Rb25det + Hks2535 @ 19psi Safe?

[DjeMz]

sorry guys, real quick q...

this is my tune:

my hks adjustable actuator only goes down to 19psi... we tried all methods, its the lowest it will go... im running a stock dump/front... some ppl say its overboosting coz of that, some say it wont matter im sick of hearing bs, all i would love to know is if running 19psi n the occasional limiter bash at winton drifts next sat will be safe?

i ran this exact setup for a year n a half n a couple of weeks ago cracked first n 6th piston (looks like an over time thing)... i would rather not have a repeat of this if boost was the cause.

thankyou in advance!

emz

[silva33]

I used to have the same setup on my R33 and to be safe I would turn the boost down on track days ad also run a quality octane boost.

Does it hold 19psi to redline? if it falls off towards the end of the rev range then it may not be to bad.

Is the motor built for 19psi?

[DjeMz]

holds 19 still redline

motor is stock

[paulr33]

why on earth would you run a larger turbo with std front and dump pipe?

no wonder you cant lower the boost, its trapped in the housing!!

change the front pipe/dump pipe even if you dont want more boost

[limpus]

We'll all heard this so many times from you...the solution to your overboosting is your stock dump...it has been told to you several times...whether or not it holds to redline is beside the point at this moment...

Now...as for 19psi at winton...its probably not the best idea...especially if your high boost is a result of a restriction...people usually wind boost down a few psi for safety at the track...couple of laps at WOT will have EGTs through the roof as well...and then risk of detonation will be another issue...its a bad idea if you ask me...and is an accident waiting to happen...

[RBwhatever]

yeah, $300 or so for a free-er flowing 3" dump/front pipe is not expensive. It should've been one of the first things to get done. And if its its not done now then do it already.

[DjeMz]

i had 2 different 3" dump/fronts

both different brands (i wont mention on the forums) one was the split n other the bellmouth design and both warped.. one from the turbo/dump n the other from the front/cat.

f**k buying cheap 300 shit.

does that answer ur question? sorry i dont mean to be rude but as a student i cant just go off n buy expensive shit, especially not a week before winton lol.

im just really after a quick fix for next weekend, then might sell my recaro seats n buy a proper jap dump/front.

cheers guys

[R32 Driver]

no real quick fix

but i guess a 2k engine isnt that expensive, rb25s are getting cheap these days anyway

russian roulette? GAME ON!

[RBwhatever]

How the heck did your dump/fronts warp? Thats the first I've head of that happening. Maybe you've got something else wrong as it shouldn't be heating up so much that it warps your dump/front pipe.

[DjeMz]

first one was kinda my fault..

every1 warned me that the gaskets that came with the kit WERE SHITHOUSE... but some people said they will be fine. so instead of going to nissan n getting some, i just used the ones that came from the kit... my fault coz i got lazy.

2 weeks later, gasket failed, exhaust leak for a day or 2... ordered gaskets off nissan, pulled the dump off n realised the metal warped, no chance it was going back on so i returned it.

different brand kit, used the nissan gaskets... this time warped from the front/cat... looks like it was caused by shitty welding.

till this day i havnt heard anything bad about the jjr items... can they be trusted?

Edited August 28, 2008 by DjeMz

[RBwhatever]

Well, I bought the Xforce bellmouth in mild steel and its been a treat for the almost 2 years i've had it.

Maybe get one fabbed up for you at a reputable exhaust shop. Shouldn't cost you a great deal more and at least you know the quality will be good. But yes being a student and funds and stuff etc etc....

[Pattygtst]

try a different brand pay a little now or pay alot later

[Al]

That boost and those a/f ratios at the top end; you're asking for trouble.

RB25's are known to have weak ring-lands and the boost and leanness of the tune will generate more heat which can cause issues. I personally wouldn't risk it.

I consider anything over 12:1 a/f ratios, on a std RB25 and doing track days a BIG risk.

I ran 18psi, with 11.5:1 a/f ratios and still managed to crack a ring-land, pics below. All other components were in top nick, even the piston top, bore, etc of the cracked piston where completely undamaged.

Don't worry about split pipes or stainless; just get a custom made bell-mouth mild steel dump from a good exhaust shop. Should not cast you too much.

[DjeMz]

^^^ thats exactly wat happened to my old 25...

"I consider anything over 12:1 a/f ratios, on a std RB25 and doing track days a BIG risk."

drifting at winton isn't as bad as circuit, we do a few corners n line up for 5-10 mins then go out again...

i need something asap before winton, im not going to risk my new motor over it..

Edited August 28, 2008 by DjeMz

[RBwhatever]

^^^ thats exactly wat happened to my old 25...

"I consider anything over 12:1 a/f ratios, on a std RB25 and doing track days a BIG risk."

drifting at winton isn't as bad as circuit, we do a few corners n line up for 5-10 mins then go out again...

i need something asap before winton, im not going to risk my new motor over it..

If your short of the $$, maybe someone close by to you would be willing to let you borrow one for a short time. Otherwise, maybe you'd want to check the for sale threads, there's cheap second hand goodies in there.

[DjeMz]

yeah im chasing up some already... theres one for 150.. jjr 2nd hand.. ill try that for now n save for a custom/decent one later down the track

[acsplit]

That boost and those a/f ratios at the top end; you're asking for trouble.

RB25's are known to have weak ring-lands and the boost and leanness of the tune will generate more heat which can cause issues. I personally wouldn't risk it.

I consider anything over 12:1 a/f ratios, on a std RB25 and doing track days a BIG risk.

I ran 18psi, with 11.5:1 a/f ratios and still managed to crack a ring-land, pics below. All other components were in top nick, even the piston top, bore, etc of the cracked piston where completely undamaged.

Don't worry about split pipes or stainless; just get a custom made bell-mouth mild steel dump from a good exhaust shop. Should not cast you too much.

Its not the afr's that kill the engine ................... it doesn't matter if you have a "richer tune" if it detonate's it will do more damage with rich tune than a lean tune.

Maybe your solution is to fit a better dump pipe then check / retune or not fit the dump and get a safer tune ?

I am not suggesting your tuner did not tune it safe but if you don't want to blow another cheap shit rb25 then get it detuned.

[DjeMz]

it was much richer before on my old block, used to pump out black smoke on wide open throttle... to me this is a much better tune then the last..

[Al]

Its not the afr's that kill the engine ................... it doesn't matter if you have a "richer tune" if it detonate's it will do more damage with rich tune than a lean tune.

Maybe your solution is to fit a better dump pipe then check / retune or not fit the dump and get a safer tune ?

I am not suggesting your tuner did not tune it safe but if you don't want to blow another cheap shit rb25 then get it detuned.

That's right, but a lean tune creates more heat, more boost creates more heat, this setup has both. What can promote detonation? You guessed it..................HEAT.

May be alright on the dyno, but on the track and under the car's own load, detonation may occur. I would consider that top end tune unsafe for a "built engine" let alone a std one. Holding 19psi to red-line ain't doing it any favours too.

Just a second thought though

-If the dump is restrictive doesn't that slow down the exhaust gasses, so shouldn't the turbo be creating less boost than expected or at least dropping off dramatically?

- Just thinking whether the car may have another issue

Personally i would give this event a miss, knowing my car is not running properly. Can you afford possibly blowing another rb25? Is this event that important to risk all?

[Al]

Just saw you sig, so obviously this Winton day is important to you.

Having my car at DECA, on my 30th B'day was important to me too, but that didn't happen; knowing now that my car is 100% ready and working perfectly is more important. There will be other events and other B'days, hell i was glad i didn't have it, as i would have had to drive it back the next morning