Why not?

I don't think it's my responsibility to do R&D for Stillen. Let me put it this way, if Stillen puts a product out there and says 'we tested this and got xyz gains out of it', then I'm happy to take the plunge on good faith and order it, even if there aren't any 'independent' dyno figures out yet. Indeed, that's basically what I've done with their exhaust and their G3 intake. But if I'm not mistaken, Stillen hasn't tested their own headers on a 370Z yet. They have them listed for sale for the 370Z, yet when I click on the icon to look at the dyno chart, it's for a G37. That alone makes me raise an eyebrow. Now add to this we've got RelentlessRY telling us that he tested them and lost a bunch in the mid-range. That's red flag #2 in my mind. He says he talked to Josh and they think the reason this is happening is that it's bottle-necking at the factory Y-pipe. Okay, sounds reasonable. So Stillen should test that theory and bolt it up to their cat-back exhaust as part of their R&D. They're the manufacturer with an R&D budget, after all. I'm just a lowly consumer.

Yeah, I see what you mean. However, I think it's safe to say that the performance gains will be similar to the G37. I think (hope?) that these will produce some nice gains when combined with a better flowing catback. It doesn't make much sense to do one without the other. Come on you're halfway there :)

Nah I understand where you are coming from, I'm thinking about buying a set myself and coupling it with a catless catback. I'll know sooner than later.

I am considering getting a stillen cat back and some test pipes and seeing what happens.... the 370z y pipe is super restrictive and anything prior to the flex joints i feel are gonna be a negative until you can open the y pipe up.

I am talking with r2c intakes right now about testing there intake, so i might splurge on a stillen cat back in the next month and not sure what brand test pipes yet.

Main reason for doing headers first was to get the PIA mod out of the way first.... only n/a install that is gonna be more of a challenge if i do it is cams and only exhaust cams seem to be a viable option but that will depend upon intake timing options.

GTM is in the final stages of getting their catback ready. One thing I particularly like about their design is the X-pipe.

I would take that over a Y-pipe any day.

Hey Guys,

Just wanted to jump in and offer a little insight into the exhaust systems that STILLEN has been developing for the past couple of decades.

Whenever we develop an exhaust system for a vehicle we typically spend a few months just trying to figure out what works best. One of the real benefits to being a "niche" company is that we can dedicate a lot more time to developing exhaust systems for Nissan and Infiniti vehicle's than most other companies would be able to. That really allows us to fine tune our products and pick up every bit of performance possible.

In 2002 we started development on different exhaust configurations and designs for the VQ motors and tested dozens of different setups. The end result is our current offering which was tested a few years ago by an independent magazine (I believe it was import tuner) to be the highest horsepower producing exhaust system on the market for the Z's and G's.

So Kyle, does that mean that the loss in the mid-range that RelentlessRY experienced is to be expected? Like it's by design, in other words? Or are Stillen's VQ headers meant to be used in conjunction with Stillen's cat-back exhaust only (to address that issue, presumably)?

I wouldn't rely on dyno charts from a manufacturer. Many times those numbers are inflated. If it's not posted by some one I trust, plain and simple, I don't believe it!

We haven't actually dyno tested a 370Z with our headers on it yet so I can't say exactly what is going on but it would make sense that the headers aren't being optimized due to the factory exhaust.

Kyle, so you're saying that your exhaust design will at least match the power produced by a true dual exhaust with test pipes? I like how your catback sounds and the gains with your headers so I have no reason to buy anything else. The only thing holding me back right now is the fact that I have the suspicion I may be compromising a bit with the X pipe. I thought maybe you chose this design for cost and/or emissions testing rather than performance. Reading your post, however, it seems that my assumption is wrong. My point is that maybe you should point out that the design is primarily performance driven. If you hadn't posted that, I wouldn't have considered an X pipe design at all. Things have changed now.

Everything that STILLEN does is performance driven. The second thought is "how will this effect emissions and/or legality."

One thing to keep in mind is that a cat-back exhaust has ZERO effect on your emissions legality. As long as you aren't modifying or by-passing your catalytic converters you can (legally) do anything you want to the exhaust system.

Your only "legality" concern with a cat-back exhaust is going to be noise. Some states are starting to crack down on noise ordinance regulations and issuing tickets for exhausts that are too loud. The problem is that the only state that actually has any kind of regulation is California. So, STILLEN went ahead and performed an assortment of tests to the California standards and we found that our exhaust is completely compliant with California sound decibel standards.

Keep in mind that STILLEN is comprised of a company of enthusiasts. Steve Millen is a world champion race-car driver. Our lead engineer has a modified 300ZX. Our marketing manager has a very cleanly modified G35 coupe. I have built a few extensively modified vehicle's myself. Our sales team consists of enthusiasts who own everything from turbo supra's to G sedan's and highly modified trucks. Everything we do, we do as enthusiasts which means cost and "ease of manufacturing" and pretty much everything else is a second thought to performance and function.

Excellent,

OK, that's what I like to hear. I will consider a catback too :)

Guys I am going to Side with Kyle here. I only posted to show the results with just headers. He is a picture I like to draw so some people can understand better... Try breathing through a straw, the end nearest to your mouth is very large but the exit is very small not matter how hard you try only the small amount will pass... Much the same is happening with my exhaust right now.

I wanted to get this mod out of the way first. It is a Major pain to install headers on this car or any z/g car. I plan on going with a cat back exhaust. I am working on sponsorship with a few companies. So please no Stillen Bashing they area great company with many awesome products.

Just and FYI the OE part numbers for factory exh manifolds are the same between the g37 coupe and 370z.

Kyle can you PM me about your Tundra?? I have a customer with one and I need some advice.

I don't think anyone's been trying to "bash" Stillen here. Just trying to hone in on some details is all. I agree that Stillen makes awesome products. I've been modding my cars with their parts since 1998.