Stavros

Going on from THIS thread...
https://passionford.com/forum/viewto...=asc&start=250

THIS is ians...



Note the pathetic pissy thin pipes coming from the manifold to feed the wastegate.

THIS is how its done if you want a hope in hell of controlling the boost level...
I wouldnt say the pics show a perfect instalation, but its good enough to control the boost and not make your engine hit 50psi and explode!






Note the BIG pipes at least as big as the wastegate itself feeding the wastegate, and the outlet just as big.

BASICLY the wastegates job is when you hit full boost, to open enough to let enough gas get out the exhaust WITHOUT it going thru the turbo, enough exhaust so the turbo doesnt keep getting spun faster and faster, creating more and more boost, then BANG!

Ians was a 44mm wastegate, and should be fed by a pipe at LEAST 44mm big to work properly, but instead it was fed by 2 bits of pipe about 10mm internal dia with no hope in hell of letting any amount of exhaust gas out, esp as hed put them NOT on the maniold but on to the EGR-ALS pipes which come off the manifold, so too much exhaust gas was going thru the turbo exhaust housing, spinning it faster and faster and faster until 50psi and BOOM.


Understand yea? Im never the best at explaining, esp as im rushing, but there you go...

Ginge !

cool, now i also see the banjo on it too , surely that has a smaller flow rate too


but cheers for the info and the explanation


now i can see what its for


i cant be te only one who aint got a clue though

hexxon

Nice Steve... Some of these manifolds are really good, others not that good, in order to ensure perfect exhaust pressure relief using a external wastegate, there should be a pipe/pipes that is able to collect as much of the exhaust gases from EACH primary pipe from each cylinder. The angle of this pipe/pipes should be as close as possible to go in line with the flow from the primary pipes from which you want to release exhaust pressure from.

The drawback with doing a solution like this is that it steals a lot of the flow even when pressure should not be released from the manifold. Therefore, its more common to perform solutions as seen on many of the manifolds in the picture, 90+-10 degrees from the appreciated flow angle.

CozzyBrom

also hexigon corect me if am wrong
doesnt the exhaust flow have to be baised towards the wastgate valve for better boost control
and running a wastegate pipe at 90 degrees of the manifold wouldnt that cause a slight vacume or depressoin where he speed gasses flowing over a aputure cusing a vacume
?????????????
sorry if you dont understand my typing

CozzyBrom

steve tial wastagtes are 50mm

Ginge !

ok i did understand, now im confused, need more piccys with coloured writing and arrows, less longer words too

Stavros

Brom- I understand and would like to know that too.

I guess as there always quite a lot of pressure in the ex manifold that it still works even at a dodgy angle or dodgy place (ie that 1 pic on the 10v audi engine where it sits on the end of the manifold) as the big pressure overcomes any vacumn the placing of it might make, but its not ideal still.

Id like to know exactly how un-ideal it is tho like you!

hexxon

You are so correct Brom! As ive said before, i understand you perfectly mate!

There needs to be some amount of biasing of the angle, to actually get any reasonable amount of gases out of there when the valve isnt opened fully. When opened fully however, 90 degrees is fine, since then the pressure difference between atmospheric and the one experience in the manifold at the moment will have a lot of volume available for equalization. The flow rate is higher, easily explained. All systems incorporating two different pressures aims at reaching the lower pressure. Thats a scientific fact.

CozzyBrom

am getting good at this techy stuff i will post my manifold up when i have finished it
but basily its a 4 into 1 primery lengths 260mm goes into collector which is slightly curved to the exhaust house
the wastage operning is directly opersite the the 4 into 1 bit so flow is bais towards this and has to do a small turn to getinto the turbo
the wastegate is angled down wards so when the exhust from the wastegate opens its flows stright down and not bend all over the place
i doubt this will work it may crack we will see but i like making things and i not spent £1000 if it does crack
sorry back to post

Stavros

that sounds the bollocks brom

how long did it take you to do? i know your mega quick with the fabrication!

hexxon

Nice Brom! Sounds interesting, you will have to post some pictures of that one, so that we may check it out Sounds like a proper piece though!

If i cant get a hold of a proper wrc tubular one, i will do mine using fully mandrel bent primary pipes with a proper machined collector... Going all the way. 2 welds on each pipe from head to turbo... How does that sound?

Ryan

i'll be doing that soon wont i steve

cheers again mate

Fastmaul

Brom, the Wastegates are actually 46mm, the BOV is 50mm

CozzyBrom

ok mate will do give it your expert thoughts
basicly crank the amps up so it penitrates the tube to the inside they die grind each part as i well it so nice and smooth using 40mm internal tube

GT2

The return from the wastegate should be made to enter the exhaust system further down than those in the pictures though...

Ryan

does it have to enter the exhaust?

I.e wouldnt a screamer pipe be better?

To stop turbulance?

hexxon

A screamer pipe, is as the name implies, kind of noisy, though very manly

If reentrance into the downpipe is the wanted solution, the connections should be performed as far down the pipe as possible, this due to the fact that the gases cool down on the way down the exhaust piping. The length of the return pipe from the wastegate should not however be taken to its extremes, as the small diameter of these pipes creates backpressures when in length, leading to performance of the wastegate getting worse... The connection onto the downpipe should be as close in angle with the flow in the exhaust piping, to create as little turbulence as possible, ensuring the least amount of backpressure and most efficient drain of the wastegate return.

RSBen

Perfectly
Good explanation.
The piss poor instalation on Ians car becomes alot more pathetic when you understand how it should work.

Dont even know Ian but I really feel sorry for him over the way he has been treated.
Totally disgusting

franky

hi i am frank and living in belgium
i am looking far a manifold for my 2door cossie .
does someone now the adresses wher i can buy these

Christian and Beccy

iTrader: (14)

Holy fucking 5-year-to-the-day thread revival!!

Alan_D

Downtown 2004.

franky

whats the matter?
i bought my cossie last year.