I'm thinking of buying a Kinetix Plenum / SMOG Legal High Flow Cat PACKAGE. However, before I spend around $700 on this package deal, I want to make sure that I will actually feel a significant difference in power.

My car is pretty much stock with only the exception being a JWT Pop Charger, and I’m not expecting huge gains out of my car, considering the car comes very finely tuned n/a from the factory, and I don’t have anywhere near the money needed for a TT or SC.

I guess I just want to know how many of you out there combination of parts feel content with spending close to a $1000 for the performance and satisfaction you’ve received.

 

I'd personally wait for more reviews of the plenum spacers.

 

I have the Crawford and love it...but these new plenum spacers seem like a much cheaper way to go....Definitely check that out.

 

yea, i'm waiting on my crawford cast plenum, and i can't wait to chuck the kinetix in the trash. i was a huge fan of kinetix when they came out, cause you get to keep your strut bar, not as much heat soak, no core charge. but i have had the kinetix plenum on for about six months and while i haven't had any serious problems, i have had to retighten all the bolts at least ten or twenty times. even with a gallon of loc-tite, the bolts would still loosen after a day or two of driving.

 

That’s disheartening. I’ve read that the newer Kinetix Plenums are pretty good and that they fixed most if not all of their previous issues. I would love to go Crawfords, as the reviews on this site are always amazing, but I don’t have that kind of cash. Kinetix seems like the most feasible for me at this point.

I don’t plan on changing the stock exhaust for a little while, but from what I’ve read, the cats on our cars are the most restrictive part of air flow, do you think it is worth it for me to go ahead and get the high flow cats with the plenum, and run that with the stock exhaust?

 

The high flow cats will help a ton...

When modding your Z, don't worry about doing everything at once. For most people, it's a step by step process....

If you're going to run the stock exhaust for now, that's fine...you can get a nice true dual or larger diameter one down the road...just make a note to self "Replace exhaust when $$ comes available".

In the meantime you can research everything and make a good decision.

DO NOT SKIMP on a part because you don't have $$ right now. TRUST ME, YOU WILL END UP DOING IT TWICE. If you get product B just because it's a little cheaper, you will end up with product A later anyhow...so might as well just wait and get product A in the first place, unless you TRULY want product B.

I started out with the crawford plenum/strut bar and JWT pop charger.

I bought kinetix test pipes later....and then I did my exhaust THREE times because I was trying not to dump $800 the first time around...well guess what, I ended up dumping the $800+on the third go around....luckily Ebay got me most of my money back...but the time invested was wasted

 

So true, I did that with my old car. I skimped along on parts, and I was extremely dissatisfied in the end.

I feel like the Kinetix package is a good deal, with proven results. From the reviews I’ve read the gains with this setup are pretty sizeable (without spending a boatload of money). I wasn’t sure if there would be a reason to get the cats without switching up my exhaust, but apparently with the plenum install it should be worth it. This is good news.

I think I’ll do the plenum install myself, but the cats I’m not so sure of. Anyone know how much an install on the cats would be?

 

The plenum install is easy. The cats isn't too bad if you have tools and extender bars....to have a shop do it should not take them more than an hour.

Any muffler can do high flow cats, make sure you get a reasonable quote.

I think it took me 3 hours in my garage.

 

yup, i whole-heartedly agree

i'm going pretty slow on my mods, doing them in stages, just because i want the best of each part that I put on there...

just got the call from Crawford -- hopefully i'll have the cast plenum and strut bar by the end of the week!

 

I'm also debating the Plenum idea... and boy does it get confusing... I wish someone would just test all of the products on the same car ... under the same Dyno testing machine on the same day... then we could at least see some of the diferences truely...

See what I don't get is Crawford says "our plenum produces an increase of 9 hp at the original peak, and a solid 17-20 hp at redline." ...

From all the other sites I've yet to see them be able to say they can give up these kind of dyno numbers... can anyone back Crawford up on this with their own dyno sheets?

 

I think a spacer will produce similar gains to a plenum, within 1-2 horsepower surely... the plenum sellers say the stock system also has actual flow deficiencies... not space problems. Even with that said, "bang for the buck" may still be best for a spacer but honestly I don't see saving $200 on part for a $35,000 car is worth doubling your chance to have air leaks on your intake manifold/plenum area. In the long run, I think a new plenum will outlast machined spacers requiring 2-3 times the total gasket count and who knows if this may lessen the ability for the plenum to act as a heat-sink having the extra pieces/gaskets as well.

I mean, let the kids with '91 Honda Civics put ebay parts on their mom's old car. Duck taped body kits and emissions system hoses plugged with bb's is their cup of tea... the car is only worth $1200 with a nice coat of wax freshly applied.

Your 2003/4/5 350Z is a racecar piece of expensive art... take care of it and think long term.

 

So the kinetix is about $700 for their plenum & cats, right? Crawford cast plenum & high flows would be $900 -- Might as well spend the extra $$ to get the better part. Even if HP is within 2-3, which is very likely, the higher quality and longer life span of the more expensive Crawfords will be worth it.

Why not give the Crawford guys a call, tell them your situation and ask them what is best deal they can give you on a combo plenum / cat buy. Even if they say "sorry, no discount" it can't hurt to ask. If you plan on buying their strut bar and/or headers later, that might be a bit of incentive for them to give you a little discount, too.

Chances are good you won't feel a huge difference, but you should feel something. It's when people get the technosquare "crawford" ecu flash after getting all the bolt-ons that they really notice the difference.

 

Have not heard of anyone having to "retighten all the bolts" or after using loc-tite, "bolt would still loosen after a day or two of driving.". Was on of the first to install their V1. Went through ALL the problems Kinetix had with V1 through V3. Installed V4, have had NO problems! Since installing V4 have installed and put over 7000 miles on V4 with Vortech SC. NO issues!

 

I would go with a spacer which has many advantages over a new plenum:

-about the same power gains
-less than HALF the cost
-keep your stock plenum
-keep your stock strut bar
-keep your stock engine cover


So for me it was an easy decision, and I've been very happy with the mod. Also the independent dynos coming out support the initial power claims and should silence the skeptics pretty quickly...

 

i have JWT and a V.4 and im verry happy with it i bought my v4 used from jismo and i had the cork gaset done over and replaced coolant block.. the customer service was great

 

Can you use the kinetix plenum with turbo?

 

we have several customers using them with vortec, a few with the greddy twin turbo.

I do not however advise it at pressures above 10psi.

The re-tightening concern I have seen with a couple customers is generally not a problem. What happens is when you install the plenum, you torque the bolts to hopefully around 72 inch lbs.

What happens is after heat cycling, the plastic that was once under pressure, settles in and if you were to go back you would find that the bolts are not at the same torque rating.

Almost always it is from the plastic settling in, and in fact the bolts are not "backing out" and dont actually need to be retightened. The cork/rubber gasket also has this "settling" symptom.

The only time you should look to re-tighten your bolts, is if your idle has changed and you may have developed a leak. Otherwise it should be fine.

Sometimes I will have customers who are worried mark the tops of some of the bolts with a marker, so they can see that the bolts dont change orientation and arent in fact backing out.

 

This is what worries me. The gains on paper look really good, but I want to know if I will truly feel a significant difference with just the plenum and the cats. Adding all the bolt-ons and ECU flash gets too expensive for me at this point.

 

Cats will gain you a pretty significant difference. But in all honesty, matching up a cat with plenum isn't the way to go to gain optimum power, you'd have to match up an exhaust with the cats to make a HUGE difference. When I put the cats on my car, i noticed it a great deal cus of the exhaust etc... If all you do is cats, you won't notice as much, obviously. But putting a cat and plenum only is the wrong combo. cat and exhaust for sure. If anything intake and plenum. But all these mods do work hand in hand.

I also had the kinetix and i didn't like it either. I had to re-tighten the bolts, and in all honesty, the cork gasket they use, on top of the stock gasket is the wrong thing to do. never double up on gaskets, is a general rule of thumb. And I did feel a power difference, but i think it was more of a shift in the power band, not a true gain. or maybe a gain in some parts and a loss in others.

Plenums are cool, just not my thing IMO

 

There is a really good possibility ....that we will have a completely new manifold (not just an upper plenum) designed and produced.
Some initial number crunching has been done.....and the engine/plenum will be tested over the next couple of weeks.
stay tuned.
BJ@350EVO.com