Rear Mount Turbo is very effective.

[evildky]

my only problem with the rear mount on the z32 is there si no reason to mount them back there, there are stock mounts to put a pair underhood, you save a lot on piping and it's just a lot easier, for other chassis it makes more sence

[DunnJH4]

Why not put them back there? According to STS and all the others it greatly decreases intake temps even w/o intercooler, decreases engine bay temps, looks bad ars and probably sounds crazy to a gearhead. I dunno bout spending 15k on the official vette system, but they have nice universal kits for 2-4k! Anybody on here have experience putting a rear mount on a 454 big block resting in a 69 Camaro. My good bud is trying to drop a second or more off his 1.4 mile time and really likes the idea of the rear mount kits. I forwarded him a link to this thread. I just hope we can find a guy w/a mendrel pipe bender that doesn't charge 100x what I could get back home, Any local info in Va beach would be much appreciated!

[SSDwellah]

I'm curious how you handle the boost control. Do you run a really long vacuum hose from the intake manifold to the wastegate or can it be tapped from somewhere else? Also do you only run a singe exit exhaust in the Z32 now?

I am somewhere between you and qsiguy: I have a Z32 with a swapped VH45 and I want to run rear mount turbos. That's s for plural. I was wondering how to route everything though because rear mounted twins sounds like a lot of plumbing. Also I never figured out how to use an electronic boost controller on a twin turbo setup. I guess there would be one solenoid with a y fitting going to two wastegates?

[qsiguy]

You don't need to reference the vacuum, just the boost pressure at the wastegate. I just have a tap from the compressor tube right at the compressor outlet in the back that goes to my boost controller then to the wastegate.

Twins would be a little more tricky but not too bad depending on how they were mounted. I saw a twin setup on an Acura that looked quite complex but I don't think they would all be that way. You only need one compressor pipe returning from the turbos. If you have an H or X pipe in the exhaust before the turbos, which most do, you would only need one wastegate If you don't have an X pipe I would make a crossover tube connecting the dual exhaust and put the wastegate on that tube. Also, since you should have the compressor tubes joined as soon as possible you only need to get a boost reference from that tube. The boost controller would be the same as any other turbo system. You could do dual wastegates and controllers but it could be tricky to match the boost settings.

[SSDwellah]

You don't need to reference the vacuum, just the boost pressure at the wastegate. I just have a tap from the compressor tube right at the compressor outlet in the back that goes to my boost controller then to the wastegate.

Twins would be a little more tricky but not too bad depending on how they were mounted. I saw a twin setup on an Acura that looked quite complex but I don't think they would all be that way. You only need one compressor pipe returning from the turbos. If you have an H or X pipe in the exhaust before the turbos, which most do, you would only need one wastegate If you don't have an X pipe I would make a crossover tube connecting the dual exhaust and put the wastegate on that tube. Also, since you should have the compressor tubes joined as soon as possible you only need to get a boost reference from that tube. The boost controller would be the same as any other turbo system. You could do dual wastegates and controllers but it could be tricky to match the boost settings.

Thanks for the info. Yeah I guess I could go with a bigger single turbo and it would be easier to plumb and probablymore efficient (less rotating mass) but the Z looks odd with just a single exhaust. I guess there are a few ways to solve that with a single turbo:

1. Put up with the fact that there's only one exit now 2. Have a dormant ("fake")exhaust pipe on unused side just for show - pretty weak.3. Have the wastegate go to the second exhaust pipe, so it would only actually be flowing exhaust when you hit your boost limit. - still kinda weak4. Mount the turbo a bit further forward so there is room to "Y" back out to two mufflers. Makes the mounting a bit trickier but it could marginally improve spooling and get the right effect.5. Use twins ok so that's not a single turbo... but what about on a VH45 where there is only one throttle body. You can run dual separate exhaust pipes, each one to it's own turbo. From there, the exhaust goes out the back to two separate tips/mufflers. The pressurized intake "Y"s together into one pipe, and runs up to the passenger side where it enters a front mount intercooler. A pipe from the drivers side runs up from the intercooler to the throttle body. Where would the MAFS and BOV be in all this? I'm guessing the MAFS would be on the last run of intake pipe, so the BOV would have to be sufficiently far from it so as not to disturb air readings with turbulence, and not release metered air.

[qsiguy]

I've seen a few single rear turbos that used the wastegate for the 2nd exhaust outlet. I'm doing that but my tips are next to each other. The driver side tip is just the turbo outlet the inside tip is just for the wastegate. Mainly cosmetic to keep an OEM look, just larger diameter tips.

If you do a blow through MAF like I did you would only need one, if you want to do a draw through MAF you would need to run wires all the way to the turbos and have one on each compressor inlet. I wouldn't attempt this unless you just can't get it to work with a blow through setup. The tuning for a rear mounted dual draw through MAF would be a nightmare. Also, you will most likely skew the voltage signal to and/or from the MAFs from such long wiring.

Also with a draw through MAF setup you would probably need to purge the BOV back into the intake just before the MAFs, major pain if it's even possible with duals. With my blow through I was able to just put the BOV in front of the MAF so I can just purge unmetered air. Seems to be working great so far.

Here is my MAF/BOV setup

[SSDwellah]

I've seen a few single rear turbos that used the wastegate for the 2nd exhaust outlet. I'm doing that but my tips are next to each other. The driver side tip is just the turbo outlet the inside tip is just for the wastegate. Mainly cosmetic to keep an OEM look, just larger diameter tips.

If you do a blow through MAF like I did you would only need one, if you want to do a draw through MAF you would need to run wires all the way to the turbos and have one on each compressor inlet. I wouldn't attempt this unless you just can't get it to work with a blow through setup. The tuning for a rear mounted dual draw through MAF would be a nightmare. Also, you will most likely skew the voltage signal to and/or from the MAFs from such long wiring.

Also with a draw through MAF setup you would probably need to purge the BOV back into the intake just before the MAFs, major pain if it's even possible with duals. With my blow through I was able to just put the BOV in front of the MAF so I can just purge unmetered air. Seems to be working great so far.

Here is my MAF/BOV setup

Thanks for the pic. Yeah I definitely was thinking blow through, and I was gonna place my MAFS in pretty much the same place, but I was wondering how the emissions, driving is with the BOV so close to the meter. Do you get a lot of backfire, or excessive richness especially if you rev and let off? I would think when the BOV opens so close to the MAFS it would read some air twice when the BOV opens. You probably luck out since you are most likely running the stock automatic and don't get off the gas between shifts on a hard run. With a manual I would think it would want to stall on every up shift. Not to mention the turbulence from the tee in the pipe being there.

I'm not knocking your setup because it probably works okay for you, but I think I would try to get my BOV further away from the MAFS, but still after the intercooler (so I guess it would be behind the bumper for me).

[aidanair]

theres a kid here with a black c6 that is supercharged AND has a rear mounted turbo. seems kinda redundant to me but idk

[devileyeam]

Haha! Thats funny!!! ^^^^

And I wanna see this quad turbo Z!

[qsiguy]

You could be right with a manual trans and some configurations, I couldn't say. In my install it runs fine and never backfires. I really don't think it would make much of a difference moving the BOV further back. When you close the throttle and the BOV opens if the air is going to flow back through the MAF it will do it whether the BOV is where mine is or a few inches or feet further before it. The air may just stay in the tube instead of blowing out the close BOV but that's not going to change it's effect on the MAF output. Also keep in mind that after the MAF the air is dead headed by the throttle body and not moving. The turbo is still forcing significant amounts of air so pretty much all the air escaping from the BOV is fresh air from the turbo.

[zmds17]

one more question -- would it be possbile in a rear mount turbo to keep your muffler -- i have the best looking mufflers on the planet & i hate to part with them ??

thanks

i dont see why you wouldnt be able to keep ur mufflers as long as you run ur turbo farther towards the front of the car.... i heard some one put it where their spare tire used to be

[chaosdrifter06]

Haha! Thats funny!!! ^^^^

And I wanna see this quad turbo Z!

Technically from the way I see it, it is possible. Have the normal TT setup from the VG30DETT, then the rear mount turbos. Talk about overkill.

[OUKNO]

I'll be doing the dyno after I get it tuned as good as I can without the dyno. I have dual stage boost controller so I can get numbers at two boost settings.

I want the dyno info, I plan on the swapping to the VH45DE and the single rear turbo would be a great add to it.Anyone got compresion #'s on the VH45DE? I just want to know how it will handle the turbo.

[zmds17]

I want the dyno info, I plan on the swapping to the VH45DE and the single rear turbo would be a great add to it.Anyone got compresion #'s on the VH45DE? I just want to know how it will handle the turbo.

i do beleive compression is 10:5:1........ but dont hold me to it

[mtcookson]

10.2:1

[OUKNO]

So mtcookson will that hold up a little better with that rear mount turbo?


Modified by OUKNO at 3:18 PM 6/26/2008

[zmds17]

my only problem with the rear mount on the z32 is there si no reason to mount them back there, there are stock mounts to put a pair underhood, you save a lot on piping and it's just a lot easier, for other chassis it makes more sence

a good reason to mount them back there is cuz at least that way you dont have to run a intercooler..... savs ya severl hundred dollars

[valkyie]

Just wondering do you have any problems with your car on a rainy day? I thinking of doing the same with my car also. Just concerned about water getting into the filter.

[OUKNO]

Hey guys, I bought the rear mount turbo Z from the previous owner that started this thread. He blew his motor so then I bought it and have been putting everything back together. The guy should be done with-in a month and I will be putting up some pictures/ vids.

Can't wait to see the aftermath of this thing hopefully a little more dialed in than before are you having the pistons changed?please post any and all changes to the long block so us other NA guys just don't grab a turbo slap it in there and boom; another NA parkedyea that "10.5:1" compresion is a little high for boost especially above 6 psi

[zmds17]

Just wondering do you have any problems with your car on a rainy day? I thinking of doing the same with my car also. Just concerned about water getting into the filter.

after talking to the guy that did the original rear mount turbo its a good idea to cut out the area for ur spare tire.... the area is tucked up under there pretty good so id think ull have any probelms

[qsiguy]

For me rain isn't a huge problem. For one because it hardly ever rains, lol. Seriously, unless I go through large puddles the small amount of offspray won't hurt anything. I have a "sock" for the air filter that sheds water.

[zmds17]

how often do u change filters? and how much hp gains and 0-60 gains do you think you got... since ya havent gotten her on a dyno could ya just give me a rough guess

[bc300zx]

im going 2 do that 2 my car.

[jrwashere]

Is there any updates on this ???

[Bohman731]

I know I am late to the party but....Awesome Work!!!!!!

[Ace2cool]

Yeah..... thread from 2008. That was before "Topic Reply Notification" existed. You'll have to email him with a link to here to find out if there were ever any updates.

[300ZXttZMAN]

I saw this thread and i figured tony bumped it up haha but yea that is nice work.

[ZXdriver]

I noticed no intercooler...? How does that work?

[New Jersey]

i think it's pretty cool too
i dunno why all the smug comments and hate though. seems to be mostly ignorance on rear mount turbo setups or just not respecting other people's goals.
i think all the ttz32 builds that go over ~425whp are stupid personally as it shifts the power curve too high,(it's still just a 3.0 v6) but i dont go hating on peoples big turbo builds
heck, im goin ls1 after much thought and a few threads, but i still think this guys setup is kinda cool.
let's get this guy to update us!!!

[New Jersey]

I noticed no intercooler...? How does that work?

its called the surface area of 8-10ft of tubing