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I love that downpipe transition. Looks great. Why dont you use or believe in using coatings?
I don't feel like paying for it. Unless I just had a bunch of extra cash, or the car was a race car, or I was having over heating issues then I would consider the coating. Not saying it works or doesn't work just don't feel like it is necessary for what I am trying to do.
Great news....my buddy cut the spacer flange this morning and will ship it out today. I also ordered another new OEM exhaust manifold gasket along with two of the stock radiator hose clamps. I should have this back together and running Thursday so definitely excited. I just hope I didn't screw up the CAD drawing.
I think I finished the last of the welding for this project by adding an O2 bung closer to the turbo. I have been running it just behind the pan, but I wanted it closer because I think it will be in a more optimal heat condition. You can see the old location circled in red. I am also going to order a programmable wideband controller so I can integrate lean cruise (15.2:1 - 15.5:1) with the stock ECU instead of the bogus 14.7:1, but I will save that discussion for a later time and after I do a few other projects on the GTR. Spacer and other parts should be here Wednesday so I should have it put together by Thursday assuming all goes well.
Last edited by 240Z TwinTurbo; May 13, 2019 at 06:12 PM.
Err. In the manual it states to place the wideband at least 4 feet from a turbine (or something like that). The hotter they get, the richer they read.
I think optimal temperature is around 600*F. The dyno wideband goes into the tailpipe and is the most reliable.
The EGT after a turbo can be 1200-1600*F so definitely need to get it away from that.
Personally experienced a magical 11.8:1 a/f reading on an overheated wideband (too close) which when I finally looked up at the dyno's record, was really 16:1.
Won't make that mistake again.
At least this is an easy thing to remedy. Simply place narrowband in the closer position, narrowbands don't do anything during wot as you know.
Err. In the manual it states to place the wideband at least 4 feet from a turbine (or something like that). The hotter they get, the richer they read.
I think optimal temperature is around 600*F. The dyno wideband goes into the tailpipe and is the most reliable.
The EGT after a turbo can be 1200-1600*F so definitely need to get it away from that.
Personally experienced a magical 11.8:1 a/f reading on an overheated wideband (too close) which when I finally looked up at the dyno's record, was really 16:1.
Won't make that mistake again.
At least this is an easy thing to remedy. Simply place narrowband in the closer position, narrowbands don't do anything during wot as you know.
There is no way you made a pull with boost at a 16:1 AFR. It wouldn't have even made it boost threshold before it would just start sputtering and not doing anything.
Err. In the manual it states to place the wideband at least 4 feet from a turbine (or something like that). The hotter they get, the richer they read.
no, they read quite good being right next to the turbo.. In fact all the aftermarket widebands usually use bosch wideband sensors that you can find as OEM part on various cars being placed right after the turbo....
You seeing 16:1 on the dyno wideband means that you have outside air mixing with the exhaust which means lousy wideband probe or exhaust leak..
I used to measure EGT on my old setup so I have a pretty good feel for the temp data. I measure at the port, right before the turbo and right after the turbo.
Last edited by 240Z TwinTurbo; May 14, 2019 at 06:24 PM.
Err. In the manual it states to place the wideband at least 4 feet from a turbine (or something like that). The hotter they get, the so richer they read.
I think optimal temperature is around 600*F. The dyno wideband goes into the tailpipe and is the most reliable.
The EGT after a turbo can be 1200-1600*F so definitely need to get it away from that.
Personally experienced a magical 11.8:1 a/f reading on an overheated wideband (too close) which when I finally looked up at the dyno's record, was really 16:1.
Won't make that mistake again.
At least this is an easy thing to remedy. Simply place narrowband in the closer position, narrowbands don't do anything during wot as you know.
Not sure what manual you are referencing. The sensor accuracy depends on it being within a nominal range so if you put it in a location that is 600F the sensor reading will not be accurate. Somewhere you can find the sensor accuracy as a function of temperature, but I didn't find it based on a quick look. However, you can download the Bosch Technical specs and Bosch recommends the LSU 4.2 run at an operating temperature of 930C so one foot off the turbo it will not be that hot. https://www.academia.edu/2583517/Bos...11435_3_pages_
Funny, here is the note from Bosch from the PDF linked above...Install at a point where the gas is as hot as possible...Observe the maximum permissible temperature
I have measured temps on the EVO 2" off the port, right before the turbo and right after the turbo so not worried about exceeding the 1030C max short duration temp or 930C operating temp 1ft off the turbo.
no, they read quite good being right next to the turbo.. In fact all the aftermarket widebands usually use bosch wideband sensors that you can find as OEM part on various cars being placed right after the turbo....
You seeing 16:1 on the dyno wideband means that you have outside air mixing with the exhaust which means lousy wideband probe or exhaust leak..
The GTR is full time closed loop with wideband O2 Sensors from the factory and they are the upstream O2 sensors right off the turbo. This is a pic of the downpipes on my GTR.
Well this is all news to me. The manual I am referencing is typically any manual for wideband sensors I've seen around here, AEM, and Innovative mostly I guess. They definitely say to keep away from high temperatures.
Its good to see that you have technical data for the sensors you are using.
And yes I ran an sr20det 15 to 16:1 it made 400rwhp without a hiccup around 20psi of boost. In car wideband read 11.8:1 data-logger didn't throw any alarms. Toasted the ring lands on the engine 2000*F EGT. It burped up a little oil.
Replaced ring lands its been fine since. but never trusting in car wideband data-log again or placing it that close to the turbo. Unit was AEM
Edit:
I have the videos and dyno runs if anyone is interested...
Last edited by KingTal0n; May 15, 2019 at 08:37 AM.
The GTR is full time closed loop with wideband O2 Sensors from the factory and they are the upstream O2 sensors right off the turbo. This is a pic of the downpipes on my GTR.
Slightly off topic... I made these for a friend and his GTR..
The flange arrived today and fit with no issues. Although it went on just fine I can notice the top outside holes need to be moved out ~0.015" so I have modified the drawing and will post below. The ports on the flange are not sized to the gasket, but to the header flange, which is very similar to the ports on the head.
Slightly off topic... I made these for a friend and his GTR..
That outlet on the turbo is exactly why I purchased the cast stainless belmouth units instead of fabricating my own. It is hard to justify all that work and cost when you can buy a used set for $300 all day long just like mine. Curious why the bellow on the downpipe when they are almost always on the midpipe?
I did make my own custom midpipe because nobody had what I wanted. It runs through the 3.5" 100CEL CAT under normal driving and I can flip a switch and the 4" dump opens at 12psi. Interesting at 700hp@wheels I lost less than 10hp on the top end running through the CAT, which is the same CAT I run on my EVO.
It runs through the 3.5" 100CEL CAT under normal driving and I can flip a switch and the 4" dump opens at 12psi. Interesting at 700hp@wheels I lost less than 10hp on the top end running through the CAT, which is the same CAT I run on my EVO.
May 12, 2019, 04:13 PM
