complete engine overhaul questions.

Skeeterbop

Found them, here is a link to my search: VQ35
Unfortunately, you will have to buy them to view them

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Srenity: "Yeah no rest needed to spread the love when your 20 that's for sure...."

Skeeterbop

Getting said tech paper so I can read it

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Skeeterbop

Not really what I was hoping it would be, but one thing to note is that from ~4k rpm (this is for the VQ35 and was written in 2002) the engine's VE is 100% and stays at or above 100% until 6400rpm. So the efficiency of the intake/exhaust in the upper RPM appears to be very good, although I'm not sure what an average efficiency would be.

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Srenity: "Yeah no rest needed to spread the love when your 20 that's for sure...."

Skeeterbop

They did put a lot of work into decreasing NVH though.

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Srenity: "Yeah no rest needed to spread the love when your 20 that's for sure...."

chii370

Well as the plan sits right now I got out of the navy as some of you know, and I've yet to find a job. Unemployment goes away in dec, and I don't get into the army at the EARLIEST next may. So right now I'm really struggling to keep the car. Ive over 18k invested in the car already "payments and extra work" and still owe 29 flat and with this economy no one will pay me what I owe so selling it's to much of a hit. Potty story aside, the moment I get into the army almost every cent I make will be put toward massive overpayments on the car, once paid for in a few months I'm immediately going to start this build. First getting a pre built 4.5L stroker from gtm and then each other part respectively. I'm estimating roughly 28k in the motor w/o forced induction. All I have to do is make my car payments somehow for another few months and my plan will come to fruition and all of you will have plenty of new data points to argue about later lol. Sorry for comming accross like an ***, but the job situations had me on edge.... As well as my fiancé just left.... So I'm kinda hitting some hard times right now. Putting hope that all this will work out is the only this that keeps me going right now.

VQStryker

Being a veteran and not being able to get a job sounds extremely frustrating. Knowing what I do, all special warfare/forces personel must score well above average on their asfaq test. Going off of this alone your a smart guy, work through these troubles and you'll come out on top. don't let the fiance thing bring you down bro, you have a life to live and a career to find. work your way through this and you'll come out on top as a substantially stronger man. That being said I'm looking forward to the all motor build

thank you for serving chii and best wishes to you. even if its not said, its greatly appreciated.

roy'sz

hey chii pm'd you with a job lead, good luck bro!

roy'sz

^^^my dad gots a 350z stock with 178000 running mobil 1 and hasn't had a catasrope yet! Just sayin....

Gearhead51

Good luck with a N/A build. I, for one, am quite impressed with the factory output of this engine. Considering it passes emissions and has a warranty is even better still. I looked up a '68 Charger with 426 Hemi: 0-60 in 5.3 sec, 1/4 mile in 13.8 sec @ 105mph. I ran a 13.8 sec @ 102mpg in my girlfriends 370 with a 7AT. The numbers of the Z look as good with much less engine, and it can rail through the mountains. BTW, I love American muscle.

Remember, in a perfect, frictionless universe you have to burn twice the fuel to make twice the power. To burn twice the fuel, you have to ingest twice the air. If you add 10% to the displacement, you still have 90% to go. 10% better VE? That will require more extensive headwork after a displacement increase due to larger cylinders pulling air through the same number of ports. Ok... If you get that, you are getting closer. Of course, variable valve systems are not necessarily an enemy... unless peak HP is all you are after. They give you good VE at low RPM and good VE at high RPM. Are you planning on a custom stroke? If so, is that with a custom crank (will it fit?) or by shortening the rods (making the rod ratio worse is detrimental to engine life.). 15% higher RPM? Rods really don't like tensile loads. They are typically many times stronger under compression. Can it be done? Perhaps. Will anything be left of the engine you started with? Probably not.

From somebody that was building imports before imports were cool, I'm impressed with what these engines can do. Back in the day, we had 1.3L rotaries with 140HP and we were hot stuff. We could port them and squeeze them to 170 by porting and increasing VE, never pass emissions, killed mileage, and lost low end power. Custom peripheral port engines were close to $10k. So we did that. Made almost 300hp, wouldn't idle under 1300RPM and made power 6500 to 10,000 RPM. Forget A/C, power steering, picking up a woman, and getting to work on time because it was reliable. The car was clearly a dude magnet. Then we found turbos.

The same 1.3L displacement that once made 140FWHP now makes 425RWHP in my RX7. FI CAN double or triple the HP of an engine of a certain displacement. While I'm another person giving you an answer you don't want to hear, FI is certainly the easiest way to make reliable power. In our hypothetical perfect world, 15lbs of boost doubles the VE of the engine... doubling the power.

Sure, we are bolting turbos and superchargers on bone stock engines... or built engines. Why is that necessarily a bad thing? Many turbo engines run lower compression, so if you want to do it "right" toss a set of low comp pistons in. Since rods are stronger under compression, the prefer the additional stress of FI over the tensile loads of RPM. If you go FI and don't have a detonation issue, it's not overheating (we ARE making more power than stock, so we have to reject more heat... this is the case with NA or FI power), cranks every time, acts like a civilized vehicle when not on boost, and has a/c what is the problem?

Personally, I love the sound of turbos whistling and wastegates opening. Even in the American muscle world, when you want BIG power, you go FI.

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Cmike2780

How about a swap with the VR38DETT, not much of a displacement bump, but it was designed by Nissan with F.I. in mind. We also know it can be boosted to produce huge numbers. N/A build would be pretty cool to see though. I think the tough part will be getting all that power to the ground without breaking the tires loose.

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Jeffblue

why would you want to do a swap? swaps have been done before. Just like forced induction, that's been done to hell. What you gotta do is something that no one else has ever done... like a built NA.... oh wait that's been done too, just less often because everyone realizes it isn't worth the money.

I still fail to see the logic in spending quadruple the amount on modding a car to get worse performance just to be able to say you were the first one to do it, when in reality a ton of other people have done the same thing to other cars in the past, its just that when they did it no one cared because the performance was mediocre and it cost a ton of money.

Cmike2780

I think the OP wants to mod this engine like it was from a classic American muscle car, and i guesss thats okay to a degree, but Nissans approach is different because the design goal was different. I get the fascination and draw to NA, but there is nothing "simple" about a properly built FI motor. No one in their right mind would say the Veyron w16 engineers took the easy route going with turbos. I dunno, I love the sound of NA engines, but ours sound like a can I rocks to begin with. If anything, the turbos drowns out some of the noise.

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[09][MB][6-Spd MT][Touring][Stillen Gen III][K&N][Borla CBE][Evo-R]

fuct

OP, sounds like you have waaaaay more important things to stress about than a silly car.

best of luck to you though!

FL 4Motion

at the end of the day, you gotta do what makes you happy, if the OP wants to blow his wad trying to build a super crazy N/A monster Z, more power to him. There's def easier, cheaper, and more tried and true ways to do 500whp (TT or stage II s/c) but hey, I'll be the first to say if it happens, I'll be pretty excited to see it cause I think n/a builds are neato as well.

roy'sz

First mod I would do in his situation is the stage 3 J.O.B. Just sayin....