Sorry for resurrecting an ancient thread, but I've been thinking about this for some time now.

Could I remove the pre-silencer from my RoadRace Exhaust & put a remote turbo setup in its place? I think there would be room, but I could always cut out & box in some more clearance area. I would also do a megasquirt EMS and possibly an air to water intercooler. Possibly a seperate turbo oil system with its own pump & cooler. I think it would be a great "sleeper NA-Turbo" setup. Has anyone done something like this yet?

Ramses666

 

You probably could do it, but why? What advantage would it provide?

The FC engine bay has plenty of space for any reasonably sized turbo and the effort spent fabbing up an adapter, mounting hardware and the figuring out the oil return system would be more then making a manifold to fit the NA engine.

 

the rear mount turbo kit is a great kit for cars that can not a turbo in the engine bay. i would like to know if anyone has had any first hand experience with this kit. one of the guys at work has just finished installing and tuning a sts turbo kit on his 06 f150. he loves the kit, it produces great power and a differnt sound then any other f150 around because of no muffler or anything after the turbo.

although i dont think that the rear mount turbo kit has a home in the fc do to its HUGE engine bay it may work wounders for any v8 swap cars and many other cars.

 

How could it not be easier to use my large pre-silencer as a starting point - cut out the chambers & replace them with the turbo stuff. Fabricating a 6-port turbo manifold seems more difficult. An old oil cooler with an electric pump & pressure sensor with an alarm & gauge seems pretty simple to put together. The advantage would seem to be using the parts I already have and lower engine bay temps. Am I in error? How about lighter weight up front?
How much does the turbo, manifold & intercooler weigh? I would have to obtain the turbo exhaust manifold & intercooler stuff, replace the radiator? I would still have work up the oil lines for the turbo.
Aren't there issues with exhaust manifolds cracking from the weight & heat of the turbo and BOV's hanging of the side of the engine? With the remote mount after the header the weight would be on it's own brackets not the engine block.

It just seems easier to me, but I'm not experienced enough to know for sure.

Ramses666

 

Think it through, then gather all the information you can. Don't ask too many opinions, because everyone is against this Idea. Hell even Aaron is not encouraging you. Aaron did the first well documented n/a turbo project. Everyone was against him, telling how he would fail, then engine would explode etc. Aaron educated himself, learned certain fab skills and made it happen.

Now, everyone and their dog is doing the n/a turbo conversion.

You might just start a trend, but don't expect lots of support along the way. If you fail, there will be lots of 'told you so' naysayers. If you succeed, the supporters will come out of the woodwork.

 

Its goign to be tough no matter which way you slice it. If you're doing an N/A to Turbo conversion ALL of the issues in the conversion will still exist whether the turbo is in the front or back of the car. You're still going to need to plumb oil returns into the pan/front cover. You're still going to need to do some manifold work, you're still going to have to do everything you would normally except with mounting the turbo in the rear - you'll now have to plumb all the extra **** in as well.

 

Can You Imagine How Fast You Could Go In Reverse!!

 

It sort of depends on where your talents lie. If you're better at the "fiddly little stuff" like arranging oil scavenge pumps, making lines, setting up the air to water cooler and pump, the gauge and warnings then it may indeed be easier for you to mount the turbo off your presilencer. But because you mentioned you would be using an intercooler either way you still have those issues, AND you now have to get some thick pipes through an area that is limited in space (and you'll be running your turbo outlet pipe right past a set of hot exhaust headers).

The way I see it, creating an exhaust manifold is much easier. Or you could take the even easier approach and just use the 2.5" spacer to move the stock manifold out enough to clear the lower intake.

The radiators between turbo and non-turbo cars are the same. A little heat wrap on the turbo and manifold eliminate engine bay temps as a concern.

A bit of confusion here. The BOV goes onto intercooler piping before the throttle body. It's weight (and maybe 1 pound at that? ) has no effect on the exhaust system. The stock manifold is thick cast iron and while it does crack, it only cracks after a hundred thousand miles or so. Cheap aftermarket manifolds crack because they are made out of crappy thin-walled tubing. Make your manifold with SCH 10 stainless or SCH 40 steel and it will never crack.

I think once you see the actual (lack of) space available down there and how easy it is to mount the turbo to the side of the engine, you may change your mind.

 

There is NO WAY that 10 ft of stainless steel piping comes close to your typical HKS intercooler.
1 Contact Surface area is greater on the intercooler
2 Heat Exchange rate is VASTLY different. Not to mention that you would be heating the charge of your return piping as you went up to the engine bay.
Sure Sure, we all agree that the exhaust sitting next to it might heat it up, but you have to realize what is infront of the turbocharging system.....the radiator, the oil cooler, a piping hot engine. Where do you think all that air is going? Its exiting directly under the vehicle and out the back.

Anyways,
Lets do some THERMO!

Energy is transferred from the more energetic to the less energetic molecules when neighboring molecules collide. Conductive heat flow occur in the direction of decreasing temperature because higher temperature are associated with higher molecular energy.

The equation used to express heat transfer by conduction is known as Fourier's Law and is expressed as:

q = k A dT / s (1)

where

q = heat transferred per unit time (W, Btu/hr)

A = heat transfer area (m2, ft2)

k = thermal conductivity of the material (W/m.K or W/m.oC, Btu/(hr oF ft2/ft))

dT = Temperature difference across the material (K or oC, oF)

s = material thickness (m, ft)

So lets say this system theoretically has 10 ft of pipe, this pipe is 3 inches in diameter and 1/8" thick.

A= 3(3.14)(10' * 12")= 233.04 in sq
Stainless has a heat tranfer coefficient of 16 (normal steel is 46) but for rust resistence i would suggest stainless.

Imagine its a 70 degree day and your charge temps are 125

That gives us:
q= [(16)(233.04)(55)/(.125)]=25.6kW of energy dispersed

now imagine an intercooler, with no fins on it, just strictly a flat piece of aluminum with dimensions of 400x260x65 (15.7x10.6x2.65in)
A=[(15.7*10.6*2)+(15.7*2.65*2)+(10.6*2.65*2)]=472.23 in sq.

Its thermal coefficient is 250 and lets say this metal is 1/8" thick.

q=[250(472.23)(55)/(.125)=811.6kW

So that charge pipe "intercooler" is a horrible idea

 

Zero backpressure = bad

 

[QUOTE=outcastcat]Pressure in exhaust systems doesnt have that much to do with the Size of the exhaust so much as how straight and how hot it is.QUOTE]

Pressure in the exhaust has a direct relationship to the the size of the exhaust.

PV=PV Boyle's Law

 

After the turbo???

That would be incorrect.

 

NO you need some back pressure initially to produce power

 

For a guy who likes to 'do Thermo' you seem to be happy to misapply inaccurate old wives tails...

Most of the time when someone says 'you need some back pressure' they have heard that in order to maintain port velocity do not over enlarge the exhaust or intake ports, or do not oversize the intake manifold runners or the header pipes or you will lose velocity of the charge or the exhaust. The proper sized exhaust for example that maintains velocity still has a little back pressure. It is not the backpressure it is the velocity! So the unknowing person misunderstands and thinks that you 'need some back pressure to make power'.

Pressure drop across the turbo has nothing to do with this other issue.. You DON"T need some back pressure after the turbocharger to make power.

 

And BTW, since you spec'd stainless for the charge pipe, why didn't you go back and do the math for a charge pipe of aluminum and front mount of stainless, just for grins?

 

NEVER EVER IN ANY CAR does back pressure equate to power. NEVER.


What spins a turbo is the higher pressure exhaust gases in front of the turbine racing to the lower pressure exhaust gases on the other side of the turbine. The greater the pressure differential, the faster the spool. Since increasing pressure on the front side results in too much exhaust at higher rpms, boost creeping, and in a high overlap engine (ROTARY!) exhaust reversion, the best option is to lower pressure on the other side of the turbo. hence why you get so much power from switching out the restrictive stock exhaust and cat to a larger exhaust without a cat. Less back pressure results in faster spool, high rpm breathing, and more power.


Let me re-emphasize that: Exhaust backpressure is NEVER good. EVER.


As for the remote mount. Go for it. It will take a lot of fabrication on your behalf, and you should talk to STS about how they came up with their turbo sizing and A/R rations, but if you want to do something differently do it. You DONT have to bring it up the ehxuast side of the engine if you dont want to, and a thin sheet metal heat shield would go a long way in reducing the heat transfer as you run the intake piping back up to the front next to the exhaust. If we can cram a true dual exhaust system on our car then piping wont be nearly as difficult as everyone says it will.

When you have figured out the A/R and turbo sizing send me a pm, I have a theory on how they choose their sizing and I would love to see if it holds true to a rotary.


BC

 

One day, people on this forum (and people in general) will actually learn that backpressure and velocity are not the same thing. Well, I can hope, can't I?

 

Hope all you want, but for every person you (or I) educate there will be another 16 yr old whos father told him that he made tons more torque on his old SBC with stock manifolds, and lost torque with his long tubes.


Its hopeless.


BC

 

You are preachin' to the choir, brother.

Aaron, all I can say is you are one of my heros for doing the turbo n/a against all bets and ridicule.

Now, to all you guys watching this thread: Who is gonna Man-up and do the remote mount turbo rotary?

 

Send me a couple grand and Ill get started. Otherwise Ill have to wait until I sell some property.


BC

 

Well, I spent some time & went through the archives for Aaron Cakes' NA-Turbo project. Didn't seem like there was enough room for the turbo in the engine bay without hacking into the frame and also access to the mount bolts was a nightmare as well. I also went & looked under my '88 SE with RoadRace Dual exhaust & there appeared to be a great deal of room were my presilencer is located to put all the turbo stuff. And I also saw plenty of room to run piping back into the engine bay.

I say NAY to the Naysayers! I would run a seperate oiling system for the turbo with it's own cooler, pump & sensors. Either a water to air intercooler or maybe aqua-mist type or both? Also a megasquirt or similar EMS along with fuel pump upgrade and possibly larger injectors.

I Think it could be done faster, cheaper, and be more reliable than What the Honorable Mr. Cake did for his swap. I mean...have you read his entire write up? All the custom hack-work? Trying to cram all that stuff between the engine and fender well? I can't believe a little header wrap could even be put around his setup and that turbo heat in the engine bay is not an issue.

Besides it would be a total sleeper and different from anyone else. I just think it would be something a little more within the reach of the "average" 7 owner as far as actually being able to do it yourself without major hacking & could also be removed fairly easily.

The part I would need help with would be the A/R ratio for the turbo & turbo sizing. I figure I could find off-the-shelf components for the oil system & air-water cooler. Am I so wrong about this?

Ramses666

 

That was not hack work. That was proof of concept. In such a case as that, there is no beauty in the eye of the beholder; you are looking for results. I would dare say that your first version of the remote mount turbo rotary will have some ugly duckling moments as well.

That being said, you can use a stocker turbo. Who cares if it is optimum? Prove to yourself that it works, then use the data to develop a model to optimize your desired performance.

Solve the piping, the oiling and the cooling. Upgrade the injectors to TII. Mod your harness to add the turbo pressure sensor and use a TII ecu. Add a stocker BOV to the plumbing. SAFC-2 for minor fuel adjustments. Hell, I have all your plans right here. Piece of cake.

When do you start? I have a spare S4 turbo that I would sell you cheap to get you started.

 

Touche salesman, touche. I was indeed thinking of port velocity.

 

PS, How do you go from this post here^,
to this post:

 

Glad to be of assistance, Engineer.

BTW, don't bother with the recalc on the little thermo problem. That was a rhetorical question.