Anonymous

MikeR will love this one i suspect


Ok, here we have 3 manifolds for cosworths, I believe i have posted them in order of worst at the top, and best at the bottom, my criteria isnt quality of build or welds etc, merely the design.
Particuarly the external wastegate take off.

Manifold 1, this looks TERRIBLE to me, the gasses come all from cylinders 1 and 2, and they have to double back on themselves to make it to the gate.


Manifold 2, same basic problems, to a certain extent although this time at least seem to be joined at the collector so can at least see a certain amount of flow from all cylinders and is "only" a 90 degree bend:



Manifold 3, i like this one, shallow angle take off to the wastegate, and seems to be well accessed from all 4 cylinders easily.

(my sexy blonde secratary will hopefully replace that pic with a better one for me asap)



So, are my opinions correct?

Any other comments on the relative merits of the three designs?

RWD_cossie_wil

iTrader: (9)

I belive martin H made a manifold adaptor for the 2wd cast manifold that took the wastegate off at 90 degrees on the small swan-neck part of the 2wd manifold, and even with NO wastegate fitted he couldn't bleed enough boost off to control the turbo safley can't remember who told me that story, but it speaks volumes on how critical gasflow and manifold design become at high power levels

Anonymous

Yes indeedy, Martin has mentioned that on here before, and Mike Rainbird has spoken of it quite often too.

EXACTLY my point on these manifolds (except the 3rd one)

xr4x4rs

iTrader: (5)

here sa better pic of the r&b manifold mate



should be an interesting topic

cossie4i+

iTrader: (15)

Im no help

But they all look pretty

Steve.

Martin-Hadland

iTrader: (2)

who's manifold is the first one?

foreigneRS

right click on picture, look at properties

http://www.petergproduction.com/

Martin-Hadland

iTrader: (2)

nice one!

Garage19

Heres one i made earlier!



Not exactly in the same league but only cost Ł20 to produce.

The external gate (not shown) was added to the back of the collector at an angle of approx 60 degrees.

It seems to control boost very well and there have been no issues with cracking.

While we are on the subject of exhausts does any one no where i can get some calcs to work out the length and diameter of primaries on a n/a exhaust?

I have a tried some but want to double check them.

Porkie

iTrader: (1)

Mart, post a pic of your Inconel one!

Martin-Hadland

iTrader: (2)

Prototype and finished product, the wastegate take off looks at first glance to be a bad angle BUT i have seen 1bar of boost at 7500rpm, might go lower but have not yet tried.

Martin-Hadland

iTrader: (2)

look up! not the best pic but i can't find another.

Martin-Hadland

iTrader: (2)

manifold 3 from inside, does not look wonderful but it does work!

Mike Rainbird

iTrader: (3)

As far as I can see you have answered all your own questions .

BlueSmoke

Well I'm non technical but can certainly see from the third manifold that the gases appear to have more or less a straight run through to the wastegate, without being obstructed which can only be good

Anonymous

Yeah but i wanted someone who actually knows shit from putty to come along and correct me if i got something wrong

Anonymous

Interesting stuff, it does indeed look like a terrible angle for a take off, but obviously its fine for what you need for your particular application if it goes as low as 1 bar of boost at 7500rpm, as it seems pretty unlikely on a car like yours you are going to want to go any lower.

Mike Rainbird

iTrader: (3)

Just like you love correcting me, if there had been an opportunity to yo' ass, I would have "jumped at" the opportunity !

Anonymous

Do you mean that harvey is engaged then, or did he agree with me, it was the organ grinders opinion i was after ideally

Can you post the figures you put up once before about what boost the r and b one can restrict to etc?

Mike Rainbird

iTrader: (3)

I never have a problem getting through, I have all his numbers .

GT30 @ 7500rpm, Tial 46mm wastegate, boost can be dropped to single figures .

I would point out that the bigger wastegate is obviously a key issure here, as most people use the cheaper, smaller versions.

Anonymous

Not just down to the gate though of course, if martin was finding even without the gate present he was still not getting enough air bypassing the turbo.

Garage19

The Ł20 mig welded item shown above held a bar of boost on a GT30 at 7500rpm with no problems on a 38mm tial wastegate.

Can't ever see Col running this little boost at that point but it shows its not really that difficult a task to construct and externally gated manifold that will allow good boost control. Certainly not rocket science.

Mike Rainbird

iTrader: (3)

You'd think that, but I have seen some on the engine dyno that were not able to go below 20psi...

msport

the first "peterg"manifold is the best of these 3 shown imo, but not optimum. (cant see reylands pipe on this machine, at work)

i would never put the wg outlet in outer bend of a pipe, the flow will follow the outward wall and hit the wg outlet and make lots of turbulence disturbing turbo spoolup and drive. Keyparameters for optimum turbodrive in my opinion: As short pipes as ever possible to take all pulse-energy to drive turbine, As straight pipes as possible to keep the pulse alive, place the wg in innerbend of a pipe to disturb as little as possible. Audi has made prototypes with holedrilled plates to cover the wg outlet that flow just enough to decrease boostpressure, but disturb the gasflow to the turbo less. I have made insane good results with my prototype manifolds on cosworth engines, have some running on rally and hillclimb cars.

Regards

Anonymous

Ah, thats an interesting reply, and was exactly the sort of contradictory argument I was looking for all along

Looking at it from totally the other point of view there to how most of us on here do, ie concentrating on the maximum power capability of the manifold as opposed to the maximum ability to control boost.

See now this seems interesting to me, basically develop the manifold so that with no gate at all, it just manages to bleed off enough gasses for the minimum boost requirement that you have, then only use the wastegate to increase the boost from there.

Which would make Martin's manifold perfect for his application of course

Mine and Mike's "control is everything" opinion of manifolds is only really of relevance on a road car, for a true performance application, I can see the flip side of the coin

Garage19

Sounds interesting. Got any pictures?

Martin-Hadland

iTrader: (2)

in certain instances that will cause uncontrollable boost!!

Martin-Hadland

iTrader: (2)

my manifold may allow less than 1 bar boost, 1 bar was the presure we started with when gaining boost control... i will pump some figures into the ECU and see how little boost i can have at top end BUT 1 bar is more than acceptable.

Anonymous

That would be interesting info

Do you individual EGT's vary with when the wastegate is operating or not?
(due to it being to one side i mean)

Martin-Hadland

iTrader: (2)

I have not tested that but i doubt it will make much difference as it's a 4 into 1 design and the take off is after they collect into 1.

Anonymous

And even if it does you can trim it out on the fuelling or timing for that cylinder on your T6 anyway

Just be interesting to see the results, however small as it all works towards making us all a little less thick, lol

Mike Rainbird

iTrader: (3)

Have not experienced symptoms of the turbulence described in either dyno testing or on the road.

Anonymous

How would you know you havent?

Your car might make 10bhp more due to less pumping losses if the turbulance wasnt there, but without trying the manifold with the wastegate hole sealed up, how would you know it was suffering?

msport

You wont "experience" turbulence as in an airplane, it only shows in lack of performance as late boost buildup, bad response/pickup, and even backpressure. When it all works great you will see the difference.

Yes I have pictures, wont bring them up here, PM if emailadress if interested. I have a complete turbo/manifold/WG package for sale makes 700+bhp(658bhp done easy, cant use due to new restrictor rules)

I had foe example 2.4bar boost, never more than 1.4bar backpressure. 0.5bar 7500rpm 422bhp, those who know understands something is made with care.

I am not typing this to claim im the best, just a tip that things can be better. I am willing to listen to all experiences and ideas also.

Regards

Stu @ M Developments

iTrader: (12)

I disagree if the picture is correctly representing the design as it appears the external wastegate is fed purely from cylinders 3 and 4 and that will give you a VE imbalance across the engine once the gate is open and bypassing exhaust gas.

msport

I bet its open up there in the collector to flow to the wg from all pipes.

Stu @ M Developments

iTrader: (12)

I would hope so too, but it most certainly doesnt like like it is from that angle!!

SapphyMike

i dont understand this talk of 1 bar at the top?

can someone explain please?

thanks

msport

No, but it has to be since it is twinentry.. otherwise it would have to be quad entry.. As long it has 2 pipes in channel it will evacuate through same wg opening, we dont want to flow into the opening, we will just release pressure, where it is made on the pipe does not matter all that much, some do it even very close to the cylinderhead with no problems. A turbo that have problems evacuating and makes a lot of backpressure need to flow out the gasses through the wg cause otherwise it would go overboost. So the turbo is always the first thing to get correct.

Anonymous

Martins car, as im sure you are aware, make lots of boost at the top end of the rev range (and everywhere else) what he is referring to is that his wastegate is efficient enough to allow his boost controller to bring this down to a bar or less at full throttle if he wants to.