ToothDoc

I am not trying to say one header is better than another... I had PPE headers put on in the fall of 2012. Ran it for a year and a half and suddenly I get CEL. Bear in mind that I had the original AF sensors for 5 years and no problems and when I had the new PPE headers put on, I put on NEW AF sensors. 5K miles later, I get CEL.

I've included a picture of a 5 year old AF sensor and a 1 1/2 year old AF sensor with PPE headers.

awkkwrd

I think it's because you don't have cats. Btw, glad you got your cel fixed lol.

ToothDoc

Now, if you look at it, the PPE header AF sensor has a LOT of carbon deposit on it. I believe it is running too rich. I don't have any means of proving it but look at the carbon deposits.

Now heres an interesting story:

Caymandive and I have identical cars in terms of Borla catback and the difference being Sikky vs. PPE. However, my car has 65 pounds of less ROTATIONAL mass than his. Prior to mods, we were pretty much IDENTICAL in trap and ET. However, despite my advantage in lower weight, he is STILL quicker than me. How is that possible? I believe Sikky headers run more lean and PPE run too rich. Caymandive and I have run at least a HUNDRED runs down the strip to optimize and find the BEST 1/4 for the IS-F community.

I understand that there are other variables, but I'm pretty comfortable in saying that PPE runs more rich than Sikky which results in less HP but there is more safety in it.

Having said that, I would like PPE to consider sending me a new O2 sim that would allow me to run a little more LEANER!!! I want and SHOULD be able to pull a 11.8 or even an 11.7@120+ with a leaner simulator based on my mods!

Let's have a discussion on this.

ToothDoc

OH, the pics were reversed. The first picture is the 5K miles with PPE (note the carbon) and the second pic is the 45K miles stock headers (note the lack of carbon deposits)

ToothDoc

I haven't taken apart the "O2 simulator" yet, but if it is simply a resistor, I might consider bypassing or halving the resistance to see what happens. I won't take the F drag racing until later this fall so I won't have any definitive numbers to prove/disprove my hypothesis. If the PPE guys are reading this, I'll gladly take "one for the team" and swap out the O2 sim and run it again later in the fall to see what happens.

Once again, I'm not disparaging PPE. I'm simply saying that they MIGHT be running richer than Sikky in order to be more safe and prevent blown motors.

Having said that, I think they could run leaner based on the carbon deposits on the AF sensors.

MRxSLAYx

Hey Doc, do you have any local friends that have sikky headers. Before passing judgement on whether or not the PPEs run richer than the Sikkys I would try switching the o2 simulators. I know that the seconday o2s only look for emotions, but there may just be a change considering how ridiculously complex the electronics on these cars are. I currently have no cats on my car and the PPE o2 conditioner didn't work for me. It was only until I realized that the PPE o2 conditioner was connected to the secondary o2 sensors that the conditioner may have been the problem.

fstpassat

O2 conditioners have nothing to do with your mixture as they are only functioning on the rear O2's. These exhaust sensors are only there to monitor catalytic converter function, nothing more. What is more likely the cause of a potential rich condition is a failing primary wideband O2, where the car will then run rich to due to false readings. Every wideband O2 sensor I have tuned with has always failed lean. That means that your car will be getting falsely lean a/f feedback and the car will run richer to bring this value back in line. Eventually the sensor fails completely, your check engine light appears, and your car goes into a limp mode state(which is also likely rich to protect the engine). PPE's sensors are located right where they should be in the merge collector for appropriate monitoring of the mixture.

ToothDoc

The problem is that we need to compare apples to apples. The only "baseline" I have is Caymandive vs. me. Before any mods were done, we were pretty much neck to neck based on DA. Both he and I have done at least a hundred runs for years on our IS350s and our IS-Fs. However, the most recent version of our F, he beats me by a full 1/10th despite the fact my car has 65 pounds of LESS ROTATIONAL mass given similar DA and the same tires.

We both suspected that Sikky gave more HP but had no proof and I still have no proof. But at least I know that PPE definitely runs rich based on all the carbon vs. stock on the sensors. If anybody with Sikky headers could simply take off the AF sensors an take a picture, I'd be greatly interested.

In addition, the fact that the car runs richer is noticeable in the fact that I've lost MPG despite the same driving style. I think PPE went the safe route with their O2 conditioner. Until PPE chimes in about the actual stats/resistance/etc, I have no proof.

ToothDoc

Admittedly, I'm no car expert. Doesn't the O2 conditioner alter the value of the rear O2 sensors? Based on those values, doesn't the car adjust A/F ratios?

There are a couple of guys here with PPE headers with failed A/F sensors after a year and not so much the case with Sikky headers.

Once again, I'm not trying to disparage PPE. I actually like my headers (except the raw fuel smell), but I am curious as to why guys with Sikky headers seem to perform a little better than PPE headers.

FWIW, another local Chicago guy with Sikky and Borla and the same tires managed a 12.0 and I barely got an 11.95 despite the fact my car has 65 pounds less rotational mass and the fact my car weighs an additional 40 pounds less. Based on the 105 pounds alone (let alone rotational mass), I should be beating him by about .15 to .2 seconds. Keep in mind that I also am considering DA and my runs were in even better DA.

The thing is we have no apples to apples comparison of Sikky vs PPE. Now that my car is no longer showing CEL, I'll take the AF plugs out in a few months and take a picture. If it's still loaded in carbon, I can only surmise it's running rich to prevent engine failure.

PPEHeaders

iTrader: (4)

fstpassat is correct. The O2 conditioner doesn't effect the A/F ratio or the way the car runs. It is wired into the secondary O2 sensors that monitor the catalytic converters.

It is the O2 sensors in the collector that read the A/F ration and relay it to the computer to make adjustments.

Headers tend to make cars run richer in general. It is possible that your car runs a little richer than others.

The only way you are going to change the A/F ration at WOT is to use an aftermarket A/F controller that alters the MAF signal to lean out the A/F mixture. This only works at WOT, during closed loop the computer will tune out a rich or lean condition on its own.

(In general these O2 sensors are very delicate, they can be damaged easily by dropping them or using air tools on them)

zojirushi

Just curious, will different brands of a/f sensors at the collector make a difference? When I had my PPE headers installed, the shop that used ordered Walker brand sensors instead of the factory Denso sensors.

I currently don't have issues with CEL but I have noticed my fuel economy decrease slightly since installing the headers. Is this affected by the car running richer or the non-factory sensors or both?

yjk1975

It's probably your foot.

PPEHeaders

iTrader: (4)

We always recommend Denso sensors for Toyota and Lexus cars. We have seen a lot of people with Toyota vehicles get CELs from aftermarket brand sensors even brand new ones. Always best to get the original equipment sensor for the car.

DCoolBeans

This is a screenshot i took with the ELM. How come it says Catalyst Incomplete and the rest Incomplete?
I have the PPE headers and the 02 conditioner instaled

My car is def running richer, my rear bumper is discolored with soot ;(

ToothDoc

PPE: Thanks for chiming in an explaining what's really going on. For not too technical car guys like me, it seemed to make perfect sense at the time.

Having said that, I do have to agree with zojirushi that the fuel economy seemed to drop a little and it's not my right foot either (the novelty has worn off. Now I just drive around normally again). I do believe the car runs a little richer than stock.

Another thing, after replacing the AF sensor, the codes reset by themselves. BUT, the very next day, the codes are back again!!! Same bank 2 sensor 1!!! Now what to do.... any suggestions?