IHI twin scroll build, Mani finished at last! New problems to sort.

[tashacupra]

Hi all, right i've finaly started the ball rolling with my BT conversion it's going to be a top mounted twin scroll turbo and i'm now in the process of getting all the bit's together to fabricate my equal lenght manifold, but before i start i thought i would ask you lot your opinion on a couple of things.

1. Flanges: for free i have a choice of 316 stainless steel or duplex stainless steel both are 12mm plate, i've made templates so i've just got to make a choice and then get them laser/water jet cut. I feel that 12mm is thick enough but i'm open to sugestions, if anyone has had problems and can suggest a better alternative?

2. Pipe diameter: agian all in stainless steel but as yet the grade of stainless i;ve not decided on, but i have a choice of.

A:2.77mm wall thickness with an internal diameter of 42.72mm or

B:3.68mm wall thickness with an internal diameter of 40.90mm

which of these would people recomend? or are neither very good and somebody can recommend some better dimentions?

3. Runner length: obviously they all need to be the same length but is there a recomended length or a way of calculating it in relation to turbo size etc or is it just a case of whatever you can get to fit?

Also in the designe i may include a pre turbo EGT boss, once i've got it all fabed up i plan to get it ceramic coated along with the first section of the DP.

last but not least if anybody has any tips or sugestions for the designe or fabrication process that may make thing a little easier feel free to let me know, thanks in advance Tasha.

 

[ibizacupra]

have a searchy here>> http://forums.vwvortex.com/zeroforum?id=27

 

[caney]

Hi all, right i've finaly started the ball rolling with my BT conversion it's going to be a top mounted twin scroll turbo

i asked jbs about fitting a twin scroll to my jbs top mount set up and they said it wouldn't fit.be interesting to see how you get on

 

[minimivic]

I made mine with 304 stainless SCH10 bends with 12mm 304 flanges. Good luck because Ive made 3 so far before I was happy, and this one has racked up close to 30hrs of work to perfect

If I were to do it again I'd buy one ready done, its only that I like doing things myself that I kept going. And the fact i wanted an underslung gt3071R with the quattro drivetrain.

 

[tashacupra]

i asked jbs about fitting a twin scroll to my jbs top mount set up and they said it wouldn't fit.be interesting to see how you get on

hi, what turbo did you have in mind, and was the issue with the fit that the turbo was just 2 big or that you existing set up could not be modified to take a twin scroll?

 

[ibizacupra]

twin scroll what base? divided T3? T4? EVO?

 

[tashacupra]

I made mine with 304 stainless SCH10 bends with 12mm 304 flanges.

hi, was it 1 1/2 inch sch 10s you used, and what was the reason for using 304, or was it just thats what you could get hold of?

 

[tashacupra]

hi bill, it's a IHI base from a subaru legacy gt, fitted from 03 onwards i think, although the one i have got has only done delivery mileage. i dont think its was fitted to uk car's though because my local subaru dealer did not list it on any uk car's but they did have a customers import that they look after that has one fitted, apparently the spool time is very fast which is just what i need for 1/4 mile action. i'll try and get some pictures up once i get started on the fab-up.

 

[ibizacupra]

www.aalco.co.uk is a good source of fittings, information & sanitary bends etc
my pukka mani was 321 stainless mandrel bent pipes etc.
The new one will likely be fittings (due to cost) - my preference is low weight, so Sch10 fittings chosen. My pukka mani is testiment to you dont have to build thick wall fitting manifolds to make them durable. Good quality fabrication is the key.

My mani is 1/5th the weight of other manifolds, but built by F1 fabricators with some mega skills & techniques.


Back purged root welds, & capped & good skills with the TIG.

 

[tashacupra]

thats very true bill, good fabrication is indeed the key. fortunatly i'm sorted with that because my other half work's as a coded welder for an offshore fabrication company and is normaly based in the stainless pipe fab shop, he also has the use of a full cnc machine shop and the best tig welding gear to make the process a bit easier. then once all the fab is compled there is also the option of various methods of NDT on the weld's to check there integrity. anyway as yourself i'm interested in the end product being as light as practicaly possible, is it 1 1/2 inch nominal bore sch 10 you will be using? also do you let the mani take the full weight of the turbo or do you run other forms of support, like a cosworth style turbo hanger for example?

 

[tashacupra]

hi all, thought i would give you an update on the progress with my manifold and post a few pictures of the flanges. all the flanges have been made from 12mm duplex ss apart from the smallest one which is 10mm 316 ss. the flanges are pre final machining/milling etc as the plan is to decide on the final position of the turbo, fabricated a jig then get all the fittings that need to be welded to the flanges welded then they can have any distortion from welding etc machined out.

i've also put a couple of pictures of the turbo on the bottom for you all to have a look at, as always any comments or suggestions welcome, regards tasha.

 

[h17och]

all looks goos so far. keep it up!!

ihi have some seriously complex flanges compared to garret


what car is all this going on? what is your aimed power and use?

 

[tashacupra]

hi hooch, it all going well at the moment, as you say though they are some fairly random shapes.

as for the car, it will all be giong on my 2001 ibiza cupra.

with regards to use, the car is going to be kept road legal (although i hardly ever use it) and primeraly used for quater mile sprinting. it's a change of plan from the original plan which was a big garrett (gt35 series) hunting the 500bhp+ mark for full on track use, but you may have noticed from my profile i also have a polo g40 and i was going to build the polo for sprinting. but i changed my mind because no mater how much money i chucked at the g40 it would never hit the 10-11 second quater mile but it makes a mad little track weapon, so its now all striped out rollcaged up etc etc and i'm building the engine (which when i striped it was running 165-170bhp and has had a shed load of work since then so should hit 200bhp, and its still only a 1300cc) as and when i get time to. so that left me with an ibiza that would be better as a sprint car but with a huge garrett blower it would be quite crap off the mark, so after having a search about i decide on the ihi unit as in it's vf34 form it is capable of getting in to the 10 second run's, but i fancied a twin scroll to help spool times a bit more so took the plunge and went for the vf38 you see above, it has a p25 exhaust housing and from what info i have the spool time is very fast, but as bill and many others have proven the ihi units can fail under sustained load so it would not be suitable for reliable track use for any length of time, but should be spot on for short blasts up the quater mile.


as for power i really dont have to much of an idea at the mo as even on the subaru sites there is very little info on this turbo as it was never fitted to uk car's and i dont think anybody has fitted one to a 20vt lump yet, but i think it should crack the 300bhp mark with no problems so i'll just build off that if it all goes to plan, but looking further ahead it will probably be getting a true 2000cc bottom end conversion, and a shot or two of laughing gas up it's snout to help it on it's way (probabley on it's way to ging bang)

 

[h17och]

are you a bird or a bloke? going by the name? lol
sorry if im insulting you

 

[tashacupra]

i'm a ''bird'' as you put it, with a very helpfull other half, read post #10 on this thread and that should enlighten you a bit more, and dont worry no offence taken.

 

[Jon@VAGWORX]

Any chance your otherhalf could knock me up a manifold to head plate???

Been on the hunt, but most aren't good enough

 

[minimivic]

Any chance your otherhalf could knock me up a manifold to head plate???

Been on the hunt, but most aren't good enough

I have a DXF file so you can get some lasercut if you want to.

 

[caney]

are you a bird or a bloke? going by the name? lol
sorry if im insulting you

lol i was thinking the same

 

[h17och]

tell me about it caney! i would love a petrol head missus!

if you ever become single tash lol









sorry to mr tash

 

[ibizacupra]

my new mani is sch10 as I dont believe there to be any advantage in sch40, so long as the fabrication technique is good. My race manifold proved it does not have to be built like a brick **** house to withstand severe duty. Mine was 2mm w/t tube previously and weighed less than any other manifold around. it was not braced either. turbo sat on top.

Now good as my race mani is, its also fecking expensive so an alternate revision of this is in fabrication now, in garrett T3 format, externally gated, based on my race mani design tho. This is is sch10 1.5" and will be double the weight of the race one, but £400 less to buy. An affordable option for those not into "raceing" properly.

Sounds like a great project.
What management are you planning on running, as alternate means for launch are possible on the larger frame turbo's so boost can be available to you off the line if desired. That and some gas... would fill the gap in turbo spool but also have the power, speed/gear related to it could be dialed into the available traction, which at the end of the day is the biggest limitation in fwd, high power 1/4 mile.

Standalone management with als etc...

great read tho. thanks for posting the pix