Remote mount turbo?

[jerd_hambone]

Has anyone ever done a remote mount turbo setup on an FC?

Maybe a twin turbo setup with split exits....

[vex]

A remote mount turbo on our Cars would not be effective. A majority of the ability for the turbo to spool does not come from gas velocity but rather the pressure differential (which is more based upon heat than anything else). The closer to the engine where the exhaust temperature is greatest the quicker the ability to produce boost. So instead of having nice hot gases that are then exposed to a much cooler volume you'll have relatively cool exhaust gases hitting cool air. The pressure differential is not big enough to produce a spool that would allow a good set up like that.

[RotaryProphet]

It's not effective on -any- car... the closer you can put the turbo to the valve/port the better; the exhaust gas will expand out from the chamber, and the shorter the pipe, the less chance the pressure has to drop (as it equalizes with the pressure in the manifold) before it hits the turbine wheel; the difference in pressure between the manifold and the downpipe at this point is what spools the turbo.

[alnielsen]

It has been done on a RX8. Search for member Rotorocks on RX8Club. He made one himself for his car. He presently is using a mid-mounted turbo that is next to the rear of the trans. He has reported success with both setups.
Squire Turbo Systems is in the process of making a kit for the RX8. They are testing a single and dual turbo setup. I don't see how a dual setup will work for the 8 but we will wait and see.

[jerd_hambone]

A guy with a Chevy Beretta 2.8 made a remote mount and saw a dyno proven 68hp increase.

Saying they are not effective is a false statement.

They run around 6psi tops, and with a rotary putting out as much exhaust force as they do, seems like it would be more than capable of boosting to 6psi and giving NA guys a little more umph.

But the car would be loud as hell

[vex]

A guy with a Chevy Beretta 2.8 made a remote mount and saw a dyno proven 68hp increase.

Saying they are not effective is a false statement. You sir need to learn the definition of effective. He had an increase of 68hp. Is that more or less effective than if he put it right off the exhaust ports on a turbo manifold? I promise you he would have seen a much bigger increase if he put it right off the manifold. If he was keeping it in the low PSI range, then it's still less effective than placing it right off the manifold. Why? think about it. How much piping for the coolant, intercooler, and oil do you have to run for both setups? All that stuff weighs something. So He threw on a turbo which could weigh anywhere from 10-25 pounds. He than ran extra long lines of coolant and oil to the turbo which only adds to the weight as well as the extra intercooler piping. When as is said and done, is it worth it to spend the money on a setup like that, that will only net you 68hp? I don't think so. Hence, not effective.

The effectiveness of a remote mount turbo sucks. There's no way around it. You will see more gains, and better performance all around the closer you put it to the manifold. Just because I said it wasn't effective does not mean it wouldn't work. It's just not very good at what it does.

They run around 6psi tops, and with a rotary putting out as much exhaust force as they do, seems like it would be more than capable of boosting to 6psi and giving NA guys a little more umph.
that's a false statement if ever there was one ;). Look the turbo works off of pressure differential NOT exhaust velocity (I'd be interested on how you know how much Force our exhaust puts out). The pressure differential for the turbo comes heavily based off of Temperature. The farther away you put the turbo from the exhaust ports on the engine the less of a differential you have. This means more spool time is required to make a specific amount of boost.

Bottom line is this: Will it work? Yes. Is it worth the time and money and head ache for it? No.

[jerd_hambone]

Not everyone is looking to get maximum power out of their cars. I think that the 600 bucks you could make a setup like that is worth 68hp. Look at the costs of doing a TII swap now a days.

Think of 1200 for and engine and tranny, then 1200 for a rebuild not counting the hard parts it might need, possibly a new clutch, drive shaft, rear end.

Honestly that is not a very cost effective mod if you look at it. Just to get rolling you are looking at well over 2k.

You could say "take the cheaper way out and keep your NA tranny" But then it would turn into a flame war with people saying to take the weak NA tranny out and do a full TII sawp.

It's proven that it works, it is definitely effective. So from now on I would like the thread to be directed in the way I wanted it.

I would to know if anyone has actually done this? Not if someone knows its a shitty setup

[vex]

Not everyone is looking to get maximum power out of their cars. I think that the 600 bucks you could make a setup like that is worth 68hp. Look at the costs of doing a TII swap now a days. I'm well aware, i'm doing a turbo 6pi at the moment. However you're going to spend the same amount of money either way if not more doing a remote mount. (i'm talking about turboing a 6pi and not a TII engine swap)

Think of 1200 for and engine and tranny, then 1200 for a rebuild not counting the hard parts it might need, possibly a new clutch, drive shaft, rear end.try closer to 300-400 for an engine and tranny and ecu. if you want to rebuild it yourself you can get a soft seal kit for anywhere from 300-600, apex seals for another 300.

Honestly that is not a very cost effective mod if you look at it. Just to get rolling you are looking at well over 2k.
If you're turboing an NA engine you're going to be looking at that price range anyways unless you're going used on everything. You still need to upgrade your injectors, fuel computer (at the least), piping, lines, modifications to the engine to support the turbo (both oil and water). Then you have the supporting modifications like gauges, blow-off valves, external waste gates/milling out the internal wastegate. Then you have to send out for repairs or cleaning on all the used stuff like injectors. Both require modifications to the exhaust but I'd be pretty sure that it would be cheaper to produce a manifold and a down pipe than it would be to try and fit a turbo under the car. On top of all this you still run the risk of road damage to the turbo where it is. It will be exposed to road debris, pot holes, speed bumps, animals, etc.


You could say "take the cheaper way out and keep your NA tranny" But then it would turn into a flame war with people saying to take the weak NA tranny out and do a full TII sawp. NA tranny's are good for about 300-350 hp unless you're doing 500+ there's no need to swap. That eliminates any conversion from the engine back. I promise you won't make enough power from a remote mount to warrant a conversion to a TII engine or drivetrain. However it will cost you MORE money if you decide later you'd like faster spool, more boost, where as if you mount it in the "normal" location all you need to do is either just swap the turbo or put in a boost controller. 600+(at the least) compared to 200+(at the most)

It's proven that it works, it is definitely effective. So from now on I would like the thread to be directed in the way I wanted it. Sorry, it's not effective. It will work, but it will not be effective. That's like saying a knife is effective at killing people during a war. Yes it will work, but it's much more effective to use an M16 or an AK, probably cheaper too... this argument seems eerily familiar....:suspect:

I would to know if anyone has actually done this? Not if someone knows its a shitty setup You already have that information.

The question is really why are you so hell bent on doing a remote mount?

[classicauto]

I would to know if anyone has actually done this? Not if someone knows its a shitty setup

I'm not aware of anyone who's done the setup on a rotary. I've seen numerous remote mount jobs on various trucks, corvettes, TA's and they all put out some nice power. And despite what you think, the one's I've seen are no slower spooling then a poorly tuned "regular" single on our cars.

IMO - it'll work. It'll work well. But it has its purpose, which is to fit a turbo or turbos where you normally can't (ever seen a C5 or C6 engine bay?) and on our cars there's plenty of real estate to fit a turbo.

That said though i'm all for uniqueness...with a proerply sized turbine and housing you'll have a decent setup. Plumbing, shielding, etc will take alot of thinking but it can be done.

[jerd_hambone]

try closer to 300-400 for an engine and tranny and ecu. if you want to rebuild it yourself you can get a soft seal kit for anywhere from 300-600, apex seals for another 300.

Sorry, it's not effective. It will work, but it will not be effective. That's like saying a knife is effective at killing people during a war. Yes it will work, but it's much more effective to use an M16 or an AK, probably cheaper too... this argument seems eerily familiar....:suspect:
You already have that information.

The question is really why are you so hell bent on doing a remote mount?

I'm not hell bent on doing one, I was asking if someone had done one on a rotary.

Why are you so hell bent in putting down a setup you probably have never used?

And honestly, I have not seen a TII longblock with tranny for 300-400 bucks. If you do manage to find one for that price, it will more than likely need at the least a housing and rotor.

They do seem to be very effective, although you seem to think not. Many people have run them with great results.

[vex]

I'm not aware of anyone who's done the setup on a rotary. I've seen numerous remote mount jobs on various trucks, corvettes, TA's and they all put out some nice power. And despite what you think, the one's I've seen are no slower spooling then a poorly tuned "regular" single on our cars. That's the thing though, were not comparing a poorly tuned "regular" setup to a properly tuned remote mount. I'm comparing (at least) a properly tuned remote mount to a properly tuned "reg". Dollar for dollar it's going to be more effective to go with a "reg". That's not to say one shouldn't do a remote mount, maybe some one wants to make it appear as a sleeper and run a completely different setup (mid placed turbo, hidden intercooler, etc). I know people personally that have done remote mount turbo setups on C5's and had great results. That's not to say that it was effective. Just imagine if they would have been willing to cut the inner fenders to fit a turbo in the engine bay? What's going to be more effective? Now the C5 != S4/5 and so they'd spend more money altering their engine bay to fit the turbos which means for them it would be cheaper to do a remote mount.

IMO - it'll work. It'll work well. But it has its purpose, which is to fit a turbo or turbos where you normally can't (ever seen a C5 or C6 engine bay?) and on our cars there's plenty of real estate to fit a turbo.
I know it will work, but I doubt we'll see the gains we would if compared to a "reg" setup you know? It would be my opinion that it would cost more to do a remote mount on our cars than it would be to do a "reg".
That said though i'm all for uniqueness...with a proerply sized turbine and housing you'll have a decent setup. Plumbing, shielding, etc will take alot of thinking but it can be done.+1

I'm not hell bent on doing one, I was asking if someone had done one on a rotary.

Why are you so hell bent in putting down a setup you probably have never used? Read above reasons.

And honestly, I have not seen a TII longblock with tranny for 300-400 bucks. If you do manage to find one for that price, it will more than likely need at the least a housing and rotor. I have seen recently an s4 na short block for 100, an s4 tii for 150, and an s5 short block for 150. Tii tranny's can be had all day for 100-250 depending on seller. Put them on a pallet and it's 150 more to ship it to your door.

They do seem to be very effective, although you seem to think not. Many people have run them with great results.alright enough with the semantics.

[djmtsu]

NA tranny's are good for about 300-350 hp unless you're doing 500+ there's no need to swap.

I can attest to that. My clutch is nearly toast but the NA tranny is still perfect.

The problem with a remote mount on an FC is space. Have you been under the car to see where you could put one? It would have to be all the way in the back (in one of the muffler spaces). Now that the turbo is back there, you have to plumb intake piping all the way back to the front, most likely occupying the same space that the HOT exhaust is already filling.

Doesn't seem like something I would want to attempt when a 6 port turbo is so easy to do.

[classicauto]

That's the thing though, were not comparing a poorly tuned "regular" setup to a properly tuned remote mount. I'm comparing (at least) a properly tuned remote mount to a properly tuned "reg". Dollar for dollar it's going to be more effective to go with a "reg". That's not to say one shouldn't do a remote mount, maybe some one wants to make it appear as a sleeper and run a completely different setup (mid placed turbo, hidden intercooler, etc). I know people personally that have done remote mount turbo setups on C5's and had great results. That's not to say that it was effective. Just imagine if they would have been willing to cut the inner fenders to fit a turbo in the engine bay? What's going to be more effective? Now the C5 != S4/5 and so they'd spend more money altering their engine bay to fit the turbos which means for them it would be cheaper to do a remote mount.

As far as this particular facet of the debate goes:

The C5 around here running this setup puts out a little over 580whp at 6psi. Up from its previous 390-410 in with various exhaust setups (engine also had other mods). Now, if you were to put a traditional set of turbos in the engine bay, maybe it would make 600-610 at 6psi? Hard to say, but the difference is very negliable make no mistake about it. Its not like running a turbo in the rear automatically means its 50% less efficent. Either setup would be VERY comparable when you omit the install/fab headaches of doing a rear mount turbo. Shit, Randy even has EMP on his setup and 6psi of MAP there's only 6.75psi EMP which is an extremely close ratio (edit: yes clsoe ratio for "low" boost, but nonetheless.)

[jerd_hambone]

That's the thing though, were not comparing a poorly tuned "regular" setup to a properly tuned remote mount. I'm comparing (at least) a properly tuned remote mount to a properly tuned "reg". Dollar for dollar it's going to be more effective to go with a "reg".

I wasn't trying to make a comparison. I just wanted to see if someone had done it.


I know it will work, but I doubt we'll see the gains we would if compared to a "reg" setup you know? It would be my opinion that it would cost more to do a remote mount on our cars than it would be to do a "reg".+1

I stated that it would be an effective way of giving an NA engine a bit of extra go. I said nothing about trying to get the most power out of an NA.


I have seen recently an s4 na short block for 100, an s4 tii for 150, and an s5 short block for 150. Tii tranny's can be had all day for 100-250 depending on seller. Put them on a pallet and it's 150 more to ship it to your door.

But then what about the turbo, manifolds, wiring harness, sensors, an exhaust to mate with the turbo manifolds, TII hood for going top mount, or a big front mount?

As I said, I have never seen a TII longblock for 400 bucks.


But look at it this way. Everyone used to say there was no way of getting power out of an NA FC. Everyone said it was impossible to turbo one without it blowing up within a few hundred miles.

But people still tried it and did it successfully.

Maybe the remote mount is the same way?

[Phoenix7]

Success is relative though. THe person who goes turbo 6 port may be satisfied with the money put into the mod. They might be satisfied with the power and reliability. They might be satisfied with their uniqueness.

In the end their satisfaction/ "success" may not be what I consider successful. I'd rather spend the money on a TII swap and modify it from there (for less money /same performance.)

perhaps the remote mount turbo is like that.

Best way is to do it and show us the results.

[vex]

I wasn't trying to make a comparison. I just wanted to see if someone had done it.And has already been answered.

I stated that it would be an effective way of giving an NA engine a bit of extra go. I said nothing about trying to get the most power out of an NA.

But then what about the turbo, manifolds, wiring harness, sensors, an exhaust to mate with the turbo manifolds, TII hood for going top mount, or a big front mount? Nickle and dime, nickle and dime.


But look at it this way. Everyone used to say there was no way of getting power out of an NA FC. Everyone said it was impossible to turbo one without it blowing up within a few hundred miles.

But people still tried it and did it successfully.

Maybe the remote mount is the same way?
No one's saying that it won't work. It's the difference between less effective and effective. This exact thing was covered quite in-depth on my local forum.

Link ('http://www.carclubvt.com/forum/showthread.php?t=16672') Unfortunately you need to sign up to see that. For what it's worth here are some excerpts from it:

Obviously I'm going to say I'm not a fan, but they work. For a smaller engine like I have it wouldn't make much sense, but with a large engine it is allowable to have some loss, I'm sure it's still better than a supercharger. I guess I have a hard time believing things couldn't be shifted around to put the turbo up front, but I can't really say. I don't see how you can say they're super efficient though, depending on what you mean by efficient. You lose a lot of turbine-driving energy through the exhaust piping to the turbo which means you have to size the hot side smaller than normal to get the same spool, which therefore results in a more restrictive hot side. On the other hand, people report such good results with them that I can't down them.

HPBooks has a book out called "Street Turbocharging" written by Mark Warner, P.E. and it talks about rear mount turbos in a positive way. It's a decent book. ^Drives an SVO

Exactly larger engines have less loss from flowing exhaust air back 8 feet to the rear of the car than say an itty bitty 1.6 liter honda engine that can barely displace enough to spool a turbo right off the header. About all Ill comment on the subject till the end of the month.^did a 600whp rear mount on a Vetter (C5 I think)
And where does this pressure differential pre-turbine and post-turbine come from? It come from expansion of the gasses.

Turbines are modeled as isentropic expansion devices. The energy in the exhaust is contained in the form of kinetic, heat (thermal), and a little bit of pulsations from each cylinder. Almost all the energy comes from heat--the expansion of the hot exhaust gasses in a turbine.

So maybe the turbine doesn't "care" if it is hot or not, but the energy spinning it's wheel is coming from the heat in the exhaust. Read a thermodynamics book instead of google.^He's just an asshole... well, a smart asshole, but an asshole none-the-less
Jebus are you really that dense? Are you really implying that we are saying that egts entering a rear mounted turbo are the same temp as air entering the engine???

air enters at say 100F, exits at 1400F. So it cools down to 400F at a rear mounted setup. Heat is still being used to spin the turbo (and yes the turbo takes advantage of expanding gasses as heat energy as you said). Heat in the exhaust drives the turbo, but it really just complements the pressure that is already there.

Fuck...come take a ride in my turbo. I can spin up the turbo on a cold engine (using your "windmill" or whatever-you-call-it joke). Heat does play a major role...I'm just saying don't discount big airflow from big engines to small rear mounted turbos to overcome a moderate heat loss in a rear-mounted setup.^Response to asshole, but raises some points one would need to consider.

I'm aware of that Semantics Man. What I was referring to was the fact that there's still a lot of free hydrocarbons in the exhaust that continue to burn (hence heating and expanding the exhaust) even after they've exited the exhaust ports. Some cars position the turbo so close to the head that there are still lots of free hydrocarbons in the exhaust even after it passes through the turbine, especially at higher rpm. This is wasted energy. Ideally you want to give the exhaust gas enough time to burn off all those hydrocarbons (hence "fully" expanding the exhaust) but not enough time to start to cool off, so the ideal place for the turbine inlet would be the hottest part of the exhaust stream where it would have the most available energy, both thermal and kinetic.

I'm not arguing this point anyway, all I'm saying is that if you can reduce the amount of heat lost through the piping, you can reduce the amount of energy lost by moving the turbo farther downstream. The turbo still works, and works well, just not AS well as having it at the optimum position farther upstream, but it's a compromise, just like everything else.^He was the OP

Depending on the application, there's enough exposed piping on the trip back up to the engine to sufficiently cool a moderately compressed (say sub 6 psi) air charge. Some applications (like TT rear mount vettes) use a front mount intercooler because they don't have enough pipe, and enough air flow around that pipe, to cool it, but a lot of the truck setups do because they're longer and the pipe is run usually right beside the frame rail.
^OP Again
I'd take the faster spool over the increased top end any day, but if you have >3.0L chances are you have sufficient power until the turbo spools to start with.

Just to comment on the heat issue, the fastest spooling header setup for a WRX/STi is STOCK because of it being cast iron and maintaining heat better than any of the aftermarket designs. It doesn't make quite as much power up top as the equal length designs, but is does have much better spool (read: over 500rpm compared to some of the headers). So what have we learned children? In real life, where you burn engineering textbooks, heat effects spool, not overall power output. Now everybody go throw out your tampons and move on to a different aspect of this setup.^2007 SCCA Prosolo National Champion- D-Stock in a 2006 WRX

[vex]

You make a good point, a lot of the vehicles this really works well on are ones that have sufficient grunt down low to flame the hides from a dig without having to have the turbo(s) spooled up already, unlike the four bangers a lot of us are used to, which means that the little bit of lag actually isn't such a bad thing, because you wouldn't be able to put it to the ground anyway. Once you're moving it's less of an issue and if you have an auto or flat shift the thing the turbo will stay spun up like a squirrel on coke.

I never said it was good for all applications, or ideal, I just wanted to get some opinions. The biggest concern I can see is keeping heat in the exhaust stream, which you can combat with coatings and wraps. Not ideal, but it helps. If you have 8 feet of piping going back up to the engine, what's the major difference between that and having four feet on each side of a front mount intercooler? Same amount of piping, possibly fewer bends, and you're getting effectively "free" charge cooling without the need for the front mount. Sure, the fmic is going to cool much more effectively, but it's also another restriction and the charge isn't as hot to begin with because the turbo is cooler and it's not passing through all kinds of heat saturated metal plumbing under the hood.

The biggest concern I had at first was the oiling issue, but that seems to have been resolved by using a scavenging pump setup with failsafe circuitry.^OP Again
I'll repeat it again, for the sake of all turbo systems, read a fucking thermo book. "The fluid velocities in most turbines are very high, and the fluid experiences a change in its kinetic energy--however, this change is usually very small relative to the change in enthalpy, and thus it is often disregarded (p188 thermo book)". So, what DRIVES a turbine is the change in enthalpy...which wiki explains nicely.
^A-hole again
I'm speaking from in-car experience with an EGT gauge, temps of the actual exhaust gases as they leave the cylinder, they cool a good 500+ degrees F in just a few feet. Idle might be 900-1100, but under WOT for a few seconds at least you will see 1300, 1400, etc., in a turbo car anyway, in fact 1800 is not unheard of in a serious turbo engine but is pretty ragged and unsafe. Now if we're talking NA engine, it can be a lot lower, but still above 1000F under full load I would guess.

Proper EGT measurements are taken 1-2" from the cylinder head exit point.

Hydrocarbons definitely burn off as suggested, but max EGT should occur around 14-15:1 as this is the point where the most energy is extracted from the fuel. Any richer or leaner and EGT should drop off, which of course is necessary to keep an engine together. I'd say it's hard to determine just how much energy from excess hydrocarbons goes into spooling a turbo in normal operation. Even under a two step, yes you have lots of excess fuel burning in the exhaust but the main thing you've done is cause combustion to occur IN the exhaust in the first place so this is a totally different mode of operation, the limiting also allows you to get mass flow way up by holding the throttle open long enough to get the turbo spinning.

I don't know if that makes any sense.^SVO Boy again
Why is this discussion even going on? If there is room under the hood, place the turbo there. If you are itching to have a turbo system and there is no room for one under the hood, contemplate a rear mounted setup. It has been done and does work in certain instances. However, I believe the underhood location would be best, and the engine bay heat is minimal at best if precautions are taken. Certainly less heat coatings would be needed to keep engine bay heat down than there would be needed for a rear mounted system. An evac system would have to be plumbed into the turbine exit, seems a bit retarded to think about doing that with a simple rear mounted turbo (why did that even get brought up anyway?).^His car runs on alcohol.

Dumped wastegates usually sound terrible but whatever, maybe not on that. It does look cool, but on a road car, it's going to get trashed from road dirt and debris, I'm sure it's no problem on that polished to death car there. I've seen some setups with the air filter right behind the rear wheel, which isn't good. I'd definitely be running some heavy steel mesh under the turbo as a guard.

Also, as I alluded to earlier, it would be nice to understand how a nice setup like the long tube equal length turbo header I posted, is able to achieve backpressure equal to or less than boost (it is possible in some cases, but not easy), this is called crossover and basically you should picture 80s Turbo Formula 1 cars.^SVO

Specifically for a 13B we have a higher rate of exhaust gases being pumped into the system, however we are not at all that big on displacement so our exhaust volume would not equal out to the V8 or the V6's hell we're smaller than most I4's. Where we are able to support larger turbos comes from the Temperature differential (which then equates to the pressure differential since the physical volume of the gases is limited to the pipe) and unburnt hydrocarbons.

Any questions? Don't make me look up Engineering papers on this stuff.

[jerd_hambone]

I'm not looking to argue, the questions been answered.

Like I said, I wasn't saying as if it were going to more effective than a front mounted turbo, just saying it would be an effective way to boost an NA engine. Not an effective way to get a rotary power house built around an NA engine.

I'll probably just set one up on my Isuzu, but I wanted to see if anyone had done it.

Vex you really like arguing haha.

I would actually probably try a mid mount, but even a mid mount is considered a remote mount. I was thinking having it placed about where the Pipes split into the Y pipe, with a small intercooler, and a small pump to pump the oil. And a small turbo. Maybe like a small Mitsubishi Starion turbo. I have one of those laying around along with a BOV and a manual boost controller, boost gauge and AFR.

I do know that on a Miata it produced very good results with a small intercooler.

[Phoenix7]

too bad Vex and I don't disagree on almost anything, I'm sure we'd have epic arguments.

I just want someone to do it and show results.

[RotaryProphet]

One other thing to consider is how long will it take to pressurize that amount of intake plumbing, and what effect will that extremely long intake tract have on off-boost performance (a very valid question, given that everything about the remote mount setup increases the spool time).

The short answer: Shitty low down torque numbers until the turbo starts to spool, and even then, the boost will come on slowly, as it now has a fairly huge space to pressurize; and it has to re-pressurize it every time you let off and allow the BOV to vent the pressure to the atmosphere...

Which raises another question: What kind of monster BOV would you need to vent that volume of pressure -without- allowing it to back-spin the turbine? Probably you would want one very near the turbo outlet, and another post-intercooler.

[jerd_hambone]

Most people have a loss of power at the low end, but as soon as it spools, It boosts back up rather quickly. Or so the videos and people who have them say.

[classicauto]

Any questions?

Yeah, what the hell are you saying?? lol

[vex]

Yeah, what the hell are you saying?? lol

My E-Wang is Huge!!!!

[jerd_hambone]

Yeah it aint!