L_perm

I'm putting on a new exhaust and decided to replace the O2 sensors for the fun of it--some corrosion, one ripped wire jacket, etc.

I talked with a Denso tech about their Air/Fuel Ratio sensors to make sure they were drop-in replacements for the OE O2 upstream sensors, and they confirmed--same voltage/lambda mapping. Just plug and play. So, I've decided to go with them.

According to Denso, the Air/Fuel Ratio sensor is just their latest, greatest version of the O2 sensor technology--more sensitive (more crossings), more durable, and works over a larger RPM band.

I figure it should be worth about 50hp! Anyone else gone this route?

LP

phillipj

Please let me know if you do achieve any HP gains from this.. Quite interesting....

L_perm

I'm sure my butt dyno will feel some imaginary hp gains, but I suspect the only potentially measureable gain will be in fuel economy. It won't be big, but I'll see what happens. My EGTs should stay a little lower on average, so my turbos and nice new HJS HF cats will like that.

Thinking about it, my guess would be that the wider band of the newer A/F sensors would help keep things cooler on the track in particular.

I wonder if the faster reponse time and higher frequency of the sensor will make the car more responsive to throttle changes? I doubt it. I think it will just make sure I don't use more gas/generate more heat than I have to.

LP

Kevin

This isn't a power mod. The pre cat O2 sensors are for full Lamda/AFR readings. The bosch 4 wire widebands are VERY very good. The ECU is calibrated for the resistance reading for the sensor. Yes, it supplies a voltage input to the ECU to determine the correct air fuel reading or mixture. 50HP (no way) from either leaning out your engine or faking out the ECU with a incorrect voltage because the resistance is off? To make power on this engine, you do it thru boost, timing or backpressure reductions. You will need to add fuel when you increase the "power" add ons. LEAN burn will make power, but on your $30K engine I would not be playing around with O2 changes. Maybe on your Honda, but not this engine. Stick with the factory Bosch widebands.

http://www.boschautoparts.com/Oxygen...sorDesign.aspx

L_perm

I had my tongue in cheek when I made the HP remark, hence the . This part change is not about power.

The Denso has the same voltage-to-lambda map as the OE part. I confirmed this with a Denso tech. The ECU won't know the difference except the voltage will fuctuate more finely and more frequently--at least that's what I expect.

From everything I've read, I have reason to believe that the Denso is higher resolution than the Bosch, leading to more continuous AFR changes. If this is true, then I should see a little better fuel efficiency and slightly lower average EGTs. If it helps the engine run more efficiently with less heat, then it seems like a good thing to me. Maybe it won't be any better than the Bosch, but I'll see.

You're right though--this is not about HP. Engine/turbo/cat longevity is what I have in mind.

LP

Kevin

Here is the Denso datasheet. I don't see any magic vs the Bosch unit. Infact they talk about the negative impact for incorrect or failing O2's..

http://www.densoaftermarket.com/oxyg...FeZaMgod9ggAAQ

If you have the stock exhaust on your engine, you are splitting hairs. You can go to the Bosch website and read the advantages for changing out new O2's.. I would go and state that any changes your get in MPG, would occur with the Bosch wideband O2's.. Infact, worldwide there are more Bosch wideband O2's used as reference sensors on Dyno's than any other brand.

Again, I would agree with changing your wideband O2's to increase fuel economy, but you would get the similar results with the factory Bosch units.

L_perm

I only see the Denso marketing web page when I use your link. No data sheet(s).

Is the wideband Bosch you mention the exact OE part for a 2007 TT? Or, is it a wider-band version of the OE part made by the OE manufacturer? I ask because Denso has an upstream O2 sensor replacement that has essentially the OE specs, and then they have what they market as their AFR sensor, which is their wideband, most sensitive line. The latter is the one I'm installing.

If the wideband Bosch you mention is an upgrade over the original OE part, then this discussion is only about which brand has the better wideband sensor. I have no opinion on that. My original question is really about the use of the wider-band, newer technology in place of the OE technology.

LP

Kevin

Bosch has Motorsport O2's and injectors including ECU's. Do you have a factory PIWIS so that you can datalog the O2 sensor in real time? Can you communicate with the factory Motronic ECU? Can you change the calibration code.

I ask is your engine stock? Stock factory tune and exhaust? Are you running race gas of pump gas? Here is a thread about my high speed dataogger.

https://rennlist.com/forums/996-turb...ger-debut.html

The factory installed Bosch O2 is Very Good. It supplies the correct data with little lag time. I will also mention that this sensor is different from other application because of it's location>> it is placed 4 inches away from the turbocharger turbine wheel. The heat generated from this requires higher quality with engineering to withstand the high EGT and placement that MOST O2 sensors don't require.