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  #25  
Old 05-19-2010, 01:19 PM
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Re: SRT Turbo

Quote:
Originally Posted by Mike_Levy View Post
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.

Used by:
- 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.

Low RPM



High RPM



.................................

Remote vs front mount.

Each has it's advantage and disadvantage.

Remote:

Cooler operation
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

Front:

Hotter operation
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
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  #26  
Old 05-19-2010, 01:43 PM
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Re: SRT Turbo

thanks for the amazing info James +rep for that one
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  #27  
Old 05-19-2010, 01:50 PM
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Re: SRT Turbo

Yeah, I'm thinking a single rear mount is gonna be the best way to go at this point. Been looking for a T88 to use, but they don't seem to ever come up on eBay. The smaller ones are alot cheaper and easier to find, but I don't wanna limit myself.

As far as why to reduce the hit, drivetrain longevity is the main reason. I've blown up more then my share of drivetrain components over the years, and I really don't wanna kill the Jeeps. Our stuff seems to be better then the GM garbage I'm used to grenading, but still, its gonna fail if abused.
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Old 05-19-2010, 09:37 PM
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Re: SRT Turbo

Quote:
Originally Posted by Mike_Levy View Post
Yeah, I'm thinking a single rear mount is gonna be the best way to go at this point. Been looking for a T88 to use, but they don't seem to ever come up on eBay. The smaller ones are alot cheaper and easier to find, but I don't wanna limit myself.

As far as why to reduce the hit, drivetrain longevity is the main reason. I've blown up more then my share of drivetrain components over the years, and I really don't wanna kill the Jeeps. Our stuff seems to be better then the GM garbage I'm used to grenading, but still, its gonna fail if abused.
Are you planning on a full engine/drivetrain swap also or are you going to stay low on the boost? Decide on your final HP goal and the amount of air you need to be pumping in and out then map out your turbo choice from there. That way you will be running it in it's optimum efficiency range.



If your bored and want to hurt a brain cell or 2 with some math and physics take a read at the link below to correctly map out your choice of turbo.

http://www.8thcivic.com/forums/turbo...urbo-maps.html
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  #29  
Old 05-19-2010, 10:23 PM
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Re: SRT Turbo

I will be building a bottom end for it at some point. I already have the top end done, though I'll swap to a turbo cam.

Drivetrain I'm not sure yet. Definetly a converter and valve body, but the rest of the tranny I'd rather not screw with. Transfer case has already been replaced several times, so a built one is probably inevitable, and the axles, when they break, I'll worry about them.

That turbo thread doesn't make much sense to me. Like I told Tim at NCTS, I'm far more used to and comfortable working with postive displacement superchargers. For this app though, turbo seems to be a better choice.
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  #30  
Old 05-27-2010, 12:28 AM
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Re: SRT Turbo

I don't suppose anyone would happen to have the Compressor map for a T88? Advan is selling them cheap and I think I may pick one up.

TURBO SPEC:

t-88 mid frame turbo charger

Intake :5 inch
Outlet: 107mm outter diameter, 82.35 inner diameter
Compressor trim: .60 ar (anti- surge)
Compressor Wheel diameter: 74.80 /102.40 (big wheel)
Turbine wheel diameter : 75.35 / 81.70
Exhaust trim: 1.05ar
Turbine flange type: t4 flange ( twin scroll )
Downpipe flange type : 6 bolt type
Cooling type: oil cool only
Horsepower rating: 1000hp+
(wet float bearing)


Can I even use this beast? I've never seen a 6 bolt downpipe flange.......
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