1996 rb26dett standard turbos question

[[XsCaPe]]

Hi guys,

I dont own a skyline, but have a turbo from a 1996 rb26dett fitted to my car. Im currently running roughly 12psi (at the intake manifold) with boost controlled via a hks external gate.

From what i understand, due to the ceramic wheels, i shouldnt run over 14psi with this turbo.. is this correct?

Is it the amount of pressure (psi) or the airflow that causes the turbo to fail? i think im pushing a decent amount of air due to having 2.5" mandrel bent IC pipes (which have a 4" opening at the tb).

Its just that i read in a recent zoom article that a guy was running like 16 - 17 psi with the stock turbos.

Also, what kind of replacement turbos are out there that are direct fits to the stock flange? i would like something a similar size but more efficent etc..

thanks

[Guest INASNT]

what engine setup have u put the turbo in??

Do u know a r33 turbo is bigger than one rb26dett turbo??

The shaft speed is what causes the bond on the turbine wheel to fail coz the more boost the faster everything spins.

[[XsCaPe]]

The turbo setup is on a mazda mx6.. (yes yes pick on me all you want but i manage to keep infront of r33 turbos with atleast exhaust mods)

Yes, im aware the rb25det turbo is slightly larger.. im not after something bigger as i already find that boost comes on a little too late for my liking..

shaft speed hey? im guessing shaft speed is relative to the amount of air the thing is pushing out? or does it depend on the difference in exhaust/intake side pressure?

[Guest INASNT]

The bigger the wheels the less speed the wheels have to spin to push psi out

[T88 ON BOARD]

The turbo has a better chance of spinning off the Exhaust side wheel because they are ceramic...Upgrade's would be The HKS series turbo's, Or Hi flow the one you got And change the blades to steel...

cheers

[Sydneykid]

Hi guys, in my experience ceramic turbines fail due to two factors. Excessive temperature and torque loading caused by excessive boost. I have never seen any evidence that one has failed from only shaft RPM. It may appear that way because shaft RPM is directly related to boost pressure.

Being ceramic the turbine is sweated/bonded onto the common shaft and therefore it does not like too much resistance ie; the exhaust is pushing the turbine while the compressor is trying to move air into the engine. Too much resistance (boost) and the turbine and the shaft part company.

Moving on to heat, the ceramic turbine will only handle a certain amount of heat coupled with this resistance. The heat builds up over several minutes of very hard driving (say on a circuit) and the turbine shatters and/or parts company with the shaft.

Leaning out the engine to achieve more horsepower also increases the temperature of the exhaust, as does retarding the exhaust camshaft timing and igniting excessive richness on overrun (anti lag).

Hope that helps

[[XsCaPe]]

hmm.. thanks guys.

by the way, can somebody provide me with the size of the turbo from an rb26dett, and that of one from an rb25det? and also, whats the difference in the amount of cfm they flow?