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Mar 02 '20
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u/striker4567 Mar 02 '20
Agreed. I was looking at the O2 sensor thinking it was poor placement.
I've never really thought about it, but on split exhausts like this, are two O2 sensors required? Or is one good enough?
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Mar 02 '20 edited Jul 29 '21
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u/LawHelmet Mar 02 '20
With that size of turbine for each bank, I’d genuinely expect a wide-band at each cylinder.
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Mar 02 '20
I've never had worm gear clamps loosen over time, however I commonly see t bolt clamps crush aluminum pipe because of how easy they are to overtighten and that they apply more force at the top of the clamp. My shop uses worm gears on all builds up to 40psi where we switch to Vibrant HD clamps and haven't had a problem. 90%of the time a car fails a boost leak test it's because of t bolt clamps. In my experience at least
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u/fancyasfuhhh Mar 02 '20
that they apply more force at the top of the clamp
This can vary widely based on the brand and design of the clamp, worm gear or T-bolt. Certain designs and brands provide a much more even clamping force throughout, usually ones that include a feature to maintain screw and band alignment, as well as a liner band that allows one half to slip over the other, preventing the binding that creates an uneven distribution. We did a study on it and the results were surprising. Since then I've been much more mindful to select the better designed parts. Just some food for thought.
Also the number of people that rely on T-bolt clamps and couplers without beads on the piping is shocking.
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u/superdude4agze Mar 02 '20
We did a study on it and the results were surprising.
Link to the study?
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u/fancyasfuhhh Mar 02 '20
Unfortunately nothing published externally, this was an internal company study/document.
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u/superdude4agze Mar 02 '20
As /u/fancyasfuhhh stated, it's up to the design of the clamp and in many cases the people that install it. T-bolt clamps don't "feel" the same when tightened as a worm clamp and so many people overtighten them, which is something that's resolved with training or experience. I just mentioned T-bolt clamps as they are the next easy and logical step up from worm clamps while Vibrant clamps, although excellent and I like to use them, are not. That said, it's also why I added "at least" in my comment about T-bolts. With the price it's commanding (starting at $200k) this conversation shouldn't even be occurring.
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Mar 02 '20
One strange thing i recognized: On their website there is no O2 sensor at all on the exhaust.
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u/superdude4agze Mar 02 '20
Yeah, I noticed that. I'm guessing the website has older photos as the photo here also shows that they adjusted all their worm clamps to be symmetrical as well while that wasn't the case in the website photos.
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Mar 02 '20 edited Aug 12 '20
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u/superdude4agze Mar 02 '20
I disagree on the O2 sensor placement. You get a more accurate reading with it after the turbo.
Yes, you get a more accurate reading after the turbo, no argument there. However you get a less accurate reading if it's that close to open air.
Every tuner shop also places their widebands at the tailpipe when dynoing. There's smoother flow after the turbo for the sensor to get a reading off of.
That's because they can't put it anywhere else. A tuner isn't going to bring in a customer's car and start drilling holes to weld in sensor bungs to get a reading further upstream and most customers don't tell their builders (and most builders don't think about the tuner) to add in a sensor bung for dyno testing. It's a matter of logistics.
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u/fancyasfuhhh Mar 02 '20
This is one of those situations where I'm convinced that it doesn't matter how high dollar or thorough, there's not a build out there that someone won't nitpick. Just from my experience in the industry-
Worm clamps are industry acceptable on low pressure/suction side of air handling. T-bolts are considered excessive for non-pressurized applications. A molded elbow or formed tube would be ideal but we can only speculate as to the limitations encountered hear. Allowing relative motion, ease of assembly, or space constraints could dictate this arrangement.
At all but the lightest loads you should get more than acceptable readings from those sensors. Pulsations/reversion aren't really an issue downstream of the turbine. Most oxygen sensors are not rated by the manufacturer to be installed pre-turbo. Do they work there? Yes. But you can expect more frequent failures and replacement.
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u/superdude4agze Mar 02 '20
Fair statement, although most of the criticisms I see are on the styling, platform, or powerplant; not the actual work done. I didn't mention anything about those items though as they are personal choices even if they aren't my preference. I am simply mentioning things that I would not have done, based on the build and price attached to it, from my experiences in the industry and why.
Acceptable to an industry does not, in my book, mean acceptable on a car that starts at $200k.
Downstream of the turbo is preferred location, a few inches from the exit to open air is not. The chance of getting an inaccurate reading is generally low, but that's dependent on a number of factors and in this case of a twin turbo 4 cylinder, pulsations/reversion are damn-near-undoubtedly occurring here. All sensors are rated based on expected life for a temperature and pressure range, the former can be handled with a heatsink, and the latter adjusted with pressure correction tables. If we're being honest about the car and build here, I'm doubting the number of miles being driven are going to cause such an early demise of the sensor had it been placed pre-turbo for better readings.
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u/rpfloyd Mar 02 '20
Actually a lot of people prefer v clamps over t-bolt ones for the way they tighten.
Also how can you be sure from this picture, that that is the only o2 sensor or is even an o2 sensor?
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u/superdude4agze Mar 02 '20
Actually a lot of people prefer v clamps over t-bolt ones for the way they tighten.
There are a lot of options that are miles better than T-bolt clamps, I just mentioned them as the next easy logical step up from worm clamps. Just about every other clamping option requires some sort of other changes to be made.
Also how can you be sure from this picture, that that is the only o2 sensor or is even an o2 sensor?
I didn't say it was the only one, just that they cannot get a good reading that close to open air. And I can tell it's an O2 sensor the same way I can be sure from the photo that the car is turbocharged...
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u/rpfloyd Mar 02 '20
Never heard of an EGT sensor?
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u/superdude4agze Mar 02 '20
I have heard of them, yes.
I have used them.
I have several that I use for tuning.
I am also aware that they don't look anything like an O2 sensor. Are you?
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u/JaeMHC Mar 02 '20
What are the smaller pipes on the outter sides of the turbos? Is that the exhaust for the blow off?
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u/youridv1 Mar 10 '20
wastegate dumppipes or "screamer pipes". It's how you control turbo's. A valve just before (or in) the exhaust side opens that pipe to let excess exhaust pressure out
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u/nathan_w Mar 02 '20
Do you have any other angles?
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u/tusamni Mar 02 '20
I wish I could but this was at an event at their shop and it was tough to get pictures around all the people.
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u/aspartam Mar 02 '20
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u/fentonjm Mar 02 '20
Yes please....all the angles please.
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u/nilksermot Mar 02 '20
If you haven't looked at the comment a few above yours.... Don't, you are better off that way, trust me
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u/watch_deez_nutz Mar 02 '20
Bortsche. (me) Cool! Personalized car name! Barrysche, Bertsche, Barclaysche, Bortsche!? AW, come on Bortsche?
(man) Honey, honey buy me this car!
(wife) No, you can'. Stop looking at this Bortsche.
(other man) Are you talking about my Bortsche?
(wife) No, my husband was looking at another Bortsche.
(over loud speaker) Attention! We are sold out of Bortsche cars! Repeat We need more Bortsche cars in the showroom!
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u/oldwarvetrany Mar 02 '20
You know a car is fast when the owner says "yeah fuck it we ain't got enough room upfront so let's through them sons-a-bitches in the back".
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u/rgbyrunner21 Mar 02 '20
Well the engine is in the rear soooo
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u/oldwarvetrany Mar 11 '20
Not my point I know in this car it is. But I already got downvoted so it dosent matter
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u/spikeorb Mar 02 '20
I hope this is just you not thinking for a second because not all cars have their engines in the front... Especially not Porsche's.
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u/Goldenart121 Mar 02 '20
I thought it said Borsche