Limits on std 1u internals

[1ulover]

Hey,

I've been searching around the forum- I'm considering a custom twin turbo project on a 1u and was trying to get a consensus on what kind of power and boost limit the STD internals on a 1ufe people would advise on.
"Limits" on engine strength are always subjective and open to interpretation however if anyone has some anecdotal experience or other info would be greatly appreciated.

So far I've read some information that confirms they are a relatively strong engine with some great features for durability.
My application would be for a daily driver with satisfactory support mods (i.e. effort into cooling, oil cooler, fuel injectors/pump, ecu etc etc).
I'd like around 400-450hp at the wheels on a safe tune of say a ~12AFR and ~13' ignition advance.


Possible with year long durability (if not abused obviously).


Thanks!

 

[poid]

450hp at the wheels will not be a problem as long as the engine is in OK nick

 

[1ulover]

Great - what kind of boost limit or safe level should be used to achieve that? Guys on the forum seem to range from 6-7 up to a few running 1bar?
Thanks for the info

 

[Lextreme II]

I am running 1 bar daily and ran up to low 20s few times. For sure 1 bar is safe with decompressed gaskets and more fuel.

 

[morris]

How many miles on the engine? I have 235,000 miles on mine. Even though the leakdown and compression tests are all good I am a bit nervous about running 15psi on the stock internal engine, what are your thoughts?

if 15PSI is safe for stock internals then what would you feel is a safe level with the newly available forged internals, rods and pistons?

 

[Lextreme II]

i would say mid to late 20s.

 

[Jeff Taylor]

How much power, or what times, are you making on that setup?

reason I ask is that 20psi on dual t25's is different than 20psi on a T70.

Jeff

 

[1ulover]

So it would be fair to say that the main vunerablitity would the piston/rings due to the high comp ratio? And you would only really experience failure from knocking & pre-ignition, so tuning is (as always) paramount.
Seeing how the standard crank and rods are forged (correct me if I'm wrong), to get to around 500rwhp would you guys suggest basically (forget ancillaries) just forged pistons with a comp 8.5-9?
Anyone in Australia know how much a shop would charge to change pistons in labour?
cheers!

 

[AGRO64]

so going by comments here would it be fairly safe to assume 12psi from an eaton m90 would be ok providing fuel and tuning are done correctly

 

[poid]

i dont believe the rods are forged, but they will hold a lot of horsepower. I would say that excessive rpm will kill them much faster than torque and hp

for 500rwhp i wouldnt change a thing, except maybe a decomp headgasket if you have to run a lot of boost. I plan on testing limits on this engine...i want it running at least 700rwhp (and i think the stock engine can hold this). Of course i am a long way off doing anything yet unfortunately

12psi off an m90 should be fine with proper tuning and enough fuel

 

[Miles B]

You'll probably want water or methanol injection, or intercooling, for that 12psi.

 

[poid]

intercooling of some sort is a must for any turbo setup on an NA car IMO

 

[AGRO64]

just trying to sort out roughly where i stand. Aimed for a safe 8psi but ended up with 12. Got a few other things to chase first but wondering if lowering the boost needs to be on the to do list also as there is no room for intercooling without big work

 

[Zuffen]

Agro,

What's the engine in?

Slipping an intercooler between the M90 and manifold is not too hard if you have the room above the engine to fit it.

You would need a minimum of 50-60mm clearance.

 

[AGRO64]

Mate its in an eh. There definately isnt enough room as one of the bonnet braces has been nipped to give clearance for the pulley so any more and its out the bonnet which is one thing i definately didnt want.

Also heard that the injectors may struggle to keep up, is this true and if so are there any that can change straight over?

Sorry to hijack the thread

 

[Zuffen]

Agro,

Search this Site under "injectors" there's miles of info.

 

[AGRO64]

cheers.

thats all i wanted to say but apparently i need 10 characters