I want to learn about turbos. I have A '89 F450 with the 7.3. I want to turbo it. Other than a few of the name brand kits I don't know anything. I've seen alot of used stuff but don't know what to look for. Does anyone know of some good sites that would explain how they work? How are they sized? What's a waste gate?

 

well the best choice for your truck would be a Hypermax turbo kit or and ATS turbo kit and i wouldn't get banks because banks is not making anything for idi diesels anymore. You could also buy a used one but be cautious and make sure it is working good but the only things you can really test without running the turbo is shaft play and visible damage, ie cracks, scratch marks, bent blades.

For how a turbo works well this site will probably explain it better than i will.
http://forcedairresearch.tripod.com/id4.html

here is a site that kinda explains wastegated turbos
http://www.streetracersonline.com/ar.../wastegate.php

hope that helps a bit, I would definetly turbo your diesel i don't think a diesel should be without.

 

a turbo pretty much puts alot more air into the motor to burn fuel more completely and more fuel when needed.a wastegate limits the amount of air going into the motor by opening up and venting pressure that is over what it is set for too much pressure will cause the headgaskets to blow or the motor will come apart.....thats about as basic as i can explain it im sure others will jump in and give ya their explaination.

 

Thanks guys. I've been doin' some research. And I don't think its as confusing as I thought it was. Would it be hard to convert one or build one. I just found a 6.9L kit and was wondering about fitting it to the 7.3L. Does the size of the turbo matter?

 

if it will work on a 6.9 it will work on a 7.3.essentially its the same motor with different displacement.as far as the size goes you dont wanna boost over 12 or 13 psi on a motor without studs so a smaller one would be fine.you can convert one off another car but its pretty labor intensive dyoung is working on a powerstroke turbo conversion i believe.as far as building one you had better be one heck of a machinist and have top of the line equipment the cheapest and fastest route would probably buy a used aftermarket kit or a stock turbo system off a 93 or 94 idi and be careful with the 94 stuff because powerstrokes came out in 94.5

 

Actually I am a machinist. I have access to all kinds of equipment. Can you add a waste gate to any system? I found a banks that does not have a waste gate. From what I have read, It sounds like it's needed.

 

you dont "need" a wastegate as long as it doesnt spool over a certain amount.im not sure how non wastgated sytems work but i know they make kits for our trucks that are not wastgated

 

A wastegated turbo has smaller turbines and will spool up at a lower rpm, a non wastegated will have larger turbines and will spool up later.

 

You can add a waste-gate system to any turbo, but it would be pretty labor intensive as far as machine work goes, due to the fact it has to be able to withstand up to 1200F exhaust temperature - not any materials will do for that, fr instance some turbos equipped with factory waste gates use ceramics for the gate itself. If you do get a fast-spooling high-pressure turbo what you can do to make sure you don't overboost the engine is add a blow-off valve (BOV) like many 4-cylinder turbocharged cars have - this thing goes between the turbo and the engine intake, so it don't see any stupid-high temperatures, additionally there are many kits for it and the installation is easy. In case you're wondering a BOV is nothing more than a fancy pressure relief valve, it's spring preloaded and it pops open at certain psi - much like how a water heater relief valve works, only this is for air.

 

From doing many turbo projects here are the lessons I have learned.
Not to contradict what was said earlier, but a wastegate has nothing to do directly with how large or small a turbo actually is, it has more to do with how big you can go before you over-boost.

Keep in mind a turbo's job is to use air (from the exhaust) to move air (to the engine). A smaller turbo will spin up faster (because it needs less exhaust gas), but may not be able to build full pressure at higher RPM's. A lager turbo will spin up slower, but also be able to maintain a much higher boost level at high RPM's.

for example on one of my projects I built a system that can deliver 12PSI at 1500 RPM, but by the time you are pushing 4k the turbo is pretty well winded and you are only seeing about 5~6 psi. At the same time, a larger turbo would spin up at about 2800RPM, delivering 10psi, and building to 24psi by 7500RPM. My goal was 10 PSI from idle to about 3000RPM, 14 PSI from 3k-5500RPM, and 18PSI from 5500 to my 7800RPM redline. The solutiion was twin turbos (using both mentioned above), a single, seperate wastegate with a multistage controller (electronic toys), and a BOV that opened at 20PSI. The wastegate managed the amount of pressure the turbos could generate, the bov protected the engine from getting force fed air to the point of exploding. (keep in mind this was an extreme setup and there were lots of other things need to address charge cooling, EGT's, ect), the other advantage to this is is because the turbos could generate more boost then needed at sea level, when I would go to high altitudes the system would still keep up, and not require adjustment (ie performance was the same if I was at sea level, or at 7500 above).

To clarify the real differences between a BOV and a wastegate, their location and their function. A wastegate is a controller in effect for how much boost your turbo will be "allowed" to produce, a BOV is a saftey valve controlling how much boost gets to the engine. The intended purpose of a BOV is when you are dealing with high pressure applications and need to relieve pressure on the throttle plate quickly (like when shifting). Even though you let of the gas, the turbo will stay spinning building pressure against the throttle plate untill you either open it (and ram all of that built up excessive pressure into the engine), or the turbo stalls (litterally stops spinning from too much force...this is mean to do to your turbos)....the BOV just flows this pressure into the atmosphere.

If I were designing a system for mine (which I still may do) I would probably look for a turbo that would spin up by 1500 RPM, and maintain about 18 PSI to about 3000RPM. Then I would use an integrated wastegate (for simplicity) to limit it to 10~12 PSI, and not worry about BOV. Having the ability to flow the extra air (keep in mind its 18psi at sea level) will pay for itself when I hit a mountain pass as the system should be able to maintain the normal 10~12 (again, a wastegate function). Then I would look seriosly at charge cooling...keep in mind, 99% of the time the heat will kill you before the pressure does. In one of my road race cars I was running 26PSI, on a 4cyl with a comp ratio 10.1 to 1....everyone who saw it said it would blow up, but the key was a charge temp of about 170 degrees, and running a mix of denatured alcohol, propane, and 105 octaine av gas....yeah, the cyl head pressure was high, but the temps stayed low enough that their was no thermal stressing...it all held together.

Sorry this is so long, I just hate (from many of the other forums I am on) when people start passing on information they have heard or read without looking into the scientific and technical reasons behind it.

 

Adding a diesel twist to what Tim said, on a diesel engine there are three main differences.

First is much higher compression ratios, 21.5 to 1 or 22.5 to 1 depending on which motor you have.

Second the RPM scale, boost above 3500 is useless, you want your highest boost between 1500 and 3000 RPM.

Third is no throttle body to stall the compressor when you shift gears, however if you are building enough pressure when you let off the throttle the decrease in heat in the exhaust can still stall the turbo.

For most practical purposes, a non waste gated turbo will spool slower since it has been designed so it will not over boost the engine at high RPM.
Waste gated turbo's can be more aggressive building boost at lower RPM since the waste gate can open and limit boost at higher RPM.

Looking at a 6.9 with 22.5 to 1 base compression ratio, add 10 PSI boost and you have about 37.8 to 1 as an effective compression ratio.
Take the same engine, 15 PSI boost and the effective compression ratio is 45.5 to 1.
Again with 20 PSI and the effective compression ratio jumps to 53.1 to 1.
One more time, 25 PSI and we are at 60.7 to 1.

Any wonder why high boost can take out a head gasket.

If we went back and looked at the 10.5 compression ratio engine, 26 PSI was in the 29 to 1 effective compression ratio area.

Given the amount of room you have to work in, making your own turbo system is going to be a challenge.
I am not going to say it is impossible, but it will be a challenge.
Here is the back of my engine with the ATS 093 turbo (same as the stock Ford turbo with a larger down pipe) and up pipe installed.



Notice how the cast iron up pipe wraps around the rear of the passenger side head.
Also on a stock truck, the up pipe does barely have clearance between the head and firewall.
However ATS used a 3" down pipe, which requires the cab seam be folded over to make room for, or a body lift will also get you the needed clearance.

I don't have a non waste gated turbo to take pictures of, but I do have an extra waste gated turbo that I will take some pictures of to show how the internal waste gate works later today.

 

Thanks for chiming in Dave, admittidly I so not have a lot of experience in the twist that the diesel adds to the equation.

As a side thought, although unconventional, in many of my gasoline racing/high performance apps I have used remote (think STS style rear mount) setups. Although it takes a little more engineering to deal with the longer charge are pipe, the result is a colder charge temp, as well as lower egt and turbo temps (being that not everything is cramped in the engine compartment, and there is airflow of some sort 90% of the time underneath the body.

I found a smoking deal on a hypermax system, but am also considering looking at engineering something going down the remote route as it would appear with the head studs if I go remote I should easily be able to keep my temps low enough to run close to 18psi without overtaxing it.

Thoughts?.?.?

 

I have looked at the STS systems.

My thoughts,
Cast turbo, very hot, down where cold water can splash on it sounds bad enough.

If you look at my engine picture again, notice the header wrap on the up pipe?
There is more on there you can't see as well as the cross over pipe from end to end.
I did that to keep all the heat I possibly could in the exhaust so I could get more boost and faster turbo response.
Also adding more volume to the exhaust and charge air pipes means more turbo lag and more heat loss = lower, slower boost.

I have been looking at mounting intake snorkels just inboard of my stacks to pipe air to the air cleaner box.
Finding a clean path to route the pipe from below the truck up to the air cleaner has me wanting to relocate the batteries back to the frame so I have an open path for the air supply pipe and possibly inter cooler pipes where my ram air is now located.

I have a problem using/depending on a pump to return the turbo oil to the oil pan, and let's not forget the oil supply line, rather long so more places for it to fail.

STS systems have problems in my mind.
Remote mounting the turbo, is a novel idea, but it has more draw backs than advantages.

There are a couple issues with the ATS system, mainly changing the glow plugs, but I still think it has the most potential of the bunch.

Head studs, milled pistons and over 20 PSI boost on a 6.9 is where I am coming from.

Going up to take pictures of the turbo now.

 

your cool

I had all of the exact same concerns when I did my first remote build up. One thing I learned is all of the rules of heat management change going this route. The turbo in general will run ALOT cooler.

Too bad i need this truck as a workhorse.....time to start shopping for another IDI for fun. I have only had it for a couple of weeks but damn I love this truck.

 

This is the turbo outlet flange on a waste gated turbo.

My son has relocated the turbo somewhere, and he is not home, so I can't show that side.

That flapper just covers a hole that lets the exhaust gasses bypass from the turbo in side to the exhaust side without going through the turbo.

And before we had talked about milling the outlet flange larger to accommodate a bigger pipe, the outlet flange walls are to thin for that to happen.

A cooler turbo is fine, cooler exhaust gasses are not.
The hotter the exhaust gets, the faster and higher the boost climbs.