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Discussion Starter #1
With all the interest flying around with turbo setups lately, how about we group it all into one thread?

My turbo is just about done. Still have some small issues to work out but it seems to be running ok so far.

Still have to get my fuel management, and intercooler hooked up this weekend but I will update after that. So please excuse the mess under the hood.



So lets see all the turbo jeeps that are floating around here.
 

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I didn't want to stink up the other thread with mine.

Draw-thru, Carbureted (was Motorcraft 2bbl, now Q-jet), V8 (was 304, now 360)

T3 hot section, T4 compressor (V-2 compressor group I got from a John Deere core, changed it over to a carbon seal for the draw-thru)

10psi max currently, Will go higher and switch to E85 this summer.

Of course conventional wisdom will say that this turbo is 'too small' but that is only 'too small' in drag race tuner terms.

For a heavy, automatic, LOW rpm engine, it works very nicely. So nicely that I have designed a version 2 carb and turbo mount for the next truck.

( I dont spin it much harder than 4000 rpm, since AMC V8's don't really oil well up there anyway - and further, if I need wheelspin, I got it, and if I am winging it past 4000 rpm, I must be in a fairly low-traction situation anyway, so it is not like the thing has to be on a good area of the map at that time)

I used stock waggy exhaust manifolds, turned the original Y-pipe into a crossover pipe, fish-mouthed a stainless weld-el and cut a hole in the pass side manifold, burned the 2 together and viola, turbo exhaust system.

I have done a blow-thru carbureted 360 with a single To4E (60) with a P exhaust wheel and a 1.15 A/R exh. housing. Made 617 Lb Ft at 2100 rpm with 10 PSI and 89 octane.

I will see if I can get a photo or 2 hosted tonight and link them.

peace
Dave

EDIT - of course we all know that carbs will never work with turbo's and draw-thru is old fashioned, wrong way to do it, all that crap. The thing everyone forgets is context. Will a all stainless, tigged manifold, Big intercooler, 2000 dollar EFI system setup make more HP for less heat than mine? Hell yes it will.

Will my 304 / 360 make enough oomph with 8 or 10 psi to make me never have to wish for an LS1. You are damn right it will.
 

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With all the interest flying around with turbo setups lately, how about we group it all into one thread?

My turbo is just about done. Still have some small issues to work out but it seems to be running ok so far.

Still have to get my fuel management, and intercooler hooked up this weekend but I will update after that. So please excuse the mess under the hood.



So lets see all the turbo jeeps that are floating around here.
What do you use to manage the Air Temp Sensor? What about the MAP Sensor?

What do you use for fuel Management?

Im about to start on my turbo 4.0 engine in my YJ. I did all my math and homework. the only question I have is it possible to use the stock ECM running a 2 bar MAP on larger injectors pushin about a modest 6 PSI, no intercooler? What about piggy back ECM's? Im not looking for a sand dragger or anything. Just something to help turn 40's when needed. Lookin for about 240-260 hp.

This will be the start and I want to get this setup dialed in before I jump into the 4.7 Turbo stroker running 10 psi, intercooled, with a quality turbo. I figure start out small and work up to the big guns slowly.
 

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Discussion Starter #4
What do you use to manage the Air Temp Sensor? What about the MAP Sensor?

What do you use for fuel Management?

Im about to start on my turbo 4.0 engine in my YJ. I did all my math and homework. the only question I have is it possible to use the stock ECM running a 2 bar MAP on larger injectors pushin about a modest 6 PSI, no intercooler? What about piggy back ECM's? Im not looking for a sand dragger or anything. Just something to help turn 40's when needed. Lookin for about 240-260 hp.

This will be the start and I want to get this setup dialed in before I jump into the 4.7 Turbo stroker running 10 psi, intercooled, with a quality turbo. I figure start out small and work up to the big guns slowly.
I dont have an IAT sensor that I know of. I am obd0 or 1, so I have a little more wiggle room than you may have as far as the senors go.

I have a one way check valve in the map sensor vac line so it wont see boost. When the boost comes on it will just read atmosphere. I may be switching to a 2 bar map to see if it will work.

I have not upgraded the injector yet because being that I only have a single injector tbi its harder for me to find a larger one that will work.

For fuel management I will be using an 3:1 FMU until I can get the mega-squirt. But if the FMU works, I will run it until I have problems with it.

I havent run it much but my stock computer seems to be doing ok recognizing all the new hardware. Seems to even be running rich. I will find out tomorrow when I get the a/f gauge hooked in.
 

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EDIT - of course we all know that carbs will never work with turbo's and draw-thru is old fashioned, wrong way to do it, all that crap. The thing everyone forgets is context. Will a all stainless, tigged manifold, Big intercooler, 2000 dollar EFI system setup make more HP for less heat than mine? Hell yes it will.

Will my 304 / 360 make enough oomph with 8 or 10 psi to make me never have to wish for an LS1. You are damn right it will.
Right on :smokin:

As far as my turbo 4.0L, soon to be turbo 4.5L goes - read this:

http://www.pirate4x4.com/forum/showthread.php?t=614289
 

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Well Im going to get this thread a swift kick in the arse and I wanna see what you all got!!

So the next post will be my research and math done to point me in the right direction and HOW to engineer a turbo for your exact engine
 

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Turbo Math

Turbo findings and the Math involved


Here is the following formulas and why they are used to get the best possible set up. First we have to set up some rules and Known numbers to make this all work out. These numbers are just ideal and do not garrentee the outcome of the final product. Use these numbers as a guideline only.

These are the following numbers I used.

Compression Ratio for the stroker: 8.75:1
Red line RPM: 5300
Using a ambient Temp of 85 degrees
Engine size is 281.33 C.I. (4.7 liter)
Base off of 10 PSI of boost from turbo
Ambiant absolute air pressure is 14.7 psi
Compressor effiency is 75.8%

These are the numbers I used.

Designing a turbocharger system requires a basic understanding of pressure, temperature, and flow of gas. (Honeywell Turbo Technologies)

First equation is to find the pressure ratio(PR). We use pr later when we look at compressor maps to properly size the turbo to the application. This pr is for the compressor side. We will call this EQ1(equation one)

PR=(boost + ambient pressure)/ambient pressure
PR=(10+14.7)/14.7
PR=1.68(or 1.61 using a intercooler)
This is based on at sea level. This can change with the use of intercoolers. It is important to try and get an ideal PR of the entire system. Using a intercooler will usually drop the system around One psi and you can just add this into the above equation Just take 10 psi and subjract one which will give you a PR of 1.61. You can use this equation every time you change the output PSI of the turbo(5, 5.5, 7, 13) Use these numbers and play with the above equation and see what you get when you change the boost.

Next is to find out the ideal temp out put going into the engine. You know that if you compress air, it gets hotter. You also now that the cooler the air the denser it becomes and better power. Remember, these are just ideal numbers. We will use the above given temp for Equation 2 (EQ2).

To,ideal=[(Tin+460) x PR^0.283]-460

=[(85+460) x 1.68 ^0.283]-460
=(545x1.16)-460
= 172.2 degrees

But this is assuming that the compressor is operating at 100 percent efficiency which is never true. Compressors run between 70-80% on the average. So we take the above number to another equation (EQ3) to get the more realistic number. We will use the given efficiency as above.( that number I will show you later in another equation)

To,actual=[(To,ideal - Tin)/efficiency] + Tin
=[(172.2 - 85)/ .758] + 85
=(87.2 / .758) +85
=200 degrees

To page #2
 

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turbo math pg 2

Now we can find out the Density Ratio (DR) of the system. Remember that density is the AMOUNT of air particles in a given intake stroke of the engine.

DR= PR x[(Tin + 460) / (Tout + 460)]
= 1.68 x (545 / 660)
= 1.39
Now lets change Tout to 120 degrees (that’s assuming out put of a intercooler), and lets use the PR of the intercooler and the DR will increase
DR = 1.61 x (545 / 580)
= 1.51
So if you can cool the air enough and keep the PR as high as you can you will get a denser charge of air in the engine equaling more power.
Do not confuse the PR and DR. PR is the efficiency of the turbo. DR is the amount of AIR MOLECULES going into the combustion chamber. Stick with me. It all makes since in the end.

The next equation is the engine displacement (EQ5)

Disp = [(#cyl)(stoke)(Bore^2 )] / 1.27
= [(6)(3.413)(3.91x3.91)] / 1.27
= 281.33 cid

These numbers are what I want to build my engine to. Your numbers will be different. So you need to plug your specs in place of mine to get your application.

The next thing we need is the Volumetric Flow Rates (VFR). But before this we need to talk about Volumetric Efficiency (VE). VE is basically the percentage of output vs. the input of any given engine. The method of intake/exhaust designe, the Head of the engine, size of exhaust, bends in intake and exhaust. There is so much to take into account. A fully race car engine can be upwards of 98 percent compared to your basic stock jeep engine can be as low as 65 percent. So lets assume we will use a larger throttle body, high flow intake, large 2.5 inch exhaust (this includes the CAT), the head on our engines are already efficient from the factory. So lets say we can achieve a VE of 85%. I don’t have an equation to get this number. Its just an assumption. If you would use straight stock intake and exhaust, I would use 65%. We will also use the redline RPM in this. So we are actually calculating the MAX VFR or our engine. This equation will be used again at different RPMs when we look at compressor maps. This number is expressed in CFM. So our next equation is as follows (EQ6):


VFR= [(disp x rpm) / 3465] x VE
= [ (281.33 x 5300) / 3456] x .8
= 366.72 CFM

Moving on to the next equation. Lets find out the air density that is possible. This leads into another equation. This is expressed in pounds per cubic foot . This is also dependent on Absolute pressure at a given tempurature. This is also the same thing we breath on a day to day basis. Absolute pressure changes with change in altitude as well. So if you really want to get specific, find out your psia at your altitude to get more concrete numbers. All these equations are based at sea level (EQ7).

Air Density = [(2.703)(PSIA)] / (Temp + 460)
= [(2.703)(14.7)] / (85 + 460)
= .073 pounds per cubic feet

And to page 3
 

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turbo math pg3

This is where we start pluggin in the past equations and we see things coming together. The next one we calculate is the Mass Flow Rate (MFR) . This number is used in conjunction with PR to look at compressor maps to find the best turbo application for your engine. But we are not done yet. So here is EQ8:

MFR = VFR x Air Density OR:
MFR= [(2.703)(psia)(VFR)] / (Tin + 460)
= [(2.703)(14.7)(366.72)] / (85 + 460)
= 26.74 pounds per minute

This is the output of a 4.7 stroker with NO turbo. So the next one is very simple to figure the out put of a turbo running 10 psi of boost. All we do is multiply the above number by the DR.

MFRturbo = (MFRna)(DR)
= 26.74 x 1.51
= 40.38 pounds per minute

Now this calculation is based on running the engine at 5300 rpm. So, run the calculations for 1500 rpm (we want the turbo to start spooling), again at 3000 rpm (the range we want the turbo to be at its highest efficiency). These are numbers I wanted to work with. Use your own numbers for what you want. It is important you do this because we will use these numbers as a reference later in the article.

MFR @ 1500 rpm = 11.43 lb/min
MRF @ 3000 rpm = 22.85 lb/min

To get your numbers first calculat VFR at the given RPM. Then take that number and plug into the MFR equation to get your flow at the given rpm. These numbers are guidelines that we must stay within to get the best possible results.

Now lets talk about possible horsepower output of this engine. Remember to plug your numbers in place of mine since they may be different. We will use the Brake Specific Fuel Consumption equation (BSFC). An average turbocharged gas engine will burn between 0.5 - 0.6 pounds of fuel every hour for each horsepower developed. We will use 0.6 pounds because these are fairly large engines. We know our boosted MFR. We must come up with a Air/Fuel ratio now. We know that we never want to go above 14:1 to avoid to lean and burning up the motor and we don’t want to go to rich around 10.5:1 to avoid sluggish washy performance. Under boost, the safest ratio is 12:1. This is all in the programming of the ECU fuel system. So lets just use 12:1 in the equation.(EQ9)

HP = [(MFR)(60)] / [(A/F ratio)(BSFC)]
= [(40.38)(60)] / [(12)(0.6)]
= 2422.8 / 7.2
= 336.5 horse power.
 

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turbo math pg 4

(Now lets talk about what can effect your overall outcome of power. After punchin numbers I found that DR and PR have the largest effect of overall out put. So these are the numbers you really want to design a system around. So Ideally, if you want a number, you design around that number to get what you want. Also the air fuel ratio and burn rate of fuel will change your numbers. The less fuel burn per hour and the leaner the mixture will net you more power. But then you run into the possibility of detonation and burning up pistons. That’s is my own theory and opinion. I could be wrong. We can see how the tuning of the ECU has a LARGE impact of the output)

Compressors

This next section is about compressors and how to find out their efficiencies. Remember the number I used earlier? This is how I get that number. In this section, we will start combining numbers and looking at compressor maps to see how this all comes together. When looking at a map of a compressor, you basically want to stay in the “zone” of a particular turbo when matching to the engine specs. Lets first look at how to get the efficiency of a compressor..

EFFcomp = [(Tin+460)(PR^.283)-(Tin+460)] / (Tout - Tin)

= [(85+460)(1.68^.283 ) - (85+460)] / (200 - 85)
= [(545)(1.16) - 545] / 115
= (632.2 - 545) / 115
= .758 or 75.8%

That percentage is BEFORE it enters the intercooler. Taking this number we are close to start looking at maps to see what we can find. These maps are produced and graphed from the engineers at the factory using math that I do not under stand. Basically those guys did all the hard work for us. This is the link to all the maps of the garrett turbos from this website: http://www.atpturbo.com/root/index.htm


Here is an example of a map for this turbo application. Just look at the airflow, then go up to the desired PR and you can see at what efficiency the turbo is best at. Now you can read these maps and make sense of it.
But before we start looking at maps, we have to size a compressor to out application. This is where we start combining past equations to see what we want. Our engine operates at 85 percent VE, a PR of 1.68 of the compressor, a PR of 1.61 of the SYSTEM (that is running through a intercooler). We have a temp out of 200 degrees F. (Remember the past calculation of EQ2).
Now we look at how an intercooler effects the system. We will use 70% intercooler efficiency (EFFic)

Tic out = Tcomp out - (EFFic)(Tcomp out - Tamb)
= 200 - (.70 x (200 - 85))
= 200 - (.70 x 115)
= 200 - 80.5
=119.5 degrees F

Now we calculate the DR using the equation from before but we already did that using 120 degrees as the base.

DR = 1.61 x [(85 + 460)/(120 + 460)]
= 1.51
Now we bring in the VFR and plug into the MFR equation using this adjusted DR. VFR was 366.72 CFM at 5300 RPM. But if you did this earlier then all numbers should be the same. So you can play with numbers and see if your DR changes your output changes. It is all in design. Now you can design your system to work in your area. Example is why run numbers at sea level at an average of 85 degrees when most of your time may be spent above 6000 feet elevation with an average temp of 70 degrees. So you can see how just your location in the world will have a severe impact of the design and output of the system. So NOW is the time to get some MFR rates at different RPMS and we can start to plot on compressor maps to find the best one for out application.
So lets work with the following numbers and start plotting

MFR of 11.43 at 1500 RPM
MFR of 22.85 at 3000 RPM
MFR of 40.38 at 5300 RPM
 

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continued. . .



Look at this map. Lets plot 11.43, 22.85, and 40.38 Using a PR of 1.68. Remember, we are plotting the turbo, not the system.
We get 70 percent at 1500 rpm, 75 percent at 3000, and we almost drop off at 5300 rpm. This is not what we want.

Next Map



Look at this map. Lets plot 11.43, 22.85, and 40.38 Using a PR of 1.68. Remember, we are plotting the turbo, not the system.

We not even on the chart at 1500rpm but look at 3000rpm. Just about to hit 72 percent then at 5300 rpm, we are around 75 percent this looks a little better but it seems this won’t give any power off idle. This might exhibit lag.
You have the link to go to the same website to see more maps. Check it out. Im still searching to this day to find the right one. And I can’t even afford a brand new unit. I was also told you can call up the right people and they can help locate the right turbo with the right numbers.

There is also a book I read and keep reading today on this subject. All my info came from this book. It is called “Street Turbocharging” written by Mark Warner, P.E. The book is put out by HPBooks. You can go to amazon.com to get this. I will keep this book in my automotive library forever.
This book covers EVERYTHING. I only hit on the main topics and bearly grazed the surface. Check it out.

Any ways, The required injectors for this at a minumum is 35.5 lb/hr using a 16.8 ms pulse width at 73 percent duty cycle. That is another can of worms to go into on the math.

And that concludes my full article on Turbo Math
 

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List is too long - but based off a 87 Buick Grand National turbo V6.
Yea ok.. that makes sense.

That is one turbo model on my donor list for my engine. Im trying to go junkyard style but still keep everything reliable
 

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Yea ok.. that makes sense.

That is one turbo model on my donor list for my engine. Im trying to go junkyard style but still keep everything reliable
The GN motor is stout and will support up to 600hp using stock internals. I only plan on running 17 psi initially - but may add alky injection and turn the boost up to about 24 psi. These motors are known to handle 30 psi.

Has bowl ported heads, 206/206 cam, 42.5lb injectors, adjustable boost referencing fuel pressure regulator, made a custom 2.5" downpipe - custom intercooler pipes, etc. Walboro 355 fuel pump - TA32 turbo - blah blah blah.

edit: turbo specs - TA32 Low 12's 2400 32 2.170" 2.950" 54(compressor trim) 3"/2" 360 0 T31 2.559" 2.121" 69(turbine trim)
 

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Discussion Starter #18
here is some free software that is great in figuring out what turbo will work for your motor. It will also give an estimated HP and TQ rating for your motor at certain points in your power band.

http://www.turbofast.com.au/freesoftware.html

This isnt the end all to figure out all your numbers, but it is a start. Was a big help in giving me an idea of what size turbo I needed.

Chris
 

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thats a pretty cool program. I downloaded it and I will play with it tonight after work. I went to one of the tabs and threw in the basics of a 4.7 liter stroker and It came up with the similar turbo I came up with in my calculations. This program seems to do more for you except fuel delivery requirements.

thats a good link you posted wckdyj:beer:
 

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That looks like the map of Hillary's vagina
 
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