[Mk2] [Turbo] GT3071R on stock engine with bolt-ons

[Rahzel]

Hi guys.

Over the past few months i've been thinking about looking at my engine next year with the intent of upgrading the turbo. My car feels slow now and i want a bit more punch from the boost.

My engine is pretty much stock including headgasket bar a HKS Silent hi-power exhaust, apexi filter, greddy type-s BOV in recirc mode and greddy profec-a boost controller and fcd. Oh and upgraded Rev 3 brakes.

I've really been thinking about going down the route of the 3071r. Whats peoples thoughts on running this on a stock block. Am i gonna need to get it forged? I know fueling, headgasket, ecu, and intercooling will be required upgrades.

Would you run it on a stock block till it blows? I know mapping will play a big part in a safe engine.

I'm not to clued up when it comes to going down the bigger turbo route and i wanna start getting some ideas what to do.

Your thoughts and advice would be appreciated

Cheers

[Ryan S]

you'd notice a MASSIVE difference on the stock turbo with just a downpipe, decent intercooler, filter and exhaust, , i'm sure some peeps will point you in the right direction!!

[3S Service Centre]

You will need forgies because the stock pistons will poo themselves, how long it lasts is another question.

One of my lads ran a gt4 over 400hp on a stock block for a while and they really abused it.

My advice is go for it keep fueling on the rich side, make sure cylinder 2 and 3 get a bit more than 1 and 4. Drill a hole in your thermostat to run the engine temps a tadge lower. If its rev1/2 atlest put a metal gasket in there, if its rev3 drill a bigger hole in the thermostat

[Chris]

Forgies and a Rev3 HG are a minimum. I can't see a Rev1 lasting 2 mins with a GT series turbo and stock pistons. Ringlands will go in no time.
That's if you can get any boost out of it with stock fueling.

[nikaiyo]

Hybrid Ct20 or TD06 at a push would prob work

[3S Service Centre]

On the basis the OP said

" I know fueling, headgasket, ecu, and intercooling will be required upgrades. "

It could well last months if mapped right, the gt4 certainly did.

At the end of the day any choice of turbo will be expensive so my advise is choose once to meet your power goals, you can build the engine in advance or simply when you have to. Its not the usual route to ride the stocky on the ragged edge but has been done before.

[gavinda]

water injection may help it last a bit longer on stock bottom end

[Jimbob]

My mate broke his GT4 at 1.2bar. Stock pistons are kek. A gt30 will be tame at 1.2bar, run it over 1.7bar and stock pistons are not viable. The risk is you really break something and scrap the the whole engine. If your happy to budget for a new block then ok, but not really sensible.

[KO Racing]

The stock pistons have proven to be fine as long as they are not detonated on. Cylinder pressure alone won't blow them up. Proper tuning/mapping is definitely the key. One good knock will crack the factory piston ring lands. If your head gasket is in good shape, it should be ok as well. I normally don't tune over 18psi on pump fuel and 22psi with 110 octane fuel on a stock head gasket and engine (gen 2). Certainly changing those parts will help to make a more durable motor, but it depends on your budget. The risk of destroying the entire motor is relatively low I think, as typically you'll get a head gasket to blow or crack a ring land. If you pay attention when either occurs, you'll be aware of it pretty quickly via overheating in the case of a head gasket, or now the engine sounds weird and oil comes out of the breather like gangbusters if the ring lands crack -- also low compression motors sound different while cranking the starter.

For that matter, if you want to get the turbo now but keep things very safe, just run low boost: say less than 14psi. The stock ecu will do fine with it and you should be well within the factory fuel capacity. You'll enjoy more power than the factory turbos at siimilar boost and can save up for mapping and engine building down the road.

It doesn't have to be bullet proof if you don't shoot bullets at it.

[Rahzel]

Cheers for the food for thought guys. I really appreciate it.

Obviously we will have conflicting opinions when it comes to stock/forged subject.

I ask because at the end of the day my engine runs. I want it to be more powerful. My thought is that i could go ct20.. get bored... then i will need to uprate fueling and intake cooling anyway... ecu etc. I had a CT20 on my old rev 3 and.. although it held boost better than my ct-26 it was never much different. So its going to cost me which ever way i approach it. So why not spend money on what i dont have ie... fueling, intake cooling, ecu and benifit from them get it mapped and run it at a safe pressure. I know im gonna have to spend on these items anyways so why not get them first and leave the block till last? When it goes then upgrade the bottom end and up the boost more

I'm trying to find the best path to get the best performance value for money out of my engine that i can.

btw i dont have a power goal as in a number figure... i just want it to be a bit faster. I think its better to be suprised than shoot for a figure.