Skyactiv Remote Turbo Build

Chris_Top_Her

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San Antonio, Texas
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'15 CX-5 Miata AWD




Hi, I am working on a low boost (4-5 psi) project to build a remote turbo set up.
A remote turbo set up is one in which the turbocharger is mounted somewhere down the exhaust stream, rather than on the exhaust manifold. Some benefits that are attractive to me:

No turbo manifold is needed - I found that even though there is space behind the engine for a turbo (specially with a shorter manifold), no one has a head flange for the 2.5 sky and you'd be paying to have a one off manifold built (unless you build your own). Even still, it's a cramped space and most turbos will be too large to get behind the engine without partial disassembly; a hassle. Also frees up the engine bay of pipes bent everywhere. A big $$$ saver either way.

Cooler air charge - Because the turbo is further down the exhaust stream, turbo temperatures are lower (up to 500f on some applications) meaning less wear on the turbo/oil, greater effectiveness of the intercooler, all around lower temperatures and better tuning potential.

Some people complain about turbo lag on remotes, some don't (but then again people get turbo lag with a front mount turbo too). I dont give a s*** about a half a second of turbo lag I give a s*** that I'm getting boost lol. THe oil line will need to be run further with the addition of a scavenger pump for return; not a big deal for te cx-5 as the transmission tunnel/space above the underbody panels provides plenty of routing space or space for a self contained oil system for the turbo. The space on the rear axle is ample thanks to it being designed to accommodate a hitch.


I am assembling a parts list. It will serve as a checklist and reference. items added as needed/time permit. Feedback appreciated. Some of these items (especially fittings) might be cheaply available at local hardware stores, but I included them here just in case.

I am assembling a parts list. It will serve as a checklist and reference. items added as needed/time permit. Feedback appreciated. Some of these items (especially fittings) might be cheaply available at local hardware stores, but I included them here just in case.

Mechanical:
Scavenger oil Pump - Turbowerx scavenger pump. Not cheap, but it's an important part that I don't want to skimp on. Needed to return oil from the turbo back to the motor. One way valve before the turbo and after the pump. T off the oil pressure, still deciding best placement for return line. The motor will be either on a switch or wired to run when the car is on. If I can find a practical set up for self contained that's even better.
Base-Model Pump

Turbo - 57/58 trim turbo with anti surge and internal WG
45XMQyp.jpg

https://www.ebay.com (commissions earned)

Blow of valve - Type - S with flange pipe
As much as I want noise, per tuners recommendation, I will be hooking this up to recirculate. A hybrid may come later.
https://www.ebay.com (commissions earned)

Electrics
Maf Extension Cord - My maf needs to be pre-turbo per tuners preference.I will cut the wire down the middle splice them and run the wiring through the firewall and out the access ports in the rear to the my corksport MAF.
https://www.ebay.com (commissions earned)
45XMQyp.jpg


3-Bar Map Sensor for reading boost (stock only reads 1.8psi)
45XMQyp.jpg


Heat Exchangers
Intercooler - Black IC, maybe the version with a hose/pipe kit f I determine those parts to fit my needs. Oem diesel intercooler would be great since the mounting point are already there, but it's proving hard to source. I'm going to keep searching though.
https://www.ebay.com (commissions earned)

Oil Cooler - 7 row 10 an.
https://www.ebay.com (commissions earned)

Fittings
New OEM drain pan to tap
dealer
45XMQyp.jpg


T3 inlet flange - Exhaust pipe to turbo
https://www.ebay.com (commissions earned) - Got one with a Vband instead
45XMQyp.jpg


Pipe weldable bov flange - for recirculation before maf. Need one for the other side as well, to attach silicon hose unless I choose to go metal.
45XMQyp.jpg

Outlet https://www.ebay.com (commissions earned)
Inlet https://www.ebay.com (commissions earned)
Ended up getting a different one

Oil Feed/Drain adapter kit for turbo. built in .0045 restrictor.
https://www.ebay.com (commissions earned)

Oil pressure sensor T - Steel Looks like a good unit.
https://www.ebay.com (commissions earned)

an4(1/4 ) hose for the turbo oil feed
https://www.ebay.com (commissions earned)

an4 end hose adaptors as needed
https://www.ebay.com (commissions earned)

an10 adaptor for pan tap
45XMQyp.jpg

https://www.ebay.com (commissions earned)

an10 hose for turbo drain
https://www.ebay.com (commissions earned)

An10 end hose adaptors as needed
https://www.ebay.com (commissions earned)

An10 inline filter - pre pump
https://www.ebay.com (commissions earned)

Internal wastegate.
Y1WLvKB.jpg
 
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(popcorn) Yes, please.

Curious if you are considering a water/meth injection kit or not? It could really aid in the turbo's performance without adding too much cost.
 
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I do not want to have more plumbing than needed. The ovtuned mz3 skyactiv it offer s water cooling kit in the stage 2 version ( more power). While that allow more output, also adds another piece of maintenance. Also have to consider it's an autlmatic so I won't be trying to run some high boost. Temperatures will be lower anyways thanks to the turbo itself being away from the engine, and the lower IAT should help a lot with avoiding engine knock.
 
Cooler air charge - Because the turbo is further down the exhaust stream, turbo temperatures are lower (up to 500f on some applications) meaning less wear on the turbo/oil, greater effectiveness of the intercooler, all around lower temperatures and better tuning potential.

You're going to have an intercooler?

What's your project timeline?

I hope you have a back-up vehicle...
 
You're going to have an intercooler?

What's your project timeline?

I hope you have a back-up vehicle...

Yea, some people don't use an IC with remote set ups but it's hot around here + high comp so I wan't the charge cooler. I want to keep engine bay temps no higher than NA and really with this set up that should be the case. I really don't even need a large IC. Time line is mainly once I can find a shop that will do the exhaust piping at a reasonable price it will move quickly from there. It's really no more than an exhaust shop would do, however I don't want cruddy welds that most exhaust shops do. And I kind of want someone experienced with turbo building to do my oil return.
 
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How far down the exhaust stream is remote? Are you going to cut out the primary catalytic (the one on the exhaust manifold)? If so, will the turbo go there?

What size turbo is that you plan on running?

It may be too soon since it seems your the first, but is there any info out their that your aware of on how much HP the oem engine internals and/or trans/tcase can handle?

Ive only seen the service manual of 2.0 not the 2.5 . The 2.0 doesnt seem like it has balance shafts. Does the 2.5L have bs? If so will you be keeping it on or removing?

Good Luck on your project.
 
Also, if your keeping the oem PCV vacuum tubing recirculated to the intake manifold, you may want to consider running a Check Valve. The PCV is usually setup as a one way check valve, but I dont know how much psi the oem one can handle or how well it can hold pressure returning to it.
 
Sounds like you've put some serious thought into your options, and the reasoning behind your choices, good deal. I'm looking forward to watching your progress.
I'm assuming you're in touch with OVTuning since you're already running their tunes. Hopefully they are sharing some of their turbo setup information with you so that you're not starting from scratch. Good luck!
 
Thanks. To answer some questions.
I've been extra busy with work so I haven't the time to jack up the car and check (to low to get under now), but the mst accessible place it to put the turbo at the rear behind the axle. There is a lot of space there thanks to the design of the car to sit higher at the fat bumper area. The other option I am considering is about midway in the awd tunnel area. I will need to get under to test fit though. The turbo I have may be a bit large, it was suggested I use a k04 type (subie/mazdaspeed/audi oem type) which are smaller. I may end up going that route if space becomes an issue. The audi version actually has a more linear shape that would be perfect for a remote.

I will be running a recirculating check valve as well to prevent boost spikes.. As much as I want the pssht lol...If this is successful sometime down the line I'll grab a hybrid BOV. I'm still trying to decide how to plumb it; it need to recirculate pre turbo according to my tuner. Pre turbo means a long return lol. Most of the recirc tubing I see has been metal, however it would be ideal if I could use a rubber/silicon hose. More research to do there. I also was told maf pre turbo, meaning wiring running to the back. I would probably run that through the cabin and out the rear through the floor access holes. I will be buying a 3 bar map for $85 from ovtuned, as the OEM map only reads 1.8 psi. I do not plan on cutting the car. The nice thing about this set up is the only cutting will be where the turbo starts (somewhere midpipe to aft). Easily revertible by welding a new pipe. I don't want an more air/oil lines than needed. Internal WG is a must in that respect. Oil system will be either a t tap at the oil pressure sensor, through the turbo, to a scavenge pump into the dipstick tube or if I can find some other place to return the oil (one source used the valve cover but I'm not sure if they used some oem connection or what). I don't intend on tapping my block to drain above the oil pan. I also don't want to tap the oil pan. The pump will be wired to the same connection as my amp so it's on only when the ignition is on, or on it's own switch.
Here is the turbo I got before I run the car with it I will have it rebuilt.
https://www.ebay.com (commissions earned)
 
Good grief, that's going to be an awful lot of work for just a few pounds of boost.

A few lbs is all you need for a high comp motor

yes there is a bs, but I'm not touching it. I don't want the engine vibrating a bunch nor do I want to pay someone if I ever need it reinstalled.
 
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Just a thought . . . did you consider a pulley driven supercharger at all? At a quick glance it could be a much simpler option considering all the plumbing work needed to do that remote turbo setup. They even offer self contained units now that look similar to a standard FI turbo so you don't need to bolt it directly to the motor. (allowing you to keep the factory intake manifold) Then all you have to worry about it a mounting bracket, new belt and some intake tubing.

I've seen quite a few Jeep guys running the Procharger kits. They seem pretty solid and a pretty small self contained kit.
 
Just a thought . . . did you consider a pulley driven supercharger at all? At a quick glance it could be a much simpler option considering all the plumbing work needed to do that remote turbo setup. They even offer self contained units now that look similar to a standard FI turbo so you don't need to bolt it directly to the motor. (allowing you to keep the factory intake manifold) Then all you have to worry about it a mounting bracket, new belt and some intake tubing.

I've seen quite a few Jeep guys running the Procharger kits. They seem pretty solid and a pretty small self contained kit.

Those cost like 3g's though lol. and the bay is pretty tight on the front/sides
 
Ovtune offers boost tuning and the only part that will need to be upgraded on the block is the OEM map sensor. It caps and 1.8 PSI so a better one is needed.

You don't need a "better" manifold air pressure sensor, you need one suitable for a manifold that will be boosted by a turbo.

Common engineering practice is to limit sensor ranges to the range of expected values. Doing this provides the best accuracy by dedicating the entire available resolution of the measuring device to the values that will actually be encountered.
 
You don't need a "better" manifold air pressure sensor, you need one suitable for a manifold that will be boosted by a turbo.

Common engineering practice is to limit sensor ranges to the range of expected values. Doing this provides the best accuracy by dedicating the entire available resolution of the measuring device to the values that will actually be encountered.

I agree about the performance limitation point. However since you went there... quoted direct from Meriam Webster..: http://www.merriam-webster.com/dictionary/better

comparative of good



1

: greater than half <for the better part of an hour>


2

: improved in health or mental attitude <feeling better>


3

: more attractive, favorable, or commendable <in better circumstances>


4

: more advantageous or effective <a better solution>


5

: improved in accuracy or performance <building a better engine>
 
The fact that you're practically sourcing everything from eBay shows the quality/feasibility of a good build. Nice.
 
I agree about the performance limitation point. However since you went there... quoted direct from Meriam Webster..: http://www.merriam-webster.com/dictionary/better

I'm just saying that "better" is relative to the intended application. A MAP sensor with expanded range is not inherently better (in fact, for a non-boosted engine it would be worse).

I also don't think the term "better" applies because the OEM sensor simply wouldn't work in a boosted application. So, your not getting a better sensor, your getting one that is suitable for your application. Just semantics but words are how we communicate.<for hour="" an="" of="" part="" better="" the=""><feeling better="">

</feeling></for>
 
Updated parts list.

The fact that you're practically sourcing everything from eBay shows the quality/feasibility of a good build. Nice.
Where else am I supposed to source everything from? Walmart down the street? You think I'm going to spend 2,3,4+x on universal parts on a setup that no one else has claimed to have done on this car? Numerically, most of the parts are low priced tubing and fitting anyways. There are plenty of turbo set ups using "ebay" (as if it's a brand) parts that are not OEM. There is always room for improvement later once everything is working, if/as needed. That's not uncommon at all with builds you find on tuner pages. The expensive part of any turbo build is the turbo itself, maybe the manifold and any custom work you have to pay for. Since there are not skyactiv manifolds, pre-bent and cut downpipe tubing, intercooler etc for this vehicle/engine there isn't really anything expensive to buy. The single most expensive item that I currently have on the list is the turbowerks pump. That's a critical item so money will be spent there. Not going to buy a $1000+ turbo when I can get an "ebay" turbo for < $200, have it rebuilt at a turbo shop for ~$100 for assurance and run it. And if it doesn't work out I didn't buy an extra expensive part. I will be checking home depot etc for the oil line and fittings as they usually sell fittings cheaply, for now I have an online source.
 
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