Twin Turbo: parallel or series?
Honda-Tech Member
Joined: May 2004
Posts: 2,625
Likes: 0
From: Baltimore, MD, US
Re: Twin Turbo: parallel or series? (nota-ex)
running two turbos on a 4cyl honda is pretty much pointless. But if you want to do it to be different or just to say you did than thats cool. I believe you would want them in parallel. Two cylinders to one turbo and two to the other.
I always thought about sending the already compressed air to be compressed in the second turbo but someone hardcore shot the idea down. I dont remember why tho
I always thought about sending the already compressed air to be compressed in the second turbo but someone hardcore shot the idea down. I dont remember why tho
Thread Starter
Joined: Mar 2004
Posts: 760
Likes: 0
From: Mechanicsville, Maryland, US
Re: Twin Turbo: parallel or series? (MooreBoost)
i was thinking that in a parallel setup they wouldn't spool as fast as in a series, but in a series you would get a lot more resistance from all the exhaust gases having to go through two turbo's instead of one.
This is just something that recently popped into my head because I just bought a small setup with a td04 turbo. Then I got back to school and one of my friends said they found a small mitsubishi turbo that was attached to a chrysler head while he was cleaning out his garage or attic or something like that.
This is just something that recently popped into my head because I just bought a small setup with a td04 turbo. Then I got back to school and one of my friends said they found a small mitsubishi turbo that was attached to a chrysler head while he was cleaning out his garage or attic or something like that.
Member
Joined: Feb 2004
Posts: 2,451
Likes: 1
From: Pearl City, HI, USA
Re: Twin Turbo: parallel or series? (nota-ex)
From a thermodynamic standpoint, you would want to run them in parallel.
Reasoning: The exhaust gas will go through the path of least resistance. When neither turbo has spooled, the lower inertia of the smaller turbo will cause it to quickly spool, sending an immediate boost to the manifold. As the efficiency of the smaller turbo drops off, and its resistance increases (when too much exhaust gas is present to go through the little guy), the exhaust gasses will then travel through the larger turbo. Net effect is quick spooling down low and plenty of flow up high. This is how most twin turbo OEM cars do it, and is in fact the entire theory behind twin turbos.
I have only seen series turbos on diesel engines where 70+ PSI was what they were after. Two small turbos, with an intercooler between them, can make the boost much more efficiently than a single, large turbocharger. (The T-S diagram could explain it better but I will leave that out for now)
Reasoning: The exhaust gas will go through the path of least resistance. When neither turbo has spooled, the lower inertia of the smaller turbo will cause it to quickly spool, sending an immediate boost to the manifold. As the efficiency of the smaller turbo drops off, and its resistance increases (when too much exhaust gas is present to go through the little guy), the exhaust gasses will then travel through the larger turbo. Net effect is quick spooling down low and plenty of flow up high. This is how most twin turbo OEM cars do it, and is in fact the entire theory behind twin turbos.
I have only seen series turbos on diesel engines where 70+ PSI was what they were after. Two small turbos, with an intercooler between them, can make the boost much more efficiently than a single, large turbocharger. (The T-S diagram could explain it better but I will leave that out for now)
Joined: Mar 2003
Posts: 545
Likes: 0
From: Alb., NM, USA
Re: Twin Turbo: parallel or series? (beepy)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote »</TD></TR><TR><TD CLASS="quote">
Reasoning: The exhaust gas will go through the path of least resistance. When neither turbo has spooled, the lower inertia of the smaller turbo will cause it to quickly spool, sending an immediate boost to the manifold. As the efficiency of the smaller turbo drops off, and its resistance increases (when too much exhaust gas is present to go through the little guy), the exhaust gasses will then travel through the larger turbo. Net effect is quick spooling down low and plenty of flow up high. This is how most twin turbo OEM cars do it, and is in fact the entire theory behind twin turbos.</TD></TR></TABLE>
Mk 4 supras are one of the cars that use this system OEM....Alot of supra owners tend to rebuild the second turbo bigger, so they still have the low end of the little one, but the power of a big turbo..
Jon
Jon
Trending Topics
Honda-Tech Member
Joined: Mar 2001
Posts: 4,408
Likes: 4
From: Somewhere in California
Re: Twin Turbo: parallel or series? (shadow103rd)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by shadow103rd »</TD></TR><TR><TD CLASS="quote">Mk 4 supras are one of the cars that use this system OEM....Alot of supra owners tend to rebuild the second turbo bigger, so they still have the low end of the little one, but the power of a big turbo..
Jon
Jon</TD></TR></TABLE>
That's the first time I've heard of Supras using a larger secondary turbo on their sequential setup. Do you have links or know of any shops that do this? I'd like to know more about it.
The stock sequential setup on MKIV's and FD RX-7's have turbos that are the exact same size. Even the upgraded twins I've seen usually have same size primary and secondary turbos. that was just for RX-7's though, I didn't look to much atthe upgraded twins they had for MKIV's.
Jon
Jon</TD></TR></TABLE>
That's the first time I've heard of Supras using a larger secondary turbo on their sequential setup. Do you have links or know of any shops that do this? I'd like to know more about it.
The stock sequential setup on MKIV's and FD RX-7's have turbos that are the exact same size. Even the upgraded twins I've seen usually have same size primary and secondary turbos. that was just for RX-7's though, I didn't look to much atthe upgraded twins they had for MKIV's.
Member
Joined: Feb 2004
Posts: 2,451
Likes: 1
From: Pearl City, HI, USA
Re: Twin Turbo: parallel or series? (BlueShadow)
[QUOTE=BlueShadow]
FD RX-7's have turbos that are the exact same size. Even the upgraded twins I've seen usually have same size primary and secondary turbos. that was just for RX-7's though ...[QUOTE]
TT RX-7's make me cringe. Their turbo system is sooo bloody complicated. There must be like 100 feet of vaccum hose.
FD RX-7's have turbos that are the exact same size. Even the upgraded twins I've seen usually have same size primary and secondary turbos. that was just for RX-7's though ...[QUOTE]
TT RX-7's make me cringe. Their turbo system is sooo bloody complicated. There must be like 100 feet of vaccum hose.
Honda-Tech Member
Joined: Mar 2000
Posts: 2,859
Likes: 1
From: Toronto, ON, Canada
Supra TT's have the same size turbos for both primary and secondary. They are regulated by an exhaust butterfly valve which directs exhaust gases to the primary turbo first, and then eventually open up the valve to power the second turbo. The layout is still parallel, but the turbo operates in a series manner.
Joined: Mar 2003
Posts: 545
Likes: 0
From: Alb., NM, USA
Re: (Tony the Tiger)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tony the Tiger »</TD></TR><TR><TD CLASS="quote">Supra TT's have the same size turbos for both primary and secondary. They are regulated by an exhaust butterfly valve which directs exhaust gases to the primary turbo first, and then eventually open up the valve to power the second turbo. The layout is still parallel, but the turbo operates in a series manner.</TD></TR></TABLE>
Good friend of mine owned a 94 Supra TT. I helped him alot on this car with mechanical work, its always nice to have an extra set of hands around. Anyway, from my understanding, they are essentially the same size, just that one turbo (the bigger one) has different wheels, wheels that can accomadate for high revs, and not choke itself up top. So off of idle, all six cylinders are being routed into one turbo (the smaller one). There is a vaccuum/boost source hooked up to a butterfly valve or some kind of diverter vavle that gradually opens and begins to direct exhaust to the other turbo and when X amount of boost is created, the valve is all the way open and is directing all six cylinerders exhaust into the other turbo (larger one).
My friend is very knowledgeable and Smart and 99.9% of the time he knows exactly what he's talking about. However, I may have gotten something wrong or misinterpreted something. Someone enlighten us all on this.
Jon
Good friend of mine owned a 94 Supra TT. I helped him alot on this car with mechanical work, its always nice to have an extra set of hands around. Anyway, from my understanding, they are essentially the same size, just that one turbo (the bigger one) has different wheels, wheels that can accomadate for high revs, and not choke itself up top. So off of idle, all six cylinders are being routed into one turbo (the smaller one). There is a vaccuum/boost source hooked up to a butterfly valve or some kind of diverter vavle that gradually opens and begins to direct exhaust to the other turbo and when X amount of boost is created, the valve is all the way open and is directing all six cylinerders exhaust into the other turbo (larger one).
My friend is very knowledgeable and Smart and 99.9% of the time he knows exactly what he's talking about. However, I may have gotten something wrong or misinterpreted something. Someone enlighten us all on this.
Jon
Honda-Tech Member
Joined: Mar 2000
Posts: 2,859
Likes: 1
From: Toronto, ON, Canada
Re: (shadow103rd)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by shadow103rd »</TD></TR><TR><TD CLASS="quote">
Good friend of mine owned a 94 Supra TT. I helped him alot on this car with mechanical work, its always nice to have an extra set of hands around. Anyway, from my understanding, they are essentially the same size, just that one turbo (the bigger one) has different wheels, wheels that can accomadate for high revs, and not choke itself up top. So off of idle, all six cylinders are being routed into one turbo (the smaller one). There is a vaccuum/boost source hooked up to a butterfly valve or some kind of diverter vavle that gradually opens and begins to direct exhaust to the other turbo and when X amount of boost is created, the valve is all the way open and is directing all six cylinerders exhaust into the other turbo (larger one).
My friend is very knowledgeable and Smart and 99.9% of the time he knows exactly what he's talking about. However, I may have gotten something wrong or misinterpreted something. Someone enlighten us all on this.
Jon </TD></TR></TABLE>
From the Supraforums tech articles, both stock CT12b twins are identical in specs. All the other common engines (1JZ, JDM 2JZ, etc...) all have identical primary and secondary turbos as well. On top of my head, I don't think Toyota ever made a TT setup with different sized turbos.
When both turbos start spooling, it will not choke anyway because... well, there are two turbos with the flow capability of two turbines Remember, they don't flow in series, they only operate in series. If one turbo for example can support 200HP or so, having two will allow 400HP of flow.
The only TT setup comes to mind with different sized primary and secondary turbos is the FD RX-7.
Good friend of mine owned a 94 Supra TT. I helped him alot on this car with mechanical work, its always nice to have an extra set of hands around. Anyway, from my understanding, they are essentially the same size, just that one turbo (the bigger one) has different wheels, wheels that can accomadate for high revs, and not choke itself up top. So off of idle, all six cylinders are being routed into one turbo (the smaller one). There is a vaccuum/boost source hooked up to a butterfly valve or some kind of diverter vavle that gradually opens and begins to direct exhaust to the other turbo and when X amount of boost is created, the valve is all the way open and is directing all six cylinerders exhaust into the other turbo (larger one).
My friend is very knowledgeable and Smart and 99.9% of the time he knows exactly what he's talking about. However, I may have gotten something wrong or misinterpreted something. Someone enlighten us all on this.
Jon </TD></TR></TABLE>
From the Supraforums tech articles, both stock CT12b twins are identical in specs. All the other common engines (1JZ, JDM 2JZ, etc...) all have identical primary and secondary turbos as well. On top of my head, I don't think Toyota ever made a TT setup with different sized turbos.
When both turbos start spooling, it will not choke anyway because... well, there are two turbos with the flow capability of two turbines
Remember, they don't flow in series, they only operate in series. If one turbo for example can support 200HP or so, having two will allow 400HP of flow.The only TT setup comes to mind with different sized primary and secondary turbos is the FD RX-7.
Honda-Tech Member
Joined: Sep 2001
Posts: 12,978
Likes: 1
From: Reading, PA, usa
Re: Twin Turbo: parallel or series? (nota-ex)
IMHO to even make it worth it, is do it like the RX7's use to. Have a smaller turbo feeding a bigger one, so less spool time and better top end.
I still think its pointless on a Honda though. Ask DRT about their brain fart with their twin turbo race car. the single turbo cars were going over a full sec faster. but they looked cool for having twins
I still think its pointless on a Honda though. Ask DRT about their brain fart with their twin turbo race car. the single turbo cars were going over a full sec faster. but they looked cool for having twins
Honda-Tech Member
Joined: Mar 2001
Posts: 4,408
Likes: 4
From: Somewhere in California
Re: Twin Turbo: parallel or series? (itr206)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by itr206 »</TD></TR><TR><TD CLASS="quote">IMHO to even make it worth it, is do it like the RX7's use to. Have a smaller turbo feeding a bigger one, so less spool time and better top end.</TD></TR></TABLE>
FD RX-7's also have two turbos that ARE EXACTLY the same size. They are twin Hitachi H-12's, and the only minor configuration is the secondary turbo has a slightly different wheel/blade configuration to help with upper RPM performance. I dont know if that is true or not, but it was quoted from a reliable source (Mike Ancas).
But other then the small difference in wheel/blade configuration, both the primary and secondary turbo are the same size. The RX-7 has twin Hitachi HT12's while the Supra has twin Hitachi CT12's.
Modified by BlueShadow at 1:32 PM 1/7/2005
FD RX-7's also have two turbos that ARE EXACTLY the same size. They are twin Hitachi H-12's, and the only minor configuration is the secondary turbo has a slightly different wheel/blade configuration to help with upper RPM performance. I dont know if that is true or not, but it was quoted from a reliable source (Mike Ancas).
But other then the small difference in wheel/blade configuration, both the primary and secondary turbo are the same size. The RX-7 has twin Hitachi HT12's while the Supra has twin Hitachi CT12's.
Modified by BlueShadow at 1:32 PM 1/7/2005
Honda-Tech Member
Joined: Sep 2001
Posts: 12,978
Likes: 1
From: Reading, PA, usa
Re: Twin Turbo: parallel or series? (BlueShadow)
oh, i always thought they were diff in size. could be wheel combo though. I just knew there was something diff about the prim and secondary.
Mike Ancas is a smart dude
Mike Ancas is a smart dude
Honda-Tech Member
Joined: Mar 2001
Posts: 4,408
Likes: 4
From: Somewhere in California
Re: Twin Turbo: parallel or series? (itr206)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by itr206 »</TD></TR><TR><TD CLASS="quote">oh, i always thought they were diff in size. could be wheel combo though. I just knew there was something diff about the prim and secondary.
Mike Ancas is a smart dude </TD></TR></TABLE>
Yah when I first heard about the TT systems on FD's a few years ago, I also thought the same thing. I guess it's a common misconception that people think FD's and MKIV's have a small pri and larger sec turbo setup.
no biggie I guess
Mike Ancas is a smart dude
</TD></TR></TABLE>Yah when I first heard about the TT systems on FD's a few years ago, I also thought the same thing. I guess it's a common misconception that people think FD's and MKIV's have a small pri and larger sec turbo setup.
no biggie I guess
Honda-Tech Member
Joined: Sep 2001
Posts: 12,978
Likes: 1
From: Reading, PA, usa
Re: Twin Turbo: parallel or series? (BlueShadow)
well IMHO , it seems like a good idea if someone were to run twins. Esp in this case. I dont know if it works like i think , but seems logical
Honda-Tech Member
Joined: Mar 2001
Posts: 4,408
Likes: 4
From: Somewhere in California
Re: Twin Turbo: parallel or series? (itr206)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by itr206 »</TD></TR><TR><TD CLASS="quote">well IMHO , it seems like a good idea if someone were to run twins. Esp in this case. I dont know if it works like i think , but seems logical</TD></TR></TABLE>
I'm guessing that if the difference between the turbines on smaller primary and larger secondary were too big then the turbine backpressure on the smaller first turbo might choke off the exhuast flow to the larger secondary turbine. It's just a wild guess, but that's the first thing that comes to mind when I think about the type of setup yo're talking about.
But didn't some of the TT Porsches have a small primary and large secondary turbo setup? or were did they also have twins that were the same size? because if they do have differnt sized turbos then they seem to be doing ok with it.
I'm guessing that if the difference between the turbines on smaller primary and larger secondary were too big then the turbine backpressure on the smaller first turbo might choke off the exhuast flow to the larger secondary turbine. It's just a wild guess, but that's the first thing that comes to mind when I think about the type of setup yo're talking about.
But didn't some of the TT Porsches have a small primary and large secondary turbo setup? or were did they also have twins that were the same size? because if they do have differnt sized turbos then they seem to be doing ok with it.
Honda-Tech Member
Joined: Mar 2000
Posts: 2,859
Likes: 1
From: Toronto, ON, Canada
Re: Twin Turbo: parallel or series? (BlueShadow)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BlueShadow »</TD></TR><TR><TD CLASS="quote">
But didn't some of the TT Porsches have a small primary and large secondary turbo setup? or were did they also have twins that were the same size? because if they do have differnt sized turbos then they seem to be doing ok with it.</TD></TR></TABLE>
The TT Porsches would be in their flat motors, and it would be one turbo on each bank of the motor. I don't think there are any TT inline Porsche motor, at least the ones I know of.
But didn't some of the TT Porsches have a small primary and large secondary turbo setup? or were did they also have twins that were the same size? because if they do have differnt sized turbos then they seem to be doing ok with it.</TD></TR></TABLE>
The TT Porsches would be in their flat motors, and it would be one turbo on each bank of the motor. I don't think there are any TT inline Porsche motor, at least the ones I know of.
Joined: Mar 2003
Posts: 545
Likes: 0
From: Alb., NM, USA
Re: (Tony the Tiger)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tony the Tiger »</TD></TR><TR><TD CLASS="quote">
The only TT setup comes to mind with different sized primary and secondary turbos is the FD RX-7.
</TD></TR></TABLE>
Maybe this is what I was thinking when I described how it worked, I guess I got the supra and rx-7 confused......Just found a Mazda website that confirms this....
http://www.mazda.com.au/articl...ID=90
Good info about the RX-7 histroy.
Jon
BTW, this is a good tech thread....Good info...lets keep this up guys !
Modified by shadow103rd at 1:26 PM 1/7/2005
The only TT setup comes to mind with different sized primary and secondary turbos is the FD RX-7.
</TD></TR></TABLE>
Maybe this is what I was thinking when I described how it worked, I guess I got the supra and rx-7 confused......Just found a Mazda website that confirms this....
http://www.mazda.com.au/articl...ID=90
Good info about the RX-7 histroy.
Jon
BTW, this is a good tech thread....Good info...lets keep this up guys !
Modified by shadow103rd at 1:26 PM 1/7/2005
Joined: Mar 2002
Posts: 4,547
Likes: 0
From: Blacksburg, VA
Re: (shadow103rd)
Cummins has created a variable turbo. It has an extra set of fins that slide out for low end and then they retract for higher RPMs. Im trying to get an internship, that would be amazing...
Thread Starter
Joined: Mar 2004
Posts: 760
Likes: 0
From: Mechanicsville, Maryland, US
Re: Twin Turbo: parallel or series? (itr206)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by itr206 »</TD></TR><TR><TD CLASS="quote">IMHO to even make it worth it, is do it like the RX7's use to. Have a smaller turbo feeding a bigger one, so less spool time and better top end.
I still think its pointless on a Honda though. Ask DRT about their brain fart with their twin turbo race car. the single turbo cars were going over a full sec faster. but they looked cool for having twins </TD></TR></TABLE>
what do you mean having a small turbo feeding a larger one? like the boosted air from the small one going into the exhaust part of the larger one?
I still think its pointless on a Honda though. Ask DRT about their brain fart with their twin turbo race car. the single turbo cars were going over a full sec faster. but they looked cool for having twins
</TD></TR></TABLE>what do you mean having a small turbo feeding a larger one? like the boosted air from the small one going into the exhaust part of the larger one?
Honda-Tech Member
Joined: Mar 2001
Posts: 4,408
Likes: 4
From: Somewhere in California
Re: Twin Turbo: parallel or series? (nota-ex)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nota-ex »</TD></TR><TR><TD CLASS="quote">what do you mean having a small turbo feeding a larger one? like the boosted air from the small one going into the exhaust part of the larger one?</TD></TR></TABLE>
No, I think he meant a small turbo which would spool up faster in the lower RPM band, and then the bigger turbo which comes on line at mid to upper RPM to work along with the smaller turbo.
The only problem I see with this setup, is that if the first turbo is too small then the turbine backpressure might have some effect on how the secondary turbine works. Once the exhaust gasses come out of the engine, it first is routed through the primary turbo's turbine, with a little going to the secondary turbine to help prespool it. Once the RPM's are high enough the secondary turbine comes fully online.
No, I think he meant a small turbo which would spool up faster in the lower RPM band, and then the bigger turbo which comes on line at mid to upper RPM to work along with the smaller turbo.
The only problem I see with this setup, is that if the first turbo is too small then the turbine backpressure might have some effect on how the secondary turbine works. Once the exhaust gasses come out of the engine, it first is routed through the primary turbo's turbine, with a little going to the secondary turbine to help prespool it. Once the RPM's are high enough the secondary turbine comes fully online.