hypergear

Generally if the turbo is performing as usual without making any sort of unusual sound then it is ok. When breather is blocked crank case pressure forces oil to leak out of seals (including turbo seals). The bearing clearance is about 1mm side to side and 10 thou in and out, So it will feels as a little play. That goes away under pressurized oil.

With RB20dets I would build some thing based on a ATR28G2 in a T3x Nissan flange pattern in .64 rear housing and a high pressure actautor. That will max around 250rwkws with excellent street response. Add: We will be back on the 3rd of Feb 2011. Any inquires please PM or email to: [email protected] Thanks

RB20det seems to always drop in torque up top. I'm not too concert if the lowest torque point is above or within the average for its power and mods. Not sure if external gate or wide opening turbine blades can help holding torque into the high RPMS. I will consult with few tuners for some answers. I will like to hear the method if any one whom have successfully brought up their torque into higher RPMs based on the same turbo. Ie. manifold, ext gate, different housings and etc.

True I will have a play with wheel's blow direct, blades and turbine housing next year. Its a testing turbo to be improved. Keep in mind I'm not using E85, not running external gate but with a slipping clutch. Its making more power through out rev ranges till 6000RPMs. So all I need is dumping E85 at 330rwkws, that will get me around 380rwkws with more power and torque every where right?

30 Mn with slipping clutch, E85 fuel mix and external gate, Its not really much of difference. I will finish off the tune next year for a better comparison and will do few modifications to the blades for improvement.

Clutch slipped off which resulted in a sharp drop in torque and a dip in power. I'm hopping to see a more ova led layout with clutch fixed, but never know. I haven't seen any RB25dets can hold torque to 7000RPMs based on a 600HP turbo. Smaller turbos seems to hold better but peak torque reached was lot less and torque held at 7000 was also less. Would you have a torque curve of your current setup? I'll be building a bolton externally gated plumb back turbo next year. Hope for better boost control and more power. Were can I get E85 in North area of Melbourne? looking to try abit of this miracle juice.

With the new head its lot better on fuel, Once oil cap released the blow by was close to none. It was breathing out heavily.

I will post all readings after clutch replaced and fully done. I think its slipping abit up top.

Small update: This a customized Billet comp wheeled ATR43G3 with sleeve bearing setup in .82 turbine and .70 comp. Clutch blew up (run ended early) at 325rwkws @ 21psi. Internally gated on RON 98 with full stock setup. I'm hopping to get 370rwkws on it at 30psi on RON98 using a twin plate clutch next year.　Might be installing a 6 boost manifold as stock manifold is restrictive at this point.

Not an exact "shift". More of removing power from upper rpms and adding them to the lower rpms. Comparing to stock cam gears, you get more power down mid-low and less power mid-top, While all peaks at similar spot.

Not point getting cam gear for stock turbo. How ever it would help to smooth out the power curve with a larger turbos, but not necessarily adding power to top end.

Please show a photo of this turbo or the person whom you've got it from, I will be able to give you some specifications of it if it is one of ours. Also check the wastegate actuator adjustment. Make sure its tightly shut. A healthy RB20det should still be pretty ok down low even without VCT. I would check cam timing and have a play with cam gear settings.

Getting the test car's engine back together at this stage. looking to do one test for the differences of having billet comp wheel before xmas if car runs ok. Will post some results if every thing goes according to plan. The new generation of turbos will go through further evaluation and testing. I want this generation to produce the best possible results and hopefully still be affordable to most high performance enthusiastic.

And this is the Gen Alfa 2 CHRA (Duel ceramic BB, Machined Billet 71mm comp wheel). Made for stock turbo high flowing. This should be very interesting.

Yea~~ 345rwkws (still going) with OP6. 273rwkws (maxed out) with 21U.

Further update: This is the very first new serie of ATR43 Gen3 Alfa, in Duel Ceramic ball bearing and Billet comp wheel setup in .82 turbine and .70 comp. This is one estimated around 560HP in a bolton form. Hopefully I can get some testing and evaluations done before end of this year. In comparison to stock turbo: There will be 4 different Alfa versions. Results and Updates will be posted.

Few little updates: Engine head finally came back together with new valves and stronger valve springs. I will still be using stock cams and cam gears at this stage, for further experimenting. Refer to this S1 Rb25det (Not sure if apples to Neo heads): My Engine builder recommended stronger valve springs that has at least 80Lbs (stock is 60LBS) set pressure for any thing that is rated 500HP+ fly wheel. Valve floating will chew out valves, and seats over time. Noticing when valves are worn: Irrational / rough idle (RB25det should be smooth as). Hard to cold start, and noticeable deteriation in performance over time after having high powered upgrades. Unsealed valves results in lag, lose of power, and makes the car feels power less specially pre-boost. I've experienced all of above. Valve springs should be noticed when building an forgied engine or pumping muscles out of stock build engine. More to read about valve floating: Quickie Vocab: "Valve float" is the layman's term for loss of separation control within the valvetrain, usually over the nose of the cam. In other words, when separation occurs within the valvetrain while the valve is open, it's called valve float. "Valve lash" is the clearance between valvetrain components, measured at the valve side of the rocker arm, when the system is at rest with the follower on the cam base circle and the valve closed. A "Valve line" is the chain of components between a single cam lobe and its valve (inclusive). There are a number of possible outcomes: * If the separation is occuring on an exhaust valve line, then the piston will be on its way up while the valve is open. Usually the piston chases right behind the valve as the valve is closing, so if the valve stays open for too long, there could be an impact. Such an impact is not necessarily catastrophic; it's not altogether uncommon to tear down a hi-perf engine and find clear evidence of piston-valve contact. It would be preferred if this contact did not occur, and if the contact is too severe, it could definitely result in engine damage. In general, you need quite a bit of "float" before you'll have such impacts. * When valves begin to "float," valve seating velocities increase substantially. This isn't good for the seat or the valve, and can cause damage over time. * When valves begin to "float," it is often the case that this will be accompanied by an undesirable increase in the duration of the lift event, resulting in degraded engine performance. Sometimes a little bit of "float" is designed into a hi-perf valvetrain intentionally, and performance is actually improved (this is the exception). Some Common Causes: * As was mentioned previously, excessive engine speed leads to excessive valvetrain acceleration, and the valve springs may not be able to maintain contact between all the components. If you know the peak acceleration rate of your cam, and you know the force vs displacement profile for your valve spring, and you know the mass & inertia of your valvetrain components, you can calculate a kinematic separation cover factor that will tell you how fast you can run the engine without the mass x acceleration overcoming the spring force. This answer will always be wrong in real life, because... * All of the valvetrain components, such as the pushrods, rockers, springs, etc., are flexible, and they will vibrate. Valvetrain vibration compounds the above, and significantly increases the required spring force to maintain contact between the valvetrain components. * The valve springs themselves may resonate (vibrate quite a bit). This is called spring surge. Picture what happens if you hold a slinky outstreched, pinch some coils together, then release them. The compressional wave travels up and down the slinky. Spring surge is very similar. It increases stresses within the spring, and it reduces (periodically) the amount of force that the spring applies to the seat and retainer. * Excessive valve lash compounds the above problems. Too little valve lash is worse, but for a different reason. Some Remedies: Valvetrain vibration: * Lower mass valvetrain components * Increased specific stiffness of valvetrain components * Increased spring stiffness (add a helper spring if needed) * Increased spring preload (add a helper spring if needed) * Use a different cam profile (to excite less vibration) * Reduce valve lash (to reduce impacts & excitation of vibes) * Increase damping within the system Spring surge: * Replace the spring with a spring that has a higher surge frequency * Use a different cam profile (to excite less vibration) * Use concentric valve springs that rub against each other. The rubbing will remove energy and attenuate the spring surge. (this isn't the same thing as "cancelling the resonant frequency," because it reduces the vibratory magnitude at all frequencies vs the same spring pack without rubbing) * Reduce the solid clearance of the valve spring, to increase coil clashing. Coil clashing removes energy and reduces the magnitude of the spring vibrations * Add damping coils to the valve spring. Damping coils are coils that change the spring rate suddenly during a few mm of lift near the fitted length. Sometimes the damping coils are completely closed at the spring fitted length. The sudden change in spring rate breaks up the spring resonance as surge sets in. How valve floats are shown on dyno:

I wouldn't care if its just valve floating. Its the damage it does. 24 leaking valves will affect lots of thing. Not 99%. 100% high flows without high pressure actuator will result in boost drop. This also apply to inlet and exhaust restrictions. Read the thread, High pressure actautor I supplied was removed by user.

Just hand file your flange bolt holes by few mms, and they fit. No big deal.

the Arias 20thou over sized pistons would be 8.6:1 using stock head gasket. With cosmetic gasket depending on what it is, would set your engine below factory compression ratio. Which means more boost is required to produce the same amount of power with laggier response as the whole power band shifts towards the right. How ever this setup is ideal for larger turbos with plenty of boost. So this baby high flow might not be the exact turbo for your application. With the stock valves and valve springs, I'm unsure at what psi they floats, conditions of it varies. Unsealed valves acts like vacuum leaks (with fuel)affecting response, power, and make the car feels hopeless pre-boost. I would definitely recommending stronger valve springs for high powered applications.

You need to get it machined to suit. Very tinny chance to find one that suits your heat shield, bearing housing, and turbine wheel in the preferred A/R size.

.82 rear internally gated low mount will be ok for 300rwkws. The twin scroll's available in .84, I personally experienced no difference, might change with a twin scroll manifold.

The the whole reason of having an high pressure actuator is to hold boost. Put it back the way it was, and go for another tune. I really don't like people tempering with the actuator as most people lefts them un-adjusted. it opens around 18~20psi without boost controller. It is not Jammed. Intake pipe is the pipe that connects the turbo to the pod filter, it needs to be an hard pipe at least 3inch in length. If the turbo can not suck in or dispatch air then it will result in lag and lose in power.

You will need a high pressure actuator to hold boost up top. Should have no issues getting 260rwkws. are you running stock intake pipe?

The Performance springs is just little bit stronger then standard. The supertech springs are probably the best you can get at this stage. Those are stronger then the type B Tomei springs which are cheaper as well.