Custom manifold/plenum/TBs
 

So, I've owned the Z not even a year and have already come to the point where NA options become very limited. I don't particularly want to go the FI route, and cams are not only expensive, but don't have proven results (in the States), and would be a pain in the *** for the entire process. Next logical option: intake manifolds and TB. I've read through the majority of threads I can find on the topic. In summary..

1 - Kinetic made a flashy looking, but ultimately failsome manifold due to no testing or airflow mapping.

2 - GTM has the GTR conversion option, but we know how that business is going right now. This required new fuel rails, cutting intakes, and a new strut brace anyways. The primary advantage to these are proven power handleing on the GTR.

3 - Synolimit is porting stock parts, but we are awaiting his dyno results.

4 - JUN has BBTBs for a ridiculous $2 grand, and there are a few manifold prototypes, but I don't think that ever reached the US or production.

5 - Mine's TBs for $1.5k, again rediculous

6 - Z1 bored stock TBs (62mm vs 60mm stock) At $900

8 - GTM's manifolds, require custom intakes/TBs which were on 1slow370's Z: HERE

9 - Z1 and Motordyne plenums, seem to be minimal impact throughout the powerband, just a little higher HP for Z1 at the redline and motordyne has slightly more torque throughout. These are simply modified stock plenums.

I've got access to CNC, 3d printing (option for plenum), and working on access to a flow bench. So i'm basically looking into the cost and power benefits of actually designing some of these. I plan on creating some CAD/Solid Works designs over thanksgiving break when I have time to get all measurements on my stock parts.

In the mean time, I'm open to any suggestions/advice/constructive criticism. Are there any options above that I'm missing? Also waiting on synolimits' results to see if this is even a worthwhile project.

sub'd

Im in

Definitely not a bad idea. Im sure someone at Vivid would be interested in distributing them if you made that happen.

Hello,

For the throttle bodies I think you forgot Mine's from japan and its $1500 throttle bodies lol

I would say for the throttle bodies, to board them out will be the most cost effective. You do want to make sure that you do not board them out too much that it will affect the airflow at the other end. For the 3D printing, I've heard that it is now possible to print functioning car parts, my only concern will be the type of material you use, you have to make sure 1. it does not melt 2. the elasticity is high enough that it does not change when the engine is running at high temps (ex: track)....BTW somebody needs to jump on those cams from JUN and see if they are really worth it lol

You missed the mani/tb's that GTM did for 1slow370. World Record NA VHR Build
Might be worth a look. I'm sure others would be interested in this if it wasn't from GTM.

Also, might want to go with non-metal components to help combate heat soak.

I'm sure they would! The problem will be getting in contact with them, wish there was a direct phone or email to them :inoutroflpuke:

I was talking about if Vicious were to build some. We are always on the look out for cool new products that build power. :tup:

I know I guess what I wrote was a bad joke lol...BTW keep us updated on the black Friday specials I might have to use some money I have saved up lol

Wow, lots of quick and positive responses.

@6MT, of course material would need to be considered for 3d printing, particularly for heat and structural integrity. I also agree someone should jump on the cams, I think some JUNs for $800 on here? I don't want to deal with that work myself. lol

I'm in for this, and don't forget Z1 offers TB's now, 895$ I think for the pair.

http://www.z1motorsports.com/g37_370...oducts_id=7591

the problem in the end will be that a whole new manifold will be costly and no one will want to fork over the money.

the TBs end up having someone local port and polish them for cheap since paying 900 to Z1 or 2k to the others is just ridiculous.

i'm hoping something different happens here thought :tup:

a $500-750 manifold with good gains would be lovely.

Well this sounds like a great undertaking and I wish you luck. Hope you have a flow bench, engine dyno, and a lot of time.
The stock system is pretty efficient for a street motor, it just needs to be massaged as a package, Cleaning up the port entries after the throttle bodies is a big help. The turns are sharp, this hurts flow at higher rpms. Port matching the lower to the upper also adds improvement to flow. A bigger issue is the oil vapor that you get from the crankcase ventilation system that is contaminating the combustion process. The used manifold I picked up was all slimy on the inside and it took a lot of degreaser to get a clean enough surface to port. For the money and time, improving what you have is probability the best bang for the buck. For a race engine, different story.

And then you woke up on the dry side of the bed :rofl2:

Good thought though

thats the pricing point where they would sell.

Z1's is like $400 or 500 i think and it sees little gains.
the kinetx one was beautiful, saw 0 gains on NA nor FI, and cost 1k
pretty much anything now is a cleaned up OEM 350 airbox. sorry not paying someone triple the cost of the OEM plastic manifold for them to play with a dremel for a hour or so. i can do that at home if i really wanted.

we need a solid gaining and good looking manifold. something that isnt stupid expensive although with the R&D and labor it's going to be.


let's face it the manifold aveune is a tough one for us. the 370 has been out for 7 model years now and this is where we are at.

Also check out CJ MotorSports manifold thread and AT Power DBW TB

If you have the drafting and flow dynamic modeling software, a CNC machine and a flowbench, all you need are the dimensions of the OEM manifold as a starting point and you can try several iterations until you see good improvements.

I think the real bottlenecks will be the exhaust cam -- which is not variable -- and the exhaust manifold. You might be able to work around the exhaust cam, but I suspect the IM will only be really worthwhile for folks with headers.

Assuming you can work around those issues, the last major hurdles will be space and cost. Fitting different runners under the hood without other modifications ( e.g., different strut brace) will be tricky.

Bigger diameter runners should give more overall torque, You might play with stepped diameters too. I believe shorter runners will net a peak torque at a lower RPM, while longer runners will make peak torque higher up.

Last major obstacle is cost -- it would be nice if these could be mass produced for not much more than a grand, and less would be ideal. so sacrificing some shiny/pretty for power seems like a worthwhile trade.

I think the fundamental problem with building an IM for the Z has been the approach; I think all other IM attempts have been based on adapting an existing IM from other applications rather than experiment with developing a totally new unit using a design where the OEM 370Z IM is the starting point so you have a clear benchmark to work with.

If you have the materials, the tools, and the knowledge to develop something like this, go for it :tup:

The goal is to decrease turns throughout from intake all the way through the lower while maintaining stock location for fuel rails and strut bar. Moving TBs to the front may be an option as that will be the least restrictive for airflow (bend wise). But Like i said, working on access to a flow bench through some family friends.


This was dumbfounding to me when I started my search, I came from owning a hyundai and we had 3-4 fully custom manifold options in the 600-900 price range.

look at AMS and their GTR manifold. it's somewhat like the OEM and based off the design but looks much better than stock.

or their new omega CF intake manifold is just pornography for car people.

seen at the beginning of this video below. if we could get something like that i would pay the money for it lol

pause video at the 28 second mark or so.

Just look up 1slow370 world record Na Build, model after his car like I plan on doing, He has cams stock block etc.... made 371 to the wheels on e-85

he has a one off manifold from GTM.

a. no more will be made from GTM i'll assume lol
b. he probably paid 1500 or more for it.

The real reason this will probably the only one GTM will ever make is because almost nobody would be willing to give them that kind of money with all the horror stories others have had regarding their business practices.

While $1500 is more than many people would be willing to spend, there is most certainly a market for a high performance mani at that price point assuming it provides considerable gains. Given that ~340whp is about the max most NA people with full boltons have got, being able to get up to the 360-370whp range is worth the extra coin.

Honestly, I don't care what it looks like so long as the gains are great. Having a shiny piece under the hood is pointless for many unless the performance gains are there.

still there is the major problem. no one has pulled big or even good gains from any manifold. Z1 got a few HP here and there but nothing worth paying that kind of money for.

i'm right there with you. if theres a considerable gain then yea i got no problem handing over the money.

just need to make something that produces power. who cares if its eye candy or not.

:yum:

Or adapt the Jenvey ITB like Sasha Anis did with the ex-Fontana Racing 350Z when he upgraded to VQ37 internals and JWT Grand Am cam package

410+hp atw is close to 500@ the crank

BTW, look what I found in the back of my ute !!!

The AMS GTR Manifold is not just somewhat like the OEM manifold... it IS the OEM manifold. They cut out some of the runner length and weld in a new floor lower down spaced further from the original plenum lids, creating shorter runners and larger plenums... which is pretty much exactly what you would want for that car. This is why there is a $1200 core charge on top of the $3200 price. This of course makes a lot more sense for a GT-R owner who stands to pick up tons of power. But a NA Z isnt going to get much HP per dollar from an intake manifold without increasing the revs. *Maybe* 10hp if you hit a home run. How much is 5-10hp worth to most NA Z owners?

I honestly believe that most the community here want one for appearance more than anything. The stock one is just so hideous. There are very minimal HP gains to be found in an intake manifold for an all-motor 370z that is going to be running stock oil pump / redline IMHO. That is why nobody has really put the effort in yet... the payoff will be pretty slim.

If HP is what you are looking for... unless you are going to make some serious changes to the engine, I think the intake manifold is the wrong place to be looking.

I hate you!

:yum: :yum: :yum:

i think someone here for $295 is a great deal then!

sounds like lower the cost would be worth it then?

sooooooooooooooo maybe with some boost it'll be worth it :stirthepot:

also stop posting and go get you manifold done. i'm tired of fapping to your cad pics. i want some real stuff soon :yum:

:tup:

hmmmm i wonder who that person would be lol

idk which direction i'm going currently. but its snowing, the Z is sleeping, so the mod bug is hitting.

Maybe with some dyno results everyone has been waiting on :yum:

I'll get you some new cad pics for fapping. :rofl2:

Soon, soon!! 11 days

Just a thought, but i came across this, and wanted to give you a heads up.. You might wanna pick this up

http://www.the370z.com/parts-sale-pr...tor-cover.html

Wow :eek: pornography is sayin little, absolutely :yum:

That's basically option 2 from the first post, you have to have a custom lower manifold, cut intake piping, and get custom fuel rails. Would be nice if it was plug n play, but that's the point of this thread ;)

Avery370z got his manifold extrude-honed, got decent gains after tune. http://www.the370z.com/intake-exhaus...-intake-3.html

^ that was gains from headers and manifold. Still no real knowledge on manifolds alone. :/


Well anyways I got my manifolds off yesterday, started doing some measurements and such on breaks from installing headers (a pain in the *** to do alone btw, passenger done, drivers side getting done sometime this week). Got to thinking about what options for manifolds can be made and what will be most efficient.

Equal length manifolds
Pros - easiest to design, equal air to all cylinders
Cons - more bends in piping, reducing efficiency

Shortest runners direct from TB
Note - a smaller plenum with short runners is also an option to help with harmonics of opening and closing valves
Pros - least bends, probably most efficient
Cons - very difficult to design, lots of math, will need to look into pressure changes from opening and closing valves, piping diameter will be different for each cylinder, longer piping slightly narrower to start. This will increase airflow velocity and overall volume to that cylinder vs equal size, this will ensure all cylinders receive equal air.

Large Plenum, equal runners
Pros - better application for turbo/boost, the plenum acts as a surge tank for when the valves open and close (pressure not released by the bov) These will have the shortest runners possible
Cons - my goal is more for a NA vehicle, but this is something to consider.

Take a peek at the Jenvey site in the UK .. here:

Throttle Body Selection with Jenvey Dynamics - Jenvey Dynamics

There are a plethora of factors that influence induction system design, none-the-least of which is intake runner length - for an NA engine.

There is no doubt that longer runners generally improve torque and shorter runners improve throttle response, so that is trade-off #1

There is also the trade-off between ultimate power at 9 gazillion rpm and the ability of the induction to support optimum engine acceleration at or around peak torque

If you are not already familiar with induction system design, I suggest you prepare to spend a significant time on the web researching.

The other point is that the induction for a full-race engine will be a pig on the road - it will p155 and f4rt on the road and generally not be tractable, BUT it will howl like a banshee between peak torque and peak HP.

The other extreme can offer monster torque in the low/mid-range but have the engine fall off a cliff when the rpm rises.

Be prepared to do lots of work on the dyno unless you have access to CFD tools and can map your chosen design to do the research in the virtual world.

None of this stuff is simple !!

Have you got or can you build a flow bench? That alone would be a good starting point to see where you have room to make improvements in cfm.

On a related note, if you haven't already played with some calculators, check these out!

http://www.wallaceracing.com/runnertorquecalc.php <-- this one is especially handy if you have measurements on the OEM runners -- start from there and see where you can make changes.

https://www.rbracing-rsr.com/runnertorquecalc.html

http://www.bgsoflex.com/intakeln.html

Some very useful tips and maths here too
http://www.team-integra.net/forum/bl...culations.html

Thanks for the links guys. I'm fully prepared for lots of research and always considering advice/comments. Otherwise it would just turn into dumping money into a crap shoot as Kinetic did...

I do not have a flow bench yet, but I DO have full CFD tools.

One thing I haven't seen anywhere yet:
When a valve closes, obviously the air that was accelerating towards the opening will rebound and send a pressure wave back towards the plenum (the point of a plenum to start with). Ideally I would think the runners should be tuned so that this wave is reaching the plenum at the same moment an alternate valve is opening, thus creating a minimal boost in pressure going to the next cylinder. This may only be optimal at a peak rpm or range though as the pressure wave frequency changes based on rpm and vacuum.