darbs242

iTrader: (5)

I mean I have some mods and im moding myself... why not have the best of both worlds... Although my tone was not so chipper when these "race cats" blew out.

Have you had any problems with rotors switching back and forth between pads like that? I have 24k on original rotors and just finished up my factory front pads at the track the other day and I have minor cracking in some of the holes on the rotor & light pulsation when braking, its nothing excessive. Im going to pad slap it tomorrow with some Raysbestos I picked up for 80 bucks at a local parts store and test them out. If I dont like them or the pulsation gets much worse Im going to get new factory rotors and a set of bobcats... or maybe another set of what I just bought depending.... They claim OE performance, fit, ultra quiet, longer life and lower brake dust.

lobuxracer

iTrader: (2)

I've not had any issues with pad swaps. I'm running Carbotech street and track though. Not sure how this would work with other compounds.

You should not have any pulsation. I haven't had any at all. If you want to get rid of the pulsation, get a set of track pads and use them on the street for a day. All the old pad material will be scrubbed off pretty quickly, then you put in what you want to run and bed them in. All will be fine.

I ran a set of rotors I got from someone who removed a perfectly good set of fronts because they didn't like the looks (or they believed their service adviser's advice - replace pads and rotors at the same time - which is pretty bad on all fronts). They were slightly thicker than 29mm so they had a nice 0.5mm lip on them, and the lip actually saved the rotors because one of the pads contacted the lip just before all the pad material went away - it was backing plate against lip - and the noise was horrible. It prompted me to check the pads right away.

FWIW, the original rotors had three track weekends with Carbotech XP-12s and measured 29.6mm thick. So Carbotech's track pads are unusually rotor friendly. They're just $300 a set...

Last but not least, I have a brand new set of rotors I had cryo-treated. I have not run them yet, but I believe I'll be doing quite a few more events this year than I originally thought, so I may be running those sooner than later. I'll let everyone know if they actually last longer and/or resist cracking better.

darbs242

iTrader: (5)

ShadowISF

iTrader: (10)

^^^ That looks like a mod. Burnt tips!

ming15237

iTrader: (3)

Just trying to help with this tip, but running the engine "lean" will cause the engine to run hot, running rich actually quenches the heat. And for what it's worth, the factory cats will take the heat with NO PROBLEM. I have NEVER seen a cat melt on an engine that was running properly.

darbs242

iTrader: (5)

^^^ My air fuel has been checked and will be check again next week. But im sure that PPE is right... fuel got into my secondary cats and ignited, causing them to blow out. For now, straight pipes is looking like good answer, if i was running that lean I would have seen a CEL for something by now... our cars light up light christmas trees when something goes wrong...

caymandive

iTrader: (2)

I was referring to the cats running hot not the engine. Seems to be some agreement now that fuel is somehow getting to the cats and super heating them. Wouldn't matter what cat you run they would all fail in this situation.

hwy1isf

iTrader: (1)

Lance, I had an experience similar to darbs on my last track day at Chuckwalla, I was running with 2 C-5 vettes, 2 mustangs, a GT, and a GT500KR, and a 911 came out for a few laps. All novice drivers including myself bottom line is that I ran away from both vettes and the GT, the 911 was on a different part of the track as he did not start with us. The 500 would pull me on the straights and I would close back up in the turns, Chuckwalla has 17 turns in 2.7 miles.

I figured it had to be the trans because they were manuals and most likely spending 1-2 seconds shifting gears, I was hitting the paddles and shifting in .3 seconds. That and I did not have to focus on the shift at all but instead my line around the track, which allowed me go into the turns hotter. I know for a fact it was not my superior driving skills so it had to be something to do with the F, and as you pointed out the vettes for one are lighter with similar HP.

ming15237

iTrader: (3)

I am only trying to help with this statement, so please don't take it like I am trying to be a "know it all", but if the engine runs lean then the exhaust will become super heated, this will also cause the combustion chambers to become hot, they are one in the same in that respect. My assumption is one of two things is happening, either the removal of the o2 sensors and replacing them with simulators is causing a fuel starvation issue i.e. the PCM can not regulate the air fuel ratio for the required demands, possibility 2. is the fuel injectors simply can't flow the level of fuel you are now in need of. Again only trying to help. But running the engine rich will only wash the cats down with fuel and cause them to loose efficiency, we see this often when we do emissions diagnostics on a vehicle with leaking injectors. What I would do is measure exhaust temps at the headers on your car and compare with a car with stock headers and functional o2 sensors. If yours is significantly hotter you may have found your answer. Hope this helps.

ming15237

iTrader: (3)

You would not see a CEL light because you have o2 simulators in the car, the PCM has no clue what is actually happening with your air fuel ratio. (this is all dependent on where the simulators are installed in the exhaust system.) Hope this helps.

darbs242

iTrader: (5)

The car is not running lean. I would have lean cylinder codes if it was. The primary o2 sensors are working perfectly and they are what adjust your fuel, it just simulates the secondary o2 sensors. The most likely cause of this is raw fuel getting into the cat and it igniting. Think of how much gas you smell when you have headers/exhaust without cats in an ISF. The engine temp was normal throughout the day. At WOT on the track you're getting 5-6mpg. It's putting so much gas through that engine. Sikkys simulator is wired to your ECM, its not on the exhaust at all.

JDMJNKY

"Darbs,"

I second the applaud from JOE Z. Great use and proper use of your ride. Sounds like you had a blast out there. The 1st ISF I saw a few months back could not be described as anything short of a beast.

The best thing about this thread is that you've found a "limit" for some things, that will help members on their future purchases. A few collective minds in here has made this a thread word reading, and I don't own a IS-F.

Again, congrats.
Joel

caymandive

iTrader: (2)

Without doubt, the converter was super-heated due to a raw fuel condition in the exhaust flow. The excess fuel ignited when it struck the hot cat and drove the temperature far above the normal operating condition of the converter. The melted cat was probably breaking down more and more as the day went on causing a blockage to occur resulting in those glowing red headers you witnessed. An engine running too lean would rarely be able to melt a converter.

We have to figure out where this excess fuel is coming from. Here is a list of things to start with. I'm sure there are more, but I'm not a mechanic by any means.

1. Faulty oxygen sensor
2. Incorrect fuel mixture
3. Worn spark plugs or plug wires
4. Incorrect ignition timing

darbs242

iTrader: (5)

^^^ My plugs are done, ive bounce off rev limiter one to many times. JE is changing them next week with my install

ming15237

iTrader: (3)

This may help a bit in the diagnosis of this issue. It is directly from the IS F repair manual
DESCRIPTION

HINT:

Sensor 2 refers to the sensor mounted behind the three-way catalytic converter and located far from the engine assembly.

In order to obtain a high purification rate of the carbon monoxide (CO), hydrocarbon and nitrogen oxide (NOx) components in the exhaust gas, a three-way catalytic converter is used. For the most efficient use of the three-way catalytic converter, the air fuel ratio must be precisely controlled so that it is always close to the stoichiometric air fuel level. For the purpose of helping the ECM to deliver accurate air fuel ratio control, a heated oxygen sensor is used.

The heated oxygen sensor is located behind the three-way catalytic converter, and detects the oxygen concentration in the exhaust gas. Since the sensor is integrated with the heater that heats the sensing portion, it is possible to detect the oxygen concentration even when the intake air volume is low (the exhaust gas temperature is low).

When the air fuel ratio becomes lean, the oxygen concentration in the exhaust gas is rich. The heated oxygen sensor informs the ECM that the post-three-way catalytic converter air fuel ratio is lean (low voltage, i.e. less than 0.45 V).

Conversely, when the air fuel ratio is richer than the stoichiometric air fuel level, the oxygen concentration in the exhaust gas becomes lean. The heated oxygen sensor informs the ECM that the post-three-way catalytic converter air fuel ratio is rich (high voltage, i.e. more than 0.45 V). The heated oxygen sensor has the property of changing its output voltage drastically when the air fuel ratio is close to the stoichiometric level.

The ECM uses the supplementary information from the heated oxygen sensor to determine whether the air fuel ratio after the three-way catalytic converter is rich or lean, and adjusts the fuel injection time accordingly. Thus, if the heated oxygen sensor is working improperly due to internal malfunctions, the ECM is unable to compensate for deviations in the primary air fuel ratio control.


DTC No.


DTC Detection Condition


Trouble Area

P0136

P0156


Abnormal voltage output:

During active air fuel ratio control, the following conditions (a) and (b) are met for certain period of time (2 trip detection logic)

(a) Heated oxygen sensor voltage does not decrease to less than 0.21 V

(b) Heated oxygen sensor voltage does not increase to more than 0.59 V

Low impedance:

Sensor impedance less than 5 Ω for more than 30 seconds when ECM presumes sensor to being warmed up and operating normally (2 trip detection logic)



Heated oxygen sensor (bank 1, 2 sensor 2)
Air fuel ratio sensor (bank 1, 2 sensor 1)
Gas leaks from exhaust system
Fuel pressure
Fuel injector assembly
PCV valve and hose
Intake system

P0137

P0157


Low voltage (open):

During active air fuel ratio control, the following conditions (a) and (b) are met for certain period of time (2 trip detection logic)

(a) Heated oxygen sensor voltage output less than 0.21 V

(b) Target air fuel ratio rich

High impedance:

Sensor impedance 15 kΩ or more for more than 90 seconds when ECM presumes sensor to be warmed up and operating normally (2 trip detection logic)



Open or short in heated oxygen sensor (bank1, 2 sensor 2) circuit
Heated oxygen sensor (bank1, 2 sensor 2)
Heated oxygen sensor heater (bank1, 2 sensor 2)
Air fuel ratio sensor (bank1, 2 sensor 1)
Gas leaks from exhaust system

P0138

P0158


High voltage (short):

During active air fuel ratio control, the following conditions (a) and (b) are met for certain period of time (2 trip detection logic)

(a) Heated oxygen sensor voltage output 0.59 V or more

(b) Target air fuel ratio lean

Extremely high voltage (short):

Heated oxygen sensor voltage output exceeds 1.2 V for 10 seconds or more (2 trip detection logic)



Short in heated oxygen sensor (bank1, 2 sensor 2) circuit
Heated oxygen sensor (bank1, 2 sensor 2)
ECM internal circuit malfunction
Air fuel ratio sensor (bank1, 2 sensor 1)

P0139

P0159


Heated oxygen sensor (sensor 2) voltage does not drop to below 0.2 V immediately after fuel cut starts (2 trip detection logic)


Short in heated oxygen sensor (bank1, 2 sensor 2) circuit
Heated oxygen sensor (bank1, 2 sensor 2)
ECM internal circuit malfunction

MONITOR DESCRIPTION

1. Active Air Fuel Ratio Control

The ECM usually performs air fuel ratio feedback control so that the air fuel ratio sensor output indicates a near stoichiometric air fuel level. This vehicle includes active air fuel ratio control in addition to regular air fuel ratio control. The ECM performs active air fuel ratio control to detect any deterioration in the three-way catalytic converter and heated oxygen sensor malfunctions (refer to the diagram below).

Active air fuel ratio control is performed for approximately 15 to 20 seconds while driving with a warm engine. During active air fuel ratio control, the air fuel ratio is forcibly regulated to become lean or rich by the ECM. If the ECM detects a malfunction, a DTC is set.

2. Abnormal Voltage Output of Heated Oxygen Sensor (DTC P0136 and P0156)

While the ECM is performing active air fuel ratio control, the air fuel ratio is forcibly regulated to become rich or lean. If the sensor is not functioning properly, the voltage output variation is small. For example, when the heated oxygen sensor voltage does not decrease to less than 0.21 V and does not increase to more than 0.59 V during active air fuel ratio control, the ECM determines that the sensor voltage output is abnormal and sets DTCs P0136 or P0156.

Please pay particular attention the the first paragraph here, "The heated oxygen sensor is located behind the three-way catalytic converter, and detects the oxygen concentration in the exhaust gas. Since the sensor is integrated with the heater that heats the sensing portion, it is possible to detect the oxygen concentration even when the intake air volume is low (the exhaust gas temperature is low). When the air fuel ratio becomes lean, the oxygen concentration in the exhaust gas is rich. The heated oxygen sensor informs the ECM that the post-three-way catalytic converter air fuel ratio is lean (low voltage, i.e. less than 0.45 V)" Meaning it needs to see that rear sensor for proper AF adjustment.

I am a ASE Master Tech, and if there is any help I can be with this gentleman, please let me know via PM, I will be more than happy to help.