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1.8t 20v 325-350hp - whats required?

Discussion in 'A3/S3 Forum (8L Chassis)' started by jasongtr, Dec 4, 2013.

  1. jasongtr
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    jasongtr Active Member

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    [Dec 4, 2013]
    its going into a mk2 golf,

    i have a 1.8t engine with forged rods. Ill be using an AGU Head too.

    What i know is the std ko4 turbo off an S3 etc won't get me past 285 isn, but I've been told a ko4 off a tfsi engine will.

    So will i need bigger injectors than the 440cc std ones - like genesis 550's with a 4 bar fpr.

    and will the tfsi ko4/manifold fit straight on an AGU head.


    Ive had a ko4/023 bam engined mk2 golf before and when i convert the next one ill be looking for a little more power as is the usual way i guess

    cheers for any advice given.
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  3. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Dec 4, 2013]
    Either one of Beach Buggy Turbo's hybrid K04's or the TFSI K04 with adaptor plate (see Prawns build thread for details of the TFSI conversion)

    550's will be fine at 3bar for 350hp

    <tuffty/>
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  4. jasongtr
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    jasongtr Active Member

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    cheers, i assume 440's won't be even at 4bar?
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  5. jasongtr
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    jasongtr Active Member

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    [Dec 4, 2013]
    just the throw something else in the pot, I've got a genuine garrett gt3071r turbo that was removed from an mr2 - whats that going to be like on a 1.8t - too laggy???
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  6. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Dec 4, 2013]
    Look at prawns build for info on the TFSI K04.

    It wont bolt straight on, but beachbuggy does an adaptor plate which allows the TFSI manifold to mount onto the 1.8T head.

    Leave the FPR alone, as it just puts unneccesary pressure on the fuel pump. You'll need larger injectors and the 550's will be plenty at 3bar. Bosch EV14's are the injectors to have.

    Your power target could be reached with a hybrid K04, but given your starting from scratch, and dont have a pile of K04/023 specific parts already, the TFSI turbo makes more sense IMO.
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  7. Prawn
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    Prawn My other car is a MINI!!!!

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    [Dec 4, 2013]
    Having had both a hybrid k04-023 at 350bhp and now a tfsi k04 at 380bhp, I'd say the TFSI is the better of the two units.;

    it's entirely cost dependant though, and also depends how much kit you already have towards a 'decent' stage 2 setup.

    if you've already got a top spec stage 2 kind of build with rods, then you simply need to add an 023 hybrid and injectors, and you're there once mapped.

    If the rest of the setup is reasonably stock and starting from scratch, I'd go down the TFSI route every time, it's absolutely fantastic and easily capable of your requirements.
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  8. Prawn
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    Prawn My other car is a MINI!!!!

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    [Dec 4, 2013]
    Oh, and stock BAM/AMK injectors are not 440, they are 386cc :)

    550's required ideally.
    #7
  9. jasongtr
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    jasongtr Active Member

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    [Dec 4, 2013]
    all i have so far,

    apy engine with scat rods, std agu head.

    the fact its going in a lightweight mk2 golf and knowing how quick they are without a diff and with 285 hp i know with 350 and a diff it will be very quick.

    the rest will be bought to suit so its a blank canvass now, that said if it runs into masses of money i fail to see the point and could go and buy a different car.
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  10. jasongtr
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    jasongtr Active Member

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    didn't know that, the injectors i sold off the s3 i was breaking to get this engine were 440cc so i assumed they were the std ones
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  11. IrishDave
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    IrishDave Active Member

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    [Dec 4, 2013]
    If I was in your situation with more a less a blank canvass I would go down thw TFSI route. In order to get the power you are looking for with a 023 hybrid you will require water/meth injection.
    The 2 set ups will roughly cost the same all in.
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  12. jasongtr
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    jasongtr Active Member

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    [Dec 4, 2013]
    are we still talking tfsi with 1.8t - and what about the idea of the garrett gt3071r (and a tail 38mm external wastegate) that i already have - surely thats just cheaper as ill just need a manifold to suit / adapter
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  13. IrishDave
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    IrishDave Active Member

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    [Dec 4, 2013]
    Yeah tfsi with 1.8t. I know nothing about the gt3071r. If it's a suitable turbo then yeah it will work out a lot cheaper.
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  14. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Dec 4, 2013]
    the 3071R will almost certainly be laggier.

    Depending on which exact model, this could be anywhere from "a little bit more" to "a lot more".

    A good manifold for it will also set you back a fair old wedge, and a **** manifold will hurt your power.

    With the K04, you get a perfect package that will comfortably do 350 and will do more if pushed hard. With the GT30 you end up with a 450hp turbo (and the associated lag) thats hamstrung by various installation issues and only makes 350ish HP.

    Personally, i'd sell the GT3071R, and buy the k04-064. It'll produce a more streetable, nicer to use car.
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  15. jasongtr
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    jasongtr Active Member

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    [Dec 4, 2013]
    no worries, the gt3071r is up for sale as a bolt on mr2 kit already,

    the ko4-064 i assume is the tfsi one, and all ill then need is the adapter to mate it to the std 1.8t cast manifold? yes….
    #14
  16. IrishDave
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    IrishDave Active Member

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    [Dec 4, 2013]
    No as far as I know the 064 is part of the manifold in tfsi cars. So the adapter plate allows this to be mated to the 1.8 head.
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  17. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Dec 4, 2013]
    As mentioned before, TFSI turbo conversion is documented in Prawns build thread... would be worth while having a read...

    <tuffty/>
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  18. jasongtr
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    jasongtr Active Member

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    yup read all that now, sent beach buggy a PM re prices, until then i guess ill not know whether to use the garrett i have and buy a manifold or maybe buy a GTx28 or go tfsi.
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  19. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Dec 4, 2013]
    If not running much boost then the GT30 will work ok tbh... on actuator pressure (15psi on my Tial MVS) mine made 300hp on a 1.8... 350hp at not much more boost should be easy enough but as said it will appear 'laggy' in comparison to a smaller turbo..... mine was spooling low 3k and on chat at about 3.8k... obviously the difference between a big turbo setup and a TFSI/Hybrid etc is a little different... the GT30 will keep going long after 7k but at that point you will be restricted by the std cams... torque drops off just before 6k no matter what the setup... thats just how std cams work... with 'cams' you can extend the rpm limit and the engines breathing capability and torque should continue to rise as will power..

    Personally I think all this talk of 'lag' is subjective cobblers... its only laggy in the wrong gear and inbetween gear changes if going for it there will be next to no lag at all as you will always be in the power band... big turbos need to be driven differently is all.. mine drives perfectly well off boost and is perfectly at home nipping through town traffic as it is cruising on the motorway or having a blast through the lanes... having driven both BT and hybrid turbo's cars I have to say I prefer the way a BT car drives but then that could be just down to the way I prefer to drive too...

    Still... that said for your particular requirements I have to say the TFSI turbo is an appealing alternative... I assume you are planning to use a standalone ECU?

    <tuffty/>
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  20. jasongtr
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    jasongtr Active Member

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    [Dec 4, 2013]
    yes it will be stand alone I'm sure, my last one had a qpeng, but for the money I'm sure theres better out there, the s3 the engine came from had a garrett copy turbo and that boosted very late - i did have a thread up about it a few months ago, now i have a genuine gt3071r I'm thinking i might swell use that, its going to be predominantly a track car anyway so pretty much higher in the revs most of the time
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  21. BoostHard
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    BoostHard New Member

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    [Dec 4, 2013]
    what engine codes do the TFSI k04's come on?
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  22. Prawn
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    Prawn My other car is a MINI!!!!

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    [Dec 4, 2013]
    I'm not sure if I'm honest!

    I KNOW they came on the CDL though.

    all 8P S3's, TTS, mk2 Leon Cupra, Golf ED30 etc etc. ko4 based 2.0 tfsi stuff.
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  23. s3dave
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    s3dave TFSI Hybrid

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    [Dec 4, 2013]
    AXX/BPJ/BGB/BWA To name a few....

    The TFSI setup is not as cheap as people may think, a load of work to do inc custom DP and custom intercooler piping + inlet, not sure if Dan has got a price for the full setup yet...
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  24. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Dec 5, 2013]
    Why not use ME7?
    #23
  25. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Dec 5, 2013]
    Its a mk2 golf... everythings going to be custom anyway!
    #24
  26. superkarl
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    superkarl MAN OF STEEL

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    [Dec 5, 2013]
    I agree with tuffty. Lag is cobblers.

    Think of things in terms or useable power band rather than lag, and where that power band will be in terma of revs.

    Tfsi ko4 = quite a big power band for a small-ish turbo from quite low revs.
    3071 = capable of big power band but further up the rev range, which in turn requires more mods (valvetrain/cams/inlet manis) to utilise it.

    Its a tough choice. Perhaps the tfsi might be too eager and torquey in such a lightweight 2wd car. And the garrett would be more useable.
    garrett will cost more no doubt, but if you already have the turbo, its not so much a big deal. Just have to choose hotside wisely and budget maybe even more dosh for valvetrain.

    Every setup has its pros and cons.
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  27. jasongtr
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    jasongtr Active Member

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    the agu head i have is std, so id strip it down a have that rebuilt so valve train can be sorted to suit, ill whip the garrett off the kit i have and see whats what
    Last edited: Dec 5, 2013
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  28. jasongtr
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    jasongtr Active Member

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    next question then, who is the best person to rebuild an AGU head with nice goodies and a rough cost as i haven't a clue what its likely to cost, I'm assuming ill need new valves, springs and hot cams
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  29. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Dec 5, 2013]
    Andrew @ ALD does some nice headwork at good prices, I'd drop him a PM and ask... assuming you want to use the GT30 to full potential then supertech valve train is advised, Bill @ Badger5 can supply those and cams... would be an idea to discuss cams with him as cams seem to be something we don't do much of in the UK... normally most fit bigger turbo's lol...

    I am going to try a set of Integrated Engineering street cams I think once I have base lined my new setup on std cams... see what they bring to the party... not sure it will be the gains they describe but as long as it lifts torque/power to my 8k redline I'll be happy

    <tuffty/>
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  30. jasongtr
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    jasongtr Active Member

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    [Dec 5, 2013]
    ok mate cheers, its a very long term project as its going in a boggo mk2 golf, so this is just the beginning really, want to know what I'm getting myself into.

    I have another decision to make regarding the engine i have, its a stock APY with scat rods, so with the head work (and i think i know the answer already) i assume i should be looking at the pistons too, or are they good for 350 hp, i really dont want any more power in a mk2 golf, especially if i can raise the redline to 7.5/8k
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  31. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Dec 5, 2013]
    I ran std pistons before I built my stroker at 400hp... have pushed them beyond that but its cylinder pressure you want to be in control of really... as long as the tune is safe then there are no worries at all...

    Check the bores to make sure they are not too worn.... Bill has an S3 in at the moment that only came in for rods but we ended up rebuilding the head due to worn guides and leaky stem seals and now doing a full bottom end build due to worn bores...

    If the bores are ok then stick a new set of rings in and hone the bores... happy days

    If planning to use as a track day car then get a baffled sump too

    <tuffty/>
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  32. jasongtr
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    jasongtr Active Member

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    ok cheers, the rods were only fitted 5k miles ago so id assume all is ok, but once the head comes off ill check
    #31
  33. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Dec 5, 2013]
    The issue is that we're all really talking about boost threshold, rather than lag.

    Lag is what you get when your at 5000rpm, cruising at light throttle, the mash the foot into the carpet. IE its the time taken for the turbo to spool, once its well inside its working range. This is most noticeable on gear changes when pressing on. A laggy turbo will take ages to spool back up after a shift, a small lag free turbo will hit full boost pretty much instantly.

    Boost threshold is the point at which the turbo starts to make boost, or makes full boost, depending on how you want to define it. Theres also the ramping up rate which is different. A small turbo will start to make boost, then VERY quickly go from 1psi to 20 or whatever your peak is. A big turbo will have a much slower ramp up as the energy to drive its much larger wheels builds up.

    For a normal road car, be it a daily or a weekend toy, you want both low lag, and a low boost threshold, because normal driving dictates your driving around at normal RPM's, and the car will feel much nicer to drive if its got a nice wide powerband extending down into the normal crusing RPM range.

    If you fit a very large turbo to a daily car, then you'll find that say at 3000rpm, you might now only have 60hp available, where a stock engine has 100 and a tuned small turbo might have 120 or more. That means when driving "normally", as opposed to giving it death, the car will feel sluggish, it'll feel like your always having to work at it to get the best from it. Its this feeling of tractable power that makes modern TDI's so popular, as you have power, everywhere. You dont have to slam it down three gears and rev the nuts off it to perform an overtake, just a gentle squeeze of the throttle and your past.

    When driving a car hard, the priorities change, because your never in that low RPM range. If the turbo doesnt do much until 4k that doesnt matter, if your spending all your time between 5k and 8k.

    Theres also the point about picking the right sized turbo for the job.

    If you use a very small turbo, strung out to its last legs to make 300hp, then it'll make a great tractable street turbo with immense midrange, but it'll suffer at the top end as the turbo runs out of puff.

    If you use a very large turbo, barely ticking over, but still make 300hp, then you'll have the boost threshold and response of a 450hp engine, but only 300hp to show for it. The balance between these two extremes depends on the use case.

    The OP asked for 325-350hp. For that power level, a GT30 is absolutely into the "too large" category, (perhaps unless its the compact one with the smaller wheels), because its a 400-450hp capable turbo.

    To get the best from a GT30, you need to do a lot of other engine work, valves, cams, intake, etc etc. After all of that, you'll have a nice 400hp. But you didnt want 400hp. So either the goal posts are already shifting, which isnt a great start to a build, or the GT30 is the wrong turbo choice.

    At the original requested 325-350hp power range, the K04-064 is a great choice. Its an OEM part and comes with a decent manifold already attached. Its small enough to give a wide powerband within the standard engines safe RPM range, so doesnt need cams and valves and other stuff to get the best from it, and yet big enough to hold strong right to the red line rather than tailing off. It also has a bit of scope to go a bit futher, as shown by prawns 380hp figure, should you decide you want a bit more than your initial target figures.

    It seems to me you need to figure out what you actually want from this build before selecting parts. Starting a build with a random assortment of bits and simply shovelling random parts at it is not the way to go.
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  34. jasongtr
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    jasongtr Active Member

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    [Dec 5, 2013]
    nice post, lets move the goal posts then - and go for 400hp - just means it will take a little longer to pay for it, always was going to be a slow project anyway
    #33
  35. JJ.Foulds
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    JJ.Foulds Well-Known Member

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    [Dec 5, 2013]
    My engine is an AXX, mine is the A3 200bhp version with a k03?
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  36. badger5
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    badger5 www.badger5.co.uk Site Sponsor

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    what a/r turbo?? gt3071 is not he full spec
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  37. jasongtr
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    jasongtr Active Member

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    [Dec 6, 2013]
    not sure, I'm not all that on turbos, where will i find it?
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  38. badger5
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    badger5 www.badger5.co.uk Site Sponsor

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    [Dec 6, 2013]
    usually on the hotside casting, inside its throat if not on the outside
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  39. jasongtr
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    jasongtr Active Member

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    [Dec 6, 2013]
    ok, ta its 0.63
    #38
  40. antwan64og
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    [Dec 6, 2013]
    since the gt3071r .63 turbo is capable of 32+psi this is relevant.Bill, what do you prefer/recommend for street driven cars. A bigger turbo like the GT30r at moderate boost say 18psi or a smaller ko4 running at full chat.Which one stresses the motor less?
    #39
  41. superkarl
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    superkarl MAN OF STEEL

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    [Dec 6, 2013]
    Whichever makes most power will stress the engine most. Cylinder pressures and stress on components isnt simply a function of boost. If they are both performing at the same Ve then stress on engine components is the same. So whilst the ko4 which will be making more boost for same power as gt30 at low boost, will be under more stress, the engine itself will be under no more or less.

    What you should ask is which turbo is under more stress, or which is performing at a higher efficiency to acheive the same result.
    #40

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