Stillen HFC vs. BERK HFC

RCZ · 04-15-2009, 12:48 PM

Quote:

Originally Posted by wstar

or reflashing the ECU to ignore them.

He shoots he scores.

import111 · 04-15-2009, 02:17 PM

With my 2005 STi, I just zip tied the rear o2 sensor under the car, so it was never screwed into the exhaust. I never had an issue.

wstar · 04-15-2009, 03:07 PM

Quote:

Originally Posted by Jesse

Now ill rock your brains. I can problably find out exactly what the computer wants to see as far as cats and rear o2 sensors. What I mean is..... The computer is looking to see the rear o2 sensor voltage within a certian percentage of the one before it on the same bank. If we could wire a resistor between the rear o2 and the front o2 tricking the computer in seeing it within that range at all times....eliminating the need for cats at all, eliminating the rear o2sensors and eliminating the check engine light. The computer wouldnt have a problem with catalyst light off time cause it would allways be in the perfect voltage range. This may even be easier with the wide band o2's the z uses right from the factory. The voltage does not swing like old school o2sensors. This is just my nerd smog tech mechanic theory. anyone heard of someone trying this? I know I can find the information with my resources........is that a pimp idea or what?!

Odds are good anyone running HFCs or Test Pipes is going to get their ECU replaced / piggybacked / reflashed anyways, once those solutions become available. Fixing it via the ECU will be much simpler.

ChrisSlicks · 04-15-2009, 03:09 PM

In theory if the secondary O2 sensor always sends a lower voltage than the front then the resistor trick could work. However in reality it could get a little more complicated than that as I'm not sure that the voltage response of the O2 sensor is linear.

The dummy sensors are similar, however they always send back a fixed voltage according to what the ideal is supposed to be.

wstar · 04-15-2009, 03:10 PM

Quote:

Originally Posted by ChrisSlicks

In theory if the secondary O2 sensor always sends a lower voltage than the front then the resistor trick could work. However in reality it could get a little more complicated than that as I'm not sure that the voltage response of the O2 sensor is linear.

The dummy sensors are similar, however they always send back a fixed voltage according to what the ideal is supposed to be.

It's more than that even. Even the existing dummy O2's that don't work for us don't send back a fixed voltage, they send back an oscillating signal.

ETA: Making custom O2 simulators

BalanBro · 04-15-2009, 06:48 PM

I'm still wondering one thing, doesn't each bank have 2 cats (4 total for both banks?) The typical OBDII arangement was:

O2/AFR-->1st cat(usually in OEM manifold)--> 2nd O2/AFR-->2nd (downstream) cat

I was under the impression that the HFC replaces only the downstream cat (after the last sensor). So how would the sensor know whats going on further downstream? It should only be monitoring the upstream catalyst efficiency in theory.

Please tell me if I'm wrong here because I'm assuming this based on the late 90's OBDII cars I am familiar with.

wstar · 04-15-2009, 07:02 PM

Quote:

Originally Posted by BalanBro

I'm still wondering one thing, doesn't each bank have 2 cats (4 total for both banks?) The typical OBDII arangement was:

O2/AFR-->1st cat(usually in OEM manifold)--> 2nd O2/AFR-->2nd (downstream) cat

I was under the impression that the HFC replaces only the downstream cat (after the last sensor). So how would the sensor know whats going on further downstream? It should only be monitoring the upstream catalyst efficiency in theory.

Please tell me if I'm wrong here because I'm assuming this based on the late 90's OBDII cars I am familiar with.

I've never heard of 4 cats, but maybe on some weird vehicles...

Our car only has 1 cat per bank. The arrangement on our car is Exhaust Manifold -> Cat -> (rest of exhaust), and there's an O2/AFR sensor in the exhaust manifold, and another O2 sensor right after the cat. The one in the manifold is the expensive wideband one that the ECU uses to regulate AFR. The simpler O2 after the cat is just used to validate that the Cat is functioning properly.

zman1910 · 04-15-2009, 08:51 PM

Quote:

Originally Posted by semtex

There are other reasons one might want to go with HFCs. Test pipes tend to have more rasp (even the resonated ones). And when I ran test pipes on my 350, the rear valance regularly got coated with a layer of black soot. So this time around I decided to go with HFCs. I haven't gotten a CEL with the HFCs, btw. At this point, I don't think a single person with a 370 has gotten a CEL from the Berk HFCs. All this talk about a fix is merely hypothetical at this point, i.e., what to do if and when we get a CEL. (I'm also the guy who said that CELs just come w/ the territory.)

Of course there are always other reasons, no one ever doubted that. However, the majority of people are looking for maximum gain(95+%).

I've had both(pipes and HFC's) on various cars and I've always thrown a CEL....every last time.

If it doesn't happen with the 370Z than that's a great thing, but I think it's way too early to even make it seem like a code will not be thrown.

gmag21 · 04-15-2009, 10:52 PM

Hello everyone,

I'm new to this forum.. ill be getting my 370z in june.

Im thinking about getting the Berk HFC's. where can i buy this 02 simulator thing or whatever? What exactly does it do?? Im kinda a noob so go easy on me :P

(thinkin about gettin the stillen headers, exhaust, and CAI; berk hfc, and hotchki sway bars- lemme know what u guys think of that setup)

Any information of this 02 thing is appreciated lol,

Thanks,

Grant

BerkTech · 04-16-2009, 07:21 PM

The ECU will only look at the secondary O2 sensor during closed loop operation (i.e. lean burn, steady freeway cruise, idle, etc). The ECU will make small adjustments to the fuel trims based on the small adjustments made during closed loop operation. This is on the order of a few percentage points. I don't recall ever seeing anything over +/-5% in the last couple of years.

If you guys have ever called Berk for tech support you've heard us say, "Clear the ECU learned values before running the HFC's. You will run less of a chance of throwing a CEL light". Over time your ECU may have adjusted based on your driving habits. By clearing the fuel trims you give your ECU a chance to start back at zero and readjust to the new cats. The cat is in essence an oxygen storage device. When installing a BERK HFC that flows twice as much as the OEM cat it does not have enough contact time with the catalyst to "scrub" the exhaust gas and let the reaction occur. So the O2 readings will be different. Most of the time the thresholds of CEL or no CEL are large enough that the ECU will readapt and the CEL will stay off. However some of you who were already operating on the outer range will pass that threshold after a few drive cycles and illuminate the CEL light.

During driving situations where the engine sees load it will completely ignore the secondary O2 sensor and go off of it's pre-programs maps. On one of our race cars we actually did not use any O2 sensors at all! We would run completely off the pre-programed maps on the stand alone. We would make small tweaks to the maps for high altitude race tracks and summer/winter weather.

So, the moral of the story..... the secondary O2 sensors technically DO make tiny fuel adjustments in concert with the primary wide band sensor in the header, but only to make the car run as clean and lean as possible during steady cruise. From the stand point of the car enthusiast, they don't do squat!

And to set the record straight in plain black and white:

Berk HFC's are not SMOG legal in CA. Can they pass a sniffer test? Yes, all the time. But Berk Technology does not guarantee emmisions performance.

The vast majority of you will never thorw a CEL. However there is a very small percentage of you who will throw the occasional P0420/P0430 CEL. Down the road there will also be a very small percentage of you who throw those CEL codes with the OEM cats!

Hope that gives you some good info to chew on!

Cheers guys!
Berk Technology

RCZ · 04-16-2009, 08:36 PM

excellent Berk. thanks for that post.

Now can you please get some pipes in stock ?

ssqpolo · 04-16-2009, 08:42 PM

^^ya berk. he's even tryna buy mine off of me!

Josh@STILLEN · 04-17-2009, 01:17 AM

Actually Jesse, Berk is dead on when it comes to the function of the secondary O2 sensors based upon my conversation with my R&D guys today on a different application that rolled into this discussion.

My understanding (and I'm in marketing, but privy to a lot of the tech going on) in regards to these sensors (including their function on previous Z's and the G35/G37s) is their drivability control, the secondary fuel trim function, when you're not under hard throttle situations where pre-loaded maps take function. Idle, cruising, CELs can be affected.

I'm not going to comment on your knowledge, obviously I would have no idea, but in regards to this car, engine, and applications, I wouldn't be so quick to discredit some of the people posting on this forum..

NIZMOZ · 04-17-2009, 07:52 AM

Actually one section of your post you are wrong.

Nissan ECU's do adjust for the type of driving you do. If you drove like a granny for a long time, then wanted to use the power out of your car for a road course or something your car would not feel like it has the power as it once did. I have seen this on many Nissans. Once you drive it aggressive after a while, it learns your driving again and makes the adjustments.

Quote:

Originally Posted by Jesse

Cats are not oxygen storage devices. They convert carbon monoxide ( CO) Hydrocarbons (HC) and oxides of nitrogen (NOx), into more friendly Carbon Dioxide and water. The precious metals used in the manufacture of cats (platinum, rhodium and palladium) will clean themselves if the input gasses are in the correct ratios. that is why it is critical that a vehicles fuel management system and air injection system are working properly (going from slightly rich to slightly lean) and injecting air at the right places at the right time (if air equiped).

Both the 'dual bed' and 'monolith' cats need differing amounts of oxygen to perform the gas conversions. The platinum or palladium metals require high levels of O2 to convert CO (carbon monoxide) and HC (raw fuel 'hydrocarbons') into water (H2O) and carbon dioxide (CO2). The rhodium element however operates well in the absence of oxygen to convert NOx into NO and O2. By comparison, the single bed catalyst only works on CO and HC.

In no way does a computer adjust to accommodate different catalysts (hence cel). The computer is programmed to 'feed' the cat to make it as efficient as possible and watch its degradation over time setting a code once it gets below a certian efficiency.

Also, closed loop is not 'lean burn, steady cruse, or idling.

Closed loop simply means the oxygen sensors are heated enough to control fuel. (some cars coolant temp needs to be up also).

all engines are different and degrade so a 'fuel trim' is incorporated. I believe the limits to set a cel are +/-13percent.....I think....been a while since I reviewed this basic stuff.

Your computer does NOT adjust to your driving habits

it just learns what the MOTOR needs at different conditions. Your computer is not going to re-tune itself to a race setting just because you race it. Now it may feel better over time if your computer is still learning to adjust to something like intake and exhaust. if these items increase air flow, your computer will learn over time to adjust with more fuel....making more power. You guys should drive your vehicle a couple weeks before you dyno your new parts!!!

By the way...your basically saying your cats flow good, but are crap when it comes to doing the job a cat was meant to do....CONVERT!

and your quote "During driving situations where the engine sees load it will completely ignore the secondary O2 sensor and go off of it's pre-programs maps. " ----what are you talking about? when your driving the engine is always under load unless you take your foot off going downhill. Your computer uses pre-loaded maps when under HARD acceleration. Also, your computer wants to see you driving a certian way before it will even run a catalyst monitor. For example, it wont check the cat if you go over 65mph or if your throttle position sensor is all over the place, if there is a problem with another sensor or not under the right load.....ect.

Your race car runs pre-programmed cause you have tuned tuned tuned with a dyno and you know what you want the settings at. In the real world for everyday driving in a car that changes over time...this wont work well. you would have to have a computer that adapts to the changing engine or keep re-tuning it every so many years.

Sorry to rant and rave...I think I got a contact high from my roomate. And he wont shut up about his Vegas trip!

NIZMOZ · 04-17-2009, 07:54 AM

Quote:

Originally Posted by Josh@STILLEN

Actually Jesse, Berk is dead on when it comes to the function of the secondary O2 sensors based upon my conversation with my R&D guys today on a different application that rolled into this discussion.

My understanding (and I'm in marketing, but privy to a lot of the tech going on) in regards to these sensors (including their function on previous Z's and the G35/G37s) is their drivability control, the secondary fuel trim function, when you're not under hard throttle situations where pre-loaded maps take function. Idle, cruising, CELs can be affected.

I'm not going to comment on your knowledge, obviously I would have no idea, but in regards to this car, engine, and applications, I wouldn't be so quick to discredit some of the people posting on this forum..

X2, but still the 2nd O2s on these cars do not make adjustments to the Fuel trims period. Ask Technosquare or UPREV and they will tell you the same.

04-16-2009, 07:21 PM	#115 (permalink)
BerkTech The370Z.com Sponsor Join Date: Jan 2009 Location: Irvine CA Posts: 279 Drives: Lots.... Rep Power: 272	The ECU will only look at the secondary O2 sensor during closed loop operation (i.e. lean burn, steady freeway cruise, idle, etc). The ECU will make small adjustments to the fuel trims based on the small adjustments made during closed loop operation. This is on the order of a few percentage points. I don't recall ever seeing anything over +/-5% in the last couple of years. If you guys have ever called Berk for tech support you've heard us say, "Clear the ECU learned values before running the HFC's. You will run less of a chance of throwing a CEL light". Over time your ECU may have adjusted based on your driving habits. By clearing the fuel trims you give your ECU a chance to start back at zero and readjust to the new cats. The cat is in essence an oxygen storage device. When installing a BERK HFC that flows twice as much as the OEM cat it does not have enough contact time with the catalyst to "scrub" the exhaust gas and let the reaction occur. So the O2 readings will be different. Most of the time the thresholds of CEL or no CEL are large enough that the ECU will readapt and the CEL will stay off. However some of you who were already operating on the outer range will pass that threshold after a few drive cycles and illuminate the CEL light. During driving situations where the engine sees load it will completely ignore the secondary O2 sensor and go off of it's pre-programs maps. On one of our race cars we actually did not use any O2 sensors at all! We would run completely off the pre-programed maps on the stand alone. We would make small tweaks to the maps for high altitude race tracks and summer/winter weather. So, the moral of the story..... the secondary O2 sensors technically DO make tiny fuel adjustments in concert with the primary wide band sensor in the header, but only to make the car run as clean and lean as possible during steady cruise. From the stand point of the car enthusiast, they don't do squat! And to set the record straight in plain black and white: Berk HFC's are not SMOG legal in CA. Can they pass a sniffer test? Yes, all the time. But Berk Technology does not guarantee emmisions performance. The vast majority of you will never thorw a CEL. However there is a very small percentage of you who will throw the occasional P0420/P0430 CEL. Down the road there will also be a very small percentage of you who throw those CEL codes with the OEM cats! Hope that gives you some good info to chew on! Cheers guys! Berk Technology __________________ While the others type fast... Berk Technology goes fast.... See you at the track! OUR NEW PHONE NUMBER: (714) 546-BERK READ THE BERK BLOG HERE

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04-15-2009, 02:17 PM	#107 (permalink)
import111 Track Member Join Date: Feb 2009 Location: Tucson, AZ. Posts: 622 Drives: 09 Nissan 370Z Rep Power: 191	With my 2005 STi, I just zip tied the rear o2 sensor under the car, so it was never screwed into the exhaust. I never had an issue.

04-15-2009, 03:09 PM	#109 (permalink)
ChrisSlicks A True Z Fanatic Join Date: Mar 2009 Location: North East Posts: 6,203 Drives: 09 370Z Sport M6 Rep Power: 653	In theory if the secondary O2 sensor always sends a lower voltage than the front then the resistor trick could work. However in reality it could get a little more complicated than that as I'm not sure that the voltage response of the O2 sensor is linear. The dummy sensors are similar, however they always send back a fixed voltage according to what the ideal is supposed to be.

04-15-2009, 06:48 PM	#111 (permalink)
BalanBro Enthusiast Member Join Date: Apr 2009 Location: NJ Posts: 318 Drives: 40th Anniv. 370Z Rep Power: 1111	I'm still wondering one thing, doesn't each bank have 2 cats (4 total for both banks?) The typical OBDII arangement was: O2/AFR-->1st cat(usually in OEM manifold)--> 2nd O2/AFR-->2nd (downstream) cat I was under the impression that the HFC replaces only the downstream cat (after the last sensor). So how would the sensor know whats going on further downstream? It should only be monitoring the upstream catalyst efficiency in theory. Please tell me if I'm wrong here because I'm assuming this based on the late 90's OBDII cars I am familiar with.

04-15-2009, 10:52 PM	#114 (permalink)
gmag21 Base Member Join Date: Apr 2009 Location: Houston Posts: 34 Drives: 370z Rep Power: 16	Hello everyone, I'm new to this forum.. ill be getting my 370z in june. Im thinking about getting the Berk HFC's. where can i buy this 02 simulator thing or whatever? What exactly does it do?? Im kinda a noob so go easy on me :P (thinkin about gettin the stillen headers, exhaust, and CAI; berk hfc, and hotchki sway bars- lemme know what u guys think of that setup) Any information of this 02 thing is appreciated lol, Thanks, Grant

04-16-2009, 08:36 PM	#116 (permalink)
RCZ A True Z Fanatic Join Date: Nov 2008 Location: Miami Posts: 6,403 Drives: '09 370Z Rep Power: 1118	excellent Berk. thanks for that post. Now can you please get some pipes in stock ?

04-16-2009, 08:42 PM	#117 (permalink)
ssqpolo Track Member Join Date: Jan 2009 Location: Florida Posts: 882 Drives: '12 Black Nismo Rep Power: 267	^^ya berk. he's even tryna buy mine off of me!

04-17-2009, 01:17 AM	#118 (permalink)
Josh@STILLEN The370Z.com Sponsor Join Date: Dec 2008 Location: Costa Mesa, CA Posts: 1,197 Drives: 2004 G35 Coupe 6MT Rep Power: 533	Actually Jesse, Berk is dead on when it comes to the function of the secondary O2 sensors based upon my conversation with my R&D guys today on a different application that rolled into this discussion. My understanding (and I'm in marketing, but privy to a lot of the tech going on) in regards to these sensors (including their function on previous Z's and the G35/G37s) is their drivability control, the secondary fuel trim function, when you're not under hard throttle situations where pre-loaded maps take function. Idle, cruising, CELs can be affected. I'm not going to comment on your knowledge, obviously I would have no idea, but in regards to this car, engine, and applications, I wouldn't be so quick to discredit some of the people posting on this forum..