Squires Turbo System (rear mounted)

[Nicklz]

Really the only added weight vs. front mount is the additional pipe going from turbo to intake.

Not to mention the weight is in the back, while probably not a noticeable difference, it would make the car more neutral in weight distribution.

Not to mention you have no intercooler = less weight. Plus you don't have to have an exhaust system, so your taking away some weight.

[phoenix64]

Originally posted by Nicklz:
Exactly my point air is under compression = more heat = hotter turbo housing = more added heat under the hood. (If mounted in the front)

A rear mount creates more backpressure in the headers, thats more heat, under the hood, and at the cylinder head.

More importantly, when pontiac was re-desgning the Turbo 3.8 in 89 for the TTA they spent thousands of hours modifing cylinder heads, exhaust headers, and turbochargers to try to get the EGT's just a few degrees cooler than they were in the 87 GN's. All in the interest of engine life. If you want your engine to last lower the EGT. Far more important than underhood temps.

[oil pan 4]

How many people here have rebuilt turbos?
What part of the turbo is going to make the compressor so hot. How is all that heap going to conduct on to the compressor housing?
The exhaust housing, and center section are cast iron. The turbine to compressor shaft is made of SS, most likely 416 or better. The oil is going to take away all that heat. 416 and better are not a great conductor of heat. Plus the shaft is cooled by oil and some times theres a water jacket around the bearing cavity too.
So all that heat will have to go through the shaft and heat the compressor wheel or go over the surface of the bearing cavity up the backing behind the compressor wheel and heat the houseing.
I think it's funny when people read there site and belive every single thing on there.
If your so worried about the air being so much hotter then get an intercooler.
There are pros and cons to each.
I have to go back home now and work on my car now [img]graemlins/naughty.gif[/img] [img]graemlins/banana.gif[/img] [img]graemlins/banana.gif[/img] [img]graemlins/banana.gif[/img] [img]graemlins/banana.gif[/img] [img]graemlins/banana.gif[/img]

[Turbo V6 Camaro]

Originally posted by oil pan 4:
How many people here have rebuilt turbos?
What part of the turbo is going to make the compressor so hot. How is all that heap going to conduct on to the compressor housing?
The exhaust housing, and center section are cast iron. The turbine to compressor shaft is made of SS, most likely 416 or better. The oil is going to take away all that heat. 416 and better are not a great conductor of heat. Plus the shaft is cooled by oil and some times theres a water jacket around the bearing cavity too.
So all that heat will have to go through the shaft and heat the compressor wheel or go over the surface of the bearing cavity up the backing behind the compressor wheel and heat the houseing.
I think it's funny when people read there site and belive every single thing on there.
If your so worried about the air being so much hotter then get an intercooler.
There are pros and cons to each.
I have to go back home now and work on my car now [img]graemlins/naughty.gif[/img] [img]graemlins/banana.gif[/img] [img]graemlins/banana.gif[/img] [img]graemlins/banana.gif[/img] [img]graemlins/banana.gif[/img] [img]graemlins/banana.gif[/img]

:eek: :eek:
how much longer you in japan for ? ? ?

[Nicklz]

The gasses flowing through the headers are 1500degrees, then they go to the turbo which further heats the gasses. All of this heat affects the engine. If the gasses are flowing to the back of the car you take away the heat from the turbo in the front. So I don't see how your point is relevant.

[Turbo V6 Camaro]

Originally posted by Nicklz:
The gasses flowing through the headers are 1500degrees, then they go to the turbo which further heats the gasses. All of this heat affects the engine. If the gasses are flowing to the back of the car you take away the heat from the turbo in the front. So I don't see how your point is relevant.

the turbo can not heat the exuast gases

[phoenix64]

Originally posted by Nicklz:
The gasses flowing through the headers are 1500degrees, then they go to the turbo which further heats the gasses. All of this heat affects the engine. If the gasses are flowing to the back of the car you take away the heat from the turbo in the front. So I don't see how your point is relevant.

If the gasses are flowing to the back of the car they are losing LOTS of energy. So more energy has to be put in at the front of the car. The turbo has to recive X amount of energy to produce X amount of boost, no matter where its mounted. Because you are losing energy with a rear mount you have to put more in initialy.

[Nicklz]

So why do cars have heat shields specifically for the turbo.

[GN-T66]

Originally posted by Nicklz:
So why do cars have heat shields specifically for the turbo.

When you run exhaust gases through the turbine, the turbine will heat up. I've seen them get red hot when you're working the **** out of a turbo. If underhood heat is such an issue, ceramic coat the turbine housing. It reduces external temps on the housing nicely. That or get a blanket for it.

[Nicklz]

viper - heat is produced from the compression. Which is what a turbo does compresses air into "boost"

phoenix - The turbo recieves X amount of energy, but depending on the turbo will produce X(+). The intake blades don't flow the same as exhaust blades.

[Turbo V6 Camaro]

Originally posted by Nicklz:
viper - heat is produced from the compression. Which is what a turbo does compresses air into "boost"

phoenix - The turbo recieves X amount of energy, but depending on the turbo will produce X(+). The intake blades don't flow the same as exhaust blades.

bleh

the turbo can not make the exuast gas's hotter... nor does it compress the exust gas's

and the way it heats up the intake air charge is no way going to raise under hood temps to affect the performance of the car......

the PCM will pull timing cause of the hoter air though.... witch is why IC's are good to have, that not that only reason i'm to tired to care.

[phoenix64]

Sorry I should have said X and Y. No you can never get X+. Basics laws of physics conservation of energy. At best you will get 1/2 the energy out that you put in.

The turbo must have X amount of energy to produce Y amount of boost. To get X amount of energy in a frontmount the engine must put out X amount of exhaust energy. To get X amount of energy to the turbo in a rear mount, the engine must put out X+all the heat lost in the pipe.

80% of your exhausts potential energy is Heat, why waste it?

[nocutt]

You guys are making my head hurt...
Nicklz
Whatever happens in the Mister2 world leave it there ;) ...you are dealing with different dynamics now...rear/mid engines suffer from what you are talking about now and it seems logical to think in that frame off mind...in cars like that ppl will kill their dogs to get cooling the way conventional cars cool...I know...I am also in the fiero world...you turbocharge one of those things you had better have a 100 and 1% heat management working in your favor...

...their are no loop holes in physics here...you compress air...you heat the air up simple as that...to what degree the air is heated will be dictated by the efficiency of the unit compressing primarily and then other factor come in secondarily...proper heat management can potentially negate the secondary issue and proper comp. match can reduce the first...it is very legitimate to think a turbo tranfers heat from the xhaust to the comp side...as a matter of fact it happens...however very negligible!! ESPECIALLY on a car that does not stagnate airflow like say a mister2 etc.

EGT's doesn't really matter because it is not a constant...we can run the same pressure ratio and I can have a cooler EGT because I am maybe spraying the air coming into the intake with fuel...
Turbos glow especially when the housings are relatively small or retarding timing...however like GNT66 suggest that is a "drop of water in a pond"...

[Nicklz]

viper - I didn't say it would affect proformance, I said for longevity of engine accessories.

phoenix - your missing the point with a properly sized turbo (not size of turbo itself alone, but the blades agian exhaust and intakes blades can flow different amounts)

Example: intake to turbo can be 1, while compressor is 3.
So every 1 cubic inch of gas into turbo is mulitplied by 3. To counteract drop in pressure from heat loss(just example figures)

I'm to the point I'm repeating myself and it's 1:30am so I quit for tonight. Later.

[T-Punk]

I say we give up. Obviously Nicklz knows more than all of us.