o snap its eric

iTrader: (5)

Im concern for since its made out of plastic. I just want some reassurance before i buy it.

FLY BY Z

The LS1 Chevy motor, which is not even out of use yet and already legendary, uses a plastic composite intake manifold. It work great and so will this one.

mofoz

iTrader: (1)

the plenum material can sustain much higher temps than what the enigne will produce, so that shouldnt be a concern, and they also added some other things to prevent flex, so you shouldnt worry about it.

PhoenixINX

Not to play the devils advocate, but isn't the LS1s manifold tubular composite? Meaning the cylindrical shape is what is giving it its strength? Not necessarily the material itself?

Was it not also mentioned this is the same material that is used for end tanks in radiators? How many times have I heard of those cracking due to age?? More so those weren't even flexed up and down and up and down hundreds of times a day.

Things to think about... Kinetix seems to have their stuff together, and I doubt he'd release a product that would "NOT" perform... though your points Cody need validity as they aren't entirely accurate.

350Z 2+2 ???

Nissan has made plastic intake manifolds too. My Maxima's VQ30 has one.


Front View


Side View

Apexi350z

iTrader: (3)

I think LSD has mentioned he offers "lifetime" warranty on these plenum? so I don't think there will be any probem...

FLY BY Z

The question was would something made out of plastic last on top of the motor. The answer is yes. It is not a question of structure and that is not what I was alluding to. I appreciate the check though, friend.

westpak

iTrader: (19)

Well, anyone can play devil's advocate with any product like will the weld on the crawford plenum hold over time with cycling hundreds of times a day?

blug35c

All valid points. Remember though that the Kinetix plenum is the upper half only. Current production cars using plastic plenums are using plastic on the whole plenum. With this half and half combo I would be interested in seeing the results of heating/cooling cycle tests as aluminum and plastic expand and contract at very different rates. You don't have that issue on a Maxima or a LS1.

The lifetime warranty should be good enough though!

FLY BY Z

Oh really, so the all aluminum motors that both the LS1 and VQ are do not affect the LS1 intake just the same? I mean, either way, they are all connected to a hot chunk of aluminum....

PhoenixINX

Over five road events, dozens of autox's, and god KNOWS how many miles.

... btw, how familiar are you with welds? You DO realize if they are done correctly they are now part of the original metal itself? Welding is NOT saudering where it can "break-loose". It is bonding itself at the molecular level.

If you get a plenum from Doug and it has poor welds, it's going to be replaced... simple as that. Though from the SEVERAL HUNDRED that have left his door, I have seen the majority... the welds are works of art!

westpak

iTrader: (19)

I am familiar with welds and different repairs with metals from welding to brazing, and I do understand the molecular levels as I have an engineering degree.

Speaking of welding, welding will be more operator sensitive, you have to make sure the person doing the welding does it the same every time, prevents any contamination of the materials, do they use a fixture to keep the two pieces in the same position and tolerances, is the welding done in a vacum booth to prevent contamination, do they test welding samples of the operator to ensure consistentency and quality.

So if you want to get into a pissing contest lets go, otherwise admit that all procedures and products have possibilities of having problems.

blug35c

Chill guys! We have what appears from the dynos, to be 2 great plenums. Each one has unique characteristics. Go for the one that floats your boat.

PhoenixINX

If you're that interested, we'll play in PM.

No need to bother in public... The whole "who's **** is bigger than who's"... Sorry doesn't interest me.

Thanks

westpak

iTrader: (19)

I have nothing to prove, it was just slightly annoying when you played devil's advocate to defend your buddies at Crawford and just to hang a big "I told you so" out there instead of giving some constructive feeback whether it was to support or put down the plastic plenum.

Then it really pissed me off when you talked down to me like you have a doctorate in physics, no you are not the smartes individual here.

D'oh

The plenum could potentiallly fail in a number of ways:

1. melting/deformation due to heat
2. high cycle fatigue due to vibration
3. low cycle fatigue due to large deflection
4. excessive pressure differential causing it to rupture

Maybe other ways as well, but I can't think of anything realistic at this time.

So, lets look at each of these and see what is a potential problem.

1. Excessive Heat - LSDunique already mentioned that this plastic is capable of handing extremely high temperatures. Also, if this is the same material that is used in other types of intake manifolds, then we have tons of data to show that temperature is not an issue.

2. High cycle fatigue (failure due to millions of cycles of small load variations) - This is not too difficult to determine if you know the types of loads that will be seen and the strength properties of the plastic. Depending on the material and the design, this might be an issue or it might not. I'm guessing that due to the thickness of matieral and the fact that the vibrations will be pretty small (no harmonic resonances that will cause large vibrations) this is not going to be a problem.

3. Low cycle fatigue - This is how you can break a paper clip by bending it back and forth a few times. This will definitely happen with plastic, but it typically requires very large deformations in order to work harden the material and make it brittle. Since the plenum is fully constrained and now has the flex elimination parts, the liklihood of this type of failure is virtually nil.

4. Rupture due to excessive pressure variation - This could be a possibility, but with the small surface area of the plunum, the anti-flex supports, and the fact that you can only draw 14 psi of vacuum, I'm betting that this plenum would never collapse. If you tried to boost 20 psi, then it might be a different story, but again, with the stiffening posts it looks like it is very well constrained.

So, I'd say the most likely mode of failure would be due to vibration, but since the part is tied down so well I think it would be very unlikely. I guess time will tell.

-D'oh!