question about single versus twin

sparkplug619

2 Supras, 1 Paycheck =[
Sep 28, 2008
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so if you have 1 big turbo you would gain more than twin? because i like the whole idea of twin, the way it hisses, looks, and especially would love to brag about my twin turbocharged car. but i dont really know much about turbo because i never actually had a turbocharged car.

also if it is true that you gain more with 1 big 1, is there any kits that have more output than 1 big 1, because i am looking forward to starting a 2jz supra for the track but i am trying to learn more about maximum performance

sorry for the noob question.. been a fan of supra since i was 12 and i barely bought my first dream mkiii so its all still pretty new to me
 

LordDigital

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May 21, 2005
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5 Years after Toyota Introduced the Twin Turbo 1JZ ,they officially admitted that a plain Parallel twin turbo setup is WORSE than a Single turbo in the following article

Now for a more sophisticated Twin Turbo setups like the USDM 2JZ-GTE or even on some Audi(s) the story is quite different.
 

suprahero

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When they go bad.......you only have to rebuild one of them as opposed to two of them.

You can make higher horsepower with a large single turbo. Good luck with your project.
 

suprahero

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One turbo works great
Two turbos work good also
The choice is yours dude.




sorry, Haiku alert.
 

Bigzavs

86.5 1JZ Single Turbo
Apr 21, 2005
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Single > Twins

the bigger single you go, the more supporting mods youll have to have to support the power it makes. you cant just toss a 74mm on the stock motor and expect to make a bajillion horsepower.
 

sparkplug619

2 Supras, 1 Paycheck =[
Sep 28, 2008
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you think i would be able to make up for these lost numbers with 2 decent sized/ rated upgrades? i wouldnt mind a big single either though, i just liked the look of the tt but i didnt know it was a crappy setup... thanks for the support suprahero... btw my girlfriend just fell in love with that pic of ur interior like 2 minutes ago lol1
 

86_sports_1jz

slow 700hp build...
Aug 27, 2006
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a twin setup also cost alot more money than a single, its twice the headache when anything goes wrong because you have two of everything instead of just one.
 

LilMissMkIII

That Aussie Chick
Aug 18, 2006
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Friend of mine down here has upgraded HKS twins on his 2J.

It is a gigantic pain in the ass when things go wrong.

You need to take into consideration what you want to use your car for... Big single is good for dyno and drag, but twins may be better suited to track/circuit racing. If you decide to go twins, you then need to decide if you want a sequential or TTC setup.

Have a good read through all the FAQs on this site, and anytime you have a question, use the search feature, as 99% of the time, someone has already asked the question :)
 

BorHor

2JZ-GZE
Jan 10, 2006
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Main reason twins make less power is because of the lack of space. It is easier to fit 1 big turbo then 2 medium ones.
 

suprahero

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sparkplug619;1198078 said:
support suprahero... btw my girlfriend just fell in love with that pic of ur interior like 2 minutes ago lol1


I"m pretty sure I just fell in love with your girlfriend..............:naughty:

.....also when you're working on your car, as I do quite often, it's soooo much easier to remove a single turbo, as opposed to the twins.
 

figgie

Supramania Contributor
Mar 30, 2005
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simple phyiscs though.

TWo turbos = two points of inefficencies v one for the for single turbo.

Simplicity.

A single turbo that is sized right will always WORK better and more efficently than a N+1 setup.
 

88supraTT

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Oct 2, 2005
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I've been sitting in the situation for awhile; trying to decide what is better twin set-up or a single set-up. I'm trying to have a peak power of 550-600 at wheels, and still be able to autox it, with the power level turned down. so i think my only option is two run twin gt25/28. i think it is feasible with todays technology, but if anyone has a good single turbo that could work for this please let me know. my interwebz time is some what limited. i've been searching off and on many boards and so forth but comming up dry, because most people are what seems to be running singles because of cost and not for performance. don't know if i worded the last sentence right but it is from my point of view.

Note; i'm the brother of this current user and have a 1jz into a FC chassis
 

figgie

Supramania Contributor
Mar 30, 2005
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88supraTT

550-600 RWHP is not the issue.

The issue is WHEN do you want the power produced within the limitations of the motor. Unfortunatly as displacement decreases, the RPM MUST increase to produce the power so you are looking at a turbo that can breath efficently at 6000+ rpm. The GT35r is about the only option with a .82 A/R (and not the smaller surge inducing A/R .63) . Anything else and you will choke the top end. Please do not do what is the habit of sizing turbos now which is a big turbo with a craptacularly tiny Aspect Ratio.

In this world, duals will never ever be as good (ie efficency, thermal losses, fluid mechanics losses etc) as a properly sized single. And you can take that statement to the bank.
 

jizake1jz

FTMFW
Feb 18, 2007
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but say you wanted to run twins, even if a single would be more efficient. say twin gt2871r's....would the smaller a/r turbine housing be the correct choice?

BIC had that twin gt28r kit and made 500 @ 20ish psi. i think a twin setup will be just fine, just different then a single setup.

i'm going to try twin gt2871r's in the spring, partly because i think it will make nice power and have a nice rpm range to that power, and partly because i really just want to make a manifold, downpipe, and ic piping for a twin setup :naughty:

i think 600-700 hp is not out of the question if i wanted a lot of power with this setup, but keeping the boost down will yield a respectable amount of power at a reasonable time (hence my choice for the .64 a/r turbine housing) for an all around fun car. i guess there is really only one way to find out though...
 

Gritz

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Aug 1, 2008
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It really donsen't matter, either can make huge power...You just have to weigh the pros and cons of both...Also if you really want a twin setup, i would go with that..it's your car so do what makes you happy...but like i said, just make sure you know what your getting into..
 

suprahero

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Gritz;1198271 said:
It really donsen't matter, either can make huge power...You just have to weigh the pros and cons of both...Also if you really want a twin setup, i would go with that..it's your car so do what makes you happy...but like i said, just make sure you know what your getting into..

figgie;1198247 said:
In this world, duals will never ever be as good (ie efficency, thermal losses, fluid mechanics losses etc) as a properly sized single. And you can take that statement to the bank.

I do what this guy suggests.........he's smarter than the average bear Boo Boo.
 

figgie

Supramania Contributor
Mar 30, 2005
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speaking of efficencies.....

http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/GT28/GT2876R_705330_2.htm

The GT2876R, the compressor map is comparable to the big boys. The Turbine map on the other hand.. An Anemic 62% efficient which in words, means that nearly half the energy is being lost in trying to spin puny little itty bitty turbo!!

2 of those and you WILL be lucky if you are above 60% efficiency and that will net you a theoretical 960HP.

http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/GT42/GT4202R_774595_8.html

One GT4202R.

Just in efficiency alone, picked up 12% over a single GT2876R, probably close to 20% on a dual setup. What this means is that more of the exhaust is used to spin the compressor instead of overcoming heat, friction etc and with a that single turbo, I have a higher power ceiling too with less complication etc ;)

In the end. Do what ever you want but just realize that attempting to justify with falsehoods that have propogated on the inet (like that backpressure bullcrap word) will lead you to an emptier wallet.
 

suprahero

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Figgie, do you feel like explaining how to read the graphs that shows effieciency? What should I look for when looking at the flow tests of a certain turbo? I have the pt67 on my 1.5jz and I'm just wondering if that's a good turbo for my application. I have the Crower cams and a ported and polished head also. I've never known what I was looking at when looking at the flow charts (I can't remember what they're actually called).