Best spark plugs and manifold removal maintenance

[09SLATEM6]

I’m about to do the spark plugs on my 09 Altima. I did a little homework. and figured out that the intake manifold from a 2017 and above flows better and should bolt right up to the existing lower manifold I also then got a salvaged throttle body from a 2014 maxima that 75 mm versus my Altima 70 mm. I haven’t done the job yet, but I’m hoping that it comes out nicely giving me a few more ponies to keep up with those two doors
I’ll call her the ALTIMAX
Also have a few other ideas of my sleeve…

my next question was which spark plug is to go with? Definitely iridium it sounds like Denso or NGK? Also, what is under the manifold that should be replaced just for good maintenance? PVC valve etc.???

[VStar650CL]

I assume you have the VQ35 and not the QR25. I hate to rain on your parade, but the plenum on the VQ's is identical from '07~'18 and the collector is identical from '09~'18. I don't know about the TB, but breathing is what it is, inhale-exhale. Going out 5mm at the inlet won't help you any without a better exhaust and may actually cost you low end power if it reduces the charge velocity. Most people don't think about air in Newtonian terms, but it is -- what's in motion wants to remain in motion. So the idea is to get it moving fast and keep it that way, allowing overlap to pack more charge into the cylinder. That's actually what your Power Valve is for, it narrows the intake passages at low RPM to increase the charge velocity, resulting in better low end torque and a smoother idle. The bottom line is, you need to consider the entire power curve when making changes like that, because bigger isn't always better. Gaining top end but losing significant line torque won't win you any stoplight races.

For the plugs, in my experience Denso plugs generally give you a hotter spark and better resistance to flooding, but they also lose metal and wear out faster. NGK's generally wear longer but they may produce a trifle less power and will absolutely no-start you if the engine floods.

[09SLATEM6]

I totally respect your opinion I see you’re very active here, but honestly, the Plenums look beefier from 16+ on. I agree that the collector is the same. I wouldn’t mind maybe losing a little torque at the bottom end I have a six speed and a pretty good driver, it’s hard to keep the wheels from spinning as it is with an aggressive start. And most spirited driving is usually above 3000 RPM
Should I be replacing anything else while that manifold is off PVC valve? Etc.?
Thanks man

[09SLATEM6]

Oh sorry I forgot to mention I have a 2017 QX 60 intake Plenum. OEM 14010-4RA0A I’ve read that the pathfinders and I can’t remember maybe one other vehicle from 2016+ and newer have this manifold which is bigger and flows better? I agree with you the Altima and Maximas are all the same for those years.

[VStar650CL]

The 14010-4RA0A doesn't show up as a good number, has to be a -4RA0B. The difference is because that manifold is also used on some of the VQ35DD's. The model you're missing is the Maxima, '16~'21. Assuming it fits, I think you'll still need to reduce your exhaust restriction to get any big gains out of it.

You'll never hurt yourself with a new PCV, but if it was mine, I'd be replacing the whole valve cover and gasket while I was in there. Back bank coils too, just because the back bank is such a PITA. You might want to consider doing the high pressure P/S hose too, it makes a big loop across the back of the engine and they're prone to springing leaks at the top of the loop where they're restrained to the manifold. Helluva lot easier to swap it out when the plenum is off.

[09SLATEM6]

Damn that’s a little discouraging, I did see a couple of 4RA0Bs too. I went with this A because it looked more complete with all the vacuum lines and even throttlebody although I’m gonna remove that anyway. I believe it had lower miles as well.
I’m still going to move forward with trying to install it. What do you think could be the part that doesn’t “fit”?

I really appreciate the other “ to do list” a lot of that was not even something I considered. My car only has 94k miles. I’m the second owner, and other than an alternator recently. It’s been problem free.

I do plan on moving to freeing up exhaust next. I live in CA, so unfortunately, I have to keep the cats and it looks like I’m gonna have to have a custom wipe made though can’t find any for my model. Also keeping the car as quiet as possible would be ideal.

[VStar650CL]

No, that's not it, the -4RA0A doesn't even show up as a good part number. If it was superseded or discontinued then it should show up that way in the database. The only way part numbers get "disappeared" is if there's a serious problem with them and Nissan doesn't want anybody using them. I think that must be the case, because the only A parts I see on the net are used.

Regarding the exhaust, I can only suggest you ditch communism and move to a free state. You can street-legal a go kart here in Arkansas.

[09SLATEM6]

Wow, that’s a whole different ballpark. WTH that changes everything. But now I wanna know why lol
I guess it’s looking for a B now.. hate to throw away the $180 I spent on it