13 or 14 psi on stock turbos?
 

Ok my fuel system is upgraded enough to run 20+ PSI on BNR's

and within the next year I will be upgrading my turbos to said BNR's

So for now .. I've had my turbos at 13 psi . I havent dyno'd it but car pulls fine .

I picked 13 psi , because its said that 12 is the safe range for the stock turbos anymore then that and they start to die quickly .

so I figured 13 ,

since they will be getting replaced within a year .


BUT just out of curiosity , why is it that I never see anyone running them at 13 PSI

everyone seems to jump from 12 to 14 psi . i know 14 is the effective range of the stockers and they start to put out superheated air after that

SOOO I started to think and I'm curious , would it make much difference to the turbo's life if I upped the PSI by 1 more ?

why does no one use 13 psi ( bad luck number? LOL )

:lol:

The only thing I can really think of: PFC sets wastegate duty based on kg/cm^2. 1 bar = ~14.5 psi = ~ 1 kg/cm^2. Easier to set in the pfc maybe? Honestly I don't think it really matters...

Because the turbos are terribly inefficent at higher boost levels, at some point, all you're doing is turning the turbos in nuclear-hot hair dryers.

Some people get away with it by running water/meth injection or using highly efficient liquid or air intercooling.

Some people are pushing 22psi and they're not getting anymore power out of them compared to someone running 16-18psi.

The limit on the turbos is right around 12 or 13 psi. Its usually the recommended SAFE boost pressure on limited supporting mods AFAIK.
The 99 spec turbos are a little more efficient at higher boost levels, but again, the BNR's are the big ticket

If you're going for the Stage 3's, and are looking to get them within a year, you can up the boost as high as you want to find the limits of the stock HT12s yourself. My guess is 16psi before you start pushing more hot air than usable.
Thats about the limit I saw with my own copy of a M2 large SMIC using a Garrett core. around 17-18psi you're risking detonation. Especially in hot texas summers like I'm in.

I've seen a lot of people punish the stockers and they held up fine for 1-2 years. And since BNR uses brand new turbos for the Stage 3's, you won't be seeing any use for them after the upgrade AFAIC.

For my stockers when I went Stage 3, I had to send my manifold to a local welding/fabrication shop to fill in all the cracks that it and and machine smooth the gasket surfaces, I also had them port the manifold a bit as well since the turbine inlets for the BNR's were a little larger. Not much, but I'm a bit OCD.

I dont think I can go any higher then 14 , since i dont have an upgraded map sensor yet .

But I guess I may as well up the boost a bit lol

I have been running 13 psi for years. I did it with my M2 stage 3 ecu (original engine), and now with my pfc on the mild port motor.

I ran 14 spiking to 16 on a Pettit ECU. Like you, I was going single and didn't really put a lot of miles on my car anyway. The twins continued to do fine.

thanks i'm gonna try and tune it for 14psi

Just keep a good margin of safety for spikes. Remember that as IAT's climb, you are not helping your engine any. If you dont have your eventual upgraded intercooler in place, I would move that direction. Water injection is also a mod that I recommend sooner, than later.

Heat is the real enemy here. Ambient engine bay heat, air intake heat, and combustion heat. The more you can do to reduce the heat at all levels, the better off you will be. This is part of the reason people move from the twins. A cast oem manifold projecting heat to aluminum housings.

already running water / meth injection , and I already have an upgraded intercooler . just waiting for free time to install it

with my meth system it runs about 5 C colder then without it , AIT at 13 psi . 39C instead of 44C i'm hoping a new intercooler would further help that LOL

Just putting it out there but there is a pretty wicked group buy on the stage 3s going on right now..
Maybe something to look into

thank you for hte heads up

If it was me, I'd stick with the 12 psi since you do not have an aftermarket map sensor. You will need to get a new sensor for the BNRs anyways and they are reasonably priced so you may want to pick one up quick before raising the boost any closer to the limit of the stock map sensor. Going over just once could be bad!

I ran 14psi on my daily driven FD for about 4 years without a problem.

what were your mods?

Just stock motor, 3" exhaust, dp, mp, power fc, intake, fmic, supra tt pump, and what other little boltons.

Back when I first started playing with FDs, I upped the boost on stock 93 twins to 14 psi, and then upped it further (not knowing what I was really doing, more boost must be better, etc)

Car had a PFC and downpipe, cat and airpump delete, stock engine, stock twins.

Took it to a race meeting at a local track, and on lap 2 the front turbine wheel (cold side) snapped its shaft, and the turbine wheel spun around inside the alloy snail, acting like a grinder, and grinding the alloy housing to bits, and mangling itself up, before wedging itself sideways in the inlet of the turbo.
Alloy chips flew through the intercooler and found their way into the engine. It blew a rear rotor very shortly afterwards.

I learned that the stock turbo's turbine shafts are very small diameter, and can shear at high boost. Look at the BNRs and the Knightsports twins. They have thick inconel turbine shafts for this reason.

ohhkay so no more then 14 psi LOL

Go ask the 10 second on twins guy about max boost.

Just because it worked for one person doesnt make it a smart decision.

I ran 12-14psi on an original 80k mile engine for about a year. I locked the motor up about 8 months ago.

That said, I was stupid to do it in the texas 100F heat without water injection. But man it was fun... Sequential 330 RWHP is damn fun on the street.

run a step cooler plugs and upgrade your fuel pump (if you havent already) and intercooler. Do you have a commander to monitor knock? Maybe experiment with less meth, more water to make sure knock numbers are low.

with enough cooling you can offset the stock turbos superheated air a very good intercooler setup + meth can offset the heated air in them .

BUT since this car is a street car and gets driven fairly often . I wanted a semblance of reliability . being the fastest car in the world is not my goal , just fast enough and still be reliable .

BUUT I did read about him hahainfact one of the inspirations for upping the boost a bit from 12 wwas that .

Get all 9s for spark plugs. Forgot that in my mods.

as far as the power goes...
it seems to work....
but.... I don't think it will last at that level

already did the colder plugs .

I'm running windshield washerfluid with which is mostly distilled water down here in miami . I make my own mix when I want a bit more using denatured alch. but cheap wind shield washer fluid is good for now. hah .

that happened to a friend of mine, the turbine wheel and shaft actually came out of the turbo, followed by most of the oil.

the turbine was missing, it actually passed thru the exhaust, and it took about 2 weeks to burn off all the oil out of the exhaust.