How to: Turbo Manifold design, need your thoughts

[RAd28]

well i spoke to the guys where i got the exhausts done, and they said the cost in doing a twin dump setup would be bloody high (close to $1K), 'cause they need to remove the turbos, and the angles would be so sharp benefit would be minimal... and i'm inclined to believe them, they were recommended by everyone i asked at the time...

[Forcefed6]

Although it may seem like a good idea... It is not really worth the effort of making new manifolds, if you are still going to retain the standard manifolds. Please don't take offense to this either.

You have to keep this on mind. When your making a manifolds, especially for twin turbos, you really have to think ahead. I mean, when you make manifolds, you also gotta make new dumps for the turbos, redo intercooler piping, air inlets, modify/redo oil and water lines. All that and try and fit it all in a ra28 engine bay.

I am speaking for experience herr, although I did not retain the standard ct12's. Instead I went with the t25g.

I you want to know more about my manifolds, have a look at the link in my signature, I'm sure there is a picture or two of them in there.

Hope this helps.

[RAd28]

checking it out now...

that also raises another concern i had with the oil and water, water will be a piece of cake, trim the stock pipe down to a manageable lenght, and just run rubber hose to suit. will try and use a resivoir tank to prevent air locks. the water feed points are movable, 2 positions on the turbo
oil lines might be an issue, the feed is from the top from memory, and drain from the bottom, will check that out on the weekend when i've got a turbo to look at.
dump and intercooler piping will all need to change obviously, i just had the idea tonight for the manifold set up differently, so still need to investigate the other issues...

[RAd28]

forcefed6 - why did you decide to stick to the twins? and not cave into the big single trend?

any tips you can offer for manifold design? i was planning on keeping one single manifold, instead of 2 smaller ones, perhaps brace the 2 together at the turbo flange, which could be braced to the block... just a thought for the moment

[Forcefed6]

I chose the twin turbo option to be a little different i quess. But now I sorta regret doing it, althought it works great...

My manifold was made in one piece, but when a manifold gets welded up, it tends to buckle the head plate a little. By cutting it into 2 manifolds allowed for the least amount of material to be removed to make them flat for a perfect seal.

The thing with the ct12's is, there just to small... The cast manfold isn't really a restriction and therefore you wouldn't really have a gain for the time/money spent to do it. This is unless you pick some bigger turbos to use.

Hope this helps again

[kingmick]

This will give you an idea how to make the pipes and the collector!
sorry for the drawing but i quickly did it in paint and im hopeless at it!

This pick has been played with co the collecter looks shrunk but you get the idea of piping and how the bends are smooth and equal length and have length to them
===


My drawing of an esy to make collecter.

[RAd28]

well yeah, i never had any issues working the collector setup out, but imagine taking that top photo of the turbo, and straightening the bend in the manifold, so the flange is now rotated 90deg clockwise... that's what i wanna do.

forcefed6 - what regrets do you have with the twins?

well lets say i upgrade the turbos, i would really like to keep the twins, from what i've read it will help out with a more drivable package, my goal is response basically, no lag, top end obviously good to... if i had the money i'd like to invest in a pair of Garrett GT2554's, small ball bearing turbos, sufficient for 270hp ea... my only doubt is that 2 of them will be too much... i'd love to stick with the twins, but want ball bearing... that's the ultimate goal

[Forcefed6]

The only regret I really had at the time was the complexity of it, and nevver thought I would get it finished. But in the end it did turn out ok.

In the long run, I could nearlly have fitted a large garret roller bearing turbo.

Although, the setup is enoigh to make my car run a low 12 sec pass, and yet be very drivable on the street.

[jonra23]

Ball bearings do not make a turbo much more efficient, maybe a little more forgiving of unkind conditions.
If it is a toss up between correct size for application or ball bearing the choice has to go to correct size for application.

regards
jon

[Forcefed6]

In saying that, they are heaps of specifications of ball bearing turbo chargers available, that it should be able to pick a correct sized turbo as well as having a ball bearing core.

[Toysrme]

This is how you fab a collector...

sched 40 pipes in 1' lengths and placed it in the band saw.


after the the blade goes through turn the pipe 90' to make another cut on all 4 pipes.

Weld your pairs together & weld the inside













Then weld all 4 together, weld the top merge sealed, and weld the inside of them again

[Toysrme]

Then cut the bottom off for the collector























I hope this expIains how you make a really good collector for a turbo, or a header. In general, the longer the better as the best sizes are generally much larger than u can cut on a 14" chop saw, or 4x6" bandsaw.

[kingmick]

its close but to do it the best way it needs a merge chamber.
Best way is to look at an proper Atmo merge collector and do the same but in a smaller size.
the second last picture shows why you need the merge chamber, you need the room for your centre point, it is very very close to using a merge chamber and in reality for most setups it makes little diffrence but if your going to the trouble to do it that well, might as well do a bit more work to get it perfect.

Very nice setup and pics! plus rep

[RAd28]

just got back from the parents place, and i brett was right on the money when he said there's shit all room for/aft. i had planned to angle the turbos out on the inlet (front) side, but there still wouldn't be enough for the rear turbo for decent dump. and then you got the issue of the front turbo exhaust housing heating the inlet for the rear turbo. not a huge drama, but worth considering none-the-less.

i still think it could be done, just not with the simplicity i had hoped, and so i won't be doing it... was considering the single turbo option, as much as i'd like to keep the twins, i'm almost totally convinced now single would be better... space, cost, simplicity, and with a correct sized ball bearing as forcefed6 said, i can't see there being any real disadvantages...

[Forcefed6]

Speaking about corectly sized turbos... screaminrolla has an 1GGTE powered ra28. It has a GT30 with the smallest exhaust housing you can get. Compared to the setup I have, both on 20psi, mine makes 230 rwkw, and his makes 245 rwkw.

Looking at the 2 graphs side by side it looks as though his is slightly less lagier, and also comes on stronger. I have attached the 2 graphs below to show.

The garrett rollers (GT30/GT35) will also be available real shortly with internal gates available on all 3 sized exhaust housings, which will make for a cheaper and simpler setup.