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erohslc
erohslc Reader
2/25/11 5:09 p.m.

Rule #17: Never pour a box of ball bearings into the inlet of a spinning turbocharger.

92CelicaHalfTrac
92CelicaHalfTrac SuperDork
2/25/11 5:13 p.m.

Rule #18: If your flange adapter is a bolt-on type, do NOT assume that the previous owner properly tightened the bolts. (Too tight is REALLY bad) Turbines do not appreciate grade 13.5 bolt heads flying into them.

Ask me how i know.

imirk
imirk New Reader
2/25/11 5:23 p.m.

In reply to 92CelicaHalfTrac:

How do you know?

carguy123
carguy123 SuperDork
2/25/11 7:26 p.m.

I'm very surprised no one has mentioned the most critical element - lots and lots of money.

ditchdigger
ditchdigger HalfDork
2/25/11 7:54 p.m.

Standalone management and a good dyno tuner are what I credit with holding my fragile little fiat motor together at 12psi. All stock internals.....vintage fiat internals that might as well be made of glass.

ditchdigger
ditchdigger HalfDork
2/25/11 8:00 p.m.
carguy123 wrote: I'm very surprised no one has mentioned the most critical element - lots and lots of money.

If you dont count the cost of megasquirt (which I already had installed) It can be quite cheap.

Volvo Turbo $40 DSM intercooler and BOV $30 schedule 40 weld el's $25 the rest of the steel for the manifold ~$20 radiator hoses for couplers $12 oil feed line $25 Ebay boost controller $5 T clamps $14 and a bit of exhaust pipe for the downpipe.

That is pretty much all it took

Schmidlap
Schmidlap HalfDork
2/25/11 11:25 p.m.

A couple of tips to help your turbocharger live:
You want the shaft of the turbo as close to horizontal as possible. In a production application they shoot for a maximum of 15 degrees from horizontal. If you're not looking for 100,000 mile durability, you can get away with a little more but you'll be putting more force on the thrust bearing.

Make sure you're getting the right oil flow and oil pressure to the turbo. Garrett's website has some info on this I think, otherwise try emailing them for some guidelines.

You want the largest diameter oil drain tube you can fit on it, though you quickly hit a point of diminishing returns. Look at the size of the oil drain hole in the bottom of your turbo and you want a larger drain tube than that.

Make your drain as direct as possible to the oil pan with a good downward slope, as few bends as possible and with no uphill sections in it. If you can't do a downward sloped oil drain, you will need an auxiliary oil pump to get the oil back to the pan and to keep the oil from backing up into the turbo.

Make sure your oil drain is as low as possible relative to the shaft of the turbo - the axis of the drain should be as close to vertical as possible (less than 15 degrees from vertical).

In case you haven't noticed, oil is very important to a turbo. An oil cooler is a good idea.

If your turbo is water cooled, make sure you're getting adequate flow into and out of the turbo. If your turbo comes from a production application, look at how they have the cooling lines plumbed, they have probably used some tricks to get the heat in the turbo to keep the coolant circulating through the turbo a little after the engine has been shut off.

It's late so I'm probably forgetting some things. I'll try to think of more.

Bob

ww
ww SuperDork
2/26/11 1:03 a.m.
Grtechguy wrote: From a guy who's never owned a forced induction vehicle. what are the "criteria" to "safely" turbocharge a NA engine? What is needed?

If knowledge is what you seek, then I recommend... BOOKS! ;)

This will get you started in the right direction for no more than $15!

http://www.amazon.com/gp/product/1557884889/ref=ord_cart_shr?ie=UTF8&m=ATVPDKIKX0DER

92CelicaHalfTrac
92CelicaHalfTrac SuperDork
2/26/11 6:35 a.m.
imirk wrote: In reply to 92CelicaHalfTrac: How do you know?

Let me paint you a picture:

Driving down the road, you're enjoying your boosted goodness when all of a sudden you hear a nice little "PINNNGGG!!!!!!!" You listen further, but hear nothing out of the ordinary, so you keep driving. Then, the realization hits you. "Where has my boost gone?" you ponder to yourself.

You pull off into a gas station, take the filter off the turbo, and see a nice bolt head that despite it's grade 13.5, has turned into a neat oblong shape and stuck itself between two turbo fins, and the turbo housing itself.

PO: 1
Supra CT26: 0

You slap another turbo on there, and weld the flange adapter to the manifold. While you're in there, you wonder where the other missing bolt head went to. You also attempt to remove the remaining two of four bolts, only to be foiled miseraly, despite using a 4 foot breaker bar. At this point, you realize that whoever "installed" the bolt-on flange adapter was a massive idiot that must have been built like Arnold in his glory days.

Ignorant
Ignorant SuperDork
2/26/11 7:01 a.m.

see if you can find this book at your local library..

It is better than anything you can find published today. It will also make your brain hurt

http://www.worldcat.org/title/turbocharging-the-internal-combustion-engine/oclc/9071850?loc=11111&tab=holdings#tabs

Turbochargers work on flow, not pressure.

11110000
11110000 Reader
2/26/11 12:19 p.m.

The advice here is good. Bottom line, you can do a turbo for cheap if you scrounge junkyard parts, drop in a RRFPR and dial back your ignition timing, and keep the boost in the 5-10psi range. You can add anywhere from 10-50HP like this and not break anything (in most cars.) The problem with boost is that you will want more. Turn it up, and when you think you're satisfied, you will again want more. When the connecting rods let go and exit the block you will still want more. As the car burns to the ground you will be thinking, "I need another turbo."

mike
mike Reader
2/26/11 1:05 p.m.

lol at 11110000's (240's) post

Rufledt
Rufledt HalfDork
2/26/11 1:28 p.m.

I always thought the 1st guiding rule of turbocharging was a simple equation:

More boost = more happiness. Always, with no exceptions.

rule 2 must then be: Crying does not fix broken connecting rods, that's what welders are for.

*my lawyers urge me to say that I am not liable for any problems you may encounter while following my 2 rules of turbocharging.

Also, thank you ignorant sir for that worldcat book.

stan_d
stan_d Dork
2/26/11 7:31 p.m.

i started off with a factory turbo car and added a n/a version of the engine went from 125hp to 311hp but i did add a 3.3bar fpr it usally took about a year to destrory the pistons .but replacement engines could be had for $100

erohslc
erohslc Reader
2/26/11 7:32 p.m.
Ignorant wrote: see if you can find this book at your local library.. It is better than anything you can find published today. It will also make your brain hurt http://www.worldcat.org/title/turbocharging-the-internal-combustion-engine/oclc/9071850?loc=11111&tab=holdings#tabs Turbochargers work on flow, not pressure.

Yah, but it's the pressure in the intake manifold that causes the increased flow through the motor. Each cycle of the motor is going to sweep a fixed volume of charge. The density of that charge is determined by the pressure.

ncjay
ncjay Reader
2/26/11 7:50 p.m.

I have a car that I drag race some times. My future plans include a twin turbo setup. Since I've never owned or driven a turbo car ever I turned to this to get started - HPBooks has a book called Turbochargers written by Hugh MacInnes. Lots of good solid info on turbos and designing a good system. Believe some of the info being posted on here at your own risk.

92CelicaHalfTrac
92CelicaHalfTrac SuperDork
2/26/11 8:19 p.m.
erohslc wrote:
Ignorant wrote: see if you can find this book at your local library.. It is better than anything you can find published today. It will also make your brain hurt http://www.worldcat.org/title/turbocharging-the-internal-combustion-engine/oclc/9071850?loc=11111&tab=holdings#tabs Turbochargers work on flow, not pressure.

Yah, but it's the pressure in the intake manifold that causes the increased flow through the motor. Each cycle of the motor is going to sweep a fixed volume of charge. The density of that charge is determined by the pressure.

Both a T25 and a T88 can show the manifold 15psi...

erohslc
erohslc Reader
2/26/11 8:49 p.m.

But not at the same RPM and throttle setting on the same motor! That's the flow part. The motor doesn't magically sense whether the manifold pressure came from a turbo, a Roots, a bicycle pump, or a high pressure front. The valve opens, the difference between manifold pressure and pressure in the cylinder causes flow into the cylinder. If whatever is causing the manifold pressure cannot maintain the flow, then the manifold pressure drops. Getting the intake charge into the cylinder is work, basically pressure x massflow, maybe it would be better if we rated systems in work units.

Carter

ditchdigger
ditchdigger HalfDork
2/26/11 9:36 p.m.
ncjay wrote: HPBooks has a book called Turbochargers written by Hugh MacInnes. Lots of good solid info on turbos and designing a good system. Believe some of the info being posted on here at your own risk.

That is a good book for basic theory but unless it has been updated since the version I have it is so out of date as to be a historical oddity.

The version I have claims that there are no benefits to fuel injection over carbs, that a log manifold is just as good as a tuned header style manifold, water injection is just as good as an intercooler and quite a bit of other things that will make any modern tuner roll their eyes.

11110000
11110000 Reader
2/27/11 12:40 p.m.
mike wrote: lol at 11110000's (240's) post

I laughed too:

BlazingInferno

92CelicaHalfTrac
92CelicaHalfTrac SuperDork
2/27/11 1:40 p.m.
erohslc wrote: But not at the same RPM and throttle setting on the same motor! That's the flow part. The motor doesn't magically sense whether the manifold pressure came from a turbo, a Roots, a bicycle pump, or a high pressure front. The valve opens, the difference between manifold pressure and pressure in the cylinder causes flow into the cylinder. If whatever is causing the manifold pressure cannot maintain the flow, then the manifold pressure drops. Getting the intake charge into the cylinder is *work*, basically pressure x massflow, maybe it would be better if we rated systems in work units. Carter

I agree wholeheartedly. My issue is that i understand that it's about flow, but anytime anyone mentions pressure my brain explodes.

I know we're agreeing, i just don't understand anything you posted here or the post prior to it.

To me, what you're saying sounds like the two turbos will make the same power at 15psi, because rhetorically, both would be capable of the same PSI at the same RPM on the same motor, and to hold up that pressure.

I dunno. Makes my brain hurt, and i've been driving turbo cars for awhile.

Like i told JamesMcD last week, i just use big ones and crank the boost and call it a day.

Ignorant
Ignorant SuperDork
2/27/11 5:43 p.m.
erohslc wrote:
Ignorant wrote: see if you can find this book at your local library.. It is better than anything you can find published today. It will also make your brain hurt http://www.worldcat.org/title/turbocharging-the-internal-combustion-engine/oclc/9071850?loc=11111&tab=holdings#tabs Turbochargers work on flow, not pressure.

Yah, but it's the pressure in the intake manifold that causes the increased flow through the motor. Each cycle of the motor is going to sweep a fixed volume of charge. The density of that charge is determined by the pressure.

yeah.. no.

A certain mass flow through a given space gives you a pressure. Flow is what does the work, pressure is just a side effect of pushing so much "stuff" through a given space.

Saying that the density of the charge is reliant upon pressure is entirely incorrect. As I could have a I could effectively have 0.001 Lbs/min of flow @ 1kpsi or I could have 5 lbs/min @ 14.7 psi. One of those flows will change your "charge density" more than other..

People constantly confuse pressure and flow. more info here. http://www.turbobygarrett.com/turbobygarrett/tech_center/turbo_tech101.html

Teqnyck
Teqnyck Reader
2/27/11 7:16 p.m.
Rufledt wrote: rule 2 must then be: Crying does not fix broken connecting rods, that's what welders are for.

Yeah, about that.

Sometimes the rods in my cars don't break. They sure lose a berkeley ton of compression though.

erohslc
erohslc Reader
2/27/11 7:34 p.m.

Umm,. ..,NO Respectfully, I am not confused at all. It's the work that's really important. Work is defined as a force (pressure) operating over a distance.

In the world of hydraulics/pnuematics, that boils down to pressure times flow. Flow can be expressed as mass flow, or volume flow. If you are dealing with a fluid (incompressible from a practical standpoint), then massflow and and volume flow are the same, just expressed in different units. If you are dealing with a gas, then the pressure (and temperature) of the gas become significant when changing from mass flow units to volume flow units.

Here's a hint: Under steady flow, the turbo will deliver exactly the same flow as the motor consumes (minus whatever the blowoff wastes).

And all else equal, the flow through the motor is determined by the mean intake manifold pressure.

Ignorant
Ignorant SuperDork
2/27/11 7:53 p.m.
erohslc wrote: Umm,. ..,NO Respectfully, I am not confused at all. It's the *work* that's really important. Work is *defined* as a force (pressure) operating over a distance. In the world of hydraulics/pnuematics, that boils down to pressure times flow. Flow can be expressed as mass flow, or volume flow. If you are dealing with a fluid (incompressible from a practical standpoint), then massflow and and volume flow are the same, just expressed in different units. If you are dealing with a gas, then the pressure (and temperature) of the gas become significant when changing from mass flow units to volume flow units. Here's a hint: Under steady flow, the turbo will deliver *exactly* the same flow as the motor consumes (minus whatever the blowoff wastes). And all else equal, the flow through the motor is determined by the mean intake manifold pressure.

Mass flow is where it's at.. I don't really want to argue with you.. I don't have the time or patience, but you're thinking about it backwards.

When sizing a turbocharger, you size for a specific mass flow and not for a specific pressure as you would espouse. The specific gains in horsepower requried are stated in mass flow and therefore you get whatever pressure you get to get whatever performance you want..

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