2.0+l 20v stroker build thread (GT2871)

jcb

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finally pulled my finger out and started putting bits together!
thought I would run a build thread for those interested.

plan was to build a torquey but high revving engine that was bullet proof that would give around 200bhp/200+ftlbs at 4000rpm and max out somewhere above 350bhp.
will be in a A4 tqs (5 spd box, my biggest issue is the lack of torque available between 2500-4000 rpm when in 2nd gear, hate going in to first when pulling away from really slow corners!). car will be running KW v3 coilovers and B7 rs4 brakes on hybrid struts and driveshafts.
never done a full engine build before and have spent about two years collecting parts and researching. sourced most stuff from the US for both cost and product choice.

Spec as follows:
Block
AJL code engine block bored to 83mm (will be just over 2l 83mmx92.9mm borexstroke)
92.8mm forged crank from a 2l VW (dowelled to strengthen timing sprocket)
Raceware Main studs
Eurospec main bearings
144mm Forged Scat rods
Calico Rod bearings
83mm Forged Supertech pistons
New water pump with metal impeller
New Oil pump
New IM shaft bearings
New seals/gaskets throughout
stock sump

Head
Ported and port matched big port head
supertech inconel/nitrided valves
Supertech titanium springs and seats
new valve guides
stock cams

Turbo/manifold/exhaust
GT2871 with vband stainless turbine housing, custom integral 44mm Tial external wastegate vband mounting on turbine housing
custom tubular equal length runner 316 Stainless exhaust manifold with "Burns Stainless" merge collector
3" stainless downpipe
2.75" Milltek exhaust

Fuel/Intake
90mm Ford Lightning MAF
630cc injectors
Bosch motorsport inline high flow fuel pump
stock FPR
Tapp Auto software on new ECU

parts porn
IMG_0912.jpg

block prepared
Block.jpg

GT2871 with vband turbine housing
IMG_0922.jpg


Block was prepped and painted and all bolt holes were cleaned up with an appropriate tap, you would be amazed how much crud came out of the holes!
bearing clearances have all bean checked with plastigage and micrometer measurements.
bearing surfaces were cleaned , top bearings fitted, lubed, crank fitted, studs fitted finger tight till they bottomed out, bottom shells/c bearings fitted to caps, lubed, tapped into place with wooden mallet and all torqued up.

crank is in place ready for run out check with dial guage (forgot my small crowbar so had to stop there!)
IMAG0178.jpg


you can just see behind the dial guage one of the dowel pins fitted to the end of the crank for the timing pully to fit onto. the pulley has two holes right through it and fits into the dowels and keyway on the crank. It is a design fault that has failed numerous times on BT engined cars I am not having that come off when I have spent so long building up this list!

more pics to follow
 
going to run a standard intake mani for a while but am hoping to fit a 007 monster intake with larger TB if I see any restrictions (and I save some cash between now and then!)
 
finally getting some progress on this. shortage of cash and too many kids slowed me down.

Head is skimmed, valve guides in, 3 angle seats cut, springs and valves go in this week.
block is being clearanced for the the stroker crank throw.
IM shaft is being lightened and trimmed to clear rod No.4]
will get some pics up tomorrow when I drop of the rest of the timing stuff

got my new inlet manifold back as well.
Ghetto!! 2" increase in plenum size, still fits between head and stock coolant resevoir.

IMAGE_307.jpg
 
Arent you concerned about block rigidity with that rebore?

I know from the vauxhall chaps building big turbo XE/LET motors that they dont really recommend much more than a 0.5mm overbore as you want to keep as much strength in the block as possible.

The big power builds tend to go with a line bored crank and then the bores machined perfectly perpendicular to the crank tunnel. Maybe its not so much an issue for 350hp, but surely if your doing a build like this you'd plan to build the engine over specced from the start so if you want more power its only a turbo change away?
 
very interesting thread, ill be watching with enthusiasm
 
i would love to do this if i had the money. i just wish either the standard turbo was good for much more or there was a simple bolt on one that worked.
 
at the boost and power I plan to run a 83mm bore is well within spec.
I have seen 83.5mm bore on 500bhp drag only engines without block issues.
way more problem come the with head and timing to worry about the bore walls.

this is a VAG not some poxy "made from cheese in Cheshire Vauxhall block" ;)

no need to line bore the main bearings if the cylinder bores were done with a torque plate in place, crank and bearings are all stock diameter.

this engine will easily cope with 500+ so long as it does not need to hit 8k rpm to achieve it.
fully forged bottom end, lightened and balanced rotating assembly (including clutch and flywheel), rebuilt head with titanium valvetrain.
no intention of revving past 7k so the stresses are well within the capabilities of the components.
just need to make sure they all go together right...which is why I removed myself from the equation!
 
I guess it depends on the factory tolerances, line boring the crank tunnel and ensuring the bores are absolutely spot on is something i'd be wanting to check on a 500hp build, simply down to longevity and the risk to the expensive components. The block is worthless, but if the block fails and takes out the crank, thats a lot of notes down the pan.

It may be "a vag" but as with anything, its built to a specification plus a bit for good measure. I'm sure the block design predates the 1.8T, and has just been tweaked over the years, so expecting it to handle 500hp is a big ask in itself.

If the general concensus is its fine at 83mm then thats good. I'm just not sure the potential risk (your boring closer to the water jacket as well further reducing strength) makes up for the gain the extra 100cc gives you.

Why did you choose to go with the titanium valvetrain if you dont plan to rev it past 7k?

What problems do you have with the cylinder head at big power levels?
 
It may be "a vag" but as with anything, its built to a specification plus a bit for good measure.

In the same way that the 1.4l turboed BMW engines the formula one cars ran were in no way built for 1000-1500bhp but BMW left them to rust outside and deliberately chose engines that had decent mileage on them before they built them up.
These engines are SIGNIFICANTLY over-engineered, not just a little bit. otherwise they wouldn't run for 250k miles on crap oil and crap fuel and being badly driven.

I'm sure the block design predates the 1.8T, and has just been tweaked over the years, so expecting it to handle 500hp is a big ask in itself.
same 058 IM shafted block that ran in the original Golf Gti 25 years ago.....if it ain't broke....
Not really a big ask, everything known to be a weakness has been replaced with components that have proven to exceed those levels. its all down to weak links in the chain

If the general concensus is its fine at 83mm then thats good. I'm just not sure the potential risk (your boring closer to the water jacket as well further reducing strength) makes up for the gain the extra 100cc gives you..

If you look at any open deck block with liners the actual liners are much thinner than anything left on a 83mm bored VAG block, the issue is not bore wall and water jackets it is inter bore wall and head gasket width. go too far and you end up having to O-ring the head and lose the fire ring on your Head Gasket, custom gaskets, O-rings etc etc are not worth the time, money or effort. that 100cc is 210cc more when stroked with a 92.8mm crank.....makes all the difference.

Why did you choose to go with the titanium valvetrain if you dont plan to rev it past 7k?

because the stock valve train is pants, suffers from valve float, coil bound springs, exhaust valves are famously crap losing valve heads at high EGT's associated with higher boost/timing.
Ti is lighter more resilient and springs are capable of higher revs.
I don't plan to rev past 7k as I have specced it out for a lower end torque delivery.
200+bhp/250ftlbs at 4000rpm
375+bhp at 6500-7krpm.
2871 turbo is out of its efficiency range past that and there is no benefit.

Engine will be capable of revving to 8k rpm (valve retainers become the weak link as mine are stock 3 groove instead of the better designed single groove collets for higher revs ranges) but as my stock rev counter doesn't go that high...its unlikely it will ever see that!


What problems do you have with the cylinder head at big power levels?
higher temps and massive cylinder pressure associated with advanced timing and high boost are always going to test a cylinder head gasket.......reason I went head studs rather than bolts and an oversized gasket. I don't envisage running too much on the timing though.

I don't want this:

blown-gasket-no1.jpg


melted-no1-1.jpg
 
All makes sense i guess. The melted cylinder head is surely more down to the mapping than anything else. Too lean or too much advance isnt a problem with the engine build.

I've heard of the valve head issues on more than just these engines, it becomes a problem on quite a lot of motors. You tend to start to need stronger springs to shut the valves under big boost, and the stronger springs apply more force to the valve head/stem. Add in the high temps and the high rpm's and things start to break.

Looking at the valve areas, i do wonder why VAG bothered with the 5v design in the first place. It has 3 27mm valves giving 1717mm^2, using 2 33mm valves (ie +1mm oversize on the old 16v head) would surely have given the same valve area and therefore flow, but with less weight in the valve train?
The newer FSI engines seem to have gone with using 2 34mm valves, so have a larger valve area the 5v motors.
 
You got any pics of the exhaust manifold?

I noticed a thread over on Vortex which 034 are running selling different stage kits.

Does not work out that expensive for a basic kit.

I read as well that quite a few people just chuck in a set of valves and leave everything else stock. As they think although the engine can hold 350bhp for a while the valves should make things last a bit longer?
 
I am going with aPAG vband log as I am months away form getting my tubular made up and I can't afford the car off the road to have it test fitted and fabricated.
It's not ideal as it is bottom mount and sits quite far forward.
the tubular design I have mocked up is top mount and moves the turbo back and left as you look in from the front, gives much more room for inlet pipe work/MAF/filter etc and I can mess around with the turbo without pulling teh front/bottom off.
(added bonus with vband exhaust housings is I am a 45 minute swap away from a bigger turbo should I want one in the future, 3071, 3076, 35r all have the same exhaust housing configuration...two vband clips, undo intake/coolant oil, refit is reverse of removal.....400-600bhp!.....[dreams])

vband_mani_v.jpg

longitudinal_vband_1.jpg

longitudinal_vband_2.jpg

longitudinal_vband_3.jpg
 
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Isnt that generally regarded as a "bad thing"... Especially when its getting heated and cooled as much as an exhaust manifold?
 
doesn't seem to make much difference on such a small part against such a heavy one (flange vs cast log)
no cracks on any of the US guys running them including Al's 615bhp Gti. sure it will be fine. may only be a 6 month thing until I get the tubular made up anyway
 
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Engine is fininshed!!
picking it up tomorrow!!

hope to drop it in for a few hundred mile run in over the break. will post up some engine p0rn pics when I can.
 
I can't wait to see the bling!!
should be swift.....thats if I don't break something either fitting it or running it in!!
had a dyno done on the stock engine
having another one done with the KO3s on the 2008cc block and a third when I bolt up the 2871.
still need a few bits and bobs for the big turbo, coolant lines, oil restrictor etc etc

Engine need a lot more machining than people make out when it comes to stroked 058 blocks.

No.4 piston needed 1/4" notched out the skirt to clear the squirter (and subsequently the others had it done). no way the copper washer bidge was going to work.

IM shaft oil gear I knew about, needs a few mill trimmed to clear the big end of rod #4also had some meat trimmed off and it balanced that for extra lightness.

Had to have a gouge out of the crank case where the big end of Cyl 2 fouls the case. luckily nice and meaty there with a boss on the outer side.

the controversial "Siena 240mm 1.8t" single mass flywheel had a bit removed to balance up the whole rotataing assembly of crank, flywheel and clutch. Clucth cover had a bit trimmed also.
All rods and pistons weighed and matched to 0.5g

Head and deck skimmed so compression should be a gnat's whisker over 9.0:1
new 3 angle valve seats cut,
new valve guides, all washed assembled and looking too good to fit!!
 
right, apart from having to rebuild my rear suspension due to a sledging incident I have been busy trying to sort some annoying things out.

Fuelling: Done.
Bosch 044 Rally spec pump in modifed OEM cage for intank fitment. Good for 600+bhp
IMAG0088.jpg


small filter on teh top is dremmeled and notched to accept the longer pump and lock it in place
IMAG0089.jpg

Intake is going to be a challenge, I am planning on running a 3"-4" bulge connector the 4" MAF a 4" velocity stack and custom airbox to exclude turbo heat
stack:
products


have just ordered one of these, already have the 44mm Tial WG and needed something that fits without 3 weeks of R&D
Michel%20A4%20297.jpg


doesn't leave me with much room but a 4" 90 deg fits down behind the headlight.
Engine is done but I haven't been able to pick it up yet. NO CAR! need to get the suspension finished!

once I have the engine I just need oil and coolant lines few bits of silicon and the whole lot can go in at once. I have scrapped the idea of running it it on the stock turbo, would let me get the engine in faster but I would have to pull all the turbo mani etc again in a few weeks!
 
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If you wedge the wastegate open, you can probably run it in on the standard MAF, ECU and injectors with the new turbo fitted.

Only takes 15-20miles of proper driving to bed the rings and then your ready to go.
 
true,
I'll probbaly just fit everything as I won't get another chance to get under the bonnet again for a while.
I am running an EBC anyway so I just going to keep boost very low and take it for a spin round the bypass to do some running in work.
quick oli change and bump teh boost up and it should be fine
 
When i was running my old motor in it was suggested that backroads are better than any kinda dual carridgeway or motorway.

You want the engine to be either under load (ie accellerating, lots of cylinder pressure) or on overrun with maximum vacuum, trying to do that on a motorway isnt particularly easy whereas on a backroad you tend to be doing exactly that anyway, accellerating down the streights and then slowing for corners?
 
Always used this
http://www.mototuneusa.com/break_in_secrets.htm

reason I use a motorway, usually at night when it is empty is it is flat so load is defined by me not the 1:5 hill coming up, I can specify how long the high gear high load pull needs to be and there is usually a lot more road to play with.
immaterial till I get the bloodyt engine in anyway, still trying to find a garage that is empty!
 
UPDATE!!
engine is in my car!!
OK so it is in the boot but it is in my possession which is a start!
this is what £2k of engine looks like!
all built, checked, clearanced new everything. even an infamous "Siena" flywheel mated to a Southbend stage three S4 clutch.

IMAG0099.jpg


Mani/DP arrives 3rd week in Feb

running round pulling together all the bits of pipe and hardware I had forgotten about .....getting there!
 
nah! twin engined at the moment
 
is that the engine i gave you? or did you move on from that?
 
yep. Its going to be a star
well, that is the block you gave me after a drastic weight loss program.
 
got my intake pipe work sorted.
Two options:
straight:
IMAG0100-1.jpg

90 degree down behind headlight:
IMAG0102.jpg


neither of them will be that long, I have approximately 6"+ of silicon I can trim down to shorten the piping.

Got my boost control sorted now also:
IMAG0104.jpg

both going in the ashtray, stealth stylee!

jsut waiting for the manifold and downpipe to arrive.........
 
How will the straight one fit in the engine bay with the filter attached?

What about Recirc, N75 etc?

Nice gauges!!
 
won't be that long. I can cut all the red bits off so it will be less than 6" long.
inlet.jpg


I am using a custom airbox with a velocity stack and stock panel filters (flat!) sitting sort of vertically behind the headlight, The MAF has a bolt on aluminium collar that I am going to fix into the box and fix the velocity stack directly to it.
Will receive air from the existing vent tube under the bnnet lip and from below under the headlight.
should fit...but I have a backup plan if that doesn't!

I am not using the N75 and will be delting anything unrelated to power and cool noises , gauge on the left is a electronic boost controller. the vac is coming off the inlet manifold. I may have to tap the aluminium joiner between the silicon T piece and the step up pipe in front of the MAF, but it should be easy enough to tap.
The T peice by the turbo inlet is for th erecirc valve. already have a Forge unit in place and lots of pipe left over from when they did my FMIC.
unfortunately as it was the development car all the pipe work they did was before they did nice shiny new blue models .......so I have my turbo outlet piping in prosthetic limb orangey brown!
 
Very clever indeed (if it works lol).

Wish I was brave enough to go for a manual boost controller too.. but I'm not so I'll make do with the N75.
What about the crank case vent/PCV connection?

Your MAF looks massive on those pics! I like it!
 
If it works I will be amazed, but if you don't try something new I could have just bought a kit ages ago.

4" Ford Lightning V8 MA..... (comes as a package with Tapp 630cc files that they are written for).

running crank case and newly tapped cam cover into a catch can. will be venting to atmosphere to begin with. If it really does stink as much as some people say then I will plumb it back into the inlet.
I don't really want that much vacuum in the crank case ventilation TBH and if I going to the trouble of getting the oily watery crap out of the intake why plumb it back into the inlet to mess up my nice new turbo compressor!
we will see...when I start choking on crank case fumes i will probably regret that decision!
 

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