what are the pros and cons between getting a greddy twin turbo opposed to getting a turbonetics single turbo?

 

Greddy will give you higher tourque numbers earlier. The turbonetics spools up a little later but makes the same or more power out of the box. The Greddy is kit is VERY labor intensive and will cost you a pretty penny to install. The Turbonetics kits should install in about 10 hours. The Greddy kit requires cutting and splicing in an emanage and injectors and timing harness. The Turbonetics kit includes drop in injectors and a reflash to tune it all. The Greddy kit requires removal of the front brace. The Turbonetics retains the front brace. There are so many more...

 

Yea, I would say it is very hard to compare the two kits on the same level. There is one thing I read about the Turbonetics kit that i didn't really like, and that it used the factory headers. I don't have a good reason why I didn't like hearing that, I just think very quality kit would give you new manifolds and everything for a very professional turbo kit. But I still plan on the Greddy TT kit myself, cause there is alot more info out their about it and it just seems like there was a lot more R&D that went into it.

The Greddy Kit is alot more labor intensive as MIAPLAYA said so installation will cost more, but will be more fun for the ones who like to do the installing themselves

Happy Turbo Hunting..

 

I dont think the use of the stock manifolds makes it unprofessional or weakens it at all. In this case the manifolds are not subjected to the heat and stress as well as extra weight of the turbo so the stock ones are sufficient for this application. Furthermore I think that part of this design was to keep the stock manifolds as to make the install easier. I believe if you ask those who have installed the Greddy kit the manifolds were the most tedious part of the install due to their position and lack of workroom.

 

From the prelimenary dyno chart that Turbonetics posted, the turbo spool up around 3500rpm or so, and because how the exhaust gases are routed, it seems like the lag would be worse in the Turbonetics system. I wonder would a header help the spool. The Turbonetics kit should be cheaper than the Greedy and cheaper to install. So if you don't mind a little more lag, the Turbonetics will probably save you some money (for forged internals when you up the boost).

 

That was an initial chart but was not even close to the final. The Turbonetics is in boost by 3k and full boost by 4k...

 

I really like the idea of the single turbo (APS nearly went down the same path until we realized that CARB approval was not possible) though your comments regarding the stock manifolds not being subjected to heat and stress is simply not correct.

The stock 350Z manifolds are subject to the identical thermal and stress loads as any turbocharged engine and in fact would be more likely to fail prematurely as the cast iron for N/A manifolds applications is of a very different specification to that of cast turbo manifolds (turbo manifolds are cast in a ni Resist iron with very high nickel content approx 45% nickel and designed to cope with extreme exhaust gas temperature of around 1800 to 2000 F).

Exhaust manifolds on N/A engines are designed to cope with exhaust gas temperature of around 1400 F.....................N/A manifolds when ustilised in a turbo application are going to fail for sure..............it's simply a question of when not if.

Please don't take the above comments as criticism as this is not my intention and I believe that the single turbo approach is a very viable option if engineered to the required standard............it's just that the stock nissan manifolds will not cope (will fail it's only a question of time) with the high exhaust gas temperature in a turbocharged application.

Peter

APS

 

So what options do we have to upgrade them?

All the headers that would work for this type of system are designed for NA purposes. Someone would have to make them spefically for this turbo setup.

Could using high temp ceramic coatings inside and out of some mild steel or stainless headers be enough to prevent this failure?

The same coatings some use for coating turbos inside and out, they are designed to handle the extreme temperatures?

 

Only two real options that will live for any decent length of time at 1800 to 2000 F in a tubocharged engine application,

1) cast ni Resist manifolds (45% high nickel content) as APS has or,

2) Fabricate headers in 321 stainless steel (wall section would neeed to be 3 to 4 mm thick to survive) with 321 SS mounting flanges.

Peter

APS

 

another option is inconel which I have on my Z32

 

Yeah inconel 713C would be another excellent option (been there and done that) though at approx 5 times the cost of 321 stainless steel................at this price casting turbo manifolds in ni Resist would be a much better option and certainly far more affordable for the average Z enthusiast.

Peter

APS

 

What grade stainless steel are most NA headers made from that are available on the market at the moment?

 

Yeah inconel 713C would be another excellent option (been there and done that) though at approx 5 times the cost of 321 stainless steel................at this price casting turbo manifolds in ni Resist would be a much better option and certainly far more affordable for the average Z enthusiast.

Peter

APS

 

So would lets say Crawford headers hold up ok?

 

I'd say not................you will need headers which are fabricated in 321 stainless steel (at a minimum) and with a wall thickness of at least 3.2 mm or 1/8".

The cylinder head and exhaust outlet flanges will also need to be made in 321 stainless steel.

Headers made from a lesser material and thickness will simply crack and fail in no time flat................in less than 10,000 miles.

Peter

APS

 

Do you know what grade stainless steel most NA headers made from that are available on the market at the moment?

 

Some headers are made in 304, 309. and 416 grade stainless steel others are just basic mild steel..............though this is only part of the problem...............the major problem is that the wall section is simply far to thin to withstand the extreme thermal loads and high exhaust gas temperature of a turbocharged engine.

Peter

APS

 

So you are saying then that the Turbonetics is going to fail inevitably? Somehow I think Turbonetics would have taken this in to account...

 

I feel a single turbo design works best with an inline 6 motor. On a V6, a twin is the way to go, so you can install the turbos right to the manifold, and you minmize lag, and maximize exhuast scavenging. On an inline 6, like a Supra or Skyline, a single turbo works exceptionally well, for the same reason...turbo is bolted to the manifold.

 

I agree 100%. The I-6 is a much more versatile motor as far as turbo options are conserned. They are easily made twin or single turbo and both very efficiently and yield similar power bands(even though a big single will always be somewhat slower). Whereas the V6 motor it is obviously possible to make single turbo and make it work, but just isn't as efficient with the exhaust gases and such.