Correct, the cat back will not cause a CEL light. Your 2 rear O2 sensors located within your stock cats are for emissions. When you take off the stock cats and relieve that much back pressure you create 2 things instantly. 1) You increase the velocity of the exhaust, 2) You reduce heat. Now in order for your rear O2 sensors to work properly they need to take a reading within a certain parameter and stay hot. Now back to the velocity aspect. By increasing the exhaust flow your rear O2 sensors will sample too large of a reading. In turn it sends it back to your ECU and reports the problem. Your ECU then trips your CEL light to make you aware of the problem. By relieving the back pressure your EGT (Exhaust Gas Temperature) decreases, hence less heat. By having our U Bend style O2 sensor non fouler you keep the heat up and the reading down.

Now it is extremely effective with high flow cats. Reason being, the cats are not free flowing and they will help produce enough heat as well as restriction. With the Resonated and straight test pipes the non foulers are effective most of the time. However, there is that seldom case where they do not keep the CEL light off. In the event of that, the only way to eliminate the CEL light is the reflash the ECU with a tune, EX: Uprev, Technosquare and Cobb.

So, in short words, your F.I. HFC's should keep the CEL off, in theory, and it is the most probable scenario and with the F.I. RTP's there is a higher probability that the CEL will light up.

To be honest, I like your HFC's better than the other options just because of this. I'm not sure what the HP gains would be from the F.I. HFC's alone compared to Berk or Stillen, but this no-CEL thing is a BIG PLUS for me.. I HATE that CEL with all my heart...

I don't think anyone with HFC's on 370's have had any CEL issues at this point.

Is that using just the Eliminators themselves, or the SS brillo pad sneak?

No pads or scotch Britte, just the non foulers.

Interesante... Gonna have to look into this.

Also, can you comment as why you chose to go with the / \ cannister look as opposed to the = look?
I personally like the / \ look myself. Just trying to see if there's truth/fiction to the reasons as to why = is better...

right, just non-foulers. I'll be putting on my Berk HFC's this weekend and have no worries about CEL's popping up.

/ \ is more of a straight shot for the exhaust
== gives a little more room for ground clearance with the mufflers

unless you are going with a big turbo pushing a lot of boost, I doubt there will be any noticeable difference in performance. :tiphat:

I have had Berk HFC's on for about 2000 miles no codes thrown

I just think the / \ looks better lol. The impact in performance wise I heard from the B*** thread was the / \ design allows for air to come up under the rear bumper creating lift, and the = helped fill this gap. Part 2 of that is that same air is then caught in the bumper and creates resistance.

I guess if your car goes to the track every weekend, maybe something to look into, but if you like me my car sees 6,000 miles a year, then I wouldn't worry about it.

guys I will shead some light on the CEL issue. I have had both Berk and FI HFC's on my G37. The Berk threw a CEL from day one. But others have not throwen them. I have had my FI HFC's on for 10000+km now and just got the CEL. but I am running with out the non-fouler. I called tony and he is shipping me out a set to look after me. But he is busy with all you dudes ordering for the 370Z. so slow it down and let him ship me my non-foulers. lol

This might be a valid concern, but it can be remedied pretty easily by making a cover yourself for the rear center underside. I'm kinda waiting to see what I end up doing for cooling the rear diff first, and then I'll look at any airflow issue there after that.

As said above, I don't think anyone's been getting CELs on the 370 with HFCs, at least not the Berk ones. And you need to stop ordering G37 parts so I can get my exhaust faster :p

As said above, I don't think anyone's been getting CELs on the 370 with HFCs, at least not the Berk ones. And you need to stop ordering G37 parts so I can get my exhaust faster :p[/QUOTE]

LOL...+1

All PM's replied!

Plain and simple: the shortest distance between two points is a straight line.

I understand that N/A vehicles need a certain amount of back pressure keep up low end torque. But, if you look at everyone Else's design, aside of the fact that they all look the same, the bends are atrocious. Some bends are as high as 120 degrees. Right now, we are only separated by at most 8-10 HP, but if you were to turbocharge or supercharge the car, we would decimate the competition in terms of torque and power across the board. If you are going to go through the trouble to scavenge the exhaust by using a good cross over ( X Pipe) then your exhaust system is contradicting itself by backing back up where it goes in to the mufflers. Yes, we sacrificed some ground clearance, but if you are conscious of your driving habits and your cars well being you will not bottom out. If you take a dip at 50 MPH well then that is your own fault.

As far as aesthetics, IMHO it fits the car like a glove. This is by far the best looking Z to date and it needs to be complimented with an exhaust that fits the bill!

Ya the set up almost looks as good as the set up on me G37S :owned:

Just to let you all in on what we are about...

Bottom line, "We manufacture horsepower"

We built this car and many like it from the ground up. In this video it made 1000 HP at the tires. Currently it makes about 1300!

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you aren't separated by 8-10 HP once you factor in the high flow cat with the cat-back combo (which most people doing an exhaust will do both)...in fact Berk Dyno'd a gain of 32hp (19 from HFC's first, then another 13 adding exhaust) with their combo...

Like I said though, add a turbo and you may feel a difference from the straight shot compared to a couple extra bends. with both having Mandrel bent piping the gains aren't going to be significant even with a turbo. Maybe an extra 3-4 hp overall running 7 - 10 psi.

Forced induction will go well with any of the exhaust combo's out there, but if you are serious about boost you are going to want to increase the piping diameter, and you will likely follow the FI routing for a straighter shot. but that is going custom anyway.

Tony, that is one sick Stang Bro!!!

I understand why you might think they picked up 32 HP but that is not the correct way to look at it. Mods do not compound like that. You cannot dyno a car with one mod 8 months ago and say oh we picked up 19 hp and then dyno it now and say well, we picked up another 13 hp from the cat back so that must mean added together we make 32 hp. Just about every 370Z out there makes right around 280 at the wheels on a dynojet in correct 1:1 gear stock!

Now, if they indeed picked up 32 hp at the wheels show me the dyno where they made roughly 312! From what I have seen they have yet to break even 300 with the cats and the cat back combined. Look, we dynoed ours in almost 100 degree heat as well and we dynoed it stock and we dynoed it with just the cat back and so on and so forth in the same day in the same environment!

From doing extensive dyno testing with this car I highly doubt any set of high flow cats out there (including mine) will pick up anywhere near 19 hp with the stock cat back on the car. The stock cat back is so restrictive it will not allow it. If there was a BS flag I would raise it, but I cannot find one.

For the turbos, with the 7-10 PSI, my friend if I know anything it is turbos for a long time now and I strongly disagree with the statement that we may make 3-4 more horsepower with the less bends. You have to be kidding, right? Yes, the more boost you make the greater the gap will be but even at 7-10 PSI it will be significant! Come on, we make more than 3-4 more HP N/A!!!

I would like a link showing those gains that BERK received because I was following that and they got something like 13whp from the exhaust but I don't recall them using HFC with it..this exhaust got 20whp without HFC. Also on the BERK video of "prototype #2, which is apparently the same as #3, there is an AWFUL rasp as the exhaust winds down after a rev. People are saying that this rasp is normal when using flex pipes, which is why F.I.'s exhaust doesn't have that annoying rasp. I friend I know said that flex pipes are necessary when you have welds on that first section of piping after the cat(which BERK has) because the welds will crack due to engine tourqe. FI's exhaust appears to be one solid piece of bent piping which will hold up fine. I know this has been discussed but I'm curious if that last part is true !?

3-4 hp was the difference between the 2 cat-backs, not the overall gain.

DDM did a baseline, then another pull with the HFC's and did 19 hp...later on down the road he did a NEW baseline, then added the exhaust and got 13 hp. Yes, the temperature was low for the HFC's compared to 110 degrees he ran in with the exhaust, so adjusted for temp and take away 10% of the original 19hp gain and you are still looking at 30hp to the wheels, or over 10% gain.

DDM did the dyno's, and he dyno'd the catback with the berk high flow cats already on the car. That was part of the explanation for the lower gains since some of hte restriction of the exhaust was already removed.

Prototype 2 was with the H-pipe, prototype 3 was with the X-pipe if I recall.

3-4 over the competition with turbos, again you have to be joking. Well when we get our turbo kit done for the 370Z (opps I let the cat out of the bag, me and my big mouth) I will show you a comparison and you will shake your head in dis belief.

I have yet to see a dyno with the stock cats and and just their cat back. Of course the cats are going to free up more power. Explain to me why you would do a baseline dyno with aftermarket cats and a stock cat back. They made with their cats and stock cat back with what we made completely stock. If you really want to break it down, the day before, a dyno was attempted with aftermarket air intakes. I wonder if the dyno had gone smooth if that wouldn't of been disclosed!

30WHp with exhaust and HFC?!:eek: That would be monumental.

Whats up brotha, how have you been?

Yeah, we averaged about 24 with that setup. Hell, we averaged about 28 with resonated test pipes and the cat back.

You are both using highly efficient mandrel bent piping, with straight through mufflers. A couple extra bends is not going to make a huge difference on 7psi of boost. I do agree that the straighter design will likely be a little higher, I just don't see it being more than a few horsepower. If you can prove me wrong then by all means show me the numbers comparison when you have your boosted Z and I'll be more than happy to tell you I was wrong :tup:

DDM said his intentions were to dyno his car in its current form and use that as a baseline, then add the exhaust and dyno again for the gains. He was never trying to mis-lead anyone.

Why did they not dyno it with the stock cats? Because DDM has had the cats on his car for months now and didn't want to have to pull them off and reinstall everything stock just to get a dyno number. Using a baseline with his current and showing the increase is sufficient to show that the exhaust makes similar power to other competitors. With his only access to a dyno being another shop that is hard to make appointments, I don't see a problem with this.

I am pointing out that compared to your high flow cat and cat back combo dyno pull compared to your baseline, you made less overall power than the Berk combo did when looking at their individual gains. Yes, the dyno situations were not the same, which may mean we are retarded for arguing about it over the internet, but it's going to be VERY difficult for either of us to prove anything unless we got the same car, dyno'd it completely stock, then dropped the stock exhaust and dyno'd it with the FI cats and CBE, then dropped that and dynod it with the Berk cats and CBE.

I doubt we are going to get the chance to do that, so for now we can continue to try and make our points :icon18:

Once the exhaust comes in I will dyno my vehilce as well and see what we get. It will be with the Gen 3 Intake, Berk HFC, and F.I exhaust. I hope to make 30whp with all of that.

Now you guys got me thinking of upping my pipes from 2.25" to 2.5".:rolleyes:

that should be no problem at all =) stillen claims 54whp or something like that with that 3-combo if you used all of their parts.

I don't think DDM was trying to mis lead anyone. I don't know them but I have heard nothing but good things about them. However, IMHO when you are trying to launch a product, you have to dyno the car in its true form (Stock) and anticipate that everyone is stock when they buy your product. This is the only way to have true real gains. What if someone called and wanted to buy their cat back but already had someone else's cats. You cannot give them a definitive answer on gains because you have nothing to compare it to. For them making more power, show me a dyno graph where they made more than 305 with their high flow cats and cat back. All I see is a 296 number. So you cannot say that their combo makes more power.

As far as the boosted aspect, it seems I am getting nowhere with you on that one so I will concede for now.

Like Tone Loc says...

Let's do it!

You will!

I agree with that. It's just not easy for a daily driver to put all his stock stuff back on to do a dyno run. I also don't see someone with berk HFC's already getting a 20 whp gain by adding an FI exhaust. You are talking a 35+hp gain then, and if that's the case then sign me up for that combo :driving:

as far as more power goes, dyno calibration and conditions can play a pretty big factor there. Again, I agree the number from Berk being so far apart isn't as credible as yours, but it was the same car at the same dyno shop so I can't discredit their effort in getting accurate numbers. If you and berk both send me catback and HFC's I'd be glad to hit the dyno for an all-day session comparing the 2 and then I'd send em back, but I don't think you guys will be up for that, lol. Plus you probably have someone much more local that could help out if you wanted to do a head-to-head.

With the forced induction, I have a point of reference for that number based on personal experience between a crush-bent muffler shop job in 2 1/4" piping compared to a 3" Blitz Nur spec turbo exhaust which was only a 6 whp gain on 12psi of boost in an SR20det. If the boost on this 6-cylinder responds that much differently to it's exhaust, I'd be glad to say I am wrong...I'm just going off of my personal experience right now.

Re: the Berk and FI results, it's all apples and oranges anyways due to different dynos and different environmental conditions really, not to mention the whole HFC vs Stock issue. They're both performing pretty well though.

So...what is lower, the FI exhaust, or the chin spoiler?

Or, preferrably, how high off the ground is the lowest part of the exhaust, and where are the low-points located?

The only concern I have about the FI's clearance is that the front of the can-style mufflers could catch on an obstacle like a speed bump or even a really crappy road.

I had side pipes on one of my Mustangs and ripped the right side pipe off when it caught on a speed bump... :(

I would be inclined to weld some sort of cover down there to prevent this from happening (if it's really going to be an issue.)

Lowest point might be the end of the round cans.