Jump to content
SAU Community

Recommended Posts

  • Replies 43
  • Created
  • Last Reply

Top Posters In This Topic

Oh, and to give a comparison, I could have babied mine around like a grandma, but all of my Kays were driving to and from driving events and at the events. I did 2 track days on one bottom end (Well, actually 3 sessions at half pace each day) and then one texi.

The other one managed to get tuned on the dyno, then make the 3rd session at a track day and everything let go.

Slappers on big turbos do NOT last long...

I've broken 2 now... With a max of 1000KM on them... Pushing 1Bar (14PSi) through TD07S housings, t66 front and a t04r rear wheel.

Nothing below 4000/4500RPM, then everything ramps in over 200/300RPM...

Rev limited at 6600RPM.

On the dyno it made "250RWKW" wheel spinning like a spastic... Using fuel consumption and AFR it would be making around 360RWKW... (69% inj duty on 880cc injectors)

so they were used bottomends not refreshed or anything with twin cam head and big turbo on them?

could i expect anything different considering its got new pistons and bearings?

what exactly let go on them? rods bend or pistons break or the bearings finally had enough or what?

wanna get more than 1000kms out of my rebuilt one hey. if it was a full slapper i wouldnt give a rats. it was meant to be cheap as shit then i decided to go new rings and bearings to refresh it then found i had to bore it out and new pistons. also got the rb25 head full rebuilt so spent extra $750 more than i planned to there. probably just gunna put standard rb25 turbo on it for now but to get some use then il put the big shit on it and wont feel so bad if it lets go.

The bearings will not let go as they are the3 same as the bearings used in aftermarket rods

The rods will not bend until about 600hp or if the tuner detos the engine

the pistons will crack if deto is present but so will forgies they just have a bit more tolerance.

Its all down to your tuner if he is good then your not going to have issues

so they were used bottomends not refreshed or anything with twin cam head and big turbo on them?

could i expect anything different considering its got new pistons and bearings?

what exactly let go on them? rods bend or pistons break or the bearings finally had enough or what?

wanna get more than 1000kms out of my rebuilt one hey. if it was a full slapper i wouldnt give a rats. it was meant to be cheap as shit then i decided to go new rings and bearings to refresh it then found i had to bore it out and new pistons. also got the rb25 head full rebuilt so spent extra $750 more than i planned to there. probably just gunna put standard rb25 turbo on it for now but to get some use then il put the big shit on it and wont feel so bad if it lets go.

It comes down to the tune and how you drive it.

My first one let rip with oil surge on a track, mixxed with an over rev when it stepped out in second gear. Well that was the initial thought. Now it appears that the thrust bearings had worn out massively allowing the crank to float and just annhilate everything.

The second motor let rip with what appears to be a cracked oil pump. But this motor spent a shit load of time living life on the hard rev limiter at a motorkhana (Big turbo, very hard to get it to keep the tyres spinning at part throttle without hitting the limiter, if it didn't hit the limiter it bogged and died).

If I drove these motors peacefully, I'm near on 100% sure the second one would still be together today (The first one, probably not... It was a PITA from the get go)

If you can break rods, you're going well. Pistons may let go if it's not tuned properly.

The biggest killer is normally oil control, get a good oil pump on there and doa winged/baffled sump especially if you plan to do ANY form of drivig events (Even if you only do one!!!)

My first one let rip with oil surge on a track, mixxed with an over rev when it stepped out in second gear. Well that was the initial thought. Now it appears that the thrust bearings had worn out massively allowing the crank to float and just annhilate everything.

IMO that's the biggest risk with a slapper. My first 30, even though it had forgies, was a slapper crank and rods and the thrust clearance was out.. destroyed an oil pump and almost the block :(

Second pass, I got the crank ground for oversize bearings and it lived a much healthier life (only pulled it apart to upgrade rods and other stuff).

The bearings will not let go as they are the3 same as the bearings used in aftermarket rods

The rods will not bend until about 600hp or if the tuner detos the engine

the pistons will crack if deto is present but so will forgies they just have a bit more tolerance.

Its all down to your tuner if he is good then your not going to have issues

thats it, GOOD tuner

  • 1 month later...

469rwkw on a 3l slapper is the current record in my shop, nothing like a time bomb :/

Slappers FTW if their mates cars who can deal with the consequences if it lets go... a no no for customers :P

Dont just say a figure like that and not give us the details

Sounds awesome I want to know more

std rb30 na bottom end, 26 head and t04z.

about to kill it with a std 1.5jz thats in the shop atm, we matched the output of 469 last thursday... shooting for 500 by the end of the week.

btw both on e85.

  • 2 weeks later...

looks like i got the only genuine slapper here, 285kw@14psi 6800 rev limit

Rb25 s2 Head Fresh Mill clean slapped on to..

Rb30 s11 Bottom end 70,000kms. Un opened.

ACL 1.3mm Metal Head gasket.

GT35r,

and other stuff but not important here.

not daily driven but 6 dyno tunes, 1 sau dyno day, 2 wakie days, 1 hill climb and 1 motorkhana. love it

i'll let you know how long it lasts...

you have a metal head gasket, not a slapper :down:

i've just got myne running a few backs, still tuning atm but i'm running 23psi from a 1.06 gt3076 through an unopened 150k bottom end, standard nissan gasket etc. will get it on the dyno after tuning to see how much power its making

  • 2 weeks later...

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

    • Harness is for a s1 Rb25det, and it is engine and lower harness.  the old harness had broken off plugs and was in very rough condition/exposed wires and splices etc. it is not able to be put back on the car, I could visually inspect to see if they had rewired any pins on the ecu plug. The fuel pump definitly isn’t turning off it’s an external pump and very loud you can hear it. Will look at the other harness tonight, am also going to pull the fuel rail and watch the injectors spray, will update here with what I find. Pretty sure at this point it has to be something to do with injectors because car will fire up on starting fluid and cas is clicking the Injectors. Fuel pressure is steady 43psi 
    • Check the injectors flow evenly, and are actually flowing what you and the ECU think they should be flowing. If it's starting up on starter fluid, you have a fuel issue. Is it possible under cranking your fuel pump is turning off?   The harness you replaced, is that the whole engine harness? Do yourself a test, and drop the old harness on and plug it into the Z32 ECU. It's possible they've wired things different. From memory S1 to S2 is different in RB25 and you may have a wrong loom
    • I haven’t pulled the injectors to watch them spray yet but they are clicking from the cas and all of the spark plugs are wet with fuel. I’ve thought the cylinders were being flooded from the beginning and was hoping fuel pressure would fix it. Tonight I am going to pull the rail and watch the injectors spray. Don’t know how to test/diagnose if the plugs are firing in correct sequence but that should be a timing thing and as far as timing goes my car still has the half moon for the cas can only install it 1 way. And my mechanical timing is 100% correct I posted photos above. Confirmed with the balancer on and off. 
    • I checked spark on all cylinders and they all visually have spark with the plug pulled and grounded, but plug 1 is the only one that fouled. This was a running swap that blew up and was rebuilt by a machine shop, put a new wiring specialties harness and did all gaskets, studs, and bolts while it was out.  compression is 135-150 across all cylinders. Aside from that from my understanding with the z32 ecu and maf the car should start regardless. The wiring for TPS and the dual 02 sensor/ dual knock sensor stuff shouldn’t actually stop the car from starting or even running well, (just slightly rich)  they just give fault codes. Car supposedly is supposed to start as long as you have z32 afm and ecu with the nistune base map and that’s info coming from a well known and trusted tuner who does a lot with SR/RB (Rsenthalpy). After more trouble shooting today where I’m at right now is that the cas is sending signal to the injectors they click while spinning the rotor, Fuel pressure is now set at 43psi, all cylinders have good compression and all of the plugs looked great (just wet with fuel) except for cylinder 1 which was very black (cylinder 1 has 150psi compression). all of the coils generate spark if pulled out and grounded out on the head. On the fuel pump car just pops into the exhaust. On starting fluid car will fire off. Hard to tell if all cylinders are firing off but definitley a couple. sounds like all of them but it’s only for 3-5 seconds hard to tell. 
×
×
  • Create New...