Rb25det Max Rwkw With Stock Bottom End?

[PM-R33]

Hmm interesting. I'm impressed that there are that many RB25's running over 300kw with standard head gaskets and still running strong.

[DECIM8]

Just do it, I mean shit if youve pump that much money into the engine hows it going to hurt when your bottom end or head gasket blows and you just have to wack in a forged bottom end. I mean after all its only a couple of grand and a bigger turbo is going to make you smile for along time.

But I dont really think 300rwkw is useful on the street anyway apart from drinking fuel

Edited May 25, 2008 by DECIM8

[R33GOD]

presonally i think youd be running a huge risk of engine failure anything over 260rwk. anything over is just a waiting game

[DECIM8]

"you'll never ever know, if you never ever go!!"

[HYPA33]

298rwkw on creatd dyno.

gt3040 turbo, 18psi, tomei cams and head gasket. stock bottom end

last 2 1/2 years so far on the limiter most of the time. done a aheap of track days.

Its all in the tune

[Cjmartz2k]

presonally i think youd be running a huge risk of engine failure anything over 260rwk. anything over is just a waiting game

And what hard info are you basing this off of? Repeating what you hear on the internet doesn't count.

[R33GOD]

no mate im not an internet mechanic like you pal. first hand from experience and having friends who OWN a performance shop and dyno tune every day tell me these answers. its only an average btw.

that and i have been modifying my r33 fror the last 2 years

[Cjmartz2k]

LOL, internet mechanic, eh? I've owned my R32 for about 4 years now (not that that proves anything) and have had it up above 400rwhp for as long as you've "been modifying your r33", so take that for what it's worth in the reliability debate. I don't feel the need to go into my friends and them "OWNING" a performance shop, me driving for them when the street tune (3 RB25's over 400rwhp in the past couple months) , helping wrench, oh, and them laughing at all the people that think RB25's will magicaly blow up over 400rwhp. That proves nothing. BTW, the shop owner has a stock bottom end in his RB25 with a built head that made over 600hp. "that's only an average btw"? What? Your not making sense.

I'm asking if you have seen an RB25 blow up, seen one sitting in the shop getting fixed, or heard actuall detailed "this is what broke for this reason" stories. I'm talking like "the block split" or "thing ringlands cracked" or "he lifted the head and blew the gasket which trashed the motor" kinda stuff. Your friends telling you RB25's aren't reliable over X amount of HP because they said so and they own a shop so it must be true doesn't fly with me.

I'm not trying to turn this thread into a "post count measuring contest" which it seems all these threads about what RB25's can make always turns into, I'm just trying to get hard evidence either way. So far I've seen numerous people posting up that they have been making 400+rwhp for years on stock RB25's, and not one person saying "I blew my RB25 up". I'm sure there are plenty of people who have blown them up, but I'm willing to bet most of them just had crappy tunes, not enough fueling, etc and had nothing to do with them breaking just because of HP.

Edited May 25, 2008 by Cjmartz2k

[R31Nismoid]

(just re-read the first page) im just a little skeptical that the old shitter T04e would rack out 400rwhp… especially dropping to .9 bar

I had one of the largest variants in a .82A/R rear (and a few people i know had similar turbo specs years ago) and it was no more than 240rwkw at best with 13-14psi, and best mph of 112-113

I mean, if you have a fairly mighty MPH around the 120+, then fair enough.

Not trying to take the thread further off course, I just find 60rwkw a bit much to take for identical setups bar ECU. That could be one reason your motor is together

Anyways, when you see the RB26's fail with say, what, 350rwkw doing circuit work. RB25's go down the near enough same road.

As an example, you could make 350rwkw and run it daily as a street car, but fact of the matter is your never going to see much past 120km/h for longer than a second or two… And the motor is hardly going to see 350rwkw on a daily basis now is it?

People saying that’s the case are kidding themselves. Also remember motors running like this are under nowhere near the stress that a motor doing weekend track work would see with regular expeditions into the 200km/h+ zone and sitting well up in the RPM scale at the same time, for a long time.

I reckon you probably could have a motor crank out 350rwkw. But would it be reliable? Depends on the situation and most likely not forever.

Max power and reliable power are different.

If a motor can run 350rwkw for 5+ years…and by that I mean seeing 350rwkw daily on a factory bottom end, I'd be surprised.

[DECIM8]

Point taken, street cars arnt driven hard enough..

Lets get the govenment to make a Autobahn

Onto another point if you want a Reliable engine, leave it stock .. better yet give it to Nissan OZ to de-tune it, they seem to have this under wraps

Edited May 26, 2008 by DECIM8

[Cjmartz2k]

Well put about the track vs. street car, and it's something to consider. I daily drive the car, and it only sees 4th gear pulls or better 1 or 2 nights a week drag racing, and than only 7-8 runs a night. No extended autocrossing or drifting. Also, like I said, I'm more willing to push my motor because I have access to $300 replacements. If it lasts 2 years, I'm happy.

The 400rwhp was on a dyno. Now, it was a dynojet style dyno, so I'll give you the fact maybe it will read higher than some. I am at sea level (literaly), so that helps. Also, the tune had pretty agressive timing maps on a stock 9:1 compression with 12.1 a/f ratios. It was set to 1.2-1.3 bar, and falling down to .9-1.0 bar around 7.5k-8k rpm. It was the big T04e with a .82 a/r ex housing also BTW.

Whether or not I was making 400rwhp or not on the T04e or not (if not, it was damn close), I certainly am making a lot more than that now. The DSM (Diamond Star Motors--a mistubishi/chrysler colaboration) guys are making 600awhp on my current turbo. I've been on that one for over 1 year making a best guess of right at 500rwhp (120+mph trap speeds, and maxing out a z32 MAF). That previous dyno doesn't have anybody to run it anymore, so I can't get on there.

[cactus]

my RB25 failed yesterday @ 390rwhp (18psi)through a built auto with stall...

i dont think that was the problem though, i think it was more my mistake ... i let a few things go and i shouldnt have which has probably cost me but oh well its just an excuse to do a rebuild. Peace of mind lol

[RNS-11Z]

my first motor with forged pistons spat a rod out @ 450rwhp, ive still got the top of the piston with half a conrod attached to it.

[Cjmartz2k]

my first motor with forged pistons spat a rod out @ 450rwhp, ive still got the top of the piston with half a conrod attached to it.

That doesn't sound like a to much hp problem to me. Especially it being forged parts.

[R31Nismoid]

Harun has stock rods i believe, just the pistsons

[2rismo]

Mine's still kicking just fine. No dyno sheet, but it's right at 500rwhp judging by the 5v's on the Z32 and 120mph trap speeds.

making a best guess of right at 500rwhp (120+mph trap speeds, and maxing out a z32 MAF).

Sorry I missed this post before. How on earth is 120mph in a Skyline anything like 500rwhp? Surely you're running high 120's (128+) to claim that horsepower?!? My car ran 120mph on many occasions with just 355rwhp. (3310lb R33 GTST)

[d k]

Does anybody have a recommendation to the order which to replace parts to reach 375-385 wkw?

Rods being the first to go, pistons next, etc etc ?

Trying to decide if I should build my motor first before installing or putting it in and building it up later. Right now it is fine but all stock.

Also considering a Greddy (or similar intake). Car is an S14 for Time Attack.

[Cjmartz2k]

Pistons would be what I would replace first.

2rismo--what are you talking about? Low 120's is just fine for 500rwhp. I will say the mph is on a gtech, so it might not be all that acurate, but still, 120's is 500rwhp territory. I might be HIGH 400's at the wheels, but that's not enough of a difference to try and say somebody is full of it over. Keep in mind, I'm spinning WAY past the 60' with 275 nitto's on these crappy Okinawa roads, and I'm not as light as you think with subs, full interior, my fat but, tools, etc. Traction can actually effect mph when you are spinning as much as me.

Also, there is such a wide varience of mph to hp for turbo cars, it's tough to say what's what. Look on dragtimes.com. There is a timeslip which I'm guessing is you that matches your times and car, and then there is another R33 making 603rwhp ripping off a 10.6@128mph (with a 1.5 60' mind you--I tick off 2.1's on nitto's here because of the roads and not track). There is also a GTR with a TO4R @ 22psi that doesn't have a dyno, but that's easy 600rwhp and he's doing 10.7@130mph.

So in summary, I'm at least high 400's rwhp, and as it pertains to this thread, RB25's can handle a lot more than a lot of people around here give them credit for.

Edited June 29, 2008 by Cjmartz2k

[jeffworld2]

mine was rebuilt with new factory pistons and race bearings, and is holding 1.4 bar through twin hks gt-ss quite well. has seen a fair bit of track duty too

[2rismo]

2rismo--what are you talking about? Low 120's is just fine for 500rwhp.

No. No it's not. It's way off - try 100hp or so.

I will say the mph is on a gtech, so it might not be all that acurate,

LOL @ GTech. Timeslips don't lie.

but still, 120's is 500rwhp territory.

Nope. Sorry.

I might be HIGH 400's at the wheels, but that's not enough of a difference to try and say somebody is full of it over.

100hp might not be a big variation if you're making 1500hp but comparing 400rwhp to 500rwhp is an overestimation of about 25%. I stand by my statement.

Keep in mind, I'm spinning WAY past the 60' with 275 nitto's on these crappy Okinawa roads, and I'm not as light as you think with subs, full interior, my fat but, tools, etc. Traction can actually effect mph when you are spinning as much as me.

Traction, even with your excuse-o-meter pinging as hard as it is, wont account for the over-estimation of your hp. Wheelspin very infrequently affects terminal speed.

Also, there is such a wide varience of mph to hp for turbo cars, it's tough to say what's what.

No there isn't.

Look on dragtimes.com. There is a timeslip which I'm guessing is you that matches your times and car, and then there is another R33 making 603rwhp ripping off a 10.6@128mph (with a 1.5 60' mind you--I tick off 2.1's on nitto's here because of the roads and not track). There is also a GTR with a TO4R @ 22psi that doesn't have a dyno, but that's easy 600rwhp and he's doing 10.7@130mph.

Mate, the very best advice you can take from my post is that MPH doesn't lie and that the time shown on a timeslip shouldn't be used to calculate power.

So in summary, I'm at least high 400's rwhp, and as it pertains to this thread, RB25's can handle a lot more than a lot of people around here give them credit for.

Nope.