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M_Dragan

What turbo size should I use?

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Need more parameters. 

 

Look up info on your own. That is part of the fun of learning. Learn how to read compressor maps if you want to know how a turbo will behave.

 

As a rule of thumb the smaller the hot side A/R the faster the spool. If you have a small A/R on a big frame turbo you will run into the turbo pushing too much air to get through the small A/R of the exhaust. Run a small A/R on a small frame and you will find you may be moving yourself out of efficiency as the turbo has to spin faster to achieve similar air flow as a larger frame. A/R is a ratio, but generally if you look at a T4 flange turbo something around .5-.7 would be good. I know you can get like .4X with a T3 flange on smaller wheeled turbos.

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I used a Holset HE351cw, awesome turbo get response. Holset in general spool fast and kick in really aggressive. A/R's for holset arent measured the same apparently. But something like a HX35,40,50 or 55 are solid choices. Hx40 is a common choice for drifters. All holsets are T3's unless you have the big ones like hx55 then its a T6. So I customized my flange to T4. At 10psi im making ~330whp on a essentially a stock motor. 10psi for a holset is nothing, they can do 20-30psi all day.

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On ‎12‎/‎17‎/‎2017 at 2:59 AM, seattlejester said:

Need more parameters. 

 

Look up info on your own. That is part of the fun of learning. Learn how to read compressor maps if you want to know how a turbo will behave.

 

As a rule of thumb the smaller the hot side A/R the faster the spool. If you have a small A/R on a big frame turbo you will run into the turbo pushing too much air to get through the small A/R of the exhaust. Run a small A/R on a small frame and you will find you may be moving yourself out of efficiency as the turbo has to spin faster to achieve similar air flow as a larger frame. A/R is a ratio, but generally if you look at a T4 flange turbo something around .5-.7 would be good. I know you can get like .4X with a T3 flange on smaller wheeled turbos.

Yeah that's what I've been reading generally. I just wanted a second opinion because people on other forums for the 2JZ cant seem to make up their minds on what's best. Thanks for the help!

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A second opinion requires a first, are there any that have peaked your interest?

 

Everyone's opinions and usage are subject. Supra guys generally will recommend turbos that will get them to 600+hp as they know as a forum people tend to want more, so they recommend larger. 

 

Keep in mind our cars are 1000lbs lighter, more if you have a 240z. Power to weight wise their recommendations are going to blow most of the tires off that we can fit on our cars. Fit wider tires and that means you have to address axles and other components keep that in mind.

 

Also keep in mind if you are buying a kit or a certain manifold that may limit your options regarding size. Like for me and another local our manifolds and engine placement lined our turbos up with the shock tower, so we had to find turbos that would work with the space we have. Turbos come fairly late in the build you don't have to figure it out now, and tech is constantly improving. I ended up picking up an E model of borg warner which has lots of improvements over the standard one. I know someone else who bought a specific turbo with plans to build around it, that really locks you in though, you really should prioritize engine placement over turbo placement, unless you HAVE to run a specific turbo.

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