rotorocks

This is an edit to the original post, as people are asking about the details of the setup.
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T04E remote mounted turbo (ebay @ $200).
It is installed in place where the muffler used to be.
Fuel System - Stock
$20 or so Boost controller from ebay
Greddy Knock off BOV from ebay again
Exhaust - Gutted cat, custom made single tip 2.5" outlet with a small resonator welded into it. Sounds beautiful.
Oil is delivered to the turbo from a sandwich plate installed below the oil filter, through about 12-14 feet of 1/4" copper line running back along the fuel line.
Oil is extracted from the turbo using a 12V 75GPH self priming sump pump, which drains the oil from the turbine and pushes it back into the engine through a tap in the oil cap. I used about 10 feet of 3/8" copper line for oil return line and the rest is 1/2" rubber hose. (connects from the turbo to the pump.
There is a large 13x27(or 30" can't remember)x3 air to air intercooler, and the air charge is delivered to the front through a 2" custom bent and welded aluminized steel pipe which runs along the drive-shaft. I do not have any clearance issues.
I use Interceptor-X EMS running in matrix mode, with 8 psi of boost.
I have a NGK AFR Gauge with the WBO2 sensor installed in place of the stock one (the original sensor is disconnected and removed)
A center console mounted boost gauge and EGT gauge.

To this day the system has close to 7000 very aggressively driven miles on it. The car total mileage is around 27000.
Running with stock tires ( presently ) I have no problems breaking traction in 1st by stomping the throttle, 2nd when shifting gears a bit more aggressively (opening the throttle in 2nd when making a turn will send the car into a nice drift), and 3rd gear if I rev the engine and drop the clutch rolling at about 40MPH.
I do not know what it runs a 1/4 mile at. I never yet dynoed the car.
At a WOT run; the boost comes into positive at 2500 rpm, hitting 5PSI at 3000-3200 rpm and full boost at 35-37K ppm through to about 7500 and then slides down and settles a5 5-6 all the way to the redline. But that is due to a cheap $20 ebay variable boost controller I use. I am sure that with decent controller I could run 10psi all the way through the redline.
This is about all I can think of.
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Original post below
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Hi, I have been snooping around more and more, and thinking how I can get my car to run better and faster, and then I have decided WTF all these guys do it, so can I. Anyway, I started out by installing and playing around with a Nitrous system, and run with it for a while, and it is fun, but not exactly what I was looking for. So I had decided to build my own turbo.

Here is what I came up with so far:

My goal is to build a system that will allow for the following:

Power: 300-350 BHP with decent low end torque.
Relatively low cost: ballpark $2500 or as low as possible without compromising the reliability.

As of today I have placed an order for the following items:

Turbo – T3/T4 T04E
This turbo promises to be a quick spooling one (2000-2500 rpm) with pretty high boost potential (up to 25 PSI)

Greddy Type-RS Blow Off Valve (like the color =) )
Big *** JDM 32X12X3 Intercooler (big and cheap) hopefully it won’t be one of those “You get what you pay for”.

Tomorrow I am adding to the bundle: Interceptor-X for the engine management (this is the most expensive part of it all)

Items Pending more research: (any suggestions welcome)

Boost controller,
Waistgate (still haven’t decided whether to use the Internal or external)
Gages:
Boost, WBO2, Oil Temp

Fuel Pump, Oil Pump

Anything I may be missing?


The Idea is to have the turbo positioned in the rear of the car where the muffler currently is with exhaust gasses exiting through either a custom fabricated smaller single or dual muffler or directly out (depending on the available space and how loud the sound is going to be)
The oil for the turbo will be fed from a stand alone oil supply can located in the trunk and cooled through rear mounted oil cooler (or the standard way using engine oil, but delivering the oil to the turbine with help of the oil pump)

The intake will most likely be located inside the trunk (to avoid the moisture) and the pressurized air will run under the car into the engine bay and to the intercooler.

Theoretically the quick spooling turbo will offset the lag that may occur due to the long tubing, so the end result; I should have a system that comes to full boost at around 3500 rpm.

As I receive the parts, I’ll begin prototyping the tubing and where everything will go.

I will begin prototyping all the exhaust and intake tubing using cheap plastic ( 2 ½” sprinkler pipes that are sold in every home depot. They are very cheap and easy to cut, which is not something I can say about the metals.
Once the tubing and mounting is all figured out, I will have the final version of the system cut and welded at a local shop.

All right, this is it.
Wish me luck

epitrochoid

you wont be able to do that at a cost anywhere near $2500

and why would you want your intake pipe in the trunk? you'll have to wear ear protection every time you drive

STS makes a system that sounds similar to what you want..so look them up

Trekk

You dont really need a quick spool turbo system on an rx-8. If you push it to 9k your not gonna fall to far down in rpm's between gears. You want a turbo that can provide good cfm up to the 9k mark, not one that flops at 7k.

The PSI a turbo can run doesnt really matter. I've run a t25 @ open boost witch was about 26psi, the CFM is so low the turbo blew up and didnt nothing to the motor. (wanted to test the 4g63) Try running a 52 trim at 26psi and see what happens.

Internal wastegate is fine for low boost. Whats it set at stock? 10-15psi?

I'm all for the DIY stuff, but turbo and cheap dont work out well unless your scrapping a turbo car for the project. Are you getting this stuff off ebay?

On a side note, I started that cheap intercooler thing on ebay a while back till people caught on. I was getting f350 intercoolers for 247$ cutting them into 3 and selling them for 300$ each. They all work well at low boost if they are built right. Mine were pressure tested @40psi, I bet alot of people dont do that.

evilmiata

There will be a lot of turbo lag with it all the way back by the muffler. I don't know if you'll even have enough room to get the compressed air back to the front of the car. I've seen the bolt-on kits that you're trying to replicate; they use small turbos on big domestic engines. Its easier to install than a traditional turbo kit, but the tradeoff is a smaller turbo to reduce lag and ultimately less power.

You can get a Greddy kit for around $2500. Go for it!

Trekk

Oh yea get a EGT , i think thats always the most important part of a turbo system.

rotorocks

I did not mean Int-X as a part of the setup. That is a different thing. I only mean manufacturing and building the actual turbo system.

The Turbo, Intercooler and BOV run me less than $400.
Polished Aluminum Piping should be around $150-170. Fabricating the turbo mount with all the fittings, another $2-300 but not much more.
Other stuff may cost another $500-700... $2500 should be well enough.

As for the intake, there are many different ways to do it which is why I started the tread, so I can share and get the feedback from others.
I know about the STS. That is what gave me the idea of doing it this way.

Buying a Greddy kit is no fun. I like to do stuff by myself. The turbo I will be using is a not a big one and ultimately should spool fast. The gases are cooler and much denser at the end of exhaust, which should make up for lag.

Time will show.

It doesn't have an internal waistgate, but one can be added.

Well 2500 without the engine management is not exactly cheap...

MadDog

I'm afraid your wrong about that. The exhaust is cooler and SLOWER - both of which are bad. You want hotter and faster in order to spool the turbo more quickly.

gh0st

turbocharging isnt cheap. $2500 for a custom manifold+ up pipe+ down pipe+ intercooling piping+ blowoff valve+ wastgate maybe....

but that still leaves turbo, ems, intercooler, oil stuff like catchcans, pumps, lines and a whole lot more. in your case theres also a custom exhaust with all kinds of body facbrication needed. try $6-8000 for what your describing.

Trekk

6-8K!! thats over kill.
3-3.5K could be pulled off easy. He doesnt have to use all top of the line brand new parts.

rotorocks

I must disagree.
Density of a hot matter is lower than that of cold.
When the gas is hot, it's density is lower. The distance between the molecules is greater. While gas is rushing past the turbine blades, it is pushing them less efficiently than it would have, be the gasses colder. However the speed of gasses as they enter the turbine is high and that makes up for the low density, keeping the pressure up.

As the air cools off, the density goes up, and though the speed reduces, the efficiency with which the gas can push the blades is greater, as there is greater number of molecules hitting the blade. (In this case the denser gas makes up for its lower speed.)

Given the fact that there is the same amount of gas entering the exhaust pipe as there is exiting, volume of gasses passing by the turbo impeller in a given period of time is the same. The same number of molecules is hitting the blades, thus producing the same amount of pressure.
And it is pressure of the gas that actually makes the wheel spin, not the speed and temperature of gas.

The lag however may occur thus to the fact that it takes longer for the gasses to reach and pressurize the end of exhaust pipe and begin moving that turbo. But we are talking fractions of a second, not seconds in this case.

unreal89

Don't discourage him, let him build it and have fun! You can't always guess whats going to happen unless you do it. I think hes a brave guy and should expiriment for the sake of everyone. We can all learn from such projects. It's nice to see the Rx8 finally start to leave the greddy path and go custom.

OfficerFarva

Sounds like fun man, but be safe! Rememeber murphy's law "Anything that can go wrong will go wrong." But yea I guess the biggest task ur up against is finances, cus at first when I read this about 2500 it seemed a little optimistic. Nonetheless, have a good one.

Magic8

Checkout STS Turbo. They make a kit for camaros, vettes, and trucks. There is a thread on this. The system works well with little lag and is completely reversible without much effort

MadDog

Its kinetic energy my man. Velocity^2. Think about taking your example to the extreme. According to your logic, you'd rather have a very cold gas that's almost stagnant since the density is somehow 'making up' for the slow speed. That's obivously not a desirable situation. And, as I've debated a few times before here, the temperature of the gas is very important. The total kinetic energy of the gas is the sum of the translational motion and the vibratory energy that we measure as heat. A hotter gas simply has more kinetic energy that can be harvested by the turbine. If you don't believe me, then take it from Corky Bell's book. Its in there. Look it up.


No. Its called Bernoulli's Law. The faster the gas is moving, the lower its pressure is.

Sapphonica

Specific enthalpy is your friend...more is better

MadDog

^I think you're agreeing with me. Enthalpy is energy per unit mass, meaning that hotter+faster is better...

rotorocks

Precisely, given that the flow is unobstructed. But what happens to all that speed and energy when suddenly there is an obstruction? What the kinetic energy of the moving gas converts to that will push the turbine blade? When you blow on your palm, what it is that you feel?
It sure isn't the kinetic energy...

Also, we are not dealing with stagnant gas here, we are dealing with pressurized gas which is in more or less constant motion where it is moving from high (Combustion chamber) to low (Atmosphere) pressure.
And the same example you brought but taken to the opposite extreme; what is going to push turbine more efficiently, cold air moving at a certain speed or superheated air moving at the same speed? I bet you it won't be the latter, because colder is denser. And denser means there is more of it per unit of measure. And in this case the more the merrier.

Anyway, I would not have attempted this just based on my logic. My logic may well be full of flaws, as I am no physicist, and a long way from school to even remember what the laws of physics are called. If I haven't seen it being done before by STS I wouldn't be brave enough to try it and would have gone with something more traditional. But they have done it, and they have done it quite successfully in my opinion.
It is unusual, and thus it is cool (the way I see it).
I bought the 8, because it is unusual, and unique, and so I want to continue to build it in that way.
And as it was said before, this should be a fun project. If it does not perform the way a like it, oh, well. A couple of hundred bucks forth of tubing, and we are “back to Greddy”.

gh0st

its a custom one of a kind project. unless hes got mad hookups and gets everything that isnt custom used, he will spend $$$.

a custom manifold will run $500-1500 depending on who he knows and how good of a manifold he wants.

custom down pipe and up pipe will run about 500-1000.

custom intake piping will be about 300-600

then hes gotta get used turbo, ems, blowoff valve, intercooler, wastgate... ect..

tuning will run at least 500.

like i said, thats not including the custom exhaust + the vents he needs to put in the side and rear of the car.

if the car is gonna work well and not look getto, its gonna cost more then what you guys are expecting.

staticlag

Uhh, Enthalpy? Comon guys, your chem teacher would cry if he/she heard you say that.

mikeschaefer

Superheated.

Look at steam propulsion in ships. Saying "superheated steam is better than hot steam" would be an understatement. If you can't get the superheater to work you aren't going anywhere.

Magic8

BTW you might want to try Mcmaster.com to acquire tubing supplies. They have a huge selection of stuff that will be useful for the build.

bascho

Huh? he is mounting this in the rear of the car.....he doesn't need a fancy $1500 manifold with 32 curves and 5 hours of welding.....he just needs to weld a mounting plate to the exhaust pipe.

MadDog

huh? My thermodynamics prof would sure approve... and oh by the way, thermo is where one learns a little something about turbines - not chemistry.

I'm not trying to bring him down. Nor am I saying it won't work. I am merely trying to point out mistakes in his logic. That location is better for some reasons - better turbo spooling is certainly not one of them.

ChrisRX8PR

iTrader: (1)

Hello,
Im a mechanical engineer with a mayor on turbomachinery and fluids. What youre saying sounds logical but is incorrect. You're aplying properties of a stationary/fixed amount of fluid to a fluid that is in motion. Below are a few things:

1. Think of an enclosed tank, which would represent your exhaust manifold all the way to the back of the car on a given instant in time. If you take a closed tank and heat it up, what happens? Pressure builds up because you're putting energy into the gas via heat creating mechanical energy that has nowhere to go so the pressure rises. Remember it is mechanical energy that moves the turbine not a certain amount of molecules per volume(density). What good do 20 molecules do if they have no energy and aren't moving very fast as opposed to 5 molecules that are extremely excited due to heat and are moving at incredible speed? If what you're saying were true then aiplane jet engines would measure 100ft long instead of engineers looking to put the turbine as close as possible to the combustion chamber inorder to loose as little energy as possible inthe transfer, which brings me to the second thing.

2. You're lookign at this whole thing from a mechanical point of view, i.e. mass, density, volume, and that doesn't work that way. You must look at it from an energy point of view, below Ill com pare both:

mechanical:

molecules of gas entering=molecules of gas exiting
More temperature=Less temperature
less density=more density = more molecules per square inch of turbine blade, Right?
true, but this is not what moves the turbine

Kinetic:
car engine works as follows:
chemical potential energy(gas)-turns into heat energy(ignition)-which turns into mehcanical energy(expanding of gas in the combustion chamber pushing piston/rotor down/sideways)-and then ends up as residual heat energy once more in the exhaust system.

The turbo is supposed to take this wasted exhaust heat energy and turn it into mehcanical energy(spinning of the shaft int eh turbo) to help compress intake air.

Now to the hard stuff. In a perfect world what you say could work the same as having the turbo upfront(not better). You must consider though, that through each of these changes in energy there are losses, for example; all chemical potential energy in the gas is not converted to mechanical within the engine, I wish it could, it would make our engines have something like 1000hp N/A. Actual engine eficiencies range form 16% to 35%. Only this percentage makes it throught the energy conversion, so, what happens to the rest? Whel here it is:

-The intake track isn't perfectly smoth so there turbulence and this in change makes it harder for the engine to draw air in(loss of energy)

-The engine is made of metal which conducts heat therefore drawing energy form combustion that could be moving the engine and puting it in the radiator.

-There is also friction between the moving parts in the engine.

These are just three major ones out of hundreds that exist.

Now asuming there is only heat and friciton losses lets go to your turbo install:

Think energywise:

Air enters the exhaust system with a fixed amount of heat+kinetic energy(lets say 100):

100(going in)-50(loss of heat via the exhaust pipe walls dissipating to the enviroment)-15(loss of kinetic energy due to the walls of the exhaust having bends and not being smooth causing friction with the moving gas)=35(going into turbo and pushing the blades

Which means that the closer you can get that turbo to the 100 leaving the engine the less energy u will lose in the transit to the turbo via heat and friction. I want to stress the fact that these numbers are not exagerated htey are that significant in real life. ANd I'm not even taking into account the intake air that has to travel back to the front of the car which is a whole other story in inefficiency. And all the meanwhile we are talking of the same amount of molecules and yes the gas at the end of the exhaust is relatively denser but not necessarily with more energy.

The reasons this is used on domestic engines are the following:

1. Space limitation within engine compartment
2.Big v8's make huge power with little boost allowing a smaller turbo than what would normally be put on a v8 to be used to compensate the lag induced by the energy losses.

I bet you I could have boost on a t70 bigshaft right next to the engine lower on the rev range than anyone would get boost with a small t4/t3 turbo all the way in the back of the car.

Hope this clears up the confusion.

Esmeril