Rear/Underside Mounted Turbo Setup.

Rear-mounted turbo setups have been around for years. And yet there are no professionally designed kits available for the Mustang. It is worth taking a hard look at the reason for that. There are no monopoly pressures to force the market one way -- it'll go wherever there is money to be made. So if a rear turbo setup were either cheaper, or better performing, the market would have already responded to fill that need.

However, obvious concerns aside, I think someone should most definitely go ahead and build one. Perhaps with first-hand knowledge we could put the issue to rest -- that's pretty much the only way the whole Thumper E7 conversation got quieted down. Let experience provide the answer.

how does heat spin the turbines? isn't it the exhaust pressure

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This is a good question, and one that most import owners don't seem to know the answer to ... or else they would quit wasting money on fart-cans and buy bigger headers instead. You could in fact decrease the size of the pipe as it gets farther away from the heads, because the gas is much cooler and denser ... big tips are only for looks.

Rootus said:

This is a good question, and one that most import owners don't seem to know the answer to ... or else they would quit wasting money on fart-cans and buy bigger headers instead. You could in fact decrease the size of the pipe as it gets farther away from the heads, because the gas is much cooler and denser ... big tips are only for looks.

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With any forced induction set-up, you want the exhaust to flow as freely as possible, because there is not the need for backpressure to produce low-end torque. The largest amount of air possible in, the largest amount of air possible out. I by no means am saying that fartcans are a good way to do this, but reducing the size of the exhaust would in no way benefit the power produced, and would probably hurt performance on most applications, regardless of the exhaust temps.

Rootus said:

This is a good question, and one that most import owners don't seem to know the answer to ... or else they would quit wasting money on fart-cans and buy bigger headers instead. You could in fact decrease the size of the pipe as it gets farther away from the heads, because the gas is much cooler and denser ... big tips are only for looks.

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Wow, I have a 4.5" exhaust on my car with a 5" tip that I apparently wasted $1500.oo on, and it is an import. I am ricer though. HEHEHEHEHEHE Oh wait I have a mustang too..

I by no means am trying to tell someone not to build a kit, I am just stating that there are some drawbacks to a rear turbo design. Hopefully if he does build one he will uses this post as a referance, of possible things to watch, and look out for.

I actually would love to see a well designed rear mount turbo kit. Please build it, and if you are in the central florida area, contact me, I might be able to help you out.

Rootus said:

Rear-mounted turbo setups have been around for years. And yet there are no professionally designed kits available for the Mustang. It is worth taking a hard look at the reason for that. There are no monopoly pressures to force the market one way -- it'll go wherever there is money to be made. So if a rear turbo setup were either cheaper, or better performing, the market would have already responded to fill that need.

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This is a very key point. I can try and tell you why it is better to have the turbos under the hood till I am blue in the face and you guys will still not listen. The fact that the after market will not waste it's time engineering a setup is very significant.

Rootus said:

This is a good question, and one that most import owners don't seem to know the answer to ... or else they would quit wasting money on fart-cans and buy bigger headers instead. You could in fact decrease the size of the pipe as it gets farther away from the heads, because the gas is much cooler and denser ... big tips are only for looks.

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This is the exact opposite thing that you want to do. You want to continuously increase the size of the exhaust otherwise you will have scavenging and back pressure. A large pipe going down to a smaller pipe will create turbulance. This is why they make stepped headers because they help maintain velocity.