Stock exh manifold question

[bnam]

I'm consiering buying a stock exh manifold from a reliable faq seller. It's for my 74 Tii -- though I'm not looking specifically for a Tii exhaust.

The one that has been offered to me looks good but I'd like help in id'ing what this port is for and whether it will be easy and reliable (no leaks) to plug - and how to plug?

Thx,

byas

[c.d.iesel]

you DO NOT want to install a NON-tii manifold on that motor!

that pipe fitting is for EGR exhaust gas regurgatation

emission control - easy to remove the female fitting

and install a short bolt to plug

[bnam]

So, let me ask a question that's been on my mind ever since I started reading about Tii vs. non-tii exhausts. The port size and shape on both manifolds appear to be the same. The size and shape of outlet where it connects to the downpipe appears to be the same. And length of each runner is the same.

So, what makes a Tii exhaust "better" - when the parameters for tuning a manifold are all the same?

Perhaps later smog-era manifolds had protrusions that impeded flow. But, the early non-tii exhausts did not have that right?

Would like to understand this more/better...

Byas

[c.d.iesel]

..... wait to hear from the class . . . ..

[FunkyLaneO]

Easiest way to plug the EGR hole is to get a brass cap from Home Depot, the adapter that is fitted in there right now is a standard pipe thread, the threads on the manifold are not so finding a plug will be alot harder than finding a cap.

But you should really replace your manifold with the correct one, that one will not flow as well as the Tii one because of the EGR plumbing built into it. It bolts up the same and looks the same externally but the big difference is internally where it counts. Yes, that will bolt up to your Tii and will work but your car will not run as well as it will with the correct manifold.

[bnam]

So, internally the non-tii ones have protrusions on other restrictions to flow? Are these non-removable?

Are the older ones which presumably do not have EGR just as good as Tii?

Byas

[FunkyLaneO]

The EGR ones have ports that lead to the that opening at the back, you could grind them out and weld the holes shut I guess but that would be alot of work and all that localized heating and grinding I would worry about warpage and cracking during the process. Look inside one of them and you will see what I am talking about.

[eurotrash]

http://www.bmw2002faq.com/component/option,com_forum/Itemid,0/page,viewtopic/t,368004/view,previous/sid,11bd71d651f31c1c7cd69d6ea5a060e3/

[jgerock]

The factory wouldn't have used a different manifold on the tii engines if they felt like the standard one would suffice. Too many $$$ to develop, produce and keep different parts in their system.

The one I removed from my crusty 72tii engine looks similar -but not exactly the same as the one in my 73. There are subtle differences - maybe the one on my 73 was a replacement...

72 manifold

Casting number on bottom

Coated one on my 73

[eurotrash]

What were the emissions standards in germany then? I wonder if the Tii simply got a euro manifold..sans the DOT emissions garbaage?

I was told by the pump rebuilder guy in chicago, when researching a pump from a Tii I was breaking, that Tii manifolds aren't very special and only due to the natural detuning of the Tii motor, over time, the exhaust temps increased causing a brittling, and accelerated metal loss in the runners. Which then led to premature manifold cracking. And he went on to explain that this is what led to the redesign in the later manifolds with the bulbous runners. He stated that the redesign simply added metal to the casting, creating the changed exterior appearance.

For what its worth..

[dp]

The manifold you are looking at flows the same as a Tii manifold, that has always been known as the poor-man's Tii manifold, at least, by those in the know (meaning usually only people who were into '02's in the 1900's :-D )

The runners (such as they are) and ports in the Tii manifold are exactly the same on these "early EGR" manifolds. The only difference between the two is appearance, performance-wise they are identical. Get a brass cap with matching thread form and cap that porthole off and then drive it like you stole it, and you can invest the 1-200 bucks you saved on one of Esty's carpet kits.

IMO the ONLY justifications for a gen-you-whine Tii manifold are:

a) its the only one you can find,

or

it is needed on a Tii to be "correct" (whatever the terms "needed" or "correct" mean to you and your plans for the Tii you are working on)

SO, now you've read about a long-kept "secret" that most kids now-a-days will chose not to believe, which is totally cool (more cheap good manifolds for us old farts when we need them!)

-30-

[TobyB]

uhhh, pretty much what dp said....

t

[bnam]

Piked up the manifold from Bryce and a downpipe in great condition from Tito. Got both blasted and painted with VHT. Got to buy the gaskets and the clamps and to install a bung for O2 sensor on downpipe before mounting these.

Blasted...

Painted

Byas