My Twin Turbo

[T4T]

Hi,
I haven't posted too much over the years but seeing as I'm now finishing my car thought I best do a build thread .
I bought my tt280 back in 2002 I think it was !
Neil (of 2.0 dohc turbo fame) from Interford helped me find the car up in Scotland .
Wasn't too bad and had done 107,000 miles .
It was a genuine tt280 with all the right bits - the option brakes , compression struts , group n diff mount ,cossie rear arm bearings etc.
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It certainly was not perfect though , nevertheless I loved it .
I knew it was a keeper and I would spend a few quid getting it good .
Little did I know !!

[T4T]

After about six months of owning it , the car decided it needed two new turbo's.

Around two months after , it decided it needed a new cam ! 

About a month after that while playing with some bright red Italian friends
it decided to get the shakes like it was really ill .
That will be the front cv joints exploding then .

Okay , time to take it off the road and give it a thorough overhaul .

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[T4T]

The plan was to strip the whole car down , weld where it was needed , a fresh lick of paint ,
but mainly give the engine and drivetrain a good going over and get it all working 100% again .

You know how one thing leads to another .............

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That's not me btw .
He's the farmer in Scotland that I bought the shell from . ( Why is it always Scotland ?  I'm in Devon !!)
I confess the old shell could have been saved but here was a unused , unregistered , unmolested - it hadn't had to deal with 340ftlbs for 13 years -
body crying out for a new owner .

[T4T]

I've had a few sierra's over my driving career . So with a little help from some cars I just happened to have lying around the place ,
I ended up with this ...
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Oh , the replacement  shell was misguided , it thought it was a facelift 1.8 .
so it needed this
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and the front chassis legs sorting .

The whole car nicely seam welded to improve on Ford's chassis rigidity and then some paint .

[T4T]

The colour scheme wasn't really working yet so I went for the previous shell's chosen look .
Luckily , my favourite for a Sierra .
Tasman Blauw as it says on the nametag .

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Now , my original intent was to keep it as a road car and therefore sensible .
Well , as I said earlier , one thing leads to another .


Inside - which I haven't ever taken photos of - is as old Henry intended .
Other than a racing driver's seat and five point harness ha,ha .
Passengers can suffer the indignity of face planting on the glass 

Outside , however , there have been a couple of mods . 
When I say a couple ............
a lot.

So:
Bodyshell
            2wd converted to 4wd and fully seam welded like so
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            Doors and boot lid de-locked - not for looks , but in case some egit wants to break in hopefully now they'll do the glass (cheap to replace !)
            Sapphire bonnet and grill for improved cooling for the whole engine bay !
            Some RS skirts because they look nice . 
            And a front bumper with a mahoosive airdam to get everything at the front as cold as possible !

[T4T]

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[Dave]

I love that front bumper  

With the GT2056's on it you won't believe how much faster it is!

Actually it's been so long since you have drove it even with the old T2's you would have a big grin on your face I bet. LOL!

Not sure what's wrong with that last picture the upload appears to be corrupt as I tried to correct it.

Try making it smaller & try again.

[Lemon-Ade]

A lot of work has gone into this mate , respect . Looks agresive from the front with that bumper ! I bet you can't wait now.....

[T4T]

Lost the server trying to upload that pic .
Just back now !!

I think the last time I drove this was 2003 !
These photos are from 2005    

I have been tempted to put this back on the road in Minkerish spec so many times
but the original idea was always for a bit more than that .  

Right ,where was I ?

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Dave , that front airdam is perfect for the intercooler I've got .

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[T4T]

So , to the important bits .....  
Some bits are not shown/ have changed in the pics .

Suspension .
At the back ,
rose jointed 6 degree rear beam with tubular arms adjustable for toe and camber on solid beam mounts . Modified escos
rear anti-roll bar on rose jointed drop links . Rear strut brace triangulated to motorsport developments poly diff mount .
Leda rose jointed coilovers with 325lb springs .
At the front ,
adjustable rose jointed track control arms , adjustable rose jointed compression struts , eccentric top mounts , solid bushed steering rack ,
modified sapphire cosworth anti-roll bar and a strut brace . Leda coilovers with 450 lb springs .

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[T4T]

Brakes ,
Hispec monster 4 calipers with 315 x 32 rotors on bells to my design ( inboard of hubs like the TT setup )
to allow et25 wheels to retain front track
and
cosworth 4x4 calipers with 300 x 20 rotors on bells standard fitting to allow et25 wheels to give me a wider rear track .


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[T4T]

That was as far as I got really , other than 3.14 rear diff (in photos) and sundries .
Braided fuel lines inside car and rear brake lines inside car .

Since 2005 its been hibernating !

Finishing it now and hopefully it will be ready before the end of the year . 

[T4T]

Engine wise :
24v boa crank
Girdled sump
Overbore with JE pistons
Early 6aa rods with arp big end bolts
Rebalanced bottom end
Melling high flow oil pump
Wire ringed block
Kent v6t46 cam
New bearings throughout including the better cam bearings
Arp head studs with head braces
Fully flowed World Products heads with 38 mm exhaust valves
Free floating rocker assembly
Flowed throttlebody , plenum , inlet manifold , exhaust manifold - (turbotechnics )
Approx 8:1 compression ratio
2 X GT2056 turbos with enlarged wastegate port .
Custom exhaust
Same intercooler as Dave runs
Omex 710 management

Phew .  

[T4T]

Drivetrain ,
front diff with strengthening plate and hopefully 3.14 c/p
mt75 gearbox with oppliger close ratio gearset and 50 nm viscous unit
if I cannot find a front c/p the transfer box will be done to effectively give me that ratio using a 3.62 c/p
rear diff is 3.14 with a gripper unit installed .

Think that's about it .  

Anyone know who to insure this with ?
Thinking classic policy with an agreed value .

Hope you've enjoyed the read .

Cheers
Matt

Front bells for those interested
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[Dave]

Oh come on where is the love for this.  

You got the right bits & addressing the problems, done your homework & chucked some money at it!

Gonna be a very nice fast XR4x4 this  

Dave , that front airdam is perfect for the intercooler I've got .

It is the perfect intercooler for a Sierra TT no question mate.
You get 100% air flow to it unlike an RS500 one & the like.
Lets you run the shortest most direct pipework.
Has very low pressure loses due to it's low friction design.
On the road it can achieve ambient air temp at full chat @ 400bhp!
Oh & it's cheap!

Fully flowed World Products heads with 38 mm exhaust valves
Flowed throttlebody , plenum , inlet manifold , exhaust manifold - (turbotechnics )

Didn't realise you was this far already.
Which V inlet manifold you using & fuel rail?

[T4T]

I'm not all the way there . If only .
I am however spending like a lunatic at the mo .

Gearbox and front diff/transfer mod are likely to be a hold up .
Engine , I have all the parts other than crank , after which I'll have a balance done .
Inlet manifold is from my old engine to match the steel fuel rail . Fuel rail has had inlet opened up though .
Why , what have you found now 
I think exhaust may take a while as well 
Needs to be completely custom because of different turbos and rear beam/arms .

I'm hoping for 3 months . If longer I can wait for father christmas 


Should be good I hope .

Matt

[Dave]

Thats the one to use.

So you have modded it like this then & removed the 4.5mm restrictor that stops you at 400bhp!

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Also make a good job of the inlet as it is the main problem as it sucks big time.

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[T4T]

Wow , my inlet isn't that bad ( it hasn't been flowed previously ) .
That nasty bump on the bottom just doesn't exist in mine at all  !
What casting is that ? I've got an 86TM

But over all , no , these engines don't flow well straight out of the box !   

Gone a different route with the rail but the std inlet fitting went in the bin a long time ago   
Matt

[Lemon-Ade]

I'm feeling the love  this thing is going to be an animal!

So much work in there Matt I can appreciate the time you must have put in.
I like your cooler i think I will do something similar on mine reduce the pipework lengths.

Mine is insured with Peter James good price on a classic policy.

Keep up with the good work and the updates 

[T4T]

Cheers mate
I been watching yours too . Awesome engine bay , just incredible .  
The whole car is .
An amazing attention to detail .
The cooler , together with a few other aspects of the engine are down to Dave .
That guy has not only pushed these 12v's developments but also published them so openly for all to share !
Top bloke I think !!
Cheers
Matt

[TwinTurbo]

Nice...

Getting me geeeed up for starting my 4x4 project properly and finishing the 24V finaly..

TT

[Lemon-Ade]

Cheers mate
I been watching yours too . Awesome engine bay , just incredible .  
The whole car is .
An amazing attention to detail .
The cooler , together with a few other aspects of the engine are down to Dave .
That guy has not only pushed these 12v's developments but also published them so openly for all to share !
Top bloke I think !!
Cheers
Matt

Cheers Matt   and defo agreed Dave is a top bloke   credit where its due  

[Dave]

Wow , my inlet isn't that bad ( it hasn't been flowed previously ) .
That nasty bump on the bottom just doesn't exist in mine at all  !
What casting is that ? I've got an 86TM

It's only when you cut things up & start realy looking at it do you realise just how bad some things are.
The V inlet passage ways are really that bad!


You have to straighten it the best you can by enlarging the port to head & making the centre wall as thin as you can.




With some work you can get the head ports pretty good.







The plenium is O.K just needs port matching & some smoothing.



I heavily reworked my combustion chambers.

I slowed down the burn so I could control it better so I could use 95 ron fuel upto 2 bar!



The whole idea is to make the top end flow like a STD 24V.
Mine makes over 400bhp @ 1 bar so I managed it but there is like over 60 hours of porting work !!!!


The cooler & pipe work really is such an improvement over the TT stuff.
Another secret of the install!

That guy has not only pushed these 12v's developments but also published them so openly for all to share !  
Top bloke I think !!

Cheers!
The 12V V6 really lacks development, I can't do it all myself as it takes an amazing amount of time/work so by sharing & helping others I learn more as more & more people get involved.
So I learn more by sharing what I know!  

[T4T]

Couple more pics and some opinions required please .  

2 x GT2056 turbos  
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So ,the turbos have a 14mm wastegate and I think this needs opening out and the port blended into the turbine housing better .
WHY ?    
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So that once the turbos are up to full boost , the engine can breathe a little easier because the exhaust flow not needed
through the turbine has a less restrictive path into the exhaust system .

I have read ( and it seems to make sense ) that the higher the boost you run the smaller the wastegate can be ,
because more of the flow needs to go through the turbine to be able to drive the compressor hard enough .
If , however , I intended to run 16 psi normally ( I think the actuators are 16 psi ) and reserve the full monty boost for on track
then wouldn't I need a bigger wastegate for general use?
Even with a higher setting , once full boost is achieved - which should be quite early from the 47mm turbine ( which I think will be a restriction at higher revs ) -
is it still better to enlarge the wastegate ?
Maybe to 20mm or something like this .

However , I have noticed the turbine wheel is completely different from the old t2's !!  
Is this to deal with the increased airflows from the larger more efficient compressor ?    


Or am I looking at it the wrong way ?
Not clued up on turbo's really .



Opinions welcome .

[T4T]

Intercooler as it was and now minker stylee  

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I have to say the people who modded it for me have done a fantastic job !  

[T4T]

Couple of bits for the back of the car .

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Gripper 45/60 plated unit for rear diff so I don't have to worry about the viscous playing up or the std planetary gears failing !

Swirlpot because I will be tracking the car and my engine guy is worried about fuel starvation .
Running a walbro gsl392 ( I have a new cosworth tank that I bought in 2003 thinking it would be designed better to avoid fueling problems  )
to feed the pot and then bosch 044 to the engine . Braided Ptfe lines throughout because of running the fuel lines internally .

Other than fine tuning engine , and suspension geometry setup to my taste , I'm trying to not have to develop the car further after it is built because
I have overlooked something . Fingers crossed .

[T4T]

Oh crap so sorry Matt but when I replyed to this post some how it deleted it?

Not sure how it happened either.


If someone has it in their history & it don't reload automatically I can put it back just post it as a reply.

Thanks.

[Dave]

The GT2056's will be a good match I think, on paper they will spool up faster than the T2's & keep going for over 400 bhp.

If everything is done well & nothing holds the engine back then you will hit 400bhp close to 16psi.

You can't compare GT's to the old T's they are simply in a different league.

The turbine side is probably the biggest improvement.



As you can see very different.

A GT has far more axial flow like a jet engine rather than a T which is more water wheel like!

This means it generates less back pressure & is very effiecent.

The A/R of the housing is almost the same as the TT T2's but the Trim of the wheel is far more which again reduces back pressure further.

What this means is a GT2056 turbine even though it's almost the same dimenison's as a T2 it can flow almost twice the exhaust yet spool up the same or even better.
Garrett states for the T2:
"The T2 will effectively cover most engine ratings from 100 to 150 bhp, in gasoline/petrol applications."

Where as the GT2056 is a 250hp turbo, if you google it you will see people have hit that power with them.
You have two of them!  

You will have to trust the wastegate, there is a ratio of size to flow/pressure etc & I would assume Garrett know what they are doing.
You may get a little boost creep at low boost but around 15psi plus it should be smooth as mine are.

Does seem small however?



Exhaust back pressure is your enemy do everything you can so it's not a problem espically after the turbo's.
Your main exhaust should have zero back pressure!

If you separate the waste gate & main flow so it joins later in the pipe you will gain a few horses as it increases flow & reduces back pressure.

[Dave]

Reguarding the engine you need to be careful with the big ends.

They was orginally for a little V4 making as little as 40hp!

Anything over 300bhp will start to cause problems unless you ensure the big ends are as good as possible.

It's something you should talk to your builder about.

I got around it by using 10W 60 oil, 70psi of oil pressure & by blocking the rod piston squirts up!

The bearings get over loaded & chunks of them disappears until they spin or start to knock.

Took a few builds to figure it out LOL!

Bearings pre mods after 400lbs of torque!



& after mods after 500lbs of torque!



I wouldn't run more than 400hp on the track as the big ends would take a hell of alot of stick.

Proper track only v6's run wider big ends for a reason. 

[T4T]

Dave , is there any aspect of these engines you haven't looked at ?  

I was thinking that seeing as I never intend running these at their max boost of 36 psi or whatever it is , it wouldn't hurt to allow more out of the wastegate ?
Reducing pumping losses to improve ve and not overspeeding the turbo .
The best power I have seen out of one of these turbos was 2 hundred and seventy something on a 1.6 polo . That guy enlarged the wastegate .
I always assume that people who are already getting good results know more about turbo's than I do .

Saying that , I would imagine Garrett have a vague idea of what they are doing .  

So do you think I can get away with not porting them ?

The turbine is even more more extreme than the one you posted .

The photo of the wastegate shows the turbine in it's entirety . There is no further part of the turbine behind that !

As for the exhaust immediately behind the turbo , I did look at keeping the two parts separate ,
but Garrett have a cutout in the casting which renders that difficult so my flanges are made to Garrett's own drawings which is single chamber .  

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