I am not disputing that BB turbos and water cooling are better than conventional. The reason that OEM's use water cooler these days is precicely because most average consumers dont adhere to proper cooling and lubrication techniques. OEM's use internal wastegates for simplified piping and installation. OEM turbo systems are usually designed for reliabilty, not for MAX performance. Internal wastergates are fine..nothing wrong with them, but if you look at most very high HP applications, they almost exclusively use external wastegates, since generally speaking, they'll have better turbo response, and less of a tendancy to creep or spike.

Don't get me wrong, I know that fundamentally, the BB design is superior to conventional. All I am trying to point out is that the emperical evidence as to HOW much more efficient they are is scant. Since very few people have done blind tests of identical cars and turbo systems, but one with BB and one with conventional turbos. I am sure the gains are there, but how much of the gains can be observed, for example, in a dyno chart, are questionable.

I too, obvisouly, would have prefered that Greddy used a BB turbo design (but kept the external wastegate), but at the end of the day, all of these turbo systems are very well matched for the car. And the MOST important element in turbo design is a properly matched turbo to the engine and application at hand. That's all I am trying to say. A poorly matched BB turbo is inferior to a properly matched conventional turbo.

 

The use of dual ball bearing center cartridges has allowed the scaling down of turbo size while maintaining the same cfm output of a larger journal bearing turbo.

The internal wastegate is of no consequence as they are designed with the max output of each turbo in mind.

There is much evidence to suggest that a bb turbo with similar characteristics as a journal bearing turbo in regards to max cfm and max psi the turbos are rated for will spool quicker and run cooler (more efficiently) than the journal bearing turbos will.

Testing has shown 15% on average quicker spool time vs journal bearing turbos.

The impeller shaft has also shown to be much more stable in a BB design with speeds exceeding 100,000 rpm,

A byproduct of the BB design is also increased longevity as well vs journal bearing.

There is much data to back these claims up read @ Garretts website journal bearing vs Ball Bearing www.turbobygarrett.com

 

I agree..

ALl things being equal...the BB is superior. But that is problem....in the turbo world, there is no such thing as "all things being equal".

 

Just to clarify one point and I'm not wanting to go tit for tat however...........turbo response has absolutely nothing to do with wastegate design. During the cricital turbo charger response period the waste gate is actually closed in either remote or integeral wastegate designs.

The Turbo Porsche's 20 years ago did utilise remote style wastegates.............however as with all things in life............technology has progressed.

I believe that the Porsche 996 TT is the best example of modern high performance turbocharging............if remote wastegates were superior then you can be 100% sure Porsche would be utilising this style of wastegate in 04.

Cost is never really an object to Porsche..........for Porsche only the best in reliable high performance is considered mandatory. Lets leave it here.

Regards

Peter

 

APS, I am getting my information regarding the pros and cons of external vs. internal wastegates from none other than then the famed Corky Bell. His book "Maximum Boost" cleared states that if performance and money are no object, then external wastegates are superior. He mentioned manufacturing and and OEM limitiations that necessitate the use of internal wastegate designs. He even mentioned my point about never seeing internalo wastgates on high HP race vehicles.

Oh, and his book also mentions that water cooling roughly doubles the life of the turbo assembly. But my point is that if the Greddy design last for 100,000 miles, do I really need it to last 200,000 miles??

And APS, even with Porsche, there are design limitations. Can you name me one OEM car that uses external wastegates? It's a serious question becuase I cant think of one off the top of my head. I just dont think OEM's, regardless of costs, wanna deal with the added complexity of the external design.

 

With respect I believe Porsche knows a little more about turbocharger engineering...........than Corky.

Peter

APS

 

Peter,
Does your company plan on designing a twin turbo kit for the 2004 Infiniti G35 sedan?

Tom

 

I guess the assumption here is that the Greddy turbos are not watercooled. Guess it depends on how long you plan to keep your car, but the longer the turbos last, the more options it gives you with your car long term.

So what are the first signs of turbo failure, other than smoke I guess.

 

running louder the sound sounds like a police siren.

 

sounds like metal on metal screeching at idle and underboost. It sounds really awefull. But smoke is a pretty darn good indicator too.

 

Tom...........most definitely..........we will ship a G35 to Australia for product development in the near future.

Thanks

Peter

 

The wastegate can effect spooling speed in that it doesn't open instantaneously but instead creeps open as boost pressure increases the actuator force. The degree to which this occurs varys with design, actuator preload and boost level. It is possible to reduce this to a degree by installing an adjustable pressure valve on the actuator line.

 

Are those electronic boost controllers only able to work with electronic external wastegates? Or can internal wastegates be modified for electronic control?
--
Jeff

 

No that's not logical..........think about it...........the waste gate is fully closed and all of the exhaust energy is directed through the turbine wheel (no gas is wasted through the wastegate).............how can this impact on spooling speed............while the waste gate is fully closed the turbos will continue to produce the maximum pressure possible..........that is until the point in time when the waste gate starts to open and waste exhaust gas.

Peter

APS

 

Guys, nobody has the APS kit yet, its only been in testing, i would wait at least half a year to a year to let the 350z pioneers to test out the APS kit before going straight on

theres bound to be problems since this is new, hold your horses with the excitement because of product advertising

 

I couldnt disagree more. Well the only thing i do agree with what you said is the fact that nobody has the APS kit yet ...this is true.

The amount of testing and R&D that is going into the APS kit is quite impressive to say the least. 20-21 months now? With the amount of time that has gone into development and testing of this kit the idea is when they release a final product there is no more testing to be done. The APS system if you read their website is the most complete kit ever developed. Everything has been designed completely for the US 350z from the ground up.

There is no reason to believe with as much information as there is both on their website and here on the forums by their rep Peter that anything has been sacrificed as far as functionality and quality. You cant even get 1/10th of the information on the greddy kit as there is on the Aps kit unless you get that info from the greddy kit owners themselves.

I believe that this kit is the most well engineered most complete aftermarket turbokit ever developed for a non turbo factory engine. One only needs to look into Aps track record for other vehicles which have been around longer like their Subaru Wrx turbo kits. Check out their 600 hp Wrx sti.

There is no reason in my mind to wait for others to be "guinne pigs" for this kit as almost 2 years of development and testing has already been performed by APS.

 

Only 2 spots left for APS special pre-order pricing! Please email me if interested.
Thanks,
Jason
jason@racemrc.com

 

what is the price? Or are you being facetious.

 

Peter has said initial offerings are at $7499 for the first 100 units.

 

A bargain if you ask me! I cant believe they are making a profit, given the completeness and quality of the components. I just hope they start selling pieces seperately, so I can ****** up some of the fuel system parts.