Rear mount turbo questions
 

I’m building my own rear mount, and I’m not finding any pics of how the intercooler piping is routed from turbo to intercooler.

Also what size exhaust to the turbo is everyone running, and what size piping to intercooler?

As far as I've seen, the people that built rear mount turbo systems have been pretty exclusively posted on facebook. Hit up Luis Garza, he can put you in the right direction. He had one of the first DIY builds for rear mounts.

They aren't on here because they just don't work that well. Save your coin and buy a quality kit. There are several good choices out there. The next thing to consider is all of the supporting mods that are needed so the engine can stay together.

They make power, but are very inefficient (lag is freaking crazy and the powerband is small.

I was being nice. LOL I still am biting my tongue.

Thought you were taken off the nipple a long time ago hahha

When the wifey offers nipple, I don't turn it down. LOL

Sounds like you guys have never had a proper rear mount before. Lag is negligible as long as it’s done right, and they can make great power. Even with supporting mods, I’ll be under $4k for everything.

No we save 3-6k more and get a high quality kit. Nobody installs that junk on here.

Hardly. I have way more than $4k just in supporting mods.

It’s the boost threshold that’s the major concern.

Yeap, the turbo kit is the cheapest part of the build.

“Proper rear mount “ that all depends on your goals/build/expectations ... if you looking for 400ish whp with less lag you will need a smaller turbo which will lose top end if you want more top end then you increase the lag severely ....you can make a base level turbo kit but no real room for growth

If you dropping 4K you would be better off saving for the Boosted performance kit .... 10k for kit and supporting mods 600hp all day long

I hear people have some kind of success with these things, but I've never seen it. It doesn't make a ton of sense from a physics perspective.

The guys on the LS forums love these and are making insane power and 9 second cars all day. Granted they have much more displacement. But a proper sized turbo for this platform has a chance. I say do it.

Keep the exhaust piping small. You want velocity and wrap it all good to keep the heat high. The big 370ci guys go 2.5 inch charge piping to intercooler so go that or even smaller.

As a starting point, take a look at the 350z sts kits and see how they did it.

RZG rear mounts makes really good power, There are 350 Z is fast as hell but doesn’t start making boost until somewhere close to 6k. Inefficient (lag) only good for straight line roll racing.

Please explain, I’ll wait

Rear mount will never be as efficient. EGT has cooled off by the time it hits the rear.

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All you have to do is look up the boost curve and torque from any turbo kit, and it will tell you all you need to know.

There is no such thing as a "properly sized turbo" when you mount it 10 feet away from the exhaust manifolds, and then run that charge air another 14 feet (depending on charge pipe layout) back to the TB's.

Like I said, maybe it's due to the displacement advantage on LS builds vs 3.7 but hundreds of guys love these over there and it's the most popular kit. Not saying it's better than a top mount or mid mount, just saying it's been done and guys seem to be having fun.

A bonus of the rear mount is that there's no additional heat in the engine bay.

But.... That's stating the obvious.

Whatever.

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Yeah, I don't know. If they like it, good on'em, it is an improvement over stock power, so there is something to like. I did a quick google search to see what the dyno charts look like with these trunk turbos, on the larger displacement engines....a 2005 Vett with twin STS kit:

https://www.corvetteforum.com/forums...urbo-dyno.html


The final numbers look great, and maybe that is the focus...but that is like an old school T88 2jZ dyno. For the displacement, there is nothing happening at 3,500rpm for example, whereas on the 370z, you'd be over 400ft/tq below 3500rpm, and it revs out to 7,500rpm

This trans am is even worse:

https://ls1tech.com/forums/vehicle-c...treet-car.html

Turbos are already well beyond maxed out, and the power band is about 2,500rpm.

I'v always been a big fan of power under the curve, vs. the peak hp/tq.

At the end of the day, it is hard to cheat physics.


Not trying to argue, and there is a product out there for everybody. I'v had customers that after some conversations, I had suggested they hit you up for a S/C kit, or Nick@SOHO for a top mount, Tony@F.I, or RJM...depending on what they are looking to get out of the car, and what they define as "fun".

Those graphs are disgusting.

Do it I'm watching!

FYI Twin turbo rear mount video

https://www.youtube.com/watch?v=zoFB4bD7Z-I

part 2

https://www.youtube.com/watch?v=0HR9_cWW1Ik

I’ve actually been hearing the opposite on the turbo lag topic. I’ve heard from several people there’s not a big noticeable difference in lag compared to an engine bay mounted set up.


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I watched those. He is using $89 dollar turbo's. LOL I guess if you are cheap and can't afford it then go for it. My issues is if you can't do it right then don't do it at all. I have seen folks that have done this and then their motor pops. They start whining and crying about it. Sometime you just can't protect people from themselves.

Facebook is a world of trash advice with people trying to push their kit or what they're running. And they're usually running it because it's cheaper. Throttle response and lag is bad. There's like 25ft of piping between the hot and cold side. Wait for turbo to spool, it spools; send boost to intercooler to cool. Send to intake manifold, finally feel boost.

That sounds like bullshjt

I can think of only two reasons to install a rear turbo: not enough room to put it near the exhaust manifold and because race car.

The closer the turbo is to the engine exhaust, the better it works. That's Physics. Sure, a rear-mount will work and well enough for most "casual" drivers (and it does look pretty cool, IMNSHO) but, if you're worried about optimal performance, you gotta be hot.

I think the big disconnect here is that a rear mount setup can be a nice bang/buck in the smiles-per-gallon kind of way as they can be super cheap and much less complex to install. The contingent who seem to believe there is no performance difference appears to be ignorant on the science of boosting and the data available to them. Lots of parroting hearsay and as SS said - facebook is rampant with this garbage. That's one thing that makes this community good (and sometimes bad) - when someone starts pushing that stuff with no real basis we usually shame them until they leave.

The biggest problem we have in this case is the usage of peak HP/TQ numbers to compare drastically different setups.

so im a few years late on the post but im also building a Rear mount kit and had some questions about getting oil back from the turbo. im in between 3 options but have heard negative remarks and was looking to clear some up if any of yall have any info it would help
Option 1= sandwhich plate to feed the turbo and return ( was told tht they are pressurised at like 80+ psi so i would need a hella strong pump.

Option 2= i was told to 'T' off the Presure sensor but that seems like it would be pressurised too, no?

Option 3= taping the oil pan ( was told nissans shouldnt be tapped cant remember the reason but that the oil needs to feed to the block not pan

thoughts comments ideas?

ive heard about the spacer but is there another way ?

You're heading the right direction - Option 1 and 2 are pressurized and might be a good way to feed oil to the turbo, but definitely not for the return. Return should go right back to the pan with a scavenge pump to get it there.


Think it would make your life a lot easier to use an oilless model like a COMP turbo.

Instead of tapping the pan, why don’t you buy a sandwich plate for the oil pan that is already tapped?

You’ll still likely need a pump to return the oil to the pan.