13B-T Mani to T3 Adapter Drama

[Texas bj-42]

Thanks to this board I just received a NIB 13B-T manifold and an adapter for the Mercedes turbo. No turbo yet but I am watching the junk yards.

The drama... when I put the adapter on the mani the square hole in the adapter covers some of the round hole on the mani. Will I gain any REAL benefits from removing the material on the adapter to match the mani? OR does the opening on the T3 turbo match the square hole on the adapter?

I know... OCD but it gives me something to tinker with while I am waiting on the frame galvanizer.

Justin

[lshobie]

Take a piece of paper and make an outline of the manifold and turbo mounting surfaces, match them up to the adapter plate and trace with a marker or etching pen. The mount the plate to the manifold and use an airtool with a carbide tip to ream out and smooth the passage into the manifold, then place it on the exhaust section (remove that from the rest of the turbo) and die grind it from the other side.

That wil give you the best possible passage between the 2. I am anal with that shit and like smooth flow with as little turbulence as possible. You can also clean up the exhaust mani with the grinder tool - get rid of some of the cast crap.

regards,

Louis

[Dougal]

Can you post up a picture?
Like Louis said, matching up the ports is worthwhile. Do you have a dremel or die-grinder?

[wesintl]

I didn't bother on mine.

[rchalmers3]

Related questions regarding turbo theory:

When mounting a turbo on a NA diesel, what is the rule for managing the VELOCITY of the gasses exiting the manifold? Does it help to straighten, restrict or expand the gasses before entering the turbo? Does distance from the manifold flange matter?

Tex posted a question that made me wonder....

Please don't tell me to go buy the Turbo bible.....

Rick

[Dougal]

Originally Posted by rchalmers3

Related questions regarding turbo theory:

When mounting a turbo on a NA diesel, what is the rule for managing the VELOCITY of the gasses exiting the manifold? Does it help to straighten, restrict or expand the gasses before entering the turbo? Does distance from the manifold flange matter?

Tex posted a question that made me wonder....

Please don't tell me to go buy the Turbo bible.....

Rick

As smooth as possible is the goal, tapering into any size/shape difference going into the mounting flange.

Keeping the distance from the exhaust ports to the turbo as short as possible to keep the pulses as strong as possible into the turbo. Shorter also minimises heat loss (the hotter your exhaust, the more efficient your turbo runs).

[rchalmers3]

Ok I got it:

Short, smooth and tapered.

More theory please and thank you dougal for offering your understanding. You are appreciated.


How does the exhaust pulses from the individual cylinders do a better job of spinning the vane than a smooth flow?

Why does heat positively affect efficiency?

[Dougal]

Originally Posted by rchalmers3

Ok I got it:

Short, smooth and tapered.

More theory please and thank you dougal for offering your understanding. You are appreciated.


How does the exhaust pulses from the individual cylinders do a better job of spinning the vane than a smooth flow?

Why does heat positively affect efficiency?

Okay, you asked for it.

The exhaust pulses when the leave the ports come out in short pulses of high velocity. Since energy is relative to the velocity squared, a pulse of twice the velocity has four times the energy.
If you can keep these pulses travelling all the way to the turbine without losing too much of their velocity then you can spin the turbo up sooner than normal. This is why some engines have split manifolds, keeping exhaust pulses from interfering before they've done their job.
Split pulse manifolds are commonplace on 6 cyl engines, but don't work as well on a 4 as you need to combine 1&3, then 2&4. Basically it gets messy so most manufacturers have simple taken the most compact manifold design instead aiming for minimal dead volume.

Turbos feed off exhaust heat and pressure. The more heat that is available, the less backpressure they exert on the engine. On my Isuzu the backpressure can reach double boost when accelerating from stopped with a cold (130 deg C at idle) exhaust manifold and turbo.
As the exhaust temps rise, the backpressure drops to get the same boost.
My current engine/turbo/fuel combination gives me a crossover point of 650 deg C at the turbo inlet, at this point the boost is equal to the backpressure on the engine.
Above that the boost is actually greater than the backpressure, this is the operating range that turbos really shine in. The net gain is taken almost entirely from wasted exhaust heat.

At cruise with EGT's around 450 deg C at the turbo inlet, backpressure runs at roughly 1.5 times boost. 8-9psi boost for 12-13psi backpressure.

[rchalmers3]

Ok, I got it:

Short, smooth, tapered, pulsing and heated!

Can you please "expand" (pun intended) on the relationship of engine and exhaust gas heat affecting back pressure?

Are you able to use your cross over point as an indicator of overall system efficiency? IE lower cross over temp = increased efficiency? Or is that too simple?

Thanks again for your understanding and I promise not to apologise for my questions!

Rick

[rchalmers3]

dougal,

You seem to indicate your turboed 'zu is instrumented for EGT, Boost AND back pressure?

Is that accurate? If so, is the back pressure transducer for good or just for set-up?


Rick

[Dougal]

Originally Posted by rchalmers3

dougal,

You seem to indicate your turboed 'zu is instrumented for EGT, Boost AND back pressure?

Is that accurate? If so, is the back pressure transducer for good or just for set-up?


Rick

Yes I have a backpressure guage which I plumb in whenever I've changed anything related to the turbo or fuelling. At the moment it's out because I needed the gauge for something else. My boost and EGT gauges live in there full-time.

I tapped into the exhaust manifold near the EGT probe and fitted a copper line. After about a metre of copper line it goes into rubber and into the cab.
An electric gauge would be a better solution and not have the risk of leaking exhaust into the cabin, but they aren't easy to find in the pressure range I wanted.

Regarding backpressure and cross-over point. Yes a more efficient turbo will have less backpressure and a lower cross-over point. But turbo sizing has a large impact too, smaller turbos will be more efficient at lower flows and create less backpressure there. Larger turbos are more efficient at higher flows and create less backpressure at higher rpms.

This is why the ricers shoot for the biggest turbo they can spin up on a small petrol motor. It gives a little more top-end power than a smaller turbo.
Of course unless you're only trying to impress people on the dyno, a smaller turbo that gives more area under the power curve will make a faster and more drivable vehicle.

[mel lowe]

Originally Posted by wesintl

I didn't bother on mine.

2x


You can polish a turd all you want, but you always end up with a polished turd.


I may have taken the time to port match if I were working on an aircraft or race car,


but not my old 3b.

[Diesel42]

Mel,
on your turbo build, how did you end up manging the turbo oil lines(pressure in and drainage)?

[mel lowe]

Originally Posted by Diesel42

Mel,
on your turbo build, how did you end up manging the turbo oil lines(pressure in and drainage)?

I purchased a turbo oil feed/ return kit from the maker of the adapter.

[Diesel42]

Sorry, I should have been clearer with my question. What i'm curous about is how they were plumbed in. Some tap into alt. line for pressure and drain. Some use the sending unit port,etc. I'm curios to how yours was plumbed and if it has been sucdessful. Thanks

[mel lowe]

Kit draws oil from the oil pressure sending unt.

There is a t there.



I have not driven the rig since installing the turbo.

[wesintl]

Originally Posted by Diesel42

Sorry, I should have been clearer with my question. What i'm curous about is how they were plumbed in. Some tap into alt. line for pressure and drain. Some use the sending unit port,etc. I'm curios to how yours was plumbed and if it has been sucdessful. Thanks

use one of the 3 free oil galley plugs. Pull the pan and weld a bung for oil return.

[mel lowe]

Originally Posted by wesintl

use one of the 3 free oil galley plugs. Pull the pan and weld a bung for oil return.

2x


I plan to replumb my turbo oil feed this way....


It is much cleaner approach to feeding oil to the turbo

[Diesel42]

Yah your right. I'm just NOT lookin forward to pulling my leak free oil pan. I've read so many posts regarding the drainage of the turbo. Hoping to convince myself that there's a simpler and perfectly adaquate way to drain(other than the oil pan!). I wonder,just wonder,,,,,, if a guy could drill the hole(oil pan above level), and tig weld a bung, while the pan is still inplace!!! O'kay, blast me, i deserve it!

[Dougal]

Originally Posted by Diesel42

Yah your right. I'm just NOT lookin forward to pulling my leak free oil pan. I've read so many posts regarding the drainage of the turbo. Hoping to convince myself that there's a simpler and perfectly adaquate way to drain(other than the oil pan!). I wonder,just wonder,,,,,, if a guy could drill the hole(oil pan above level), and tig weld a bung, while the pan is still inplace!!! O'kay, blast me, i deserve it!

If the block is thick enough there, you could just drill and tap it just above the oil pan.
Thread in a pipe fitting and bingo.

Then you've just got to flush the filings out of the sump.

[Otterav]

Originally Posted by Diesel42

Yah your right. I'm just NOT lookin forward to pulling my leak free oil pan. I've read so many posts regarding the drainage of the turbo. Hoping to convince myself that there's a simpler and perfectly adaquate way to drain(other than the oil pan!). I wonder,just wonder,,,,,, if a guy could drill the hole(oil pan above level), and tig weld a bung, while the pan is still inplace!!! O'kay, blast me, i deserve it!

hello,
I returned my turbo oil to the tappet cover, the cast opening in the block return to the sump/pan area was about 3-4 square inches, plenty of area for the drain area. Just remove the cover, drill a hole through the outer panel and through the inner baffle and braze into place, I used the old TIG machine and silicon bronze rod. Oxy-Acetylene and brazing rod would work fine also. Or you could go one step further and get a piece of cold rolled .250 steel and weld bungs to the plate where ever you decide and now that leaky sheet metal monster is done.
eric
P.S. drilling the block is iffy, not knowing where the reinforcing areas are could lead to a lot of drilling.

[Diesel42]

That sounds like an excellent idea. My rig has been down at the body shop for a couple of weeks with the engine completely covered so I hadn't gotten a chance to scope the area out. Any chance you could post a pic of that specific area I think i'll go that route.Thanks

[wesintl]

I had a leak free pan. Pulled it welded a bung and put it back with blue permatex rtv because I wanted to go back in not to long later and replace the bottom end bearings and I dying to drive the truck turbo'd. I haven't been back in and I still have a leak free pan. When I was going to do the final job i was going to ue the toyota fipg.

It's not difficult to get a leak free pan with rtv or fipg. I think it's tougher with the cork gasket. My 64 was a pita til i figured out how to do it right.