Going Fast for Cheap!
Modifying your car for speed is a very popular and exciting hobby. The problem is that to a beginner in the hobby can spend countless amounts of dollars on dead end upgrade that do not deliver the power desired. There is an old saying in building fast car’s “There is no replacement for displacement” while this can be true there are some short cuts. These shortcuts include forced induction options or power-adders. These include items like turbo, supercharger, and nitrous. With the advent of high manufacturing turbo are now more affordable than ever. Superchargers have become increasingly cheaper but still can cost you some decent coin. Nitrous has always been the cheapest of the three but to setup nitrous safely your budget will rival that of a turbo or supercharger.
The main focus on this article will be in building a low-cost turbo system using used or new parts at substantial price savings. When equipping your car with a turbo you need to think about some things first. The compression and fuel system of your engine is the most important information. These items can be researched through the internet and it is readily available information. The next thing you want to do is take a look under your hood and see if your car can fit a turbo under the hood. If these space looks to tight do not worry you can go with a rear turbo setup. Rear turbo setups have become popular recently because of the easier fabrication and competent low boost setups.
The problem with most cars is that a normal buyer will be steered into such upgrades as a cold air intake, exhaust headers, muffler, chip tuning. While viable options they will not produce anything close to the horse power and torque even a low boost turbo will give you. A low boost turbo setup would be a setup consisting of less than 7 pounds of boost. Most engines can be equipped with a turbo a simple FMU and boost 5 pounds safely. Those 5 pounds will produce much more than a similar intake, header, exhaust setup.
Another consideration of going with a rear mount or front mount turbo will be the availability of turbo manifolds for your car. These days many cars have turbo manifolds readily produced for many Hondas, Nissans, Toyotas, Fords, and Chevy’s. Check your local auction site for a great deal. Just buy the cheapest manifold you can buy. Sure an equal length manifold will produce great gains on a track car but we are doing this on a budget. It has been shown you can make good power on a regular log manifold. The next step is finding a turbo. Once again check the auction sites. Most 4 and 6 cylinder cars a t3 or t3/t4 hybrid turbo will spool fast and produce great horsepower and torque. If your car is an 8 cylinder you will most likely need a big t3/t4 turbo or a straight t4. If you want to save money get a turbo with a built in waste gate. You can adjust the boost by adjusting the shaft on the waste gate.
The next step is piping and piping connections, once again check the popular auction sites. A cheap piping solution is to buy mild steel U-bends cut to desired shapes and paint it. Stainless steel is nicer but is more expensive. The connectors you use will be important but not as abused as a high boost setup you can go with the cheap standard rubber connectors or the more expensive silicone. Rubber connectors should hold up under 10 psi.
Now we will go to fuel management or FMU as mentioned before. The FMU or fuel management unit is a device that multiplies fuel pressure based on vacuum. The more vacuum or boost the FMU sees the more it will multiply the fuel pressure. They sell adjustable regulators and static regulators. It is advisable to use anywhere from an 8:1 to 12:1 FMU. Check out the forums on the internet regarding you specific model to see what others are having success with.
The turbo is lubricated with oil so you will need to source engine oil from someplace usually the oil pressure sender or oil filter. The oil passes through the turbo and cools as well as lubricates the inner propeller then it is dumped back into the cars oil system. You can save some money by using a punch and an oil fitting then using JB weld to secure it to the oil pan. If you go with a rear mount turbo you can drill a hole in your oil fill cap and let the oil return there. The reason you can do this on a rear mount turbo setup is because you will need an oil scavenge pump to return and draw the oil into the turbo. A rear mount setup requires the additional pump because with the turbo being under the car and near the exhaust the oil has to be transported fast and evenly.
A low boost setup does not require and intercooler. The intercooler might even hinder performance in a low boost setup. The problem with an intercooler is the bigger the intercool the bigger the potential for a drop in boost. If you do decide to go with an intercooler and low boost chose a smaller intercooler.
If you are going with a front mount turbo you must now “mach up” the plumbing or try and draw or figure out where everything will go and how all the piping will connect. You will need to mount the turbo manifold to your engine. Remove your exhausting headers and attach the manifold. Then attach the turbo. Try to plan the piping route from the turbo charge side directly into the engine intake manifold. It is good to use flexible joints so that you have room to make up for tight spaces. Then you will need a downpipe to connect to your existing exhaust setup. You can get this done at a muffler shop for a good price if you tip the worker well.
If you are going with a rear mount setup you will obviously require more piping to cover the long distance of the charge pipe the engine. It is hooked up in the same manner only the turbo is further from the engine bay. Remove your existing exhaust and try and figure out how you can mount your turbo. A good idea is to buy a turbo flange and cut a small area out of some pipe and weld it or have it welded in place. They also weld a small metal rod to the pipe so you can mount the turbo with existing muffler hanging hardware. Once you have a good place for the turbo and its secure you need to route the exhaust to the turbo flange. This should also be quiet easy for a good muffler shop. Tip the guy well and explain what you need done. Now that the turbo is mounted to the exhaust you need to run the charge piping to the front of the car. I find it is best to use rubber or silicone connectors but long runs of pipe. This will keep the assembly flexible and slightly rigid resisting the light twisting of the engine turning operation. I would also consider wrapping the piping or having it ceramic coated to resist heat. No you can install the oil scavenge pump and route it back to the oil fill cap. The FMU is mounted the same way as the front mount system.
Once you have the turbo system installed on your car you will have to keep boost low. I would recommend no more than 5 psi at stock timing. If you reduce the timing of your engine you can probably run 8-10 psi. Enjoy your turbo!