Okay folks, while at the Darryl Starbird show with the Amsoil booth I decided to take a tour with my trusty camera and start recording some of the eye candy that was there, (CARS folks!!! Get your minds out of the gutter).
Anyway, I ran across a gentleman there selling something that just blew me away. A rear mounted turbo system. He was using a Camaro SS to show it off too complete with dyno charts and all. I didnt get to speak to him personally and ask any questions but I did listen to him talking to people about it.
1. No intercooler required, though Im sure you could use one.
2. No cramped engine bay.
3. Easier to install, atleast thats what he said.
I got a picture of it, but it was the unit on the car and I photographed its reflection in a mirror since I couldnt get in there to get low enough to get a straight on shot on the car.
Basically the air filter and intake tube are mounted on the underside of the rear end behind the rear wheels. That goes into the turbo which is then piped up to the throttle body. I assume that there has to be an exhaust pipe that comes back to the turbo to drive it but from the angle I was looking at it, I couldnt see it very well and then it went to a center mounted split dual exhaust pipe.
Now, Im no expert on turbos, but this has to be just the most fantastic idea I have seen in quite some time. First, heat is so much less of an issue because you got all that pipe going up to the motor and back that cools things off. Secondly, room is so much less of an issue. Obviously without the turbo in the engine bay, under-the-hood temps are not going to go up significantly. Thirdly, what better place for the air filter. I mean its back there on the rear end where its got nothing but clean cool air. Now that being said, I would be concerned about water ingestion and that was one of the questions I would have asked the guy had I been able to do so, but I would say they have that figured out or they wouldnt have spent the money they did to be in that show demonstrating it.
Below is a picture of a rear mounted turbocharger. Its not mine but one I found on the web to give you an idea of what all this looks like. I would think, and Im just thinking out loud, this type of install would open up worlds of doors for the focus.
Dont bother asking me too many questions at this point 'cause I just dont know. Im going to try and shimmy over there tomorrow when I go back and see if I can pick his brain.
____________________ My car is a synner! It uses Amsoil Synthetic Lubricants.
2001 Pontiac Grand Prix GTP
It whines a lot, but I like it
Ohh, I thought I would add that you dont have to drill the oil pan or whatever it is that is normally done with a turbo install for the oil return line as they have a special oil fill cap (at least for the camaro) that the line ties to for the return and they get the oil supply comes from just above the oil filter, though I dont know what all is required to hook up the line to get at the oil source.
____________________ My car is a synner! It uses Amsoil Synthetic Lubricants.
2001 Pontiac Grand Prix GTP
It whines a lot, but I like it
ijust so happened to see this segment on speed channel on cable just two weeks ago.i think it was a silver slp camaro. i started to try and fab one for my 9.8 sec dohc neon(yea i know that word is blasphemous on this site),but i now have an 01 dohc ZTS sedan .ironically it was t-boned by a ford exscursion . iwant to try this set-up on my ZTS,can this be done?
the rear mount turbo was pioneered by ST. the oil return on any turbo is not REQUIRED to drain into the pan. the reason its most often done that way is so you dont have to use an external oil pump. It also puts the oil back to where its needed most: in the pan.
the benefit of the ST kit is that the long charge pipe with air flowing across it acts as an intercooler without the pressure drop. the downside of this arrangement is that the compressor is far from the exhaust manifold and the exhaust has cooled down considerably. this leads along with the lengthy charge pipe leads to increased turbo lag.
not sure how you would want to run the blowoff on that. its an awful lot of air to recycle into the manifold but free venting it would likely cause you significant A/F problems when you drop out of boost.
I don't know about the induction set-up on a camaro, but insted of a MAFS if it used MAP could you vent into the atmosphere? The reason for rerouting the intake charge back into the intake track is because the MAF already read the air charge, if you vent that charge the car will run rich between shifts or when you drop out of boost. If you use MAP the ecu reads the air pressure and temp. inside the intake manifold so venting the air in the intake track into the atmosphere wouldn't cause the car to run rich, and you wouldn't have to reroute all that back into the intake track.
That's what I'm thinking, someone please correct me if I'm wrong.
____________________ Honda's are like assholes, everyone has one.
thats correct. IIRC, the pectal replaces the MAF with a MAP. maybe if you went that way with it.
of course, you could also just run sans BOV.
I do really like the idea of the ST turbo but I dont think I would buy one unless it were SIGNIFICANTLY cheaper than other turbo kits. It just isnt as efficient as other kits. the turbo dosent get the benefit of being close to the exhaust housing, the charge pipe is huge so the turbo lag would be significant. Especially noticeable when going from no boost. The other thing I dont like is the long oil lines. probablly not much of an issue but I personally like to keep the amount of exposure that oil has to the outside world to a minimum.
from a DIY aspect, changing the wastegate spring would require getting under the car. slightly annoying.
You wouldn't need to get under the car to adj. the wastegate if you had a electronic boost controller.
I had asked Tom about no BOV and he said it would be alright. But I don't like the idea of the intake charge rushing back through the compressor housing. It seems like it would make the turbo fight the to keep spooling.
Also I agree about the oil lines. I would rather let gravity do it's job than to rely on a pump. I've seen electric pumps fail, but never gravity.
____________________ Honda's are like assholes, everyone has one.
Since everyone has mentioned the turbo lag, I figured I would mention that from the reading I have done, and I wasnt able to talk to the guy tonight, the turbo lag is no worse than any other turbo because of the design in the tubing, something about how it is sized and such. As I mentioned Im no turbo expert but they apparently thought of that and were able to effectively deal with it.
I saw the dyno sheet for the Camaro SS and it was extremely nice. I dont specifically remember the torque but I do remember there being something around 125 hp gain and the curves, at least to me didnt indicate any substantial lag of any kind and the torque curve was fairly flat. So I dont think turbo lag is any more of an issue with the rear mounted set than it is with a traditional set up.
Plus its all bolt on too. They apparently now, after being able to look into it a bit more, do away with the muffler, so that is where the exhaust input comes from. And because of the long runs of the oil line and intake tubing they dont have to run an intercooler and suffer no less effiency, as well they dont have to use turbo timers or idle down becuase of the long run on the oil line so there is not baking the oil to the bearings which to me would seem real adventageous.
I know in dealing with Amsoil that on a turbo'd motor the oil life is reduced. Amsoil usually recommends only three times longer drain interval on turbo'd motors because of the heat issue. With this set up it would seem that would be a much less issue. Though I would want to do some oil analysis before stretching it back out to the full capability of the oil.
____________________ My car is a synner! It uses Amsoil Synthetic Lubricants.
2001 Pontiac Grand Prix GTP
It whines a lot, but I like it
The oil change interval with turbo cars is much greater, I change my oil every 2500 miles.
Also not to be a jerk but their is no such thing a "turbo lag". When people refer to turbo lag they really are talking about spool up time. The larger the turbo the longer the spool time.
Where the turbo is located on the camaro it would take the exhaust gases longer to get there so that would increase the spool time.
____________________ Honda's are like assholes, everyone has one.
actually there is turbo lag, but it isnt what most people think it is. turbo lag is the delay from when you open the throttle till the boost actually reaches the TB. This is not to be confused with boost threshold which is the time it takes the turbo to spool.
By virtue of the long charge pipe YES there will be a greater turbo lag.
Because the turbo is so far downstream from the manifold, the turbo will take longer to spool. this is just basic thermodynamics. To combat this, they probablly use a smaller turbo. you would have to look at the compressor map and see if it is actually efficient enough to push the CFM needed for your engine in the RPM range you want to use.
the oil thing. Its not true that it acts like a turbo timer. if that oil pump shuts off when the car does than the oil in the line would remain stationary as gravity can not drain it into the pan.
Its not a bad setup, dont get me wrong. But if you were striving to get as much power out of a system as you could, you wouldnt use this setup.
Last edited on Sun Feb 20th, 2005 01:06 pm by TXFO
i read the HCI review of this turbo system...according to the authr of the article on the acura integra they had this set up on there was "surprisingly little to no turbo lag".....thats all i know....they said something about the design of the turbo and matching to each application...i dunno....
hey the website for them is http://www.ststurbo.com they have videos and all and if you are worred about water they also have a vid of a toyota tacoma running through water and mud
actually go on the websight, if you can still find it. They have a few vid's of the cars with the rear mounted setups. They claim less turbo lag and I def believe it based on the videos (massive power on the cars/trucks that it was put on). I dont know, its hard not to believe the videos? Try to find the sight and let me know what you think.
____________________ 02' Infa-Red SVT Focus
93' Red F-150 Lightning
This isn't a new fangled thing at all. I remember seeing something in one of HotRod Mags back in the late 80's with this setup, and I believe they referenced someone even older by a decade or more?
People always seem to complain about the lag. But honestly, if you havent been in one, then how can you tell.
