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Turbo sizing

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Looking for help to select appropriate turbo and manifold for my 3.4 vvti 2jz + bmw dct, as much street friendly, as possible , pump fuel 95ron permitting, approx 650hp-700hp

Would be nice if somebody could calculate for me, I just don’t trust myself on this. Would prefer internally gated, but if that’s no good , I’ll just go what’s working best.

Getting engine built using brand new head, block etc.

Head has upgrades: bronze guides, GSC valve train , S1 cams, shimless buckets, pocket port.

I apologize, I was sure I responded to this.

Did you want that HP at the wheels or crank? If at the wheels, it would help to know on what dyno so we better understand how much power, and thus how much airflow we are talking about.

If you pay attention, you wouldn’t find a query in my post about how good or bad, or cheap or expensive any turbocharger is.

I’ve tried Garretts boost adviser, Borg warners matchbot, but I’m not sure about my understanding of it.

And yes, I deleted the previous post, because of irrelevant answers to the question.

No offence , you’re just not paying attention, please refrain from posting on this tread.

If you still need help with calculations I'm still willing to help since noone else has done it so far. Just let me know what exactly you need help with and I'll do that. First time the topic name made me confused...

Ok, I’m not sure where did I go wrong formulating my question, but basically in looking for most appropriate turbo selection on street car limited with 95ron fuel.

Just by saying , go with the 3582rs , would be insulting to Borg Warner Matchbot. Why is it even there then, if it’s that simple.

I’m not saying 3582rs is no good to me, even for example exhaust ar size and why, g35 770 smallest housing vs g30 770 biger housing, etc,

Let me know what more you need to know, il try to answer.

You're looking at this the wrong way round - you're limited by the fuel you're intending to use, which means you will need to work around the compression ratio to figure out what torque/power you can roughly expect, with the charge cooling and everything else taken into account.

Then when you've a realistic figure, you should be able to narrow it down, depending on what characteristics you want - if it falls between two options, usually the best option is the smaller one for response, earlier spool, and general driveability.

At the moment I can only guess the ratio, if I’m going with 9:1 pistons, combustion chambers will be slightly reshaped, so it’ll result in less than 9:1.

Charge cooling, i think I’ll go with this https://plazmaman.com/product/600x300x63-pro-series-intercooler/

Looks like, Ill be better of instead of guessing , come back to this when I’ll have exact figures?

I'm on the business trip at the moment. Please let me have a few days and I'll try to elaborate... Basically Gord already said what i was going to talk about but we will discuss it anyway.


As others have mentioned, you'll have to compromise based on the fuel you're using. Choose a turbo you can operate in a high efficiency range on the compressor map, size the turbine for reasonable exhaust temps and pressures to allow for reasonable power production without knock.

I mentioned what fuel I’ll be using.

You’re just basically extending my question.

Ok, I'm back. I'll share my experience as we have been dealing with tonns of jz cars. In general they are very prone to knocking even with 8.5 CR (as 3l vvti for example) and even WM injection isn't 100 percent guarantee from failure. The bottom line is if you wanna get real big power on reliable basis you need ethanol. Even high octane pump gas has its limit about 1.8 bar maximum (I'm taking 8.5 CR - higner CR will make this figure even lower). If your goal is to get real 650-700whp we are talking about 800+ hp at the crank which is automatically 2+ bar of boost which is automatically weither race gas or ethanol. Low octane fuel will not get the job done and most likely will burn the engine sooner or later.

This is something that needs to be realised before moving to the next question- turbo size and spool.

So acording to your advise garretts adviser is off by miles?

So acording to your advise garretts adviser is off by miles?

On 1jz with gtx3576r at 1.55 bar it made 516whp/ aprx 580hp (Dynapack) at the crank, 550cc injectors pum fuel.

This is something I have been talking about for years - not all the dynos show the same results. I'm an old school - my favourite dyno is Mustang as it's most conservative one and it's completely in line with general automotive industry rule that it takes 1 lbs of air per minute to produce 10 hp at the crankshaft on high octane pump gas. Not sure about Dynapack how accurate it is.

But easiest way to double check is to look at the catalogue. 1jz in NA state produces 200hp. Assuming NO LOSS due to increased intake charge temperature ( which in real world is never the case) and high 10.5:1 CR we can simply multiplay 200 hp by 2.55 (absolute pressure) and we'll get 510 crank hp at most (theoretically)... But real result will be even less because it will definitely start knocking with such a high CR. If you reduce CR you won't get 510 hp... So whichever way you go you ain't gonna get even 500 hp at the crank in real world.

Well, I'm sharing my experience. Maybe it's the quality of local pump gas but even with octane rating 98 or even 100 the most boost level our JZes are working reliably on is 1.8 Bar. On 95 pump gas 1.3 bar maximum... As far as others' figures go I always remember one saying I was taught long time ago by a wise man: never believe what you hear and believe only half of what you see...

By the way- our quickest jz is 7.4 so we are not strangers to jz world.

And yes , 1.55 bar was on pump fuel and hks fcon piggyback and very close to 9.0:1

But what dyno?

That 3.0 you referred to was on the US "93" Octane - (RON+MON)/2 - and equivalent to around 98 RON, which is the rating the UK used - significantly higher than what you're using. UK's 95 RON is ~91 using the US rating (known as PON - Pump Octane Number). It's one of those things that can catch folks out when trying to compare across the ditch.

You are going to be fuel limited, as said, but you may be able to squeeze a little more boost by keeping the charge as cool as practical, using water/methanol injection and, pertinent to the topic, sizing the turbo to operate in it's highest efficiency area - something I can't really help you with, but suggest you have a good think what you expect to be using the engine for when leaning on it, as that may affect the hot side housing more than anything else, around the airflow you need.

This is something that someone claims to be the truth. Just like I said before i was sharing our experience dealing with jz engines. If someone's got different personal experience so be it. I would love to see as many personal experiences from real world as possible...

Are you saying Andre is talking shite? :)

We usually reply within 12hrs (often sooner)

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