Where to put egt probe?

[Monotalonawd]

Hello fellow 5ers! I am currently in the process of turbocharging my 535i with the turbo from a Cummins diesel Dodge Ram pickup. You can see some pictures here:

http://www.cardomain.com/ride/2152662/1

Don't you laugh at my custom made exhaust manifold... this is a project with a really limited budget! So my question is... after which exhaust port is the best place to mount my egt probe? Or in other words, which cylinder generally runs the hottest and/or leanest on an M30 engine?

[rundatrack]

I really dont understand the manifold....

I dont care how it looks cuz your beginning and braver than me and 98 percent of people that armchair mechanics...

But I dont understand the 2 into 1...what happen to the other 4?

This is in no way trying to be funny...

I just dont understand if it was incomplete or what ya trying to accomplish....

Dont care about the looks at all but I dont understand the logic....

[Monotalonawd]

rundatrack, my homemade y-pipe is only to connect the two stock exhaust manifolds together... since we have two of them on the m30. I just switched the two exhaust manifolds upside down! Hope it answered your question. That was done to cut on cost. I don't have a high horsepower goal, 350 crank hp should be enough!

[bahnstormer]

that is a neat idea!

have u considered temp problems with the turbo and manifolds so close
to the other junk in the engine?



[Edit by bahnstormer on [TIME]1129872394[/TIME]]

[Brad D.]

I tend to think that placement of the probe in the turbine collector(right before the inlet flange) is the best place in a FI car. It gives you the best global view of what is going on inside the engine. I tend not to rely much on the EGT gauge in my turbo car as the wideband is far more useful. Once I finish my current rebuild, I dont think Im going to put the EGT probe back in. Once you have some wideband data, you will be able to find out what sort of EGT your engine runs at while at a safe, target AF. The EGT varies so much with so many different factors I wouldn't solely use it as a tuning tool, but since you have a wideband you are off to a good start. Here is some good reading for you.
http://www.sdsefi.com/techegt.htm


[Edit by Big Bronze Rim on [TIME]1129872318[/TIME]]

[Monotalonawd]

[QUOTE="bahnstormer"]that is a neat idea!

have u considered temp problems?[/QUOTE]

Yes, that's why my y-pipe has those strange bends; to clear a spark plug wire and all the metal lines running on the side of the engine compartment (want to keep my a/c). Once my downpipe is fabricated, I'll make some heat shields from aluminum sheet and run some air dryer hoses to direct fresh air from under the bumper toward the turbo area. If I'm not mistaken, the 745i had an electric fan to blow air on the turbo to keep the underhood temp in check?

[Monotalonawd]

[QUOTE="Big Bronze Rim"]I tend to think that placement of the probe in the turbine collector(right before the inlet flange) is the best place in a FI car. It gives you the best global view of what is going on inside the engine. I tend not to rely much on the EGT gauge in my turbo car as the wideband is far more useful. Once I finish my current rebuild, I dont think Im going to put the EGT probe back in. Once you have some wideband data, you will be able to find out what sort of EGT your engine runs at while at a safe, target AF. The EGT varies so much with so many different factors I wouldn't solely use it as a tuning tool, but since you have a wideband you are off to a good start. Here is some good reading for you.
http://www.sdsefi.com/techegt.htm

[Edit by Big Bronze Rim on [TIME]1129872318[/TIME]][/QUOTE]

You're right, one should not use the egt temp solely as a tuning tool. But it's a good protection to have. I'll be mostly using my wideband for tuning purposes. But since I already have that egt gauge, I want to use it!

I also thought about putting the probe right before the turbo but I think it'll be too far from the exhaust ports in my application. On my turbo dsm, I had the probe in the cylinder no.1 exhaust runner because t has been proved that cylinder was the hottest running one from the four; had to do with how air travelled inside the intake manifold.

[booker]

Couldn't you find a bigger turbo?

I give you props for doing it, but will the M30 have the capacity to utilize that thing?

[Monotalonawd]

[QUOTE="booker"]Couldn't you find a bigger turbo?

I give you props for doing it, but will the M30 have the capacity to utilize that thing?[/QUOTE]

A 2.0l 4 banger (Eclipse, Talon, Laser) can spool an Hx-35 20 psi by 4000 rpm. So I don't think a 3.4l inline 6 will have a problem with that! The turbo may be big in size but it's airflow capacity is more comparable to the one of a Garrett t3/t4 50 trim (smaller I think than what TCD offer in their kit, 60-1?) The big size of the compressor housing is mostly due to the "Map Width Enhancement" groove; it feeds air to the outer edge of the compressor wheel thus, improving its efficiency.

I don't think I'm going to run more than 15 psi on the m30; I originally bought that turbo for my talon but since it's now gone... why not use it!

[Brad D.]

I also thought about putting the probe right before the turbo but I think it'll be too far from the exhaust ports in my application. On my turbo dsm, I had the probe in the cylinder no.1 exhaust runner because t has been proved that cylinder was the hottest running one from the four; had to do with how air travelled inside the intake manifold.

I understand where you are coming from. I know the turbo Nissan guys ask this same question all the time. Since most of the sr20det guys dont really have the manifold distribution problems that the dsm's seem to have, most mount it to read globally. Thats how I have mine mounted.
Its just really hard to say without some testing if one cylinder actually runs hotter/leaner than another on an m30 with stock manifolds, etc(Im sure there are variances, but is it worth singling out one cylinder?). You'd really need to tap every runner and confirm. I don't know if anyone has actually done that. I think that without that info I would still put it at the collector as its still useful.

[Monotalonawd]

[QUOTE="Big Bronze Rim"]I understand where you are coming from. I know the turbo Nissan guys ask this same question all the time. Since most of the sr20det guys dont really have the manifold distribution problems that the dsm's seem to have, most mount it to read globally. Thats how I have mine mounted.
Its just really hard to say without some testing if one cylinder actually runs hotter/leaner than another on an m30 with stock manifolds, etc(Im sure there are variances, but is it worth singling out one cylinder?). You'd really need to tap every runner and confirm. I don't know if anyone has actually done that. I think that without that info I would still put it at the collector as its still useful. [/QUOTE]

So in the collector my egt probe is going to be!

Maybe I'll try to mount it at the exit of one of the exhaust manifolds and switch them around to determine which half of the engine runs the hottest. That would be easy to do.

Now, only need to fabricate the oil lines and that baby is gonna be ready to fire up!

[bmwfan2304]

I was just wondering where you're gonna put the pipes from the turbo to the intake manifold... the opening seems to be a pretty tight fit here... just curious.

Nice work on the headers though! i mean they're not pretty but look pretty functional... i hope they work out great for ya!

[Monotalonawd]

[QUOTE="bmwfan2304"]I was just wondering where you're gonna put the pipes from the turbo to the intake manifold... the opening seems to be a pretty tight fit here... just curious.

Nice work on the headers though! i mean they're not pretty but look pretty functional... i hope they work out great for ya![/QUOTE]

I have a front mount intercooler laying around from my dsm but at first, I'll run the pipe directly from the compressor housing to the throttle body (not intercooled). Just like you noticed, the outlet goes directly toward the air box bracket. But you can clock the compressor housing in a better position without much problem with this turbo; doesn't have locating pins. Once I figure out the pipe routing and bends I need, I'll modify the outlet position to have it exit at "10 O'clock". As for the air box bracket, I'll remove it completely since it interferes with the wastegate actuator arm.