Science of Speed Twin Turbo

[Mac Attack]

I see all kinds of misinformation here.

First off, any kind of forced induction (neglecting nitrous), i.e. supercharging or turbocharging can have "lag" introduced in the discharge of the compressor to the intake valves. On a stock engine, the "lag" effect arises over the piping length, diameter, number of bends, and intercooling method from the supercharger or turbocharger compressor to the throttle body.

In addition to the "lag" effect on the compressor discharge side, turbochargers use exhaust heat, pressure, and flow to spin the compressor as opposed to a supercharger. Therefore, it is desirable to minimize the distance between the exhaust ports and the turbocharger housing to reduce exhaust gas friction and energy (another type of "lag") before it gets to spin up the turbine.

So, because "lag" can be introduced on the inlet AND discharge side of a turbocharged system, YOU HAVE TO LOOK AT THE WHOLE PIPING LAYOUT - NOT JUST KEEPING THE TURBOS CLOSE TO THE EXHAUST PORTS.


While the SOS system is very nice, it is still a compromise. While this system does reduce the exhaust discharge turbine spool time by keeping the distance between it and the exhaust ports very small, you have to understand that their goal to make it integrate well leads to a lot of piping length and bends on the compressor discharge (engine intake) side. So, ultimate performance still isn't attained because there is a lot of volume of compressed air and a lot of restriction on the intake side that will lead to lag when you mash the accelerator (dynos don't measure this explicitly because they don't plot torque as a function of time - it's plotted as a function of RPM).

There is no perfect system out there to suit every need. Everything is a compromise in some respect. That's not a bad thing - we all have different "needs." OK - who really needs a turbo on an NSX :tongue: I think this is a great system for those that want an OEM look and finish, while still offering some unique features.

But, is it the ultimate way to produce power in the NSX or the best layout design? No. Only a no-compromise system would be capable of that. But then you loose rear visibility and requires much more extensive modification.

Is it worth the extra cost over other systems? Only the unique needs of the individual buyer can answer that :smile:

My $0.02.

Dave

 

[StmpoRaceProducts]

335is and z4sDrive35is are staying with the twin-turbo set up. Both are 2011 models.

probaly because Milton is right...

twin turbochargers are the most efficient use of exhaust energy

thats why the dynos produce lower numbers....

 

[JLCoolman]

From Wikipedia.
For the 335i, the N54 twin-turbo I6 will be replaced with the similarly powerful but more efficient N55 (single) TwinPower turbo with Valvetronic. The new 335is trim will have a higher-performance version of the N54 twin-turbo and will have an optional 7-speed dual-clutch automated manual.



I still would like to know how much psi is being used in the STMPO dyno?

 

[StmpoRaceProducts]

From Wikipedia.
For the 335i, the N54 twin-turbo I6 will be replaced with the similarly powerful but more efficient N55 (single) TwinPower turbo with Valvetronic. The new 335is trim will have a higher-performance version of the N54 twin-turbo and will have an optional 7-speed dual-clutch automated manual.



I still would like to know how much psi is being used in the STMPO dyno?

12 lbs... and please look at 4k rpms... the mid range of the car... where the word spool and lag can be thrown out the window...

oh yeah... our car is equipped with Twin windows... oem from the factory... one on the passenger and one on the driver... it is the most efficent OEM way to allow the driver and the passenger the ability to roll them up and down

 

[chudson1549]

let's not forget the AMG 5.5L biturbo which is new for 2011. Although I still like my 6.3 motor.


Back on track. Chris with this system, you know I'm a keep it simple guy, I asked Cody, Angus and now you, Can you do an air-air intercooler setup? The placement of the intercooler is in the same place Angus would put his. Is Is it possible for those guys who do not want to run the water lines and mount a radiator blah blah blah?

Charles

 

[JLCoolman]

12 lbs...

Thank you

 

[Juice]

So, because "lag" can be introduced on the inlet AND discharge side of a turbocharged system, YOU HAVE TO LOOK AT THE WHOLE PIPING LAYOUT - NOT JUST KEEPING THE TURBOS CLOSE TO THE EXHAUST PORTS.


Dave

Dave, would it be safe to say that the relevant transient time from onset of the combustion cycle to obtaining boost as a result of compression is then directly correlated to entire volume (hot side + cold side) of any given system? I doubt that the math is this simple, but using this line of thought we could determine "theoretical lag" by calculating the volume within any given system. Of course, this neglects to care about optimizing boost for output because ultimately you wouldn't want to decrease the volume of your system (ie smaller diameter piping) if it meant killing output.

 

[Mac Attack]

Dave, would it be safe to say that the relevant transient time from onset of the combustion cycle to obtaining boost as a result of compression is then directly correlated to entire volume (hot side + cold side) of any given system? I doubt that the math is this simple, but using this line of thought we could determine "theoretical lag" by calculating the volume within any given system. Of course, this neglects to care about optimizing boost for output because ultimately you wouldn't want to decrease the volume of your system (ie smaller diameter piping) if it meant killing output.

Kinda, but it's not just volume, you have to balance it out with flow restriction too (big enough diameter for the calculated flow rate so it's not overly restrictive, and then try to reduce the number of bends, etc).

It's all a balancing act :biggrin:

Dave

 

[NetViper]

Kinda, but it's not just volume, you have to balance it out with flow restriction too (big enough diameter for the calculated flow rate so it's not overly restrictive, and then try to reduce the number of bends, etc).

It's all a balancing act :biggrin:

Dave

Dave, are you working on a turbo kit to balance out your new exhaust?:biggrin:

 

[TURBO2GO]

Actually the most "OEM" of all FI systems is the old CTSC. The factory computer is maintained, all the CEL functionality is maintained. The exhaust is completely factory. Yes, there is no intercooler, but also no heat exchanger sitting in front of the radiator, no extra piping under the car, no electrical pump moving liquid back and forth across the car. Factory cooling system, maintained. There is no visibility lost in the rear glass. Factory cats are kept, and it is 50 state legal. No body parts are modified other than the targa cover, and you get a new one for that. No "tuning" of the system is needed at all. The old CTSC may not make the same power as a twin turbo system or a supercharger system with an intercooler, a heat exchanger, bigger injectors and aftermarket engine management, but it does do away with whole ton of complexity. Even the power curve is like stock. That is as "OEM" as any FI system in the world to me.

 

[NetViper]

Actually the most "OEM" of all FI systems is the old CTSC. The factory computer is maintained, all the CEL functionality is maintained. The exhaust is completely factory. Yes, there is no intercooler, but also no heat exchanger sitting in front of the radiator, no extra piping under the car, no electrical pump moving liquid back and forth across the car. Factory cooling system, maintained. There is no visibility lost in the rear glass. Factory cats are kept, and it is 50 state legal. No body parts are modified other than the targa cover, and you get a new one for that. No "tuning" of the system is needed at all. The old CTSC may not make the same power as a twin turbo system or a supercharger system with an intercooler, a heat exchanger, bigger injectors and aftermarket engine management, but it does do away with whole ton of complexity. That is as "OEM" as any FI system in the world to me.

Don't forget it could also be installed by a dealer and not void the warranty!

 

[JLCoolman]

I guess you can say it's unfair... the dyno chart I used has less boost than the twin turbo dyno.

Less boost and more power at every rpm range...

I love the OEM'ness coment.

Like the removal of the OEM Front Sub-frame, The removal of the OEM computer, the use of OEM - NON TURBO CATS (yes there is a difference),

The NON-OEM water pump for the WTA, and the best of all... The OEM High compression motor... maybe honda made a high compression motor designed for a turbo while all the other car makers made OEM low compression motors... because Honda is that good... there OEM NA Motors are OEM turbo motors

Regards

I missed this post earlier when I had posted my second question about the psi. Man this thread is jumping fast.

There is no perfect system out there to suit every need. Everything is a compromise in some respect. That's not a bad thing - we all have different "needs." OK - who really needs a turbo on an NSX I think this is a great system for those that want an OEM look and finish, while still offering some unique features.



But, is it the ultimate way to produce power in the NSX or the best layout design? No. Only a no-compromise system would be capable of that. But then you loose rear visibility and requires much more extensive modification.



Is it worth the extra cost over other systems? Only the unique needs of the individual buyer can answer that



My $0.02.



Dave

Well put.

 

[StmpoRaceProducts]

I missed this post earlier when I had posted my second question about the psi. Man this thread is jumping fast.

its jumping so fast because it has 2 turbos...

 

[TURBO2GO]

Don't forget it could also be installed by a dealer and not void the warranty!

I gotta say, its an oldie but a goodie. It's kind of like the old girlfriend, she isn't as hot or exciting as the new ones, but man she is reliable, intelligent, considerate, you can live with her day in and day out. LOL....

I blamed a few of my problems on the CTSC a few times and it was never that system. I've grown rather fond of this old but reliable system, and the more I see other higher HP systems, the more I see a hot yet high-maintenance girl.

I wish more NSX'ers tracked their cars and saw value in suspension, brakes, and most of all DRIVING ABILITY, and cared less about "well what did that get on the dyno"...

I'm exiting now, I think its a shame we derailed Chris's thread like this. I for one apologize.

 

[Juice]

I'm exiting now, I think its a shame we derailed Chris's thread like this. I for one apologize.

Actually, this isn't Chris's thread. This is Chris's thread. So don't apologize as we are having an intelligent debate here of the merit of designing a turbo system with 2 turbos.

So another question: If you decide to be less OEM like how would a meth kit integrate with this setup?

 

[doc_tai]

wonder if this turbo kit comes with exhaust?

 

[TURBO2GO]

wonder if this turbo kit comes with exhaust?

No.

 

[NetViper]

No.

I thought it said you can use your stock exhaust or the SOS hi-flow. Was the hi-flow extra???

 

[chudson1549]

I thought it said you can use your stock exhaust or the SOS hi-flow. Was the hi-flow extra???

extra

 

[doc_tai]

400 whp running stock nsx exhaust? good luck on your motor.

 

[Mac Attack]

Dave, are you working on a turbo kit to balance out your new exhaust?:biggrin:

Yeah, but with how long it's taken me to run a simple exhaust, I doubt the twin turbos will ever get done :redface:

Dave

 

[roondogg]

Why is there so much hate on this topic? SOS simply gave us another option for FI. They never mandated that we must all buy this. Therefore, it remains our choice. Now, there are cheaper options out there, for sure. However, the prototype fabrication looks to be superior to almost any other kit available, save for a few. Their customer service is excellent and they run a professional establishment. The price is high, I will concur with that, but you get what you pay for in most instances. Other vendors jumping in here must feel threatened in this economic downturn. I find that distasteful and unprofessional on a public forum.

If customers want to praise or bash the kit as a whole or it's parts, then that is their right. We can all accept that. I, personally, would never pony up the coin for this operation, but if other options sucked and I was tired of my car getting beaten by civics/subys/etc.., then I would consider this option. I actually trust SOS but that trust comes at a cost.

People need to give their opinions, so here is mine.
+ No oil pump needed
+ No cutting up the chassis
+ Use your stock cats and any exhaust of your choice
+ Turbo close to the exhaust port
+ Back purged welds
+ Can potentially past smog and noise restrictions very easily

-Two turbochargers (cost)
-weight added from all the material
-Overall price approaches and can exceed building a motor
-1.5-1.6 liters per GT28 is pretty darn efficient. Small turbo feeding small displacement will work! If you put twin GT30s, then you are toast, as lag increases and transient response is poor.

Dogg

 

[doc_tai]

any exhaust of your choice means you need to add 1000 to 2000 dollars on top of 12k

 

[swerve2007]

I wish more NSX'ers tracked their cars and saw value in suspension, brakes, and most of all DRIVING ABILITY, and cared less about "well what did that get on the dyno"...

i guess you can't 'bench race' if you suck at real driving unless it just requires mashing the go-pedal and holding on:biggrin:

 

[Jack Sparrow]

Other vendors jumping in here must feel threatened in this economic downturn. I find that distasteful and unprofessional on a public forum.
Dogg

BMW & Audi have recently been directly competing against each other and have put up adds to sway the consumer.

As someone who just joined this forum, I want to know all the dirty shlt that you rarely every find out unless you have been on a forum for ages. Sure you can do all the research you want but some things can't be found as easily.

In the end, the decision is still made by the consumer, no matter how much drama is created on a message board.