5-Cylinder turbo golf

Document your project with images, pictures, etc., and share with others.
Syncro
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5-Cylinder turbo golf

Post by Syncro »

Ok then, time to share with all of you my project as promised. Sorry its taken so long, my daughter has been showing me how to upload photos to the forum. I'll be needing some help and advice from you decent folk in the future so its fair that I share with you what I'm building.

Its a 150HP NA Volkswagen engine I imported from the USA. It has more or less the same base specification as the 340HP turbo lump found in the Audi TT-RS and RS3.

2480cc
Cast iron block, cast aluminium head
82.5mm bore
92.8mm stroke
10:1 compression
Cast aluminium internals

The Audi turbo engine has forged internals and slightly lower compression but the main difference is that they used FSI rather than port fuel injection as on the VW version. To buy a complete Audi engine would cost anywhere between £5k and £10k. I paid $500 for a complete VW engine then £750 to ship it, so a small saving there. There are some other technical differences which I will explain in detail as I go on.

Engine, stripped of most ancilliaries, mounted to 5-speed gearbox.
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Original intake manifold was this big ugly plastic thing. Ditched that for a genuine cast alloy one from Audi. Its a work of art. The plenum is divided internally with charge being forced through a wide slit before entering the runners. This promotes laminar flow, I guess?
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Cylinder head removed. It has now been stripped, ready for porting although its worth pointing out that in standard form it flows pretty well apparently. You can see the solenoid for the intake VVT sticking out at the top. The engine is chain driven and the timing can be thrown out by rotating the engine in reverse so it was a relief to find everything straight inside.
The Audi FSI engine has sodium filled exhaust valves which conduct heat better. They are identical in size so I have bought genuine ones to swap out. I weighed them and they are 2.5g lighter each due to the sodium core.
The FSI intake valve heads are 1.5mm wider so I bought some of these too. The head will be gas flowed for good measure.
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On closer inspection I found that the lobes on the cams were heavily pitted. The mating surfaces of the rockers were also shot. This engine hadn't been looked after too well by the previous owner(s). The top end of these engines are prone to wear if the oil isn't changed on a regular basis.
Image

Block, completely stripped and ready for machining...
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...for these forged JE pistons. I bought them before the engine had arrived so ordered slightly oversize (83.0mm) just in case the bores were scored. I sent the pistons off to Camcoat for ceramic coating of the crowns. They did a fantastic job.
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The pistons will be mated to IE forged rods with AGE625+ bolts. I'm hoping to set the rpm limit much higher than standard.
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When VW started making these engines in 2005 they used forged cranks. In 2007 they changed to cast ones - maybe for cost reasons as forged cranks are totally unnecessary in a NA engine. My engine came with a cast crank (on the right) so I bought a forged one (on the left) from an early engine. VW also changed the timing chain (see difference in sprocket width).
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Light weight flywheel from TTV Racing. I'm worried that its maybe even too light at 2.7kg. The new one is on the left.
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Rotating assembly, ready for dynamic balancing. The rods and pistons will also be balanced.
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Bosch 1000cc (@ 3 bar) long nose injectors. High impedance of course. I chose these because they have a wide spray pattern. Took me ages to find - most high flow injectors seemed to be of a rotating ball/plate design which produces a thin jet like a garden hose. I'm not convinced that atomisation would be any better with those.
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More interesting (in my opinion) photos to follow soon.
AWD Golf 2.5T
Boardpaul
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Re: 5-Cylinder turbo golf

Post by Boardpaul »

good read so far, keep it coming.
Alex DTA
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Re: 5-Cylinder turbo golf

Post by Alex DTA »

This looks interesting!
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ignitionautosport
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Re: 5-Cylinder turbo golf

Post by ignitionautosport »

woooh nice, I have a bit of a thing for 5 cylinders, always wanted one :)
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gnutz2
Posts: 190
Joined: Tue Jul 03, 2012 2:33 am
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Re: 5-Cylinder turbo golf

Post by gnutz2 »

Thanks for the update, and don't spare any detail this is interesting stuff.

What are your plans once the car is finished, road car? Or will you be racing 8-)

I think you're correct in keeping a wide spray pattern as I've had experience of un atomised fuel washing the piston tops with the type of injectors you've explained.

Cheers Baz :)
Syncro
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Re: 5-Cylinder turbo golf

Post by Syncro »

gnutz2 wrote:What are your plans once the car is finished, road car? Or will you be racing 8-)
Will be road legal but not much use on it. I hope to drive it (very carefully) to events.

I would like to sprint, track and hill-climb it but they are such vastly differing conditions that its difficult to spec an engine and gearbox combination that works well in all I think. So I'll do my best. I hope to be able to drive it to the 'Ring one day.
gnutz2 wrote:I think you're correct in keeping a wide spray pattern as I've had experience of un atomised fuel washing the piston tops with the type of injectors you've explained.

Cheers Baz :)
Glad you concur! I don't have any experience personally, just a gut feeling about it. I know where I stand with conventionally atomised fuel.

It could be that technology has advanced and these ball/plate injectors are the next great thing, but I don't know enough about it. My ignorance really.
AWD Golf 2.5T
Syncro
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Re: 5-Cylinder turbo golf

Post by Syncro »

I had a mix-up with the clutch discs I ordered from Sachs. The standard set comes with hubs that have a deep splined hub but that meant the inner disc touched the nose of the crank.

I bought direct from Sachs and they were very helpful and agreed to let me return them for discs with narrower hubs. Now they fit perfectly.

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However, now I realise I made another error with the spacer ring for the release bearing (the round clip on the spring fingers in the middle) - I didn't order a deep enough one. The clutch lever will touch the cover. They are very specific about how the clutch should be set up - the release bearing should touch the spring fingers at all times. So, rather than second guess I'm going to drill a small inspection hole in the bellhousing and use my £7 Chinese USB inspection camera to see how much bigger a spacer ring I need.

I also ordered a set of race cams from Cat Cams. Sent them the spec of the engine and they put together a custom profile for me. They have made similar cams before so I didn't need to send my knackered old ones. I didn't want to change to solid lifters so the profile has been made to suit the original hydraulic ones. I had already bought a set of Ferrea lifter shims to complement the setup.

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Since I want to increase the rpm limit I also ordered their dual valve spring setup. Originally the head used single valve springs.
AWD Golf 2.5T
Syncro
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Re: 5-Cylinder turbo golf

Post by Syncro »

Bottom end has been dropped off at the engineers for over-boring. The forged crank was checked and the journals polished.

I bought mains studs from ARP which were designed specifically for this engine - but they don't fit! The shank of the stud is wider than the original bolts so they won't fit through the holes in the mains caps. Each cap needs to be drilled now. Bit of a pain but an easy job for the engineer. The main journals need to be line honed afterwards.

The rotating assembly needs to be balanced as it's a mish-mash of parts from different places. The pulley, crank, flywheel, clutch, pistons and rods are either new or from different engines. The 5-cylinder engine is a bit of an odd beast and some of the engine balancers I spoke to either can't do them or want to charge a fortune (>£500).

For amusement, below is a picture of the trigger wheel for this engine. It has a continuous magnetic strip all the way around the edge. Apparently its 60-2 pattern??? Fortunately its keyed to the crank so I cant put it on the wrong way. The engineer is fitting a dowel pin in the crank for the flywheel and this disc fits between so I'll have to drill a clearance hole in the disc.
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I imagine I'll be posting a scope capture at some point so that the sensor angle can be worked out.

The cylinder head needs some work now. Theres a big list of things to do on it so I need to find someone trustworthy to take it on. I managed to pick up a spare head from the USA for £120 delivered.
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Alex DTA
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Re: 5-Cylinder turbo golf

Post by Alex DTA »

Most of those crank trigger patterns are 60-2.
Be careful though, a couple of the diesel versions are 60-2-2, with the two gaps opposite each other.
Post a crank scope when it's ready.
gnutz2
Posts: 190
Joined: Tue Jul 03, 2012 2:33 am
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Re: 5-Cylinder turbo golf

Post by gnutz2 »

Thanks for the update.

It's such a shame that these engines aren't readily available over here.
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