Turning A Negative Into A Positive?

[Gaz81]

Hey guys,

was driving along a couple of weeks agoin my R33 minding my own business when i heard a nasty noise and lost boost. A little investigation revealed a blown turbo. Although i was a bit upset with having my car off the road i seen this as an opportunity to upgrade. I took it to GCG and had them rebuild it and high flow it. When we installed it again and started the motor one of the cylinders were missing and the motor was making an even more horrible noise. A compression test revealed thet a peice of turbo has damaged on of the valves. My question is, in the interest of turning another negative into a positive i was thinking of doing some head work and cams and i was wondering who would be able to do a port and polish for me in western sydney and how much it would cost and what cams are suitable to use with a standard ecu.

I currently have

3" exhaust

FMIC

GCG highflow

Thanx guys

[Mumbo#5]

if your engine has suffered from a ceramic wheel letting go.. I'd say you will have to rebuild the whole engine as ur engine really doesnt like ceramic dust on your big end and main bearings, rings, well.. pretty much everything.. so ive been told anyway.. forged pistons and rods time for a positive eh

[Gaz81]

Ceramic wheel is only on exhaust side dude. nylon wheel on the compressor side. Only one cylinder has dropped compression and it is a valve, so i am hoping to get away with a top end rebuild. I have the head off and the bores look really good (no lips or scratches).

[lordsnipe]

hmm.. you are too optimistic

I know if i blew a turbo and the head was broken i'd be crying ....

[RB30-POWER]

The head flows so well from factory, why waste money on porting it, for minimal gains.

Just get it all built to standard spec and spend the $ on a set of cams for a worthwhile performance increase.

[T04GTR]

i dont mean to scare you or anything but il tell you what happened to my rb26.

it blew the rear turbo on boost and it spat bits of ceramic all through the motor.

some how the wheel fragments made there way UP the manifold and destroyed the motor.

my engine looked as if somone hat fed it a big handfull of sand. 40thou to clean up the bores.

the machine shop confirmed this almost imposible senario. they broke 3 head shaving tools from the ceramic imbedded in the head surface!!!

but this is a weird one and yours shouldent of had it go to this extent.

id get the bores inspected with a borescope just to be safe but.

[wrxhoon]

i dont mean to scare you or anything but il tell you what happened to my rb26.

it blew the rear turbo on boost and it spat bits of ceramic all through the motor.

some how the wheel fragments made there way UP the manifold and destroyed the motor.

my engine looked as if somone hat fed it a big handfull of sand. 40thou to clean up the bores.

the machine shop confirmed this almost imposible senario. they broke 3 head shaving tools from the ceramic imbedded in the head surface!!!

but this is a weird one and yours shouldent of had it go to this extent.

id get the bores inspected with a borescope just to be safe but.

<{POST_SNAPBACK}>

Thats very common on rb26's when a turbo lets go , i have seen heaps with ceramic dust through them , i must say i havent seen it in an rb25 .

He said he has the cil head off , so he can see the condition of the bore , a borescope is put in through the sparkie hole to inspect the bore .

[R31Nismoid]

The head flows so well from factory, why waste money on porting it, for minimal gains.

Just get it all built to standard spec and spend the $ on a set of cams for a worthwhile performance increase.

Agreed, as always, you and i know whats going on RB30-Power

[benl1981]

What part of the turbo let go? Are you saying the nylon side let go...it's usually the ceramic turbine wheel that I hear about.

I thought a lot of turbos have given up on rb25s and no ceramic dust has caused problems.

[cerci]

that sux man i thought i had probs!

so why did the turbo let go? what boost were u running?

[Gaz81]

I was running pretty much standard boost, i mean i had done the mod on the standard boost controller to run the high setting right through the rev range so with the exhaust freeing it up i was getting about 10-12 psi. Both sides of the turbo let go, there was nothing but a shaft left. I assume the compressor side let go and peices of that destroyed the exhaust side. Can anyone tell me what cams to get, where i'll get the best price and how much they will cost me. Remember standard ecu!

Thanx guys

Looking forward to seeing the results of a turbo upgrade and cams

[benl1981]

freer exhaust won't give you 10-12psi. I've seen on 2 r33s before and after exhaust upgrade they still run the same boost (within 1psi).

If the solenoid wasn't there then they would run exactly the same boost.

Because the solenoid is there it bypasses the same amount of air so you may get a very small boost increase but not much ! I noticed fitting an R34 intercooler gave a 0.5psi increase exhaust about the same

What people dont understand is that it is a pressure actuator and will do what it can to maintain 5psi (solenoid open allows it to hold 7-8psi as it bypasses air that would otherwise go to the actuator)

Somebody mentioned that freeing the exhaust actually helps it control boost as the wastegate is no longer choked up by the crap standard dump pipe.

Unlucky about the turbo

Edited October 10, 2005 by benl1981

[RB30-POWER]

The PowerFC ecu, should be done well before a cam upgrade or at the same time atleast.

No point of cams with the standard ecu, as the ecu is the biggest bottleneck in the system.

[shanef]

Sounds pretty much exactly wat happened to me 2 weeks ago to this very nite, but i just blew a chunk out of the compressor housing...dont want to lookinside the engine as i was on boost (and redline :lol: )

Anyways its pull apart engine time and get forged everything, gt35r and so forth...i looked into the rb30/26 route but was gonna be too expensive as i wanted a reliable set-up..

let us know how it all turns out

shane

[benl1981]

shanef - what boost were you running? Sounds scary. Are standard turbos time bombs

Edited October 10, 2005 by benl1981

[R31Nismoid]

of course they are, especially with bad treatment.

its been covered so many times before and its pretty common knowledge they wont last forever if your running more than what the car came with factory

[TommO]

I would love to see some figures of how many engines WERE and WEREN'T damaged when the turbo lets go.

Very scary really...

[Sydneykid]

Hey guys,

was driving along a couple of weeks agoin my R33 minding my own business when i heard a nasty noise and lost boost. A little investigation revealed a blown turbo. Although i was a bit upset with having my car off the road i seen this as an opportunity to upgrade. I took it to GCG and had them rebuild it and high flow it.

What blew on the turbo? Turbine or compressor? Did you ask GCG?

My guess is compressor, something caused a blade to break and the engine sucked it in. Hence the 1 cylinder damage.

Is it an inlet valve or an exhaust valve? That's also a good indication.

I have NEVER seen or heard of an RB20/25 with ceramic in the cat disease that had any engine damage from the turbine letting go. I have personally replaced 11 RB20/25DET turbos and never seen any indication that the ceramic dust went anywhere other then in the cat. With 6 cylinders pumping out exhaust and one turbo it would take a miracle for the dust to get sucked backwards.

I have only replaced 5 turbos on RB26's with ceramic in the cat disease, and NONE of those showed any indication that the ceramic dust went anywhere other than in the cat. But (there is always a but) with 3 cylinders and 2 turbos, it is slightly more possible that some ceramic dust could sneak back into one (or more) of the 3 cylinders connected to the blown turbo. The turbos I have replaced have been on GTR's that were on the circuit at the time they blew. So they were at high rpm and lots of load, hence plenty of exhaust flow. But 2 of them got driven home, slowly and had ZERO evidence of ceramic dust.

As for porting, the standard RB25/26 cylinder head is over rated, they have average ports and the casting is far from uniform. Remember they were designed in 1987/88. The combustion chamber volumes are not equal, so neither is the compression ratio. There is plenty to be gained from porting and almost as much from polishing the combustion chambers and equalising their volume. Plus it is a far superior method of decreasing the compression ratio, if you want to run high boost (2 bar plus). Matching the inlet and exhaust manifolds to the ports is also very worthwhile.

When ever the cylinder head is off any of my engines, it gets ported. It removes a restriction so that I can make the same power at lower boost, or I can make more power at the same boost.

The old school thinking was "don't bother about porting, turn up the boost". Just push that air past the restriction. Those days are gone, now we make huge power at comparatively low boost levels on unleaded fuel by removing restrictions and avoiding detonation. Good sized/shaped ports and smooth combustion areas are one of our best weapons.

Enough from me..........

cheers

[pnblight]

I was running pretty much standard boost, i mean i had done the mod on the standard boost controller to run the high setting right through the rev range so with the exhaust freeing it up i was getting about 10-12 psi. Both sides of the turbo let go, there was nothing but a shaft left. I assume the compressor side let go and peices of that destroyed the exhaust side. Can anyone tell me what cams to get, where i'll get the best price and how much they will cost me. Remember standard ecu!

Thanx guys

Looking forward to seeing the results of a turbo upgrade and cams  

<{POST_SNAPBACK}>

Tomei poncams are the go from greenline.jp or nengun.com

the beauty with poncams is they are bolt in replacements, i normally surgest adjustable cam wheels so the cams can be fine tuned on the dyno, plus it give you the able to tune to different characteristics.

pete

SK you may not believe me BUT GTR can and offen do cop damage from an explosing exhaust wheel and it's not so much dust more like little chunks which get hammered into valve seats/piston top and head surface, plus normally the cylinders in line with the turbos 2 or 5 bear the brunt of the damage.

[maccattack]

"As for porting, the standard RB25/26 cylinder head is over rated, they have average ports and the casting is far from uniform. Remember they were designed in 1987/88. The combustion chamber volumes are not equal, so neither is the compression ratio. There is plenty to be gained from porting and almost as much from polishing the combustion chambers and equalising their volume. Plus it is a far superior method of decreasing the compression ratio, if you want to run high boost (2 bar plus). Matching the inlet and exhaust manifolds to the ports is also very worthwhile."

Would have to agree - recently had mine done and fully flow tested during a rebuild. Combined with cams the difference is unbeleiveable. Huge increases in both power and torque.