LTH = Installed, Review
 

* No pics or video, my photographer friend flaked on me*

*It's been brought to my attention I'm coming off as dissatisfied, but I'm far from it. I love the sound and it's the volume I want. There's no rasp. As to the his, I'm pretty sure there's an exhaust leak and we can blame the fast install. While on the dyno I only heard a bit of hiss on decel, the trip home revealed a slight hiss on accel. I will be re-dynoing later and try to do it in 5th too.*

Sorry guys, I got nothing to offer in terms of pics or vids, I do have a before and after dyno sheet, BUT, the dyno was done before and immediately after the install and the ECU had no time to relearn anything so there was almost no change. I will say though that from 4k through redline there were signs of both HP and TQ gains but not so much peak gains, which will only get better as the ecu learns. Ill post the charts as soon as I get them emailed to me.

Dyno: Dyno Jet, 4th gear
Result: Before: 302 hp 240 tq
After : 301 hp 244 tq
for some reason, the TQ is all messed up in the graphs i was sent. It wasn't like this when I saw it on his computer. I cant go by RPM either or parts of the graph vanish. Run 1 and 2 is pre-header. Run 3 is right after with no time for the ecu to relearn.
http://img691.imageshack.us/img691/7610/whp.jpg
And what I see when I look at TQ... lulz
http://img528.imageshack.us/img528/1315/lulzy.jpg

Id also like to mention my install only took 3.5 hours to do them and he seemed to know his stuff! So i got a great deal altogether. Hes also going to get back to me on the Cobb AP tune if they can adjust timing or not, and if not what he thinks he might get gain wise with a A/F tune.

On to the sound... keep in mind my mods in sig bellow.
Honestly, it sounds like a rattlesnake. I don't mean civic kind fart can, and i don't mean raspy. Its incredibly smooth, deep, and overall incredible sound. But we all know that 370z hiss... and with no restriction its there, and loud, and makes itself heard. If you like it, then its great. But if your like me and think the hiss overpowers the sound, then its not so great. There are certain RPMs and load/throttle % where it will go away, but as soon as you let off or gas a little more its there until about 4k rpm. After that its auditory bliss. Ive also found that the hiss is more present when the clutch is in, let it out and the engine seems to calm without as much hiss.

Just to be sure, Ill take it back in a few days (read: week) and re torque all the bolts to be safe. Maybe the hiss will reduce by then.

Again, I apologize for no pics or video, and I know I don't post here often and am not known, but Tony's LTH are incredible. I may have some video later when another Project-Definition video is made, Until then, refer to SEMTEX, I'm sure he will have everything you guys want to look at and hear.

Cool review...especially since you're the first...it would be interesting to see the real gains once the ECU adjusts....overall you sound satisfied...Maybe the hiss will settle once some miles are put on..

sweet can't wait to see the pics and vid nice post

Congrats on beating me to the install, man! :rofl2:
Mine are actually getting installed this morning. Installation starts 2 hours from now, to be exact. :woot:

When everythings said and done, could you PM me pertaining to what my friends referred to as the 'rattlesnake' sound? Im wondering if another car will experience it as much or if something my be awry. I really think its normal though, just more pronounced. Although pounding the gas and still hearing that hiss/rattle sounds more like an exhaust leak...:ugh2:

Well, I plan on making an interior sound video where I just let the camera roll inside the car while I drive around a while. Will that help?

Yeah, that would be good. I think it will either come down to 1 of 2 things, Yours will sound the same, and have an "Oh.." moment, or It will sound amazing and you'll tell me somethings broken. :icon18:

Well, I'm running Berk HFCs right now and can tell you that even with HFCs there's a hiss. And when I had a 350 I ran Kinetix resonated test pipes, and there was a hiss. So I wouldn't worry about it too much just yet. But I guess it's a question of degree. i.e., how much hiss...the magnitude of the hiss.

Thanks for the review. Keep in mind, you have to do about 6-8 dyno pulls to see the gains. I have noticed that through all of the dyno testing that we have done with this car, once a new mod is installed it takes that many pulls for the car to react. If you are coming from stock cats you will pick up a substantial amount across the board. If you are coming from our high flow cats, you will see good gains in the low end and mid range and less up to. You will still see a overall gain.

I think once you put some miles on the car and go back to the dyno, you will be impressed as to what the headers will do.

EDIT: To add one more thing, the "hiss" on deceleration will be slightly more noticeable with the headers over high flow cats. It seems like less restriction with this car = more hiss! However, some like it and in my opinion it is a trade off for the performance gains...

Thanks, Tony

I just discovered that I'm missing two bolts and 3 nuts from my package. Hngonzalez, was all your hardware complete? I have to run out to get the missing stuff now.

Look in the box and makes sure that the hardware packet did not rip. I packed it myself. You should have 4 bolts and 4 nuts.

It didn't rip. The packet was totally intact. It's missing the two large bolts/nuts, and also the little 6mm nut for that small bracket. But we should be able to just use the bolts that are currently on my HFCs. No biggie.

wow. 3.5 hour install on a job i thought was supposed to take 6 to 8 hours. NICE. I can't help but feel that you're a little dissappointed tho. Is this hiss really all that bad? time will tell. Hopefully Semtex isn't let down and goes bananas in his review about how sweet FILTH is. haha

Sorry bro, it was one of the first sets to go out. I possibly could of brain lapsed.

Tony

I am impressed as well. The only way I could do it anywhere close to 3.5 hours is with help and I can fly through an install.

I don't think he is disappointed. I can tell you that the hiss is more noticeable with the 12" opposed to the 18" resonators. I have installed a set with both sizes and the 18" make a big difference. At this point, the hiss is unavoidable if you remove the stock cats off of the car. I notice it alot more with the 370Z opposed to the G37 or earlier 350Z.

Tony

Haven't heard it in person but from the vids... I like the hiss. sounds crazy!

Patiently waiting trying to hold back my excitement! Btw, Tony, I want the loudest CBE out there, not a fan of resonators I can put up with the rasp do you have something along those lines?

I think you will get plenty of rasp with no resonators and the headers. It will sound very exotic. I personally am not a fan of that sound but I am a V8 guy, I like things deeper and smoother.

So I called HNGonzalez. We spoke for about 10 minutes. He feels that he may have an exhaust leak. He is going to double check the install and make sure everything is tight. He told me there were no install issues and everything went smooth. We also spoke about the dyno runs. The car was run in 4th gear which is the wrong gear for the 6MT it needs to be 5th which is 1:1 gear ratio. He will be going back soon to get it squared away...

Thanks, Tony

Tony it looks like you have my car on your lift! And you already gave me my free CBE too! Thanks gai! :tup:

I was actually missing 2 bolts and 2 nuts too, I was later mailed the little black heat shrink tubing too. Tony was on it, I didn't even know I shoulda got those :p. Everything else was solid, my shop had spare bolts. As for the install, yeah, it was fast, but he also may have torqued some bolts wrong as there seems to be a leak. I think having an aftermarket intake cut on install time too cause he litteraly took out my injens in ~10 mins. I'll look more into it later, I'm having too much fun now :)

ID like to mention that with my 12" res there is absolutely no rasp. The sound is amazing and the shop as well as bystanders had to pick there jaws off the floor. Myself, I couldn't stop grinning :tup:

Headers on a 370Z/350ZHR are sooo much easier to install than the old DE's :)

You probably dont have an exhaust leak. I didnt install my LTH's yet i got them in the mail yesterday btw. I currently have non resonated test pipes and you hear a small hiss durring heavy acceleration im 99% sure its the air traveling through the x pipe at such high speeds.

I have always had a feeling that these headers would turn out this way.. im pretty sure they are great thru the mid-range. The hiss should be the same as mine gives on resonated test pipes. It is pretty loud when decelerating at about 1k -2.5k RPM's with the windows down and the radio turned low. Many people think something is wrong with it or say my car is cheap for making noises and being new. But most of these people making these comments are car dummies.

I have asked this question and never got a straight answer...does anyone know what is the actual cause of this hiss noise? I have the FI CBE + FI test pipes and the hiss is pretty loud already, I imagine with the LTH its even louder. Its a tradeoff for the killer exhaust note but if I had a choice I would eliminate the hiss.

I absolutely agree with you

The hiss is almost the same with the headers as the test pipes. The one trade off is the headers promote less drone inside the cabin because they promote a higher exhaust note. The exhaust will not be as deep and bassy. Some may like it and some may not!

As far as what causes the hiss, I do not have a definitive answer so i do not want to speculate. Obviously the sound is promoted by aftermarket exhaust components because the tubing wall is thinner and the sound escapes easier.

Tony

Tony I was doing some reading up on the hissing noise. some of the guys on my350z.com used the magnaflow resonated x pipe the same one you use on your 350z catback exhaust and the hissing went away. And with some further searching on google other people that have x pipes and no cats on there cars for example mustangs they were getting hissing too when x pipes were used.. Im pretty sure thats what it is.

I have heard other systems on this car that used H Pipes. They had the hissing noise as well. I can even hear it with the stock exhaust, no X pipe there! The X pipe we use on the 350Z will limit your power and that is not we want to do. That is a step in the wrong direction. If the X is the issue which I think it is not, then I myself would live with it for the performance trade off.

BTW, did you get your care package, what do you think?

Thanks, Tony

Maybe the hiss is the pounds and pounds of carbon monoxide and NOX that the car is emitting now that the cats are off.

^^^^ gtfo

You dont have a leak. The hiss/rattle/metalic flutter on these cars once you go test pipes + exhaust is, IMO, horrible. The LTH's are amazingly gorgeous pieces. The fact they're being made by F.I. is an honor as their work is proven perfection. Only problem I see with them is they magnify that test pipe rasp 2x. Maybe they made a way to make the rasp sound good, ie; rattlesnake ;)

My opinion on the rasp is, its harmonic. It seems when you hear it from below the car you can nearly feel the rattle coming from right before the Y/H/X setup. Seems that exhausts that have resonators right before that point in the system have MUCH less rasp than anyone else. Also, and I'm not sure how true it is but I heard "true duals" that have no connection to each other have no hiss, but I cannot confirm this.

Tony - After all the exhaust issues i've gone threw etc etc I may cave in and order a system from you after the SC install. Most likely 18"/CF - I really love the sound your system gives out. Good work, top notch!

If and when you are ready, call me...

Tony

My install has turned into a total, epic disaster. We started at 9am this morning. It is now almost 10pm and we have quit for the night. We have the driver's side done but we cannot get the passenger side header off. The problem? Just one single nut -- the bottom center one, won't break loose, and now the nut has rounded and we're f*cked. This is a f-ing nightmare. I'm going to bed.

You're right... drove a friend's Z with HFCs and one of the true dual CBEs and no hiss at all.

Yikes... good luck getting that sorted.

Damn. Sometimes walking away is the best thing. Good night and good luck tomorrow!

Keep your head up brother. It will all be worth it when the job gets done. A new day awaits u tomorrow. I cant wait for your review

lol yup got my care package. looks great just have to find some time to install these.. I already did the x pipe myself thats easy.. as far as the headers do you absolutely have to disconnect the steering knuckle.. if i remember correctly your test pipe install said to do the same thing but i got it done without disconnecting it..