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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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I don't know anymore. It seems they are stepping up their game a bit on the offbrand/knock off world.

 

Personally I agree, I'd rather spend 6-800 on a borg warner, than 3-400 on an off brand, and that is what I did, I paid extra to have a specific hotside, and it spools like nobodies business, plus if anything goes wrong I know the turbo is most likely not the cause and is covered under warranty.

 

But if you have say $200 or so in your motor, buying a $1600 turbo seems a bit stark. At $400 or so you are already doubling the amount you spent on the engine, and at that price range there is only used older style turbos. If I was in that same boat I would be really hard pressed to click away from something from like CX which offers a ball bearing GT35 clone for $425.

 

Then there are middle ground suppliers, I think on3 might be included in them, but driftmotion for sure is one of them. They take aftermarket housings and put garrett center sections in. The steel and aluminum may not be as pure or rated the same, but the work horse is in theory reliable and serviceable.

 

The tradeoff for sure is reliability. You might not have a balanced turbo, it might start leaking at 10 miles, and it seems they rarely make it over 10k miles. Granted if you don't drive very much that upper level 10k mile lifespan could mean years. If that is the difference between a project going ahead and not, then maybe it is a choice for some.

 

But, if the turbo lets go, you really can't blame anyone or get on your high horse and talk about how bad it is. It is a knock off and you knew that going in.

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2 hours ago, seattlejester said:

I don't know anymore. It seems they are stepping up their game a bit on the offbrand/knock off world.

 

Personally I agree, I'd rather spend 6-800 on a borg warner, than 3-400 on an off brand, and that is what I did, I paid extra to have a specific hotside, and it spools like nobodies business, plus if anything goes wrong I know the turbo is most likely not the cause and is covered under warranty.

 

But if you have say $200 or so in your motor, buying a $1600 turbo seems a bit stark. At $400 or so you are already doubling the amount you spent on the engine, and at that price range there is only used older style turbos. If I was in that same boat I would be really hard pressed to click away from something from like CX which offers a ball bearing GT35 clone for $425.

 

Then there are middle ground suppliers, I think on3 might be included in them, but driftmotion for sure is one of them. They take aftermarket housings and put garrett center sections in. The steel and aluminum may not be as pure or rated the same, but the work horse is in theory reliable and serviceable.

 

The tradeoff for sure is reliability. You might not have a balanced turbo, it might start leaking at 10 miles, and it seems they rarely make it over 10k miles. Granted if you don't drive very much that upper level 10k mile lifespan could mean years. If that is the difference between a project going ahead and not, then maybe it is a choice for some.

 

But, if the turbo lets go, you really can't blame anyone or get on your high horse and talk about how bad it is. It is a knock off and you knew that going in.

 

 

totally, You don't need a GT series Garret turbo. You can get a very nice Holset or entry/mid level Garret for $7-900.  We have learned the cheapest is not always the best solution..>Blown up motors, redone work..... Do it right the first time from what I have learned... Pay a bit more or find something good quality used.... 

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On 12/16/2017 at 10:52 PM, M_Dragan said:

Just wondering what size turbo I should use for my 2jz build if I want to start spooling around 3,000 RPM, what do you guys think?

 

There are a lot of questions to figure out a turbo size. Why did you pick 3,000rpm?

what fuel you plan to run?

how much power you want? 

Built motor? Stock motor?

what do you want to use the car for? Street?drag?autocross?mile?track?

 

once you know what the motors mission is give the guys a Real Street a call. They really helped me choose my turbo with dyno graphs and cam choices. 

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On 5/29/2018 at 9:27 PM, OverkillZ said:

 

There are a lot of questions to figure out a turbo size. Why did you pick 3,000rpm?

what fuel you plan to run?

how much power you want? 

Built motor? Stock motor?

what do you want to use the car for? Street?drag?autocross?mile?track?

 

once you know what the motors mission is give the guys a Real Street a call. They really helped me choose my turbo with dyno graphs and cam choices. 

Thank you! I'll have to give them a call when I'm close to completion.

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