im having my morning coffee and chuckling getting ready to go to work as an auto tech, ive been at both ford and gm dealerships for years of my time being a mechanic, im not interested in arguing... im aware of differences, but ive built my own engines since 16, now at 32 years, I could potentially know a few things, im more than happy to truce....

 

There is no fuel in suspension in the upper intake. It is injected further downstream in the lower intake close to the cyl head

 

except he said he did the lower too =P

 

Hardly likely, the injector is directed to fine spray down onto the back of the inlet valve

 

Agreed ^ my upper and lower plenum is smoothed down to a near mirror finish. Didn't touch the lower manifold, but it wouldn't have mattered.

Car is tuned with Uprev Osiris and I have no problems

The finished product (Also cleaned up the upper)


Closeup


Compared to my stock lower


Dyno Results are about what I expected since mine is just the DE. However, it did prove a nice gain throughout my entire powerband so I was able to do something right. This was paired with a spacer as well.

 

You guys are using revup lowers like I am correct?

 

Pretty sure rev-up lower plenum is worse in every way. There was an article I read doing side-by-side testing, and except for a very small bit of the powerband the rev-up plenum always performed worse.

I have been searching for this article again, as it is now my limiting factor NA-wise, and can't find it though.

 

Care to look at the drag racing section?

 

 

ok just completely ignore what the op himself said, also do you have any idea of the spray angle of the injector fan? or what injectors are even being used? your making a generalization that since they are pointed in a general direction then it dosnt matter when the fact is they do still seat in the lower intake, spray in a mist not a jet stream, and do come into contact with the intake manifold. good job not having a clue though.
ill quote him though since you seemed to ignore where he said he did the lower too. also porting mirror smooth in the intake side isnt done by any pro porters anyway since using a slightly rough finish allows a boundary layer of air, no matter how smooth the metal is air will always generate less friction moving over air then metal the slightly rough finish allows the boundary layer of stagnant air to form, it also allows bigger chambers while the engine believing the chambers are still small too since the engine will "see" the smaller cross sectional area after the boundary layer is formed.

 

thats not a mirror finish though, you can plainly see the grinding marks that tell tale sign of a professional level job.

significantly different from something like this, the way yours are done are the proper way to do it, at least according to the world champion engine builders. http://www.xtremethings.com/Images/M...hed_Runner.JPG

 

Fair enough. I just remember it being smooth to the touch. Not nearly as rough as it was beforehand.

 

[QUOTE=jerryd87;10251679]ok just completely ignore what the op himself said, also do you have any idea of the spray angle of the injector fan? or what injectors are even being used? your making a generalization that since they are pointed in a general direction then it dosnt matter when the fact is they do still seat in the lower intake, spray in a mist not a jet stream, and do come into contact with the intake manifold. good job not having a clue though.


My initial post was a response to your assertion that the fuel would fall out of suspension because of highly polished surface of the OP's intake manifold.
I pointed out that there is no fuel in suspension in the upper manifold.
Your response was that the OP had also polished the lower manifold.

The injectors do not spray into the lower manifold. They are fitted in the lower manifold but spray directly into the cylinder head.
The inlet port on the cylinder head has raised cut out to accommodate the tip of the injector.

Please clue me up as to how the the fuel can go back up into the lower intake
& then fall out of suspension.

I won't get into an argument with you about air flow, boundary layers & what the motor "sees", but point out that more & more high output production motors are using plastic for there intake manifolds & by there very production method are a lot smoother & polished than a sand cast aluminium intake.

 

Red is my VQ35DE built and tuned, blue is a VQ37VHR tuned.

This is with the non-revup lower, 5/16" motordyne spacer, JWT pop charger, C8's, DC headers, test pipes, and Bassani true dual exhaust

Would a revup plenum shift my powerband right, but allow me to climb higher? Been talking today with someone about it. I think Kinetix would be ideal, but if I can pick up a revup for cheap/free I might throw it on, and it makes sense to do so I might consider it considering I can rev to 7500 or a bit more if I choose to on my DE.

 

wanna bet? obviously you have not had the intake apart the fuel travels through several inchs of the lower intake. the injectors dont spray in a jet stream learn how things work they spray in a mist that swirls in vortices in the airflow, if the manifold is too smooth those vortices dont exist there is nothing to tumble the air and the fuel falls out of suspension and just pulls on manifold and cylinder walls, dribbling down to the chambers and causing inaccurate fuel metering. the injector hits the bottom part of the runners at the bottom of the lower intake, PLUS it has no tumble at all till that point meaning there isnt any mixing going on in the airflow.

ummmm have you ever even seen the inside of those plastic intakes? they arnt even remotely close to smooth.................. in fact how about we bring up a picture of one, factory ls2 intake



its good you dont want to argue since you have said anything valid

 

not enough people willing to try back to back tests of stuff, they just follow the leader. it COULD be the intake might help, it might be higher flowing heads will help, the vq35 flows stellar but the HR heads flow 50 cfm more from the factory so i suspect the vhr is similar if not more. it could simply be the plenums arnt large enough.

 

Jerry you want to bet me, accuse me of not having a clue & of obviously having no idea or experience of the DE motor.
Do a search of me & you will see that I have been a member of my350z since 2002 when I first posted up about a 350Z that I was building to race in an International 24 hour race. This race car turned out to be the 1st 350Z to take part in in any sanctioned auto race in the world.
I have built many 350Z race motors & completely built race cars including 1 national championship car.
Does that make me the font of all Knowledge? Of cause not, but I do know that there is absolutely no fuel in suspension in either the upper or lower manifolds & thats all I've ever said. I repeat the injector fine sprays (similar to mist) into the cylinder head at the very base of the lower manifold not a few inches back up inside.
I wont bet you as there would little chance of settlement, but I will dare you to post up a photo of the underside of a 350Z lower manifold showing me with that Bic ballpen where the injector resides & how the mist gets back up into the lower manifold a few inches.
As to have I seen inside a plastic manifold? Yes I have and a lot of them are just as shiny & smooth as the outside. Landrover comes to mind.

 

if you say so............ ive never EVER seen a smooth intake manifold or ANY completely smooth intake built by anyone who is a pro. thats cool you race a car in a professional race but dont think i havnt checked you out, you had to race on a stock engine so your not helping your case on knowing what your doing. i also know your original websites for those races dont even exist anymore, must not have been a very successful series. ignoring that though send me a intake and ill point out pictures of areas of the lower that get hit by fuel then ill make you a video with injectors blasting through it, im not pulling my intake off again just to prove you wrong.


especially after you handily just decide to completely ignore all my comments of air turbulence and tumbling in the intake and how that causes fuel to fall out of suspension. by your comments even if you help assemble engines you definitely dont do any of the port or intake work, the engines would detonate in short order.......(which is reinforced by your own profile listing you as a manager not even tech, or engine builder, manifold builder, porter, anything just the paperwork guy)

based on your posts nothing would indicate you have engine building experience, which isnt saying alot about your stockish class's you raced in, so nothing you have posted on the website has helped with your credibility at all.

sorry if you feel insulted but even without fuel entering the manifold(which it does enter the lower some) the tumbling of air still starts in the intake the fuel is injected before air enters the combustion chamber and if the air isnt someone turbulent the fuel wont stay in the air plain and simple that air need vortices that come from the intake manifold, that dosnt exist with a mirror smooth manifold. how about going to a one of the championship engine building competitions. not a single one of those builders is using a mirror smooth anything on the intake side, obviously them and people like myself saying your wrong know something you dont.

 

especially is that smoothness existed in all manifolds and was so much better then every manufacturer would use them from the factory since they are significantly cheaper to produce then cast ones.

 

Jerry with all your slander & innuendo your missing the point.

You criticised the OP for polishing his manifolds & said that the fuel would fall out of suspension & then went on to say that the fuel would dribble down the insides of the manifolds & cause inaccurate fuel metering, jet sprays, mists, votices, turbulence ect. I have made no comments whatsoever about any of these things, but for the third time I now repeat there is NO FUEL IN SUSPENSION in the upper or lower manifold.
You took offence to that simple statement but can provide no evidence to the contrary.
The OP was smart he got out of this post with a smile a week ago. I'm a bit more stubborn so I guess as you wont take up my dare I'll post up some photos that prove what I am saying in the next day or two.