That's is not that much money. Trouble is people have been spoilt with cheap shiny looking manifolds, then baulk when a reasonable manifold appears with a high price tag.

Already looked at the tig art one and it does look very well made. I don't think the price of that one is excessive either. I've just gave the go ahead on nearly £5k worth or gearbox and £1k worth of Brembo floating 2 piece discs so price doesn't put me off if it's the right thing. My whole car is pretty much tailor made for my own use and there isn't much on it that's OE so again i don't mind that. I might speak to Tig Art and see what they can do. It's the Israel thing and being so far away that kind of puts me off. I like to be able to speak to people and get some real information.

In that case take your car to one of the UK exhaust specialists and let them loose on making the pipes to connect to the turbo. You get to call the shots and specify what you'd like.

Doh!

Yes I heard you the first time !

On the nail matey.

for decent exhausts in the uk,with no budget restrictions id go to OJZ engineering.quality craftsmanship

dog gear kit marco?

Rich yes a full custome dog gear kit with altered ratios and final drive, forged steel selector forks and a full race diff. Should help a bit.

it seems this thread did not reach any conclusion about a manifold that would work better than stock...
it seems the john s one is the only one thats made better power
anyone know a custom manifold builder in uk or has anyone heard yet of a manifold known to make better power?

it seems that what will make good power on a 2.ol does not necessaraly do so on a 2.5!

Custom manifold builder = OJZ Engineering, but it won't be cheap and he is always fully booked so a couple of month lead time. Alternatively you could try Nortech, deal with a lot of Vauxhall's

Try this company, they know a thing or two.

Click me

A UK firm originaly, Aylesbury iirc, you can bet your life it'l make the tig-art look cheap but if money really is no object you will be looking at design and quality foremost.

Problem is, the off the shelf manifolds cant be customised to suit your own cam, head and engine combinations. I've just had help designing my own with simulation from a US firm, it's suprising how many variables are involved and a thing like cubic capacity can change the primary length by a foot !

Looking very nice indeed.

Do you know an price indication?

Regards

Remco

Sorry chap I have no idea, but knowing how much the raw materials are and the time it would take to design and build a one off onto a car - probably £ 1500 to £ 2000 maybe more or less ?

Rich

I was told £1200 to £1500 but got the impression that was loose and it'd possibly it could rise when actually there paying the bill. The most expensive 321 I've ever seen too so off to a bad start. There's no doubt they would do a first class job, it's quite a setup they have.

Quite nicely priced then actually, given the work needed to make one and like said the costs of the 321. I wonder how much experience they have with the turbomanifolds though. You dont want to see cracks soon for this kind of money.

How far are you pro's (tricky,1nro) with yours now btw?, or still no time for progress yet?


Regards and all the best,

Remco

Hi Remco, I think the cracking is down to a combination of bad fabrication technique and wrong material choice which usally seems to go hand in hand. I might drop by at goodfabs one day, there only 30 miles from where I live might be a good learner

I'm staring on an exhaust mani within the next few weeks, finally ! This is what I've been so busy doing for the last few months . . .


http://s139.photobucket.com/albums/q305/oakleyintegrale/?action=view&current=IMG_2659.jpg

http://i139.photobucket.com/albums/q305/oakleyintegrale/DSC01408.jpg

Nice inlet manifold. First photo at GC's by any chance?

No I've been going to see GC for a while now, he's been a great help.

Hi,

Aha, indeed that must have taken quite some work to get it this far, really really nice sir.

Is that an scuderia comp. fuelrail by any chance?

The injectors seem to be a bit high?

Nomally i make the manifolds about 95% outside an jig, i wonder how they do it. Hopefully you can get some expert info and are willing to share. If they have enough turbomanifold experience that is ofcourse.

Material is always going to be an problem it seems, good things just come with an price.

Thanks for the pics, and keep the good work up.

Remco

I believe the cracks that manifolds suffer from is a combination of the material choice and sub standard welding that most suffer from but the biggest reason IMO is the construction techniques which cause a lack of ability to absorb expansion. Everything bolted up rock solid and then there's suprise when it splits after some heat cycles, no wonder I say.

It's just made from a blank -8 rail 11/16" ID.

What I found quite interesting about goodfabs is when tube supplies dry up, they make their own tube from sheet steel before mandreling it into bends. Quite a skill I think you'll agree !

True indeed, 321 and inconel can an will crack easily when not " treated" properly. Especially the thin wall pipes are prone to work alot when welded, especially when the fitter part is done wrong, and the weldingtechnique that follows it.
As you know stainless has the tendency to go all over the place if you dont pay attention how you weld the pipes, and that includes the speed of the weld, and the power that is put into it.

I am no fan of the jig welded manifolds at all, ofcourse if everything is worked out perfectly then it might be no problem at all.

Expension solutions, like the slip or double slip joints like you use are very important to prevent these issues.
But on the other hand, money money money, haha.

Sadly enough, i still am using to much 304, but thankfully things seem to change a bit, and are people more willing to make it right the first time, so they dont have to worry about cracks of even complete turboflanges that seem to fall of just like that.

That also reminds me about the turbo support, tubular manifolds need one! You cant expect an turbo with all his weight and everything that is fitted on it to keep it hanging on an red or more glowing manifold. You dont want to know the forces that the piece of kit needs to cope with when there is no support at all. But you know all of this already ofcourse .

Regards, and show your progress whenever you have time.

Remco

11/16th, sorry i have to calculate now, i am used to metrics only . But indeed if they have their own pipe making machine then for sure they are large, as normally these are quite big to start with.

I just asume that they have alot more speciality's then just exhausts then?

Remco

It's true, the turbo support bracket is worth some care. It was the Mk 4 bracket before I was happy everything was were it best might be and suitably strong.

I see the double slip collector as cheap insurance that the manifold will survive use, not that expensive really considering all their merits. A manifold that needs repair or reworking soon become expensive, it's never cheap doing it twice.

I used 321 that was formed out of sheet and machine welded before being bent, couldn't find anything else in this country that was cost effective in that grade. Not sure what the likes of Burns sell but by the time it comes from the States with shipping and duties paid it's way expensive, they are good for some things but bends are available for less.

I stress cutting tube, so expensive and so fraught with potential mistake, practice helps a lot. Some mild steel bends to play with makes sense if you've a need to practice, a lot cheaper to mess that up than the precious 321.


Nik

not sure why a low carbon steel manifold is used / made.

Stainless looks nice, but is crap at thermal fatigue, especially at those temps !

I'd personally have a decent manifold made from a good quality carbon steel & have the outside plated / passivated.

It won't rot & will be stiffer than a stainless jobbie. PLus they are tons easier to weld & are easier to get a better root.

I bet 90% of them manifolds would fail radiographic examination ( oh & I have access to that ! ).

why not try for a steel version, it'll be MORE durable ion the long-run, as after all, you'll want to heat wrap / put a heat shield over it to preserve your engine bay !

HTH

no idea if these guys are any good, but they do Formula ford stuff....

http://www.jpexhausts.co.uk/gallery.asp?foldname=manifolds

" Stainless looks nice, but is crap at thermal fatigue "

- Not if you pick the correct grade, mild steel is no good for turbos, full stop. EGT's get way higher than in can safley handle.

I'll prob meet you about 30% of the way

Problem with most builders is that they don't prep, stainless is VERY hard to do right.

Just because the TIG weld looks nice, means nothing

A GOOD carbon steel will do better than most stainless. Less susceptible to cracking. Stainless is horrible for this.

And to be fair, I never said MILD steel, I'll let FIAT use that for bodyshells

I'm talking about a specific alloyed steel, the typical stainless grades used I don't think are up to it, hence they usually crack a while later, they just cannot take the thermal cycling... that I can assure you is a fact.

I will however agree that a GOOD weld prep, and I still believe post / pre heat is essential, as this is where the key to longevity lies.

Some have said post weld heat treatment is not worth it, however if you were to ask a heat treater, they'd probably recommend, as in reality you'd only achieve a high enough temp to solution treat the steel for a minute / so in road use, you need to do it for a specified time ( calcs done on material thickness etc.. ). Also a good time to get the bend out of the metal, then you could reface the mounting flanges correctly ( these always distort ).

I'm no expert & would love to see a good manifold, however for anything less than £2-3k, i would be cautious. Unforunately, this is a large outlay for what many may seem as a bling item perhaps ?

cheers

Firstly all steel is made with carbon, iron + carbon = steel therefore mild steel is carbon steel. There are different amounts of carbon introduced according to which strength steel is being made more carbon % = a high carbon steel as opposed to a mild steel - low carbon content. Thats the first thing I learned at college some 14 years ago.

Incidently a lot of vehice manufactures use high carbon sheet to press the structual panels in a car these days because of it's better overall strength, this requires a special welding plant in vehicle body repair and training to use it.

Stainless is a great thermal barrier compared to steel and if you use the right grade needs no wrap or ceramic coating to help keep the heat in. Wrapping a manifold like you describe made from mild steel would cause it to fail very quickly due to it's inabillity to loose the heat it conducts away so easilly.

It's not heat on it's own that causes stainless headers to crack, common grades such 316 - 316l - 304 and 310 that are regulry used suffer from carbide precipitation at the sort of EGT's our turbo cars run at. Coupled to that, rarely is an aftermarket manifold designed with expansion of the tubes in mind and even rarer than that does anybody support the wheight of the turbo properly. In my experience aftermarket manifolds ALWAYS crack near the flange.

"I'm talking about a specific alloyed steel, the typical stainless grades used I don't think are up to it "
So what particular grade are you talking about ?