Turbo talk

ISPKI

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Hey guys. I have seriously been considering picking up a turbo for my 94 f250 7.3. Got to talking with my Co workers about turbos and he was saying that a tdo5h out of mid 90s mitsubishis are perfectly sized for these engines when keeping boost under 10psi. This got me thinking about how to figure out air flow and pressure differentials etc

I know everyone seems to say to get one of a few different turbos but I would be interested in seeing if there are more options out there. I would also be interested in seeing if running twin small turbos would be more beneficial than running single turbo.
 

DaveBen

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It is too small. YES it will keep the boost under 10 psi, way under 10 psi. Get what works with this engine and quit re-inventing the wheel.
 

ISPKI

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It is too small. YES it will keep the boost under 10 psi, way under 10 psi. Get what works with this engine and quit re-inventing the wheel.

That's what I was thinking, but when we started doing the math, it is capable of providing more than enough air to supply the engine. Keep in mind that an eclipse turbo is built to keep up with an 8000rpm motor, that's more than double what our motors are designed to handle.

And if we just keep doing the same old thing, we will stagnate and die out. This thread is all about different ideas.
 

Hydro-idi

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Why do you need to keep boost under 10psi? The entire goal of a turbo is to make as much boost as you can! You can safely max out at around 13psi without an intercooler. Of course you need a large enough turbo to supply the air.
Anything above that requires an intercooler because air charge temps become way too hot, loosing much of its efficiency. I would say 20 psi is a safe maximum for a healthy 7.3 idi or 6.9 idi engine with an intercooler. However, the 6.9’s will surely require studs.
I was able to squeeze 12-13 psi boost with my stock 088 setup without intercooler. Didn’t make much whistle but it did put out some good power.
 
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Thewespaul

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Here are the calculations and research you need to do,

First you need to find the air flow that your engine na flows.

Next get a target air boost pressure, 10 psi is an easy number to work with.

Atmospheric pressure is about 14 psi, so with 14 psi of boost you are doubling your engine air flow in an ideal situation, however in the real world this is not the case as it’s near impossible to have 100% volumetric efficiency

Intercoolers and exhaust wrap help increase your efficiency, so that needs to be considered

Once you have an idea of what VE you are going to be working with, multiply your target total intake pressure by your na airflow then by your volumetric efficiency (ie. 24/14 * 650 cfm * 70%) and you will have your target airflow.

Look at some turbo options that meet that target airflow without entering the surge line and you will have a good idea what turbos will work for you.

This is a really over simplified explanation and theirs a ton of research that goes into picking a turbo setup. For the engine I’m building an s366 will fit my needs well.
 

79jasper

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Sure, it'll make enough airflow for the engine, but what's the back pressure look like?


Sent from my SM-G892A using Tapatalk
 

pelky350

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Find a used kit, have @typ4 do the rebuild on it or just purchase a kit from typ4, conestoga, or r and d and call it a day lol unless you do want to build your own kit but in the end it's probably going to cost you about the same unless your really resourceful but I understand the desire to make it your own also this forum could provide much info if needed. I'm running typ4's rebuilt upgraded factory system and very happy with it, also fuel system by r and d.
 

ISPKI

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Great question jasper, and that is one reason why I made the thread.

Borg warner has an interactive form on their website that helps calculate alot of these values and compile it into use able data if any cares to take a look.

The idea behind running a smaller turbo that cab still flow enough air is to spool super early to eliminate boost lag, not to mention these turbos are much more readily available and cheaper than the usual options
 

ISPKI

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Find a used kit, have @typ4 do the rebuild on it or just purchase a kit from typ4, conestoga, or r and d and call it a day lol unless you do want to build your own kit but in the end it's probably going to cost you about the same unless your really resourceful but I understand the desire to make it your own also this forum could provide much info if needed. I'm running typ4's rebuilt upgraded factory system and very happy with it, also fuel system by r and d.

well I am very resourceful and capable, I have a ton of manufacturing equipment I have access to. However, that really isn't the point of the thread. The point was to talk turbo options, how to plan for a turbo, how to figure out which turbos can work and which ones wont.
 

no mufflers

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Haha, yes sorry, thought I quoted you. That is a he'll of a turbo, how did you come to the decision to use that?

that was the turbo that mel started to sell for the IDI platform. i had the banks but this one just runs great.

the specs are on the form some where but its a .72 a/r on the charge side and i think .98 a/r on the exhaust.
 
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