If you're just here for the pictures, i won't waste your time, here's the end result:


Here's more pictures of the unboxing and finished installation if anyone's interested

I ordered the Typhoon intake system (K&N 69-7071TS Air Intake) from K&N directly this past Sunday for my 08 Z. K&N has free 2/3-day shipping on orders over $20, so I got it Tuesday! I really wanted to install it during the week, but my engine bay is just too hot after driving home from work, so I resigned to waiting till today; luckily Canada Day made my wait one day shorter!

Unboxing:

Although the packing was interesting in my opinion - just a lot of packing paper rather than bubble rap or something - everything arrived in tact. The intake system includes 2 K&N intake tubes, 2 K&N air filters, a bunch of hardware to put everything together, and some really awesome, detailed instructions. I think the finish on the tubes is really nice - looks better than I expected.

Installation:

Thanks to the instructions that came with the kit, installation went very smoothly.

One thing to note, I've found it's recommended that you open the doors before disconnecting the battery. This is because the windows in the Z do the little "jump" down when you open the door, and "jump" back up when you close it - you want them in the slightly lower position because otherwise you could potentially damage the window/door while opening and closing it while the windows have no power. So I opened both doors, and then disconnected the battery to start my installation. At the end, I opened the doors before reconnecting the battery and then powered them all the way down, and then back up. I've heard this powering down and up is recommended to re-calibrate the windows - I'm not really sure if it makes a difference, but I didn't encounter any problems while following these recommendations.

The hardest part in my opinion was installing the smaller pieces of silicone tubing. For example, 1 piece connects the passenger-side intake tube to the crankcase vent chamber, and it was a huge pain to actual slide the tubing onto the intake tube connector and the crankcase vent chamber connector. I prefer the clips that are used to connect the stock components, since then it's easy to connect and disconnect the tubing.

It took me almost 4 hours start-to-finish, while taking my sweet time. I'm sure you could do it much faster if you didn't spend an hour struggling with silicone tubes like me :P

One slight con to this system is that I think it will be a big pain to remove and replace relative to the stock system. For example, if you need to change your spark plugs on an HR Z, you need to remove the intake tubing, and that would be more difficult with this system I think. Luckily I changed my spark plugs recently, but the point still stands.

 

End Result:

Note, I've only driven the car for about 15 minutes after installing this system.

I'm very pleased with the aesthetic design of the system, and this one of the main reasons I got it. In my opinion, the typhoon system is much prettier than the stock intake system, with the ugly air box and tubes.

In terms of sound, I think there is almost no difference when starting the engine or at idle, or even low (less than 2k) rpm. I notice a difference in sound when driving and revving up to 3k or more rpm. I find it's slightly different, at least louder. Overall, not a huge difference, but a nice little boost to the sound of the engine.

In terms of performance, this is K&N's dyno specs for the system. Even K&N's results are relatively negligible, and since I didn't do my own dyno test, I really can't honestly say exactly what difference the system made. That said, I want to say it feels like I get slightly better acceleration, especially as I reach higher rpm, but this could just be wishful thinking/placebo effect. It's definitely not anything to go crazy about, but it seems like it could definitely be slightly better than stock.

So that's pretty much it. I'm hoping this could be helpful for anyone else considering this system, since I didn't find much in the way of user reviews for it.

 

Never really understood the reasoning behind these things besides looking cool.The car is now sucking hot air directly from the engine bay. What are the advantages of this...

 

Advantages.....his car and money. If he is happy with them, that is all that matters

 

Well looking cool is the main reason I got it - I'm not racing my car so any performance impact is mostly a side-note for me. Also, I think these sort of intakes typically improve a car's sound, so there's that as well.

Performance-wise, I can definitely see the concern of taking in warmer air. However, I think this is intended to be offset by the fact that more air may be drawn in relative to stock due to the air filter's design. Additionally, I think that perhaps heat shields do more than most people give them credit for, and the air that's sucked in isn't as hot as you think. But I think everyone (including me) is really only speculating as to the impact heat shields have.

In terms of the actual data for short ram intakes, they almost certainly improve performance a slight amount at high rpm. For example, the dyno result K&N provides (which I linked in my post) shows a 8hp gain at 5800 rpm in third gear. I think slight gains at high rpm are widely shown by actual test results for SRIs as far as I've seen. In general, I think they have little to no impact at lower rpm, or potentially even slight performance loss in some cases. To me, this means that worst case scenario, I end up essentially no worse off than how I started performance wise. My point is, even given the concern of hot air being sucked in, the empirical evidence shows that performance may still be improved a tiny bit with this sort of system.

My colloquial experience so far is that the intake tubes actually remain surprisingly cool. I was inspecting things after a drive this evening and I would have expected the stock intake tubing to be hot to the touch, but the K&N aluminum tubes actually felt like the ambient temperature. Similarly, the air filters were cool, and the heat shields weren't hot. So I think perhaps these sort of intake systems are designed better than people like you give them credit for.

 

Good review OP and Trav is correct, if OP is happy with the product its all that matters..

I've used these types off intakes on my Honda coupe and Lexus is300 in the past with complete negative performance gains. My reason for being biased to dislike such products..

 

Fair enough. I only looked into results for Z's, and tried to find results for HRs specifically, so I'm not well-aware of SRI's effectiveness on other cars.

My guess is that the VQ35 may be a higher power engine than those of the cars your tried SRIs with - I wonder if the Z therefore gets more out of the (theoretically) increased airflow from an SRI relative to the cars you tried them with?

 

Kiss your piston rings goodbye.

 

I don't follow - is this bad for my piston rings? if so, why?

 

Because PLENTY of grit will pass through those shitty gauze filters, and the parts that grit will damage most are your piston rings. There's not a thing wrong with the stock HR filter boxes and paper elements, and you won't see a better OEM setup on practically any other car. Nissan did it right. K&N and the knock-offs are the biggest scam going in the auto parts business, and none of their claims about better air flow or better filtering have ever been substantiated independently. It's all pure BS.

Carry on.

 

K&N's drop in air filters are widely regarded as the best practical solution for the majority of applications, and are arguably the single best $/hp gain for the 350z.

 

It makes sense that there would be a trade-off between filtration and air-flow, so I think there is some truth to what you say in regards to K&N filters having less filtration. Thanks for making me aware of this.

But to say that there is no evidence for K&N filters having superior air flow over OEM filters is simply ignorant as far as I can see. It doesn't take much looking to find third party results showing this. I've also not found any such evidence that this is not the case. If there is any evidence that K&N filters don't live up the the claim of increased airflow, I'd love to see it.

If the trade-off isn't worth it to you, that's cool, but let's not pretend it's entirely BS just because you had a bad experience.

This is what I've seen quoted a lot, especially here - one of the reasons I figured a K&N intake system, with k&N filters, should work fairly well.

 

All BS. To show the supposed restriction in the stock paper filter, you'd need to show a pressure drop across the filter. Show me that. The only "evidence" you'll see of increased airflow is from the makers and vendors. No independent evidence from a non-interested third-party, i.e. The SAE. Do you get any increase in airflow if you simply remove the element from the original airbox? The trade-off of more airflow versus less filtration is moot, because you're not getting more airflow. It's all marketing, and very effective, which I will admit.

 

The results are literally a google search away. Here are a couple of tests that showed up among the first 5 results for a google of "auto air filter comparison":

http://www.bobistheoilguy.com/airfilter/airtest1.htm

http://www.nicoclub.com/archives/kn-vs-oem-filter.html

The first link specifically shows a lower pressure drop using a K&N filter vs a Napa paper filter. The second link, which appears biased against K&N if anything (since they seem to be trying to debunk K&N's claims), admits that K&N filters provide greater flow vs paper filters.

As I admitted before, it makes perfect sense that increased flow comes at the cost of slightly poorer filtration ability. The results show that you're entirely in the right for claiming that K&N filters may not filter as well as standard paper filters. But as far as I can see, you're the one talking BS in regards to air flow.

 

Didn't check those links, but what's important in a filter is "filtering". I know how much grit gets by the K&N from personal experience. Like I said, kiss your piston rings goodbye, and if there is a performance difference you can measure or feel, your butt-dyno is better than mine. There may be a small pressure drop across the paper filter, but remember to compare the size of the filter(s) to the size of the MAF(s), and consider if that's an important factor. OEM air filters are generally far larger than they need to be so service intervals can be extended.

 

I'm not sure I understand what you mean - is there a particular reason this is important? Or a particular point you're trying to get at?

In my particular case, the MAFs are the same with the stock and K&N intake - the kit suggests you simply move the MAFs from the stock intake tubes to the K&N tubes.

The filter surface area is larger, I might guess by roughly 75%, with my new filter. However the geometry on the new filter is quite different than the stock one. I would guess this is beneficial for filter longevity since with the stock filter, I would imagine most of the airflow is through a small circular region in the large rectangular filter. Whereas with the cylindrical filter, I'm sure certain areas still get more airflow than others, but I would imagine it's distributed a little more than the stock one.

I think a larger filter alone, such as the one I now have, would allow more airflow. Since you raise a good point regarding filtration, this actually makes me curious if there are any paper filter replacements I could use in place of these K&N ones. I think there must be somewhere, but either I'm bad at searching or they're unusually hard to find.

 

Thanks for the review m_0g, very clean looking bay with those intakes.

 

The OEM paper filter cross-section is already so much larger in cross-section than the MAF that a small restriction in the filter won't make any difference at the MAF. Airflow across either filter will be distributed evenly across the the medium, why would it be otherwise?

 

I think that's simply not true though. Here is why:

The pressure drop between atmospheric pressure and the pressure in a cylinder after air has been drawn in is indicative of how much air was drawn into the cylinder. Therefore, the lower pressure drop, the better in terms of performance (ignoring filtration). A lower pressure drops also means that more air must have moved past the MAF.

The two things that I assume will most affect this pressure drop are the intake geometry and the performance and geometry of the filter used. For simplicity's sake, I think it's also reasonable to assume that on the other side of the filter is atmospheric pressure. I think this is certainly a reasonable assumption for a short ram intake such as the K&N typhoon. It is perhaps less true for the stock system due to the air duct leading to the filter (which may restrict air flow leading to the filter's outer surface), but let's ignore this for ease of analysis.

There will be a natural pressure drop over the length of the intake tubing, and a longer tube would mean a larger drop. Let's also assume that the stock and K&N tubing is the same length leading to the air filter, since I think it's relatively similar, or perhaps the stock tube is longer leading to the air filter.

If my above assumptions are accurate, this means the primary factor affecting any performance difference between a stock air filter and a drop-in K&N filter is the filter's resistance to air flow. A filter that is less resistant to the flow of air would presumably result in a lower pressure drop, and therefore more air mass being taken in. I believe empirical evidence of this pressure drop was provided in this link, which I provided earlier.

I think this logic leads to the conclusion that any difference in restriction at the air filter will alter the mass of air that may be taken in by the engine, and therefore affect the engine's theoretical power output. Additionally, for air intake tubing of a similar length and geometry, the air filter will play a role in dictating the engine's volumetric efficiency. I think there are likely statistically significant differences in performance between different air filters, even if small.

A filter of larger size will provide lower overall resistance to airflow through it. Therefore, I don't think your statement is accurate. Additionally, I think this also means that a cylindrical filter of the size I have will always be better than a filter of the stock size, since the cylindrical one has larger surface area.

Think of water flowing in a river - it flows fastest in the center. In a scientific sense, air is a "fluid" like water when it comes to the physics that dictate its flow. For this reason, I think we can be confident that the air is flowing fastest through the center of the intake tubing, and almost certainly also through the center of the filter. This effect will be less drastic for air than water since it isn't as viscous as water, but it will certainly be present to a degree.

Feel free to disagree with my opinions, but you can't argue with the laws of fluid mechanics that dictate how an engine performs. My point here is not to say that a filter which permits more airflow is worth the trade off of decreased filtration capacity, as appears common in practice. My point is only that such a filter almost certainly does provides some degree of performance improvement, even if small.

 

That's a big effort defending a filter system which doesn't filter, and doesn't provide any measurable performance increase in exchange. As mentioned, K&N's marketing department did their job well. Stay in school - maybe take a few classes in engineering and physics.