Internals for Big turbo

ibizacupra

Jack-RIP my little Friend
Jul 25, 2001
31,333
19
glos.uk
misfit a valve for example and you will break a valve in seconds, ruining your fresh built engine... and is easily done on the 20v head for those not aware of the issues and care req'd when fitting.
many a vag technician has suffered this failure & they're trained (you would hope)
 

ibizacupra

Jack-RIP my little Friend
Jul 25, 2001
31,333
19
glos.uk
ah i see im ok ish i suppose would feel confident for the rods and pistons if i had a step by step guide thing but valves im not to sure at all lol

ring gap it correctly, get it bored paralle etc... some basics req'd. not rocket science but methodical process.

eg. My ibiza engine was built precisely balanced components etc... assembled by someone who has built race engines for a number of years. Runs fine, has done since day #1. minimal blowby despite race seasons under its belt. Built Oct 2005.
I could think of another engine on the other hand, which rattles with piston slap like you would'nt believe, consumes oil at an alarming rate, and has such "rattle and slack" on just over idle it pings the CF corrections to 11's. Generally all the same kinda spec components used, but clearly not assembled and bored to the same precision.

Skill is a factor in building it right, and not just buying the "right bits" from whereever it was read on the .net, and throwing them into the motor & calling it "built"
 

ryan_s3

Full Member
Mar 27, 2004
1,270
0
its too big on the comp housing to fit a JS manifold tho.. sadly.
Owens one would be the upgrade path on a JS mani, with some fettling to make it fit. :lol:

Thats a shame,Is it really worth going to all that trouble for 30bhp?? In my opinion never upgrade a turbo for less than 100hp gain.A vf34 at 1.5bar is nearing max efficiency same with a 18g.
 

h17och

the hunt is over. 460bhp
Sep 1, 2005
3,504
1
Dunstabubble
danny mine was running gt28rs back then.

made 300hp with a broken fuel pump. more like 350hp when new pump was installed
 

ibizacupra

Jack-RIP my little Friend
Jul 25, 2001
31,333
19
glos.uk
if upgrading, then its a balance.. of initial cost (if upgrade is likely then first considerations for manifold etc is key)

If you choose the popular IHI JS type approach you have the benefit of it being the most popular BT upgrade in the UK. All courtesy of Jabbasports initial developments. A solid 300-320bhp its a good starting point. Now.. if you always plan on evolving things, doing rebore, adding some forged internals, valves, springs etc etc.. considering bigger turbos etc, then that initial choice of manifold, downpipe would now be a significant factor/limitor.

top mount vs bottom mount etc.. being an example.

Using the JS example, IHI VF34 or equivalent TD0x unit, the size limit will be determined by what will fit under there comp housing wise. Owens unit is a heafty power packer, well designed, and I've heard is flowing >500bhp on a modifed manifold(external gated added)

Balance of mods and the first rungs of the ladder you wish to tread. You may have to go back to go forward again if you choose the wrong start point.
 

caveo

Guest
I belive we discused this for me the other week bill? And any turbo worth going to seems to require a different mani etc , so like starting again.
 

h17och

the hunt is over. 460bhp
Sep 1, 2005
3,504
1
Dunstabubble
i know all about that lol

very true what bill is saying. if you want an upgrade you really need to know what you want in the future when 300-330hp aint enough
 

ibizacupra

Jack-RIP my little Friend
Jul 25, 2001
31,333
19
glos.uk
I belive we discused this for me the other week bill? And any turbo worth going to seems to require a different mani etc , so like starting again.

if you are on bottom mount IHI, you have the option of an Owens one.. which is available in different levels of spec.
 

ibizacupra

Jack-RIP my little Friend
Jul 25, 2001
31,333
19
glos.uk
We ALL want more!!!

well actually I'm not so sure you would..
tractable power. now thats the challenge when only peddling thru fwd as a road car on road tyres in all road conditions, wet or dry on congested roads etc.

My personal example is MrsB Lupo.. its ~220bhp/250lbft on its bog stock AUM engine & K03s. 970kg car. I thought I would want more.. and was all set to stick on one of my old setups onto it.. Pe1820,VF34 or whatever else I have lying around here. BUT.... it spins up in 3rd now in the wet. is faster than most on the roads, and has great instant throttle response and big torque urge.
The conclusion is- leave it alone. only if K03s expires would I consider a hybrid Ko3s/K04 perhaps and 270bhp/300lbft torque.

Please folks dont get fixated in power numbers. thats all they are. numbers

drivability is THE important factor for your road car, not headline power figures which take much rpm to spin/spool up. (think overtaking, think about how fst you want instant urge to propell you past them) - (Then think, first fish out a suitable gear so its revving high enough to be responsive, then the power may well be brutal and sudden when it does arrive, think about if its wet @ the time) too big or mismatched spec of BT will actually ruin your road car.

choose carefully
 

caveo

Guest
Thats why next on my list is clutch/fw , diff , arb's and some fat porche brakes in early sept so i can make the most of my set up. The rebore etc is just going to be part of my rebuild so she goes another 123000 miles ( yea right )
 
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