sweet spot in the powerband in second. When you climb closer to the limit, you're hitting second gear past peak torque and it'll cause slower acceleration. (This is the same with every gear, but I don't recall optimum shift points other than first off the top of my head simply because by the time I'm through second, my opponents are typically so far in my rear-view that it doesn't matter how perfect the rest of my shifts are.)

I'm hoping the 10k rpm comment was an exhaggeration, but I'm treating it as if it weren't simply for information purposes.

entropy31

i think i saw a pic of a vg30de with ITBs somewhere.

MikeZ

Hmmm... Zlover, your right. I hate to admit it. Trying to coax 10,000 rpm out of that design is, well a goal that is unreachable. It was just an idea that was thrown out there. Pardon my gung-ho way of writing.

I again would be using this car as an experiment, as I plan to go into industrial tech in college, after these next few semesters of JC.
If anything I want to learn and gain knowledge, even if I blow things up.

I do appreciate the feedback from you guys, really. I don't know what I would do if it weren't for criticism. Thanks

Any other info that might help with my(now lowered) expectation?

ZLover4Life

I can respect your aspiration to do something new... if no one ever did anything new, every 300ZX would still be stock. However, I think you should do modifications that are more reasonable. Independent Throttle Bodies are an interesting idea, it's just very complicated. I just don't think you should expect 10,000 rpms out of this engine... it will fail and render you engineless.

But my sole purpose on the 4 Z car forums that I frequent is the safety of the Z car first... so I don't sh*t in your wheaties for fun, I simply do it because I don't want to see any 300ZXs end up in the junk yard - I guess you could say I'm a z car conservationist.

CanyonCarver

Mike, Nissan went to great lengths in designing the vg30 with the dual t/b's and the ugly upper plenum and crossflow design. There are postings around the net about it. It is probably an area where a change from the original design would hurt performance more-so than benefit. In attempting to build a better n/a, you'll most likely get the biggest improvement from increasing displacement and airflow through what already exists.

MikeZ

Okay so how much can the NA engine be displaced? I'v only ever seen the JUN kit that strokes to 3.2 litres. Does stroking become detrimental passed this litrege?

MikeZ

Oh and Zlover, everyone needs constructive criticism. I think that you do it better than most. Harsh sometimes, but correct nonetheless

CanyonCarver

There are arguments for and against going with the equivalent of vg33 pistons which are 91mm. Some people say it can't be done, and others say the blocks are identical except for some water passage variations. The naysayers might rightly be saying that it can't be done when boosting, although the vg33der came with a supercharger running ~6 psi.

I say it can be done. even if you have to install cylinder liners.

Another thing that I've researched are some small journal crank rods They are copies of Honda rods. They are capable of higher h.p. per liter than the vg and can handle ober 9k rpm. With the rods, you can offset grind the stock crank without welding and with the larger pistons get to 3.45 liters.

Crower.com will custom build you the complete rotating assembly for ~$5k. You could go with that and spec out your 91mm pistons.

I've now talked to three different non-nissan tuners and engine builders that say you can easily run a 13:1 compression ratio on pump gas with the proper ecu tuning.

I'd guestimate that the displacement and c/r increase would put you over the350 mark at the crank. Except for the crower kit, I don't have any proof of the above, so I expect to get some flamage.

b300z

i like that idea CC. build a stroked, higher CR engine. and then lose as much rotating mass and weight from the Z as possible. stiffen up the suspension, and you have potential for one helluva track car

MikeZ

Awesome! 5k for a completely custom RA? That sounds like music to my ears! So I would need sleeves to keep the thinner walled cylinders from walking? What kind of lubrication system would be necessary do you think? Would the block have to notched for rod clearance?would have to Hey, it's like a Z33 without the 30,000+ price tag, all most.

MikeZ

"Some people say it can't be done, and others say the blocks are identical except for some water passage variations."
-CC

So if the blocks are identicle, would the intake plenum from a Z33 be trans-plantable onto Z32 block? If so the design in the Z32 restricts the flow in a way that ZLover mentioned before, could the Z33 design make an improvement? Granted that the entire fuel, ignition, Throttle, etc. would be accounted for. (These are all assumptions that will probably make an *** of me)

ZLover4Life

VG33DER is NOT a Z33 (350Z) engine. The 350Z block is a VQ35DE. The VG33DER is from the Pathfinder if I recall correctly. VG series engines are iron blocks, VQ engines are aluminum.

And the VG30DE's intake setup will outperform any other equivalent stock Nissan system. It's just not conducive to super high rpms. People have done over 1000rwhp with it - it doesn't need to be changed.

MikeZ

1000hp...Gotcha I misread, my bad.