This project is based off of my daily driver. It is a mostly stock '89 Cavalier Z24 with the 2.8 V6. At the time I installed the turbo system, it had 172,000 miles on the original engine and transmission. I got the urge to turbocharge my Cavalier while I was in the middle of restoring my TT IROC-Z. I was seriously longing to drive a turbocharged vehicle again, and since I upgraded to larger turbochargers on the IROC, I had two spare turbochargers to play with. After a few weeks of planning and two days of actual work, I was driving a turbocharged Z24.

Update- As of October 2006, my Z24 now has over 200,000 miles and a 328HP Remote Turboed 3400 V6 is under the hood. I've recently done some rust repair and painting to the body as well, and hope to continue using it for daily transportation... indefinitely I guess. I really enjoy the car!

The goal of this system was simplicity. A simple turbo system is reliable, quick to build, and easy to service (not to mention cost effective). Around the time of designing this turbo system, I became intrigued by the remote mount turbo theory, as pioneered by Squires Turbo Systems (STS). Though much of the tech info STS has on it's web site is sketchy at best, I couldn't deny the reports of successful results. I too laughed at the idea of mounting the turbo all the way in the back of the vehicle (where the muffler once resided), but I felt I had to test it before making any decisions. My Z24 became the test vehicle, and was fitted with a remote mount turbo system using a spare turbocharger from my IROC-Z. (See more info on remote mount turbocharging in my FAQ/Tech Info Page)

The first step in building this turbo system was upgrading the fuel pump and installing a RRFPR (Rising Rate Fuel Pressure Regulator). The RRFPR would add the needed fuel once the turbo started boosting by increasing fuel pressure. The RRFPR was installed in the fuel return line, between the fuel rail and fuel tank. (See more info on rising rate regulators on my FAQ/Tech Info Page) After a few quick tests, I found that my stock 170,000 mile fuel pump was not up to the task of feeding the extra power produced with the turbo system, so I upgraded my fuel pump as well. I installed a Holley 255lph in-tank pump designed for the F-Body TPI (Jegs PN 510-12-914). This pump was a direct fit to my Z24 fuel tank sending unit.

Once the fuel system upgrades were finished, I test drove the car to verify that there were no drivability issues before building and installing the turbo system. It drove like stock, so I proceeded.

As a side note, I did not plan to use any form of boost-spark retard for this project. Becuase of this, I filled my tank with premium fuel before beginning the turbo install to (hopefully) prevent detonation. I figured that since GM tuned the 2.8 for low grade (87 octane) fuel, the spark curve would be mild enough to prevent detonation if I were to run premium (92+ octane). As it turns out, this assumption was correct for up to around 8psi of boost. Read on for more details on that later. The 2.8's low static compression ratio (8.9:1) is also pretty good for turbocharging, further lessening the need for spark detune when under boost.

This is the tricky part of installing a remote mount turbo system. It is not very difficult to build the oiling system, but it did take some research and testing on my part to get it to work properly.

Turbocharger Oil Feed- The turbocharger requires pressurized engine oil for lubrication. For this system, I tapped into my engine's oiling system by installing a 'T' junction at the oil pressure sending unit. One leg of the 'T' retains the original sender, while the other leg feeds the oil line leading back to the turbocharger. I fabricated the oil feed line from 1/4" steel brake tubing, while using industrial 3000psi hydraulic hose in the areas that required flexability.

Turbocharger Oil Drain 'Problem'- This part is where it gets complicated. In general, a turbocharger needs a good gravity drain to remove the drain oil from the turbo's bearing section. In standard turbo systems, this is provided by a large diameter hose (1/2" ID minimum) leading straight down to a fitting in the oil pan. If there is any restriction in the turbocharger oil drain, the turbo will leak oil and smoke, no matter what condition the seals are in (the seals primary function is to prevent combustion/inlet gases from entering the oil system, therefore they were not really designed to seal oil leaks). On a remote mount turbo system, with the turbo mounted away from the engine, we need some other way to deal with the drain oil. This is accomplished by using a pump to 'scavenge' the oil from the turbocharger. This same pump then pumps it back into the engine. This idea is not new, in fact it has been used for years in turbocharged airplane enignes, where the only convienent spot to mount the turbocharger(s) is below the engine or low and to the side of the engine. Even the Callaway Twin Turbo Corvettes used a turbocharger oil scavenging pump because the turbochargers were mounted too low to drain properly drain into the engine's oil pan.

Turbocharger Oil Drain 'Solution'- The drain system for my RMT system consists of a trunk mounted oil scavenge pump. The pump was obtained at a local hardware store- (SHURflo PN 8000-643-236). This pump is rated for continuous duty at oil temperatures of 180°F, and a flow rating of 1.8 GPM. The oil is pulled out of the turbocharger through a 1/2"ID hose and goes up to the scavenge pump in the trunk. The pump then sends the oil through a 3/8"ID hose front to the engine, where the oil re-enters the engine through a fitting installed on the front valve cover. You could also return the oil to the engine's oil pan, but it is easier to remove the valve cover and tap it for the drain fitting than it is to remove the oil pan. STS actually pumps the oil back into the engine through a fitting in the oil fill cap- this would get the job done, but I feel it looks a little too 'rigged up' (it doesn't remind me of a professional installation). I wired the scavenge pump through a relay, and it automatically runs whenever the ignition key is turned on. The oil feed and return lines are routed under the LH side of the car, along with the brake fuel lines.

This oil system works well, but it should have a sump in it to catch the oil drain from the turbocharger after the engine is shut off. I found that the turbo would puff a bit of blue smoke after it sat for a while without the engine running. This could be cured by adding a small sump to catch the oil until the engine was restarted and the scavenge pump began pumping again. As an alternative, I found that if you turn the key back to 'run' afor about 20 seconds after you shut off the engine, this scavenged all the oil from the turbo and it would not smoke upon restart. I actually purchased a Turbo-Timer off eBay (a cheapo $25.00 unit) and wired it in so that it automatically runs the scavneg pump for 20 seconds after the engine is shut off. This makes the system very reliable and user friendly, although I believe a small sump mounted below the turbo drain would accomplish the same thing with even less complexity. For more info,see the RMT Oiling system section on my FAQ/Tech Info Page.

Update- This turbocharger oiling system has been functioning with-out fault for about 13,000 miles now.

The turbo I used for the initial turbo build was one of the spare turbos from my TT IROC project. It is not ideally sized for my 2.8, but it worked very well. I had two of these left over when I upgraded the turbos on my IROC, so I figured I would put it to good use. This turbo started life on a late eighties Volvo I4. It is a Garrett/AiResearch 45 Trim TBO3 (.42 Compressor A/R, .48 Turbine A/R). I rebuilt it before installing it on my IROC, so it was in good condition. These 45 Trim T3's are a very common size turbo, and should be fairly easy to find in a salvage yard, or on eBay. Like I stated above, the turbo worked very well and provided good response, but I was operating it near the choke line (out of it's efficiency range). A 60 Trim compressor would have better suited the 2.8V6, and you would defenitely want to go bigger if you were running even more displacement.

The turbocharger is mounted in the rear, where the muffler once was. I used the original muffler hanger to mount the turbocharger, then routed my exhaust and intake plumbing. This system omits the muffler, but the turbo itself is surprisingly effective at quieting the exhaust note, lessening the need for a standard muffler (as a side note, no muffler after the turbo provides a real mean turbine whistle- I love that sound!). The exhaust is stock back to the turbo. The intake charge pipe leading front to the engine runs over the rear axle, and then down the RH side of the car (right next to the body pinch-weld). The charge pipe then goes under the sway-bar and transmission, and up into the engine bay (there is a lot of room there once the stock air intake/filter box is removed). It then connects to the throttle body. Somewhere in this area is where you need to mount the blow-off valve (BOV) if you are going to be runnning one. You can see my TurboXS Type HRFL BOV in the engine bay pictures (also note the RRFPR mounted in the upper right corner of the engine bay pic). The lowest part of the system is where the charge pipe passes below the sway-bar (see pictures). I get a lot of questions regarding ground clearance issues, and I can honestly say that it is not a problem. My car is lowered nearly 2" via Intrax springs, and I have no problems entering sloped driveways or going over speed bumps. I don't believe ground clearance would be an issue unless you regularly take your Cavalier off-roading!

This is a simple boost controller I devised for my car. I like to run 6psi of boost for daily driving. A flip of a switch is all that is needed to bring the boost up to 10psi when desired. I also made this system to have an adjustable Stage II setting, so I could actually bring the boost up much higher than the engine could tolerate. Turbochagrers are nice in this way- increasing the boost is very easy to do, but you must make sure other parameters are kept in line or you will carry your engine home in a basket!

This boost controller is very similar to many commercially produced dual stage boost controller units. You can buy one of those for $80-$200 or you can build your own following my diagram for next to nothing. I paid $10 for the fancy fighter jet switch, the rest of the parts I had laying around my shop. This is not a full auto boost controller (these are very expensive and have many features, most of which I feel are not really neccessary). This is baically a manual boost controller that can be turned on or off from the driver seat.

There is so much info on alcohol injection systems on the net, so I wont go into too much detail here. I made my own system for about $150 and a few hours of time. It is worth over 20HP at the wheels, lowers the AFR, and cools the intake charge. Well worth the time in my opinion! The system is armed with a switch on the dash, and then automatically starts to spray the alky mix at 6psi of boost.

This engine swap is what took my Z24 to the next level. I performed this swap at around 185,000 miles. The engine is a stock 3400 from a wrecked '02 Venture minivan. It really wakes up on boost! You can read more about this type of swap on www.DomesticCrew.com. It is a pretty straight-forward swap, the main obstacle is custom fabricating the front engine mount bracket. I think I only cut three or four wires to do the swap!

The 3400 is still controlled by my stock 2.8ECM, but I upgraded to 19lb/hr fuel injectors to add the needed fuel. It's as smooth and quiet as the original 2.8, but makes a lot more power!

Of course you can't install a bigger engine and expect the little turbocharger to keep after. A few days after the 3400 swap was completed I reconfigured my remote mount turbo system for a larger T3/T4 Hybrid turbocharger and a TiAl 38MM external wastegate. I did retain the original 2" charge plumbing between the turbocharger and engine, however a larger charge pipe may allow for increased high RPM HP. The turbo specs are as follws: Compressor is a TO4B V-trim, and the turbine is a T3 .63A/R with the Stage II turbine wheel.\

Phase I system: Best ET- 13.9 at 99mph, Best Trap Speed- 14.1 at 103mph

Phase II System: Best ET and Trap Speed- 12.59 at 114.77mph

Who says you can't drive a remote mount turbo system in foul weather? I drive mine every day rain, snow or shine, and heres the proof! This was an early (December) snow storm for our area, and I had a long drive into work (17 miles in snow too deep for a Cavalier), but I made it all the way there safely, and then get stuck trying to get into my parking space!