Nissan 370Z Forum - complete engine overhaul questions.

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- - complete engine overhaul questions. (http://www.the370z.com/engine-drivetrain/45894-complete-engine-overhaul-questions.html)

I feel its possible and "tuning" vvel is not nessesary, general timing and AFR should be fine. don't forget higher compression pistions. As for fuel, IDK if it will be possible on 93 octane but as for the theory of making approximatly 500whp, I would'nt look past it.

http://www.the370z.com/forced-induct...ile-stone.html

^^^vvel not tuned/broken....whatever you want to call it

pulleys, flywheel, 4.5 stroker kit, ported heads, oversized valves, stronger head studs the list goes on I think it could happen.

3.7= .62L per cylinder

4.5= .75L per cylinder

the 300zx TT made 300 HP (N/A 220HP)

nissan made the 370z N/A 332HP

So theoretically .7L increase made the new Z 112HP, so a .8 increase should net a total of approximatly 440HP from the 4.5 stroker kit alone. higher compression pistons, ported heads, flywheel, pullies, oversized valves, larger intake cams........etc etc etc..... COULD be possible chii be ready for a headache bud.

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Originally Posted by chii370 (Post 1423782)

How is it so inconceivable, I see mags and shows on tv for example "top gear" that feature cars like a WRX, an EVO, or a RX7 or any of those cars ALL of which have a much smaller displacement engine, and in the case of the top gear pep it was a 1000 HP EVO 8 I believe. YES I understand that's AFTER it was turboed, but you expect me to believe that the turbo alone is producing 600 of those horses? U have to be about retarded. And then say a motor that's ALMOST double it's size can't make half of that on it's own? It doesn't take much. Mine dinoed at 368 FWHP bone stock. Bolt on stuff ALONE would get it close to 380-390 if I did all bolt ons available. Just puting a good pair of heads on an engine helps dramatically. Or at least it does with a old V8. and guess what? It's the same dame thing, minus 2 cylinders.

Turbos work by cramming more air into the engine. You are dealing with an entirely different animal when you have FI. NA, it's a massive struggle to get to 100hp/l in many cars. When you are running 45 psi of boost on an FJ, you are dealing with an engine that can mix air and fuel like a 10L engine:eek:

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I didn't say I don't know how a transmission works or a clutch or anything else, I told you I'm old school muscle car. Have a question about a torqueflight trany? How about a ford 9in rear? Or whether you can put 351 windser heads on a 302 "Aka boss" then Im the man to ask. But if you ask me about all this new ****? viscis rears, quad disk dampened clutches and all this other ********? No I DONT know much about it. It's called learning, so how about a little respect and not insta flame someone because they may not know something you do? How about trying a nifty technique called teaching.

Nothing has really changed since the old days. If you know old stuff, you know new stuff.
I think most people's negative reactions have been related to a perceived attitude, but there are plenty willing to share their knowledge if it is asked for politely (I will share whether you ask politely or not:p_

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Did u ever think that maybe I was ok with investing time and money into trying to figure it Out like a true mechanic rather then be a ******* instant gratification whore and go the easiest route possible because of any lack of real knowledge? Aka turbo solution. Most people talk big, but don't actually know what it really takes to build a race engine. Not just a stock engine that's blown, procharged or turboed.

If you are down to do the work, get out and do it. No one on here has done it, no one here can pass you any advice. Get 'er done, then come spread the knowledge. I'll check out the build thread if there is one.

I'm going to go find these white papers you mention, I'm curious to see what they say. If you already have links or might be able to point me in the right direction that would be awesome. I'm off to google for a bit!

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

Getting said tech paper so I can read it :D

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.

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

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.

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Originally Posted by chii370 (Post 1424771)

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 :tup:

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

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

Quote:

Originally Posted by chii370 (Post 1424457)

well, skeeterbop has kinda hit the nail on the head with the first reply, the whole point here is no ones done it. yes it will be expensive, and it might not be for everyone. but all results are just based on speculation right now. and as for the TT SC claims i made, i have a friend that was in guam with me, had a white 370 base with a stage 2 GTM TT, and it DID NOT make claimed power.... not even close, not to mention other issues like overheating and a host of other annoying things. and i dont know how many "i bought a SC and im dissapointed" threads ive seen in the past 3 years all over the internet. TT.... not so much, but ive heard a TON of people bitching about there SC build. Your right, just as many are satisfied. Yes theres a lot of perfect builds out there that do exactly as intended. but you still keep missing the point to all this.

Did your friend have the proper cooling options needed? The VQ motors run a bit hot, especially the 3.7L, also what type of dyno did he run on? Did he do a full baseline so he can do a delta comparison, just throwing it on and saying I only made 300whp means nothing if bone stock he was only getting 180whp or something. Really need more facts on your friends built to understand why it was unable to meet your 'requirements.' Also, how was the car tuned?

Please provide me with some threads where people are unhappy with their SC, either Stillen or GTM. Stillen had a few issues early on but they have done a lot of make customers happy and resolve any tuning issues. What point am I missing, you keep just hammering on about how you think it should be something but you have not provided any facts on what you claim, just your opinion.

personally i drive my car EVERY DAY "except winter" and i plan to do so until the wheels fall off. dont even start a bitch fest about gas and all that... i dont care. point is, if your one of the people who blindly slapped on a TT or SC on a STOCK car your running a huge risk of shaving off years of its life and reliability. thats the difference between building a engine thats MADE to take the abuse opposed to forcing a stock engine to perform outside its normal specifications.

You are running the risk of blowing your block up just as fast if not faster with your built NA motor. Tearing open the block and replacing parts will just as easily shred the motor, especially if you are the first and testing parts. I daily drive my Z, honestly if my motor blows up after 8 years it survived plenty. Again you are 'assuming' a lot of information, people just 'blindly slapping' a TT or SC, most if not all builds I have seen online and in person are well thought out. From cooling to engine supporting mods, people are taking a lot of precautions, mainly because we have years of VQ35 motor history to work off of. The 350z is a value asset in knowing how the motor will survive FI to NA builds.

Do you know what your engine will be made to take when you build it?

i can bet, ten years from now all these 500-600 hp TT 370s will all have to have rebuilt engines, transmissions and all kinds of other problems. lucky if it even hits 150k miles without blowing up. especially if you beat on it, and thats what happens 99% of the time dont lie. short term reliability has been rock solid so far i will give you that, but this engine is NOT designed for that and it will fail.... mark my words. building an engine up is by far not a cure all to that but it most definitely makes it far less likely to be a problem since its BUILT TO DO IT.

I dont feel like dealing with a blown engine 8 years from now when the car has half of its miles it could have. this is my daily driver, and some day i plan on passing it on to my son or daughter as our generations "muscle car" just like my dad did with me with a matador red with white stripe 1971 AMC javelin SST 401 fully restored. so i would rather not give it to them in useless pieces lol.

Passing on a car is great, though add boost or even a built NA motor will not be the determining factor in if it will survive the ages. How you treat the car and support it throughout these years will, I have seen 350z motors with stock blocks go for over 100k miles boosted making 450whp (DE motor which was good for that motor). They tear the motor down and it still looks great, why? Because the owner takes care of the car, from pre-track work to post-track, to proper maintenance to understanding the motor.

You really need to take some time to read more from this forum and my350z, a lot of great information on the VQ motor and what it is capable of.

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

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.

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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Originally Posted by Cmike2780 (Post 1429567)

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. :p

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.