1.8T engine in a VR6

[Kevin Bacon 5]

cheers kev, i want close to 400 when i spoke with the TT shop last week they seemed confident that a BAM with a K04 and emerald would be 280ish, with garret/ihi this would push it to 350ish but this is the limit of the internals of the 1.8t, a mate at work had an ihi ibiza cupra and made 347bhp and he said he always worried he was sailing to close to the wind with standard internals.

 

Yeah I'd agree with all that mate. 350hp is about the limit of the standard internals and even at that power, I would personally be running uprated rods and valves.

280ish defo the max safe limit of the K04.

GT28RS (Aka Disco Potato) will take you to 350ish but I would be looking at the GT3071R personally as it's a much nicer turbo and will do an easy 400hp :D 450-500hp max chat.

IMO you want the turbo to lead an unstressed life and it will last longer, so spec bigger than you need. A larger turbo flowing more air with less boost is always more efficient than a smaller one spinning itself to death. Lag is the obvious trade off, but full boost below 3500rpm is mostly wasted via wheel spin.

 

I was thinking 1.8t rather than VRT purely as i have been told the fuel economy is about 40+ on the motor way and average is about 30. You run your VRT daily right? how many miles do you cover?

 

40 mpg from a 1.8T is the stuff of dreams mate, don't believe a word of it. They are juicy engines. My missus's bog standard, 150hp, Polo 1.8T does 35.2mpg, and that's the newest version of Bosch ME7 running it and a K03S turbo. We worked it out over 3 tanks and it's pretty much bang on what VW quote for the car. On the missus's "live" MFA, at 60mph with a very, very small throttle opening, the MFA reads about 54mpg, but as soon as you brush the throttle a tiny bit and get anywhere near boost, it'll drop to 28mpg straight away. So 40mpg is difficult to achieve with normal driving.

A 280hp K04 1.8T in a heavier Corrado won't get close to 35mpg on a run, let alone 40, and that's assuming you can monitor mpg, cause you won't be able to with a standalone :wink:

My VRT's average is around 26mpg and I do 40 miles a day. It can drop to 8mpg at full throttle! For a 400hp car, 26mpg is very good imo and about what you should expect tbh.

I've tuned mine to be as lean as possible without sacrificing performance. It could go much leaner, but the resultant drop in performance and drivability isn't worth the few extra mpg.

It's "possible" to get good economy, but you have to drive very slowly and keep the turbo off spool all the time :D

 

So with a VRT your working with old engines, whats the best way to ensure a solid spec as my aim is 400, what ever my decision i want to build the engine seperately and then look to install it rather than work with my own so is it best start with an old knackered engine and rebuild the head with bigger valves? forged rods pistons etc? (i appreciate this is probably covered in your build thread and the forced induction vr one but i am trying to get an idea where to start!) Or try and source a vgc low mileage or new head/block?

 

I would start with a knackered 2.8 AAA block (they're stronger, don't ask why, I have no clue!) and fit some Wossner forged pistons and that's about it.

That will then give you 600hp capacity. After that you need to look at rods etc.

Optional extras include reworked heads for more flow, stronger big end bearings etc, but they're not essential.

 

The VRT is indeed an old engine, but it's smoother and a lot stronger than the 1.8T out of the box.

 

The 1.8T dates back to 1998 ish and is literally just a reworked 16V block with 20V head on the early AGUs.

 

So neither are especially cutting edge, but both are very competent at what they do and reliable.

 

It's the management and mapping that makes or breaks a project like this mate, so cut no corners there.

 

At the 400hp level, you can choose between VRT or 1.8T, the difference in cost won't be as great as you think.

[junkie 0]

Im going AGU now and i was looking into the GT3071R already, so Kev you say its a nice turbo can you shed some light on how nice it is please??? Also i think that will be too small lol im thinking go bigger, looking at Garretts site there seems to be alot of GT30's too, care to explain about them mate.

[Kevin Bacon 5]

You want bigger? LOL, nutter :D

 

"GT30" is just the family name of turbos in medium frame size category. Garrett are quite confusing with their model numbering as you will discover!

 

For example, quite a few people assume 'GT' turbos are all ball bearing, but they're not. It's the 'R' in the model name that denotes dual ball bearing. A plain "GT" will usually be a journal bearing, but there again, you can mix and match CHRAs (centre housings) and end up with a ball bearing "GT" turbo....all very confusing and stupid if you ask me, but Garretts are the most configurable and popular turbos out there and nearly every manifold except OE will be T25, T3 or T4 based, so it's definitely the right platform to be with right now.

 

Anyway, I digress....

 

The GT3071R was developed for Mitsubishi Evos wanting 500hp as the Mitsi turbos can't get close to that, so it's designed to be a very quick spooling turbo for small engines. It spools around 1000rpm sooner than the GT3076R. KadVR6's mate bought my old 3071R and he's installing that onto a built 1.8T, so I'm sure he'll give us some feedback when completed.

It's a nice progressive unit, and I think it will kick in around 3500rpm on a 1.8T, which will be spot on. It'll haul arse right round to 7000rpm, which is where the standard 1.8T falls short. It has virtually nothing past 5000rpm. The 3071R will soon correct that :D

 

I would get the external wastegate version and it will do 450-500hp.

 

You can't get more than 450 to the ground with FWD, so be careful how big you go!

 

If you want 500 - 550, you'll need the GT3076R and if you want 600-650, you'll need a GT3582R.

650+.....GT40Rs etc etc.... the "Large frame" big bastards....

 

Then again, you don't need a GTR at all, you can use a T04S, T3/T4e, IHI TD05, T60-1 etc etc.... the choice is almost endless.

 

The hardest part is deciding what you want from the engine. Choosing the turbo for the job is the easy bit.

 

The GTR turbos are expensive, and bear in mind that ball bearing turbo doesn't necessarily give you a massively faster spool over a journal bearing turbo. BB turbos have fewer parts, so tend to be more reliable and you don't have to be so religious with switch off procedures. Oil quality isn't as critical with BB turbos compared to journals either.

Loads of advantages.

 

So what are you after then? Quick spool and huge power I bet? :D You can't have both with one big turbo on a small capacity engine I'm afraid, there will be the inevitable lag!!

[junkie 0]

Cheers Kev once again your the man.

 

Yes in an ideal world i would like both good traits of no lag and huge power but i know its not possible.

 

Basically i dont need or use the car as a daily so im going to make it into a very nice toy lol, so im thinking if its possible to have the power band between 4k - 9k on a middle size turbo - to big bastard, ideally 450bhp i had in my mind already and an external wastegate version, rods pistons and valves and maybe and most likely 1900 to help spool the big boy sooner :D

 

I do get the "GT30" is the frame size but they have renamed/rebranded the "names" of the turbos from years ago, as i used to know it the T3 was middle size and T4 was huge so what does this mean now for the manifold side of things?

 

I know it is alot of power for FWD but how do you know its too much 450+, is it possible with the right set up and im not talking just a diff and sticky tyres but full on proper well sorted chassis etc?