Rearmount turbo?

[Sick280zx]

Anyone on the forum attempt this? I just got a new job and may save up during the summer collecting turbo parts. Im about to order the corkey bell book on turbo charging also so I can do it right the first time. I've looked at how other kits are done from STS just wondering if its gonna be more of a hassle then trying to find a turbo exhaust manifold.

 

 

Thanks for the help guys!

[z-ya]

the problem with rear mount is all that plumbing: oil, compressor in, and compressor out. It's like having two more exhaust pipes.

 

Turbo manifolds are easy to find. I have at least 4 of them if you need one.

[Sick280zx]

yea that was the one thing I was scratching my head about is the oil lines and how to get them back there but how much for one of those manifolds?

[_Donovan_]

There is an insane amount of plumbing involved in a rear mount set up. For earlier Z cars there is plenty of engine bay room for a normal turbo set up so there is not much need. Rear mount is mainly for cars with not that much room for a turbo or to try and "hide" the set up. From what I have seen on this forum it would be much easier to just go the traditional route.

[Six_Shooter]

The plumbing for a rear mount turbo is no more complicated than a conventional turbo set-up, just longer, and the need for an oil return pump are the only differences.

 

There would be just enough space in the trans tunnel to run the cold side of the turbo plumbing back up front, leave the existing exhaust where it is (along the driver side, if it's a stock or stock like L28 exhaust system), and run the cold pipe along the passenger side of the trans tunnel. Oil lines could be routed along side the cold side tubing as well.

 

That being said, I wouldn't do a rear mount in an S30, unless some obscure rule of some race organization I was running had a rule that would dictate such a thing. Weight distribution would be another reason, but the S30 doesn't really have a problem with this.

 

There is plenty of space under the hood for a turbo, and as said the exhaust manifolds are not that hard to come by. I'll be selling mine at some point in the future as well. If you really couldn't get your hands on a stock turbo manifold, you could adapt the N/A manifold by making a piece that attached to the N/A manifold outlet and routed the exhaust to a turbo. I was going to go this route until I found a turbo manifold from another member on here.

 

There are also other benefits to running a conventional set-up including higher thermal temps of the exhaust itself, which is part of what makes a turbine work, pressure differential is another large part, so a large or free flowing exhaust system is usually a norm with turbo systems as well, less tubing and piping, reducing cost of materials, and no electric oil pump needed to return the oil back to the engine, also reducing cost and slightly reducing complexity. My biggest concern with a rear mount turbo set-up is not the functionality, but that electric oil return pump failing, if that happens, it can cause a lot of problems, including blowing oil past the seals in the turbo, causing the exhaust to become drenched with oil, which could also cause a loss of oil, that would then starve the engine, which could take out your engine.

[Joeoski]

Could you no put a oil cooler in the back with oil in it to feed the turbo or would that need a pump still or does the turbo not have enough power to suck is oil from the oil cooler its self , Hearing about this setup makes me wonder has any one done a twin turbo setup with the turbo in the engine bay and a turbo in the rear ?

[BLOZ UP]

You need the pump if the turbo is lower than the return on the oil pan. Otherwise the oil would back up against the turbo, which is bad.

 

Having one turbo in the engine bay and and one in back would be a waste. There's enough room in the engine bay for two turbos, at least if you have the will and means to go that route in the first place. You couldn't do a true twin setup like that anyway, unless you were aiming for an unbalanced setup to begin with. You could do a compound/sequential turbo setup like that I suppose, but why?

[Gollum]

Hell, I bet there's room in the engine bay for THREE turbos! (man I'd love to do that...)

 

I'm personally not at all a fan of rear mounted turbos, and that subject has been beaten to death. But yes, the S30 is no different than any vehicle, and it could be done. I'm glad you're going to read corky's book, which will explain very well why the STS systems are NOT the most competitive in the world and don't operate all that wonderfully. The benefits are for a very select crowd which rarely happens upon HybridZ, let alone becomes a regular contributing member.

 

Getting a turbo manifold should be easy, and cost less than $150. I sold my last one for like $40 because it had a stud that needed replacing and was going to be a pita for anyone to do in a garage. I bought my last turbo longblock for $200, though I had to pull it myself in an evening in the guy's backyard. Only thing I didn't get was the wiring and turbo. I just about broke even selling the parts I didn't need, and gave good deals to fellow members.

 

And if you really had THAT hard of a time finding one, you could build one for not too much more money. Take the cheapest header to can find as a flange donor, cut it up, reuse some of the piping if you want, order some bends for the rest, tack weld it in place if you can't weld it yourself, bring it to a welder, done. Probably cost you around $200 in materials and $200 for the welders time if you pay him REALLY well. Shouldn't be much more than an afternoon project if you've got it all lined up right. I plan to make a turbo manifold down the road, but only because I want to place my turbo in a very particular spot that isn't very close to stock and would be hard to extend the stock manifold to. Plus the stock manifold is like 20 pounds, it's a heavy beast. Oh, and I've seen guys build turbo manifolds for under $150 on their own, but they were fairly competent fabricators who did it all themselves from scratch spending most of their money on nice SS mandrel bends.

[Cannonball89]

If you want to do something "outside the box", a cool project I think would be to have a full equal length header made (or make them yourself) that wraps down under the oil pan, and have them come up and out on the other side of the engine with a T3 or T4 flange at the secondary collector. This would get all of that heat away from the intake manifold, which is the biggest problem I have right now using the stock turbo manifold. The heat soak after 5-15 minutes is just vicious in my car in the summer. Plus having equal length headers going to the turbo can't hurt performance either, although response time may suffer slightly, but I doubt it would be too noticeable. Having a smoother less turbulent flow going into the turbo would probably offset the extra distance between the turbo and the exhaust valves *I think*.

[Tony D]

Yes, it would be eminently better to put 1100 degree heat source directly below the oil pan. That would get most of the heat away from that intake!

 

I guess just compensate NASA Specification Fluoroelastomer crank and pan gasket sealing strips, along with an oversized oil cooler to reject the heat added to the pan.

 

 

Simple blanketing stops heat transfer on the non-crossflow head since the manifold is so small costs of proper shields is low.

[Gollum]

Tony is completely right. Heat shielding is cheap compared to all that work.

 

That said... I've been toying with an idea for years now of running intake runners over the valve cover. It makes more sense to run the maybe 200 degree compressor outlet by the oil pan than it does the 1100 degree exhaust manifold.

 

My reasoning is that you could minimize pluming, adding an air to water cooler if needed while minimizing the amount of exhaust to intake heat transfer. And while heat wraps do wonders, they're still not perfect and after extended time under boost you're still going to be baking your intake.

 

Obviously electromotive did fine at 1000 HP, so I'm not saying my idea is necessary, just another way to approach heat management.

[Cannonball89]

Yea scratch that idea. Curved runners over the intake would make for a torqy little motor too. I met a guy at carlisle last year with a N/A fairlady that had the intake manifold with the 180 degree curved runners. It was the P65 intake. He said it pulled a lot harder at low rpm than the standard straight runner manifolds.

[Gollum]

Yea scratch that idea. Curved runners over the intake would make for a torqy little motor too. I met a guy at carlisle last year with a N/A fairlady that had the intake manifold with the 180 degree curved runners. It was the P65 intake. He said it pulled a lot harder at low rpm than the standard straight runner manifolds.

 

Well the taper matters as well. My design doesn't have any longer runners than what some of the carb'ed NA cars on here have had. I think some of the longest I've seen where when Paul was doing experiments in his yellow car with runner length. You can do the design with runners under 24", and the top end won't really be killed much unless you don't taper the diameter, which I would plan on doing at that length.

[HowlerMonkey]

Biggest concern is the piping between the engine and the turbo will be nearly white hot which endangers anything nearby to catch on fire.

 

Ask around the STS guys and you will find more than a few carpet or trunk fires.

[Gollum]

This was posted in another forums section here. I think this is the coolest rear mount setup I've seen. It even doubles as a heater!

 

 

Turbo shows up around 1:25.

[BRSanko]

The rear mounted turbo seems to have far more disadvantatges than advantages. The main one in my mind would be that the exhaust would cool down considerably, thereby reducing exhause pressure, thereby reducing the amount of boost to be extracted. I guess the big question to me would be why do you want to do that? I have looked on Car-part.com and found turbo manifolds for like $75, all that piping and such would be sure to run you in the $100s.