Egt Sensor Location On Twin Turbo Rb26?

[Behind Horizon]

Hey guys,

where do you recommend placing the EGT sensor on a twin turbo RB26?

Do you recommend two EGT sensors or is one enough?

If I decide to install one sensor I assume the best location to attach it is in the exhaust manifold runner of the 6th cylinder as it is known for running lean sometimes?

If I choose to use two EGT sensors should I both place in the collectors of the exhaust manifolds just before the Turbo?

Or should I place the rear sensor (Cyl 4-6) in the exhaust manifold runner of the 6th cylinder?

Six EGT sensors are exceeding my budget if someone wants to suggest that

Thanks!

[kitto]

I will be using 7.

One for each cylinder and one in the dump.

For you. Use two. One in each dump pipe.

[GTSBoy]

I took a slightly different approach. I only have one (and it's an RB25, so only one turbo and standard manifold). I think the temperature upstream the turbo is the one to worry about seeing as the gas loses some temperature across the turbine. So I installed mine into the (standard) turbine housing itself, just near the flange. That's a lot easier to organise than putting it into the manifold at the collector. I would have been just as if not more happy to put it in the manifold. I have the thermocouple head just peaking through into the gas stream, so the response time is not super dooper quick, but neither does it unduly upset the gas flow into the scroll.

FWIW, on an RB25 Neo running the standard tune, it idles at ~400°C, I see 600°C driving with moderate load and well up towards 800°C when working it hard. The highest temp seen on my (peak recall) was close to 900°C. That looks and sounds worrying, doesn't it? I'm hoping that even with reduced fuelling in the upper ranges of the map that it will actually cool down due to adding in some real timing (the factory maps are sooooo retarded!).

So, with respect to the OP's question, I would concur with kitto's suggestion that you use 2, one in each dump. But if you prefer to know the temp in the manifolds, then it becomes two, one in each turbine housing, or in the collectors, depending on what's easy, and how expensive the turbine housings are!

cheers

[scotty nm35]

On an RB26 I would stick it into the top of each manifold, it was good enough for Gibson...

[Behind Horizon]

Isn't the whole point to measure the exh. temperature before the turbo?

So why are you advising to mount the sensors behind the turbo in the dump pipe?

Furthermore I don't think that there is a big difference between mounting the sensors in the collectors of the exhaust manifolds or in the turbo exhaust housing.

But I rather prefer not to modify my new exhaust housings.

[XRATED]

Hey guys,

where do you recommend placing the EGT sensor on a twin turbo RB26?

Do you recommend two EGT sensors or is one enough?

If I decide to install one sensor I assume the best location to attach it is in the exhaust manifold runner of the 6th cylinder as it is known for running lean sometimes?

If I choose to use two EGT sensors should I both place in the collectors of the exhaust manifolds just before the Turbo?

Or should I place the rear sensor (Cyl 4-6) in the exhaust manifold runner of the 6th cylinder?

Six EGT sensors are exceeding my budget if someone wants to suggest that

Thanks!

One in each dump pipe, as close to the turbine as possible.

Most K type thermocouples will fitt next to the 02 sensors on the stock twin set up.

Cheers

J.

[scotty nm35]

I read about 100 degrees C less in the dump, as long as you take that into account you should be fine I guess.

[CrimsonLey]

How many EGT sensors does the BNR34 run? And where exactly are they located?

22740 - AA300

I'm doing a MFD install on my GTR and I want to have to enable the EGT read-out.

I want to say that only the Vspec and N1 have a EGT sensor(s) and the associated outlet pipes (with the bung to attach the sensor). I suppose I'll need those particular BNR34 outlets pipe(s) to install the sensor(s). Can someone confirm that?

Edited October 8, 2013 by CrimsonLey

[KiwiRS4T]

Just drill and tap a hole. I think I'll follow GTSBoy's example and put it in the turbo as its too tight to get into the manifold before the turbo and I don't want it after the turbo.

How many EGT sensors does the BNR34 run? And where exactly are they located?

22740 - AA300

I'm doing a MFD install on my GTR and I want to have to enable the EGT read-out.

I want to say that only the Vspec and N1 have a EGT sensor(s) and the associated outlet pipes (with the bung to attach the sensor). I suppose I'll need those particular BNR34 outlets pipe(s) to install the sensor(s). Can someone confirm that?

[GTRNUR]

A standard R34 Gtr run the EGT sensor in the dump pipe before the front pipe flange. They will read around 800 degrees most of the time under full load and idle down to 400 and the go off scale below 400 when you can shutdown. Its not a tuning aid, its a run down aid after giving the car a flogging.

I ran an EGT in the narrow band position and saw 850 -900 degrees under full load, but really the maximum temp is determined by how long you hold full load.

I advise against running them in the manifold or the turbine. Thermal expansion differences between the iron of the turbine and the Inconel of the sensor mean you always end up with an exhaust leak. That is unless you run no heat shields on twin manifolds, run a single manifold, or you really enjoy pulling your car apart to fix exhaust leaks.

Sensors in all the runners 1" from the port is the only way to get effective data to use as a tuning aid, but the same issue with leaks caused by thermal expansion still applies.

[CrimsonLey]

^^
Thanks for the reply. I sent you a PM on GTR UK as well, btw. Same question so no worries if you choose to ignore it.

The BNR34 has two dump pipes (aka outlet pipes), which pipe contains the EGT sensor?

Also, both dump pipes have an O2 sensor attached of them, right? Moreover, they are both relatively small so how can that long EGT sensor fit in there?

I'm doing a MFD into my BNR32 so, at this point, I'm only interested in configuring my EGT like the BNR34 UK, N1, VSPEC EGT setup. I'll probably buy BNR34 N1 dumps since they should have the O2 sensor bungs and EGT bung. Does that sound reasonable so am I totally off?

Apologies for all the questions.

[GTRNUR]

Im not on the UK forum much lately... too busy with work generally.

I believe it is the rear dump that has the EGT sensor in the BNR34's, its there for ease of placement and access. Not for any other reason. Its quite cramped in that area of the car as you know.

Yes you could buy some standard dumps from a vspec, The R32's are a cast dump so you can't easily weld a bung for the 16x1.5mm sensor probe to it. Best to switch to an after market dump and if necessary tig weld on the sensor bung in the appropriate position.

Yes both dumps have a narrow band EGT port. I used an adaptor from the 18x1.5mm to the 16x1.5mm that is the standard GTR EGT probe thread. I just welded a few tangs on around the inside of the adapter so that the sensor probe wouldn't fall inside the exhaust, and bolted it in with a copper washer seal.

[CrimsonLey]

Yeah, not a lot is happening on GTR UK. Like walking into a bar and only seeing a bunch of dudes. I saw your reply to a familiar post so I figured you were the right individual to ask. Ironically, I also noticed that you put Oz as your location so I was hoping to touch bases with you here.

When you said, "I used an adaptor from the 18x1.5mm to the 16x1.5mm that is the standard GTR EGT probe thread," you mean that my standard BNR32 O2 probes will not screw into the bung on the BNR34 Vspec dumps that I want to buy?

[GTRNUR]

Yes correct.

Although its a 18x1.5 down to 12x1.5 adapter. Not 16x1.5 like I said before.

http://www.ebay.com.au/itm/BASSANI-ADAPTERS-REDUCE-02-O2-SENSOR-PORTS-BUNGS-18MM-TO-12MM-HARLEY-MODLES-/141083999349?pt=Motorcycles_Parts_Accessories&hash=item20d942fc75

Many narrow band are also 12x1.5. Some are 18x1.5 but all widebands are defiantly 18x1.5.

[CrimsonLey]

FINALLY.

I found some BNR34 Vspec outlet pipes from YAJ:

Gentlemen, thank you for your insight. I love how passionate ya'll are about Skylines.

Ian, thanks for the info. I'll have to buy the adapters you mentioned as well.

Cheers.