Jump to content
SAU Community

Recommended Posts

am doing a rebuiild in the next 2 months

apart from fixing the prob i have all the upgrades im looking at doing is forge piston, as the internal of the engine can easily handle 300rwkw no probs at a safe limit, so this is fine for me as i don't want more 250rwkw

shuey

Hahahaha how can you not want more then 250 ? You so DO!! look at the look on your look. Its a I want 300+kw

am doing a rebuiild in the next 2 months

apart from fixing the prob i have all the upgrades im looking at doing is forge piston, as the internal of the engine can easily handle 300rwkw no probs at a safe limit, so this is fine for  me as i don't want more 250rwkw

shuey

We have had 2 Rb25dets, with just stockish mods blow ring lands on pistons and melt number 6 pistons, At around 190 - 200rwkw mark, So pushing any more then that with defiantly reduce the reliability of the motor and it will only be a matter of time until you blow the ring lands, as they are the weakest point on the rb25 motor.

I personally would save up some $ instead of modding it now.... and do the pistons and even by a set of GTR rods for insurance, and then blot on your turbo, injectors, computer, other wise it become very expensive when you do blow your ring lands and score your bore, damage your valves, and so on. Your maching bill goes up very quickly.

BBQ.

If you have had 2 motors pop ringlands at 190-200rwkw then I would seriously look at why they broke.

Obviously either the tuner is pumping too much ign. timing in at peak torque + running the AFR's on the edge or there is a injector or fuel pump problem.

Thanks for the replies guys! Some excellent info here

Hrmm well i guess i'm aiming for the 250rwkw mark - with a good tune it should be ok. I'd love to mess around with the internals and forge em but I haven't quite cracked the $18 mil Powerball yet! hehe. I guess 250-300rwkw out of the stock internals is pretty good considering how many RWKW these cars push out stock ( to the best of my knowledge its about 140-150ish?)

I think it really depends on the health of the motor before you even started modding it.

Some people will have a motor in better condition than others.

This is a very good point - what tests are best to determine engine health before i start thumping on more mods? compression test?

This is a very good point - what tests are best to determine engine health before i start thumping on more mods? compression test?
Leak down test would be my first choice, then have the oil tested for contaminents.:(

We have a DR30 with a stock RB25 with twin 25/30 HKS turbos that is a full time Barbagallo race car that has made 400rwhp for 3 years on pump BP fuel and does 63 sec laps before the track resurface still runs fine so it is possible.

Car is Gary stewert and the driver is Rob marcon and the car is well knowen and a championship winner.

BBQ.

 

If you have had 2 motors pop ringlands at 190-200rwkw then I would seriously look at why they broke.

 

Obviously either the tuner is pumping too much ign. timing in at peak torque + running the AFR's on the edge or there is a injector or fuel pump problem.

The main reason was because the cars were thrashed pretty hard for about 6 - 8 months, and onces they were up around 100,000km mark they tend to become pretty week in the ring-lands. and just couldn't take it any more.

It was more a less an experiment to see how long and how much we could get out of a stock motor. as we had planned for a fully forged internal re-builds.

Too tell you the real reson why, Is we fitted an AVC-R into the car and had it comming on fully boost by 2500 all the way though to red-line.

And after a few runs at that setup, it just blew the ring lands.

http://www.skylinesaustralia.com/photopost.../sort/1/cat/all Pic of piston here....

well i wasnt going to relpy to this but i have to now after someone saying they fried 2 skylines at close to 200kw, I am running standard iners and turbo and have been making reliable 200rwkw for well since the car was brought in to aust and prob well before that, all that is different is a remaped standard computer and some normal mods like exaust and crap, and have friends that were running 300rwkw but thats when things get iffie, just be careful of leaning out.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Been a long time since r31 got some love, my brother dropped a shitbox ls1 crapadore in my lap to fix up.  Put a wiper motor in as the flooded one was no longer alive.  got windscreen wipers now. Time to clean respray and install back in the titanic  IMG_0505.mov
    • Nah its a server spammer thing  Although, now that I manually approve all the accounts I can probably loosen up some of the restrictions.  
    • Thread bump, again! Although, no bad news this time. Posting for the sake of possible root cause. Basically, I rebuilt it (mostly stock), installed Haltech + sensors, had it running fine on new ECU.  Still not really understanding why it cracked pistons last time. Got to tuners, and while checking timing, noticed +-10deg of timing scatter while revving. Changed CAS, and it was rock solid. While not definitive, can't imagine seeing 20+ psi with that amount of scatter would be a good thing. Also glad I found something.   Bit more of a run down; Carried out a stock rebuild, a set of stock pistons, out of a spare bottom end. Everything stock apart from head studs and oil restrictors. (so I can pretend I didn't let the Nissan out, ha.) Armed with the measuring gear and FSM, set about doing overhaul. Oil restrictors as per oil control thread for a RB25, stock oil pump, drifting. Head drain/vent from rear of head, to passenger side of sump above oil level. Two dash 10 vent lines from drivers side of sump (unused atm) Hi octane style cam cover breather kit Splash covers over last 2 cam caps. Both breather lines from cam covers to vented to atmosphere catch can, not plumbed back into sump (wanted to see what it was actually breathing). Got it run in (did about a 1000km) no to low boost scenario, As I had questions over old ECU setup. Installed haltech +sensors for flex Retune on E85 (finding CAS Issue along the way), made 300rwkw at 20psi, out of wastegate. Did a drift day the next day (yes, it was a big weekend!) and was checking catch can throughout the day, ZERO blowby. I mean nothing. Lines from cam covers are not even wet. Done a bunch of street driving, spirited and catch can is still dry. Early days I guess, but pretty happy so far. Also now run 10w60, up from the 10w40 that I used to run. Oil pressure is significantly better, especially when hot (as you would expect)      
    • Thanks buddy. I thought it was a server storage thing. 🤣
×
×
  • Create New...