http://forums.nicoclub.com/zerothrea...967&page=2

7th post from the bottom 500 HP b4 turbos...810HP after

 

why not replace the giant mid muffler? That would cut down on piping and give better flow. That guy used all sub par parts and did a really bad job. A good fab job would make the rear mount a much better concept and much more functional.

 

The thing that is difficult about turboing a 12v is that the two exhausts don't come together until the rear of the car, after the cats. Maybe he thought it would get better exhaust flow when all of the exhaust is flowing through one pipe instead of two...

 

then, connect the headers, run them to the turbo and run it back. All it takes is some thought and planning, both the guy above did little of.

 

THought they only did this on corvettes

 

it was designed mainly for full engine bays stuffed with v8s to get more power. It applys in this case also.

 

Yeah, I've seen this kind of setup mostly for trucks. And they are sick.

 

Ok, I somewhat understand the whole turbo being next to the ports working better because of increased velocity, but wouldn't a remote mount work just as efficiently just with more lag because it is after all the same amount of exhuast gasses coming out of the end up the tailpipe as it is coming out of the exhaust ports. PSI is PSI isn't it? I know the 30v's can only make it to what...12psi before there's a hole in the piston, so it'snot like a big turbo is needed, a single KO3 would work perfectly, small so it spools fast too. Wow, I hate it when I forgot what I was saying, so I don't have anything to follow it up with. Anyways, remote mount it cool. Lets see....LS2 is 400hp, dual exhaust, so that's 200hp coming out of 1 side for 400 total. 30v is 190hp coming out of a single pipe, so it would be working almost as effective as the Vette's that they did on Horsepower. Well...they had 2 turbos making I think 7psi...but still...I'm done, I think I've said enough, hope I didn't say too much, and wish I had a new Z06 Vette, with a remote mount twin turbo set up, Haha

 

The exhaust really doesn't make boost or psi. If you measured the "boost" of the exhaust it would be very low, my guess around a couple psi & high RPM. A turbo works off of heat & exhaust flow. As the exhaust gas goes down the muffler is cools off & slows down (lowering pressure). Then the exhaust, especially on NA cars, has pulse waves, to help pull the exhaust gas out the back. So now you have a cooler, slower, gas, that is coming in waves (hold your hand over your exhaust pipe, it's not a continuous flow).

Part of the reason it works on a Vett is the high output of the 7l engine. There is a TON more flow & heat at the back of the Vett then any Audi A4.

Yes, a K03 would not be a bad choice for a rear mount. But any rear mount is going to give up a ton of efficiency to a normal mount. There is gong to be lower boost & more lag.

 

Apparently you've never checked drive pressure on a turboed vehicle. A properly tuned setup will require slightly more backpressure (exhaust boost pressure as you're stating it) than the boost it is producing (1:1 is ideal, but very hard to achieve). In my pickup, at 52 psi boost, I run slightly over 60 psi drive pressure into the turbo. That is without a wastegate. When I actuate the wastegate, drive pressure drops to around 40 psi and boost to 45 psi...but my egt's skyrocket because I'm not getting the massflow neccessary to cool all the fuel. In this case, the turbo is still on it's map at 52 psi, and therefore the wastegate is worthless (ie, I don't have enough fuel to push the turbo past it's limit). Granted, everything above is in regards to a 500rwhp diesel engine, but when it comes to forced induction, the concepts are the same.


Turbos work off the expanding gasses coming from the exhaust manifold. The hotter the gas, the faster it expands, the faster it flows, the more power you have available to spin the turbine in return spinning the compressor. Just like on a jet engine, the turbines ENTIRE PURPOSE is to turn the compressor to create, well, compressed air which in turn spins the turbine...quite the circle.

A buddy ran the numbers on his twin-turboed diesel (compounded...in the diesel world, called "twins") the other day. He runs a hybrid Holset HX-40 as the secondary (little turbo) and a Garret GT42 as the primary (big turbo). His setup requires 360hp just to spin the turbos...any less and they would never light to full power. Luckily he has a touch more than 360hp (580+) so he's in the clear.

Remote mount turbos?...no way. Would it work? Yes. Well? No. The power from a turbo comes from the hot, expanding gasses.