Originally Posted by Mike_Levy
Well, since we have a turbo thread, I'd like to get some thoughts from you guys.
Single vs Twins?
Front mount vs Rear?
This is just a quick overview but should help you out.
There are several different types of a turbo setup. Single, separate twin, sequential twins and a twincharged setup. There is also the variable geometry single turbocharger.
Single vs Separate Twins is purely a show point. Since each turbo is separate from the other they are each only getting half of the exhaust gasses to power them, hence smaller turbos are used. This does allow them to spool very fast but can (if not sized properly) hoke the engine up top. Since each turbo is also flowing into a Y pipe before the throttle body they MUST be perfectly setup or one turbo will choke the other. The boost will follow the path of least resistance being the other turbo.
A benefit would be that each turbo is smaller and can be fit relatively easy on each side of a V style engine from the factory
. Drawback is that you have more components/systems. Seen below.
Now lets look at sequential twins (one powers the other)
This compound system when setup properly runs cooler and provides more power quicker, but it is very complex to setup and tune as it is a boost multiplier. Seen below.
We also have the Twincharged setup incorporating a supercharger into a turbo setup. This is a boost multiplier setup as well and when setup and tuned perfectly is offers the best of both worlds with the only drawback being the complexity and proper function of the setup.
You get the awesome low end torque of the supercharger (boost is instant) and when the charge is at it's optimum from the supercharger the large turbo takes over and the supercharger is mechanically decoupled from the drive belt and bypassed in the piping. If a supercharger which produced 10psi (pressure ratio = 1.7) alone blew into a turbocharger which also produced 10psi alone, the resultant manifold pressure would be 27psi (PR=2.8) rather than 20psi (PR=2.3). Getting the transition right is the challenge! Seen below.
Lets look at the variable geometry single turbo. This turbo alters the angle of the intake vanes to allow for an almost instant response.
- Many turbo diesel engines
- 1989 Honda Legend Wing Turbo
- 1989 Shelby CSX (Garrett)
- Porsche 997 Turbo (BorgWarner)
The Jeep Grand Cherokee WK has an option of 3.0 liter Mercedes-Benz OM642 CRD V6 engine with Honeywell-Garrett VGT.
Remote vs front mount.
Each has it's advantage and disadvantage.
Cooler underhood temps
Cooler charge temps
Longer life span
Easy to access and maintain
More pipe to charge
More pipe to purchase and fit
Secondary Oil system
Best aftermarket solution
Hotter underhood temps
Hotter charge temps
Shorter life span
Hard to access and maintain
Less pipe to charge
Less pipe to purchase and fit, if you can fit it in there!
Depending on placement may or may not need an aftermarket Oil system
Aftermarket solution will be very expensive
All in all a remote mount is the best choice and I believe the main reasons it was put directly on the manifold from the factory is ease of building a compact powerplant that is simply placed on the engine cradle and installed into the vehicle and also a refinement issue as I'm sure the standard driver doesn't want a beast as a daily driver as when a large single turbo hits you definitely know it!
The hit can be turned down but why would you want to do that!...LOL