[Sered]

Originally Posted by cstavaru

I would be really interested in a true twin-turbo upgrade (with larger turbine casings), in order to keep some of the low-end the N54 is known for.

Fundamental misunderstanding of how turbos work here. Let's stop perpetuating it. Having twins on a car won't spool up any faster than a properly sized single.

[farbmw]

Nice!

[benzy89]

Originally Posted by Sered

Having twins on a car won't spool up any faster than a properly sized single.

Key word -- Shiv/HPF are trying to make a drag strip/dyno monster. Turbo lag is going to be a necessary evil if you want a high HP N54. I don't race my car so I like the immediately response of the twins, which is what made this motor so damn good... Like BMW marketed this motor, the N54 runs more like V8 with the immediately turbo response.

[A418t81]

Originally Posted by Sered

Fundamental misunderstanding of how turbos work here. Let's stop perpetuating it. Having twins on a car won't spool up any faster than a properly sized single.

That's actually not true. Twins with the same capacity as a larger single each have lower moments of inertia with regards to the moving bits in the CHRA than the larger single, and actually do spool up slightly faster.

[cstavaru]

Originally Posted by Sered

Fundamental misunderstanding of how turbos work here. Let's stop perpetuating it. Having twins on a car won't spool up any faster than a properly sized single.

The rotational inertia of a single turbo is bigger (20% ?) than the sum of rotational inertia of individual turbos. It's written in many books about turbochargers. If it wasn't BMW wouldn't use 2 turbos instead of one.

[Lulz_M3]

Originally Posted by cstavaru

The rotational inertia of a single turbo is bigger (20% ?) than the sum of rotational inertia of individual turbos. It's written in many books about turbochargers. If it wasn't BMW wouldn't use 2 turbos instead of one.

So why did they switch to twin scroll?

[A418t81]

Originally Posted by Lulz_M3

So why did they switch to twin scroll?

Less complexity and hardware costs. Plus a single turbo that spools up as well/better than the twins will (and is) be significantly smaller, with less overhead, which means less "excessive" power can be generated by the aftermarket on the stock hardware.

[Lulz_M3]

Originally Posted by A418t81

Less complexity and hardware costs. Plus a single turbo that spools up as well/better than the twins will (and is) be significantly smaller, with less overhead, which means less "excessive" power can be generated by the aftermarket on the stock hardware.

No thanks, ill take a properly sized twin scroll turbo over twins any day. Que Full-Race circa Spring 2013.

[stratos_335]

Nice Invetor creation.

Will you convert it to Solidwoks format for CNC machining? Will you use just a single billet piece of aluminum and a 5 axis machining center or several aluminum pieces?

Well done. I don't know if you made a finite element analysis for the flow but it looks nice.

Reserved for a machining video

[The Morkinator]

Man, dudes fighting over turbos on a manifold thread, ha. Manifold will be cast aluminum, the tooling that makes the mold will be cut from wood or plastic. As for flow test, I don't have the Autodesk suit that does that, so the when the rapid prototype is done I will have to test that, the phenolic spacer and rp will be cut at a customer's shop My CNC will not be shipped until late summer, we are having one custom built with a 13kw head and 16"z 60"x 96"y. Right now all I have is a knee mill, and it only cuts x and y, plus I still make so patterns the old school way by hand. I made one for the 4g63 if any one wants to see it?

I can post a .iges file to my CAM program, so Autodesk works just fine.

[benzy89]

Just keep us updated as the fabrication goes along, I love pictures

[nafoo]

Emailed

[luster]

I remember a member tapped each port with a methanol bung in the past. Was there any merit to that design?

[dlbrooks18]

Very cool, and very interested!

[The Morkinator]

Originally Posted by Lulz_M3

If you could fit velocity stacks inside the plenum i would be interested. To really prove that this manifold is of benefit, you need to come up with a working prototype and show indivual cylinder A/F ratio. One of the biggest concerns is equalization of airflow across all cylinders. Blindly creating a manifold that will only flow more air is half the battle.

Having velocity stacks would be hard to do bc of the restrictions of cy 1. The oil filter body goes through it, so we have a dimple in the runner, so you will not see equal airflow bc of the inherent design of the n54 on any manifold, including the stock Mahel. I would have to model the plenum beyond the stock restrictions in order to make velocity stack into the plenum, which I am hesitant to do.

I did not blindly create a manifold...there is solid theory in that model.

[The Morkinator]

Originally Posted by luster

I remember a member tapped each port with a methanol bung in the past. Was there any merit to that design?

No, a lot of work, and adds a lot to the price of machining. You can do it yourself by drilling a tapping each hole.

[Sered]

Originally Posted by benzy89

Key word -- Shiv/HPF are trying to make a drag strip/dyno monster. Turbo lag is going to be a necessary evil if you want a high HP N54. I don't race my car so I like the immediately response of the twins, which is what made this motor so damn good... Like BMW marketed this motor, the N54 runs more like V8 with the immediately turbo response.

You didn't even read what I said.

Originally Posted by A418t81

That's actually not true. Twins with the same capacity as a larger single each have lower moments of inertia with regards to the moving bits in the CHRA than the larger single, and actually do spool up slightly faster.

It is actually very true, twins flowing the same amount of air with identical hardware otherwise do not have lower moments of inertia. If that were the case, you could run an infinite amount of turbochargers and get free power.

Originally Posted by cstavaru

The rotational inertia of a single turbo is bigger (20% ?) than the sum of rotational inertia of individual turbos. It's written in many books about turbochargers. If it wasn't BMW wouldn't use 2 turbos instead of one.

Really? What books? Don't bother linking Corky Bell's stuff; a lot of it is based on turbocharger understanding from the 1980s.

BMW uses one turbo now. A twinscroll turbo only has a different exhaust side; the CHRA is still the same.

[jippii ensio]

Originally Posted by Sered

It is actually very true, twins flowing the same amount of air with identical hardware otherwise do not have lower moments of inertia. If that were the case, you could run an infinite amount of turbochargers and get free power.


Really? What books? Don't bother linking Corky Bell's stuff; a lot of it is based on turbocharger understanding from the 1980s.

Actually not free power, but less inertia. There is diminishing returns to it though

Any basic physics book will do

[benzy89]

Originally Posted by Sered

You didn't even read what I said.

Go back to hating on 5 year old threads

Scrub

[phazen23]

Originally Posted by Sered

You didn't even read what I said.

t is actually very true, twins flowing the same amount of air with identical hardware otherwise do not have lower moments of inertia. If that were the case, you could run an infinite amount of turbochargers and get free power.

I don't understand your argument (though I'm not disagreeing). Two turbos that flow the same amount of air will certainly have a similar amount of inertia. Some of us here are talking about twins vs a bigger single turbo, and in this case smaller twins will most certainly spool quicker (and run out of breath before the single obviously).

To those that are talking about N54 vs N55, yes they'll certainly have similar spool times because they're sized similarly! BMW didn't replace twin turbos with a much larger single, they replaced it with a similarly sized turbo and hence limited the potential power gains vs twins.

Your theory is sound, but your practical application to the conversation isn't.

[sdstatestud88]

How about back to the MANIFOLD.

Things to think about...

1. Aluminum heat soak? IATs...
Just spray meth to cool IATs like currently? apply a ceramic type coating?
2. Can the TB be moved further back from the runners, allowing better dispersal to each runner?
3.....

[The Morkinator]

Originally Posted by sdstatestud88

How about back to the MANIFOLD.

Things to think about...

1. Aluminum heat soak? IATs...
Just spray meth to cool IATs like currently? apply a ceramic type coating?
2. Can the TB be moved further back from the runners, allowing better dispersal to each runner?
3.....

It could be moved back maybe .5". There is not much room to spare, it needs to work with existing parts, but my next model will have a much larger plenum, I am adding 1.5" on top and 1" on bottom, so that will help with your tb placement issue just with more air avaiable.

I need to research coatings, I don't know about that one man.