Would This Be A Safe Tune?

[bored33]

hey guys,

currently my car (r33 s2) has the following modifications done:

- pod

- 3" catback

- 34 smic upgrade

- running 12psi

i have had it dynoed at bd4s and achieved 180rwkw, im planning to get the f-con v pro with the evc 5 (will be running 14psi). bd4s have told me that they can make 200rwkw, so the question is - would this be a safe tune? the reason i ask is because there are other skylines (same model for comparison) with twice as many modifications (comparing against cars with fuel management systems and other modifications) making only what they promised to get for me. any inputs guys? i just dont want to make that kind of power and end up blowing something later on.

cheers

[R31Nismoid]

14psi is NOT safe on the stock turbo.

Anything more than 12psi is a risk to killing it.

[bored33]

cheers thats plenty of an answer for me to not go through with this modification

[LatinR33]

I would not risk pumping anymore than 10psi through the stock turbo just to be sure.

Also I dont think you would gain anymore power over 12psi on a stock turbo anyways.

[joeyjoejoejuniorshabadoo]

my hks 2835 pro s is in a container somewhere between tokyo and here..... the stock turbo has been on 12psi and spiking out to 15 at times (lazy bleed valve install that i CBF fixing with new EBC waiting to go in) for a year now...

so less than a month to last... talk about rolling the dice!

/topic gank

[Simon-S14]

oh god... better not boost it to over 1 psi... might risk killing it!

seriously people. grow a pair!

10 psi is dick all, 12 psi is fine, and even 13 psi is doable.

Boost doesnt kill turbo's, shaft speed does. and most stock turbos that are boosted ive seen spike to 14 psi in the midrange then die back down to 11-12 psi at 7000 rpm.

the shaft speed of 14 psi at 3500 rpm is much less then that of 14 psi at 7500 rpm....

[R31Nismoid]

so you wanna tell the countless people who've run more than 12psi ... they should grow a pair of balls because their lacking them killed a turbo?

Seriously...

[Munkyb0y]

how about this? lets say you run 14psi, or 15 or 16. and it doesnt blow up. does running the turbo past it's efficiency mean that it's now creating hotter intake temps? ie unhealthy - detonation scenario?

Edited March 12, 2008 by Munkyb0y

[MR 33]

Yeah keep it under 12-13psi if you want any kind of reliability. Mine used to spike (from other causes) to around 16.5psi and drop back to 14.5. This lasted for 4 weeks lol. Though it's demise came from the bearings shitting themselves rather than the exhaust wheel exploding.....Up to you really. I know 1.1bar was fun for that 1 month

Edited March 12, 2008 by MR 33

[Pal]

i've run mine on 12 psi since having it 4 years now. if you dont thrash the living guts out of it, it will last. (maybe)

mine is set up to spike to 12 psi and then drops back to 10 psi at end of rev range

Edited March 12, 2008 by Pal

[fab34]

well i just put in a ebc and my low boost is on 6 and high on 14 on a stock turbo r34gtt its been like that for 5 months now and no problems (YET)

Edited March 12, 2008 by fab34

[bored33]

i have been running 12psi for about a year now with no problems what so ever (ofcourse with the occasional thrash here and there) but at the end of the day a 96 built car is getting old and no point risking it! maybe ill just upgrade the rest of the car to get the power i want but driving a tuned car feels so much more nicer. mayb even tune the car and keeping on 12psi wouldn't hurt.

[GOT04]

14 psi is perfectly fine for a standard rb25 turbo and engin... i did it for a year and a half, not 1 problem

some people have no idea

[paulr33]

whilst we could all sit here all night and debate compressor wheel speeds and various turbocharger failures etc none of it is %100 guarantee

its all based on experience, state of the car, state of the turbo, state of the tune, state of how the car is driven and many many many other factors

just cos XYZ run 14psi for XYZ days and it didnt fry doesnt mean that ABC can run 14psi and not fry it. likewise at 12psi, just cos it works for most dones't guarantee you wont fry it.

can you afford to rebuild/replace the turbo if it fails?

you have option of a 2nd hand stocker $500 ish

you have option of a new ball bearing unit $1300+ (gt28 vanila garret etc)

you have option of rebuilding to highflow spec $2000

- yes and happy to spend $ when it fries

run 12,13 or 14psi and away you go

- no but if it came to it, i would find the $ to replace it

run a safe (12psi) moderate setting and hope it doesn't fail

- no and absolutely cant afford $20 to fix anything

run a safe 10psi and leave it at that

other info

12psi on an rb25 and 12psi on an rb25 attached to an rb20 are not the same thing, the rb25 engine flows more gas - its not the same comparison

there have been known cases where turbine failure can cause engine failure, which means engine rebuild which is usually $2000 ish in reasonable cases

heat is the main killer usually, from state of tune or shaft speed too high (higher boost means faster shaft speed)

the compressor wheel is rated to a given PSI, after that PSI level any increase results in minimal gains but excessive stress & heat

most guys on this forum will say 12psi is about that level for the stock rb25 turbo - so going to 13psi is great, but it might not give you much more power, even though "its more PSI, so it must be"

in most reasonable cases, once the compressor is past its effiency (lets say it is 12psi) then you just dial more heat into the engine (as the compressor is spinning too fast) and put excess stress on the shaft and wheels etc.

commons signs of turbocharger failure

- oil in the intake pipes (oil seal is shagged) - if you see oil in your pipes, wipe it away and check in 2 days, if it comes back, your oil seal on the turbocharger is leaking (note: CATCH CANS HIDE/MASK this issue away, so if you have one, check that)

- whinnny / noissy compressor windup can indicate shaft / bearing wear

- puffs of smoke, pops and then lack of boost would indicate turbocharger failure (exhaust wheel fail)

- small bang and then lack of car power could indicate compressor wheel failure (its plastic on the rb25 turbo) and this can be ingested into the engine (we saw a compressor mashed into bits and stuck at the throttle body on one engine)

turbochargers like most things dont live forever, there are things you can do it try and keep it for as long as possible

as per the nissan spec (pretty sure) they should be serviced every 100,000kms and i can guarantee most don't do it

by service i think it means new bearing kit, balance the items and inspect any other compressor/wheel damage and replace as needed (ie: almost rebuild)

[R31Nismoid]

14 psi is perfectly fine for a standard rb25 turbo and engin... i did it for a year and a half, not 1 problem

some people have no idea

Yep, you

The number of people that have killed them is support enough for the argument.

If it was a number you could count on one hand, i'd agree... but it simply isn't. Have a read of the turbo failures

[joeyjoejoejuniorshabadoo]

sorry to start this one paul / ash

i know that 12+ psi is a boo boo... i just don't massively care... if it blows i'll fix it. but most people don't really look at it like that...

if i have to rebuild it then thats ok as i have a fresh motor waiting for me anyhow....

prolly should have stated that in my post

Edited March 12, 2008 by joeyjoejoejuniorshabadoo

[paulr33]

also for the original poster get a suitable FMIC, i woudlnt bother with a SMIC given the cost of FMIC kits these days

most workshops can do a std style FMIC fitted for $500 and dont even bother with the f-con

only HKS dealers with pro access can tune FCON and there would be like 2 in austrlaia

go with a local supported - motec, microtech, powerfc, autronic etc etc - ask some local tuners (pick 5) what they can and do support

FCONs are a great ecu, just a pity no one can tune them in AUS

[bored33]

ahhhh the FMIC.. i have been looking around to getting one of these but for the power i want to achieve didn't seem worth while to get (maybe i'm wrong comparing $500 to $1800) ive been looking around for other alternatives like the powerfc though so im taking my time doing alot of research before i make my decision. its not so much the power i want but the tune for a better ride.

as for the turbo itself, sure maybe one day it will blow.. everything does! but keeping it on safe boost levels will delay this outcome so i will stick to 12psi at most on my stock turbo until i am forced to buy a bigger turbo.

apart from that thanks alot for all the input guys!

[Simon-S14]

how about this? lets say you run 14psi, or 15 or 16. and it doesnt blow up. does running the turbo past it's efficiency mean that it's now creating hotter intake temps? ie unhealthy - detonation scenario?

no if these turbos had steel rear wheels they would run at 15-16 psi effectilvly all day every day, with the power gain to go with it,

They are not as weak as people make them out to be, And as i said before, X amount of boost does not mean they will fall apart! its over all shaft speed that kills the ceramic wheel

[R31Nismoid]

Who is going to run a half asses setup that doesnt hold boost past the midrange?

So a spike to 14psi and then a fallout to 10-11psi?

No-one because its a crap way to setup a car just to save a turbo