1.8T Turbo Choice - Read a lot already, after opinions

[fussellwadman]

Hi,

Just signed up as I know there will be a lot of people here who know this inside out.

I've read a lot about the various options here and elsewhere but the more I read of all this general info the more it gets muddied up.

If we forget any issues of fitment, plumbing and custom downpipes and just focus on the engine and turbo that'd be cool.

The criteria is oddly specific as I would like to be at the lower end of the 300bhp to 400bhp bracket on a stock *sized* 1.8 AGU with a near stock rev limit and some rods in the mix.

To get it out the way first, K04 Hybrid. Eevery time I see one mentioned it's maxxed out and has WMI and this and that. That's all good and there are some impressive cars about, Badger5's Lupo and so on, but without Meth and without a need to go much past 300bhp for example, would EGTs still be mental?

Either way, I come back to the usual worries over cracks forming and the tiny housings naturally lending themselves to getting hotter than hell...

So that leads to the next option which would be a Garrett. I like the idea of a 2860 but I'm not sure if it would run out of puff for trackdays? If that would, a K04 Hybrid sure would, so kind of a mute point I guess.

Next in line seems to be a 3071 as you're not sacrificing hugely in the lag department, yes there's a chunk more, but on a track with a gear stick at your disposal it is what it is, but with way more headroom.

I think being honest that a 3071 would give more power than is required, I have a lightweight FWD A3 and will use it at Thruxton which is relatively wide open. Would exhaust valves want to be included if it went this far or would it be no more (or even less) of a concern than with a red hot K04 Hybrid?

Interested to hear the opinions around on this. What did you go for or what are you planning on going for?

Thank you!

 

[fussellwadman]

Forgot to mention, missed an obvious one in the post before.

This K04-064 that's on a few quick 1.8T's (some of which seem to reside here) I've seen at tracks recently... Bolted to a 1.8T with one of the available adapter plates, running at 330 / 340, would you be as concerned with cracking of the manifold / housing as you would with an old 1.8T K04?

I know given the larger size and capacity the EGTs won't be as worrying and especially as I won't have to push it as hard.

Truth be told I'm leaning toward the K04-064 or possibly a GTX2867 but it'd be on a sh*tty cast manifold if I went Garret, so not ideal, plus I dislike the whole Garret "no servicing, buy a new core" deal almost as much as I dislike the idea of cracks showing up in OEM K0__s.

Thanks again!

 

[fussellwadman]

Wow forums really are dead.

Thanks to everyone who had a gander either way.

 

[Bluepower]

The K04-064 will suit your wishes pretty well. as you already mentioned, at least upgraded rods are necessary. WMI is optional, but does help prevent knock and lower EGT.
but for yourself, you need to make the comparison in budget between a K04-064 with all parts needed(adapterplate, DP, oil/water lines, intake) vs the GTX2867, to see which is the more preferable.
If ' only shooting for around 350hp, I would get the K04-064, although at those power levels, the turbo is almost out-of-breath. the GTX will push beyond that, but at considerably higher costs(core turbo+manifold is more expensive then a K04-064)

 

[ZpiX]

For your power range go GTX2860, and have room for improvement if you go for Rods and so on

My brother had a Caddy Mk1 with 360hp on a AGU running GT3071 and stock internals, but the boost came late and explosive, not that driveable for the road with a limited slip diff (car got stolen )

Now he got a Golf mk 1 with 440-460hp on AGU with a GTX2860 (Flex fuel oct 100/E85) even with 100hp more its soo much more driveable on the road even with limited slip diff
Best 1/8 is 11.98sec.
(This one has ported head, JE pistons, rods, costum intake with planum and bigger E-gas throttle and cast iron manifold. the old was on stock internals only run 1.4 peak boost, and had WMI)

The cast iron manifold is only to "hide" the turbo in the engine bay, so far it makes good numbers and no cracks, been in use for 4years.

 

[ZpiX]

Edit: Was abit fast, get confused with those garret numbers
You could go up to GT3071R if you want that more power, but not bigger for a track car.

The Caddy was GT3076R and the Golf has GT3071R, my bad

 

[EG-Nath]

must admit i was looking fir the same info, cant believe 20 years on people are still selling turbo kits for 2k+ for these engines

and the used market seems to be non existent unless you sit pressing F5 on ebay lol

if you go through the hastle of fitting rods then you may as well do other stuff at same time, then fit the slightly more power capable turbo and have some breathing room to go from 300-400hp if you ever wanted to

 

[desertstorm]

The problem with any K04-23 "standard" size turbo is the manifold . Really there is only one option that will reliably do 330bhp plus and that's a ported Chinafold. All the other tube manifolds will crack especially on a track car . Badger 5 used to sell a complete package but no longer sell the Chinafold probably because of the work to port it and make it work right but also supply may be an issue these days.
https://badger5.co.uk/turbo-exhaust...old-aet-k04-380-v2-2-tipexchangespecial-order
This setup has made over 400bhp on well tuned fully sorted engines. Would make a reliable 340bhp on a track car.
There are plenty of used turbos and manifolds on the 1.8T . The K04-064 setups are awkward to install with the position of the turbo and not so great compared with a big turbo when used on track.
Your best bet would be something like a GTX2867r , Turbos like the GT3071 are good but Garret don't make these now . The Mamba turbos have been used by people with good effect. Try to avoid a T25 manifold, small bolts on the turbo flange have a habit of coming undone. T3 is better.
Getting a turbo with a built in wastegate usually makes things cheaper and less complicated.

 

[fussellwadman]

Firstly many thanks for the replies, some good bits and pieces to mull over and real world experiences are immensely useful, so thank you!

I know Badger5 do a lot of big power 20v's but I have no use for more than 350, so many people use power to make up for driving and power to weight will be verging on a BTCC car so there will always be faster lap times to come from the chassis and the driving ability than more power and it feels like cheating to just throw more at it.

Agreed the Garrett option sounds the most fitting, but again I know the core / roller bearings have their advantages over journal bearings but I very much dislike the "a bearing has failed, please give us a grand+ for a complete new core" side of Garrets. With modern wheel design a journal bearing turbo can behave perfectly reasonably.

Starting to think someone really needs to get a good - cheap - TD05 manifold together

 

[desertstorm]

I read your first post again and if the main track you are going to is Thruxton then power makes a LOT of difference there. It is one of the fastest track's in the country My car has done 511bhp on Badger 5's dyno on the top map. I use an Ignitron stand alone ECU so have 4 different maps all changeable on the fly 1.6-2.1 bar with the cruise control switch. And a race mode to enable anti lag and launch control, also puts the ECU onto the highest boost map. On track I don't run on the top map all the time usually run 1.8-1.9 bar and use the race mode switch like a push to pass.
The EGT's are too high after more than a lap or so on a track such as Donnington or Castle Combe if you run 2.1 bar.
It's one thing making 350bhp on a dyno where the car is running flat out for 45 seconds compared to 15 minutes flat out on a track session. You want some in hand to make the car more reliable. High EGT's and IAT's don't help power at all. So if 350bhp is your target on track build it for 400bhp.
As for journal and roller ball bearings, pretty much all modern turbo's are roller ball as they offer much better response from spool and efficiency. And if you are running the turbo at it's limit
A BTCC engine may make 360-370bhp , nobody will tell you how much or show you a dyno pull but they will probably make another 40-50bhp as they are boost limited . This makes them more reliable as they are only run around 85% of their capability.