View Poll Results: Where is best mounting location for a turbo
On the exhaust manifold
24
44.44%
In the engine bay - in front of engine
16
29.63%
Rear mounted
12
22.22%
other
2
3.70%
Voters: 54. You may not vote on this poll
Turbo placement - where is best ?
01-26-2008, 08:21 AM
#26
Soon to be born.....
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...........
01-28-2008, 12:06 AM
#29
RotoRocks Powered
Wear protection, then. I got nothing to hide, or be ashamed of. Don't pass judgements on things by their appearance. I bet that Corvette driver that was left sniffing my exhaust a couple of weeks ago is still rubbing his eyes, trying to clear his vision... 
02-06-2008, 06:20 PM
#32
Other than that possibility, I agree with you.
Directly at the manifold is where I keep my turbo, anyway.
02-06-2008, 06:31 PM
#33
Well, there is still some question as to the long-term effects of a lot of heat retention directly at the ports and its effect on the side seals and the corner seals.
Other than that possibility, I agree with you.
Directly at the manifold is where I keep my turbo, anyway.
Other than that possibility, I agree with you.
Directly at the manifold is where I keep my turbo, anyway.
02-06-2008, 07:13 PM
#34
Still, exhaust pressure is one of the penalties of a turbo to some extent, so you can expect there to be 10 PSI or so of additional pressure in the manifold.
I don't know the truth with regards to the long term effect. There has been some speculation that ranges from none to complete annihilation of the human race, so YMMV.
02-06-2008, 09:30 PM
#35
RotoRocks Powered
What the hell are you talking about when you talking lag?
Turbo is not spun by the heat, but by the volume and speed of flowing gases. Apparently with the rotary there is enough of that regardless of where the turbo is mounted on the exhaust.
02-07-2008, 02:39 AM
#39
Heat is much more useful for spinning a turbine than pressure.
Though, energy is energy. You are just working with much less of it, so you size your turbine accordingly.
As an aside - this is one of the places where negative timing split is useful.
The combustion at part throttle is much more efficient, but produces a bit more EGT, which keeps the turbo closer to its spool-up point.
02-07-2008, 10:05 AM
#40
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On the T3-T04E in the back, right now, it spools to 10 PSI by 4K rpm and it runs the turbo out of it's efficiency zone by around 7K just like it should, and drops from 12-13 PSI back to around 9-10.
What the hell are you talking about when you talking lag?
Turbo is not spun by the heat, but by the volume and speed of flowing gases. Apparently with the rotary there is enough of that regardless of where the turbo is mounted on the exhaust.
What the hell are you talking about when you talking lag?
Turbo is not spun by the heat, but by the volume and speed of flowing gases. Apparently with the rotary there is enough of that regardless of where the turbo is mounted on the exhaust.
What dictates the speed of the exhaust gas? That's the thermal energy of the exhaust gas which creates high exhaust pulse and velocity.
With volume being equal, which engine do you think will spool a turbo faster?
1. 1.3L with ceramic coated manifold and the turbo right on the collector.
2. 1.3L with regular manifold and the turbo far back from the manifold.
The EGT difference in those two will be significant and #2 will suffer in spool RELATIVE to #1.
That's what the HELL I'm talking about.
02-07-2008, 01:28 PM
#41
RotoRocks Powered
T3-T04E out of efficiency range by 10-12 psi? You've gotta be joking me.
What dictates the speed of the exhaust gas? That's the thermal energy of the exhaust gas which creates high exhaust pulse and velocity.
With volume being equal, which engine do you think will spool a turbo faster?
1. 1.3L with ceramic coated manifold and the turbo right on the collector.
2. 1.3L with regular manifold and the turbo far back from the manifold.
The EGT difference in those two will be significant and #2 will suffer in spool RELATIVE to #1.
That's what the HELL I'm talking about.
What dictates the speed of the exhaust gas? That's the thermal energy of the exhaust gas which creates high exhaust pulse and velocity.
With volume being equal, which engine do you think will spool a turbo faster?
1. 1.3L with ceramic coated manifold and the turbo right on the collector.
2. 1.3L with regular manifold and the turbo far back from the manifold.
The EGT difference in those two will be significant and #2 will suffer in spool RELATIVE to #1.
That's what the HELL I'm talking about.
Could be an issue with the waist gate letting go due to excessive pressure, could be cooked and wobbling bearings, could be all together. It is a .51 AR compressor, if I remember correctly now. And it is not enough for the renesis.
No, you were talking about lag. You can bring as many theoretical examples as your imagination permits, but if the turbo spools up to 10PSI by 4K, it spools up, and does so quickly. So what lag are you talking about?
Yes, maybe if... it would sooner, or maybe if something else... it would differently, but you were talking lag, and I am giving a real life example.
Other reasons why I like it back there, (or soon at the "G" spot) is because everything runs cooler, so if i am loosing pressure due to the drop, I gain it back through colder charge, and cooler running engine, cooler oil, and just because having it there gives people something to talk about, discuss and every time i bring the car somewhere and pop the hood, it gathers a crowd
. It is fun to watch people get down on their knees (hot young chicks do too, by the way , I should take a picture next time) climb under the car after they hopelessly tried to locate the turbo in the engine bay. Now answer me this: how many of you have a car that's fast and makes people kneel and drop on their four behind it?
02-07-2008, 02:18 PM
#42
The Professor
Pressure is 100% of the equation.
The fact is heat doesn't do anything to turn anything. It is purely the pressure that turns the turbine.
Heat does make the exhaust gasses expand which increases the pressure. Ideal Gas Law, PV=NRT. Increase temp and you increase pressure, increase pressure on the turbine and you increase the power to the compressor side of the turbo.
Now locate the turbo back where the EGTs have a chance to cool a couple hundred degrees and we are talking about loosing pressure. I don't have the specifics so I couldn't give you exact #s,
but Volume is the total volume from the plane of the exhuast port to the turbine. Temperature is the average temp of the gas in that space. R is a constant, and n is the number of moles of stuff in the gas.
On a manifold mounted turbo, we are decreasing the volume and keeping the temps higher, which would result in an exponential increase in efficiency vs a rear mounted.
Heat does nothing by itself, heat is infrared radiation. Now heat effecting water to make steam can power engines, or other gasses to drive turbines, that is how work is done, through the medium.
The fact is heat doesn't do anything to turn anything. It is purely the pressure that turns the turbine.
Heat does make the exhaust gasses expand which increases the pressure. Ideal Gas Law, PV=NRT. Increase temp and you increase pressure, increase pressure on the turbine and you increase the power to the compressor side of the turbo.
Now locate the turbo back where the EGTs have a chance to cool a couple hundred degrees and we are talking about loosing pressure. I don't have the specifics so I couldn't give you exact #s,
but Volume is the total volume from the plane of the exhuast port to the turbine. Temperature is the average temp of the gas in that space. R is a constant, and n is the number of moles of stuff in the gas.
On a manifold mounted turbo, we are decreasing the volume and keeping the temps higher, which would result in an exponential increase in efficiency vs a rear mounted.
Heat does nothing by itself, heat is infrared radiation. Now heat effecting water to make steam can power engines, or other gasses to drive turbines, that is how work is done, through the medium.
Last edited by staticlag; 02-07-2008 at 02:20 PM.
02-07-2008, 02:44 PM
#44
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12PSI is where my boost controller is set to, not joking. up to 7K if I shut the waistgate, it will spool god only knows how high and hold boost, past that, it begins to drop and will eventually settle on around 9-10 at the end.
Could be an issue with the waist gate letting go due to excessive pressure, could be cooked and wobbling bearings, could be all together. It is a .51 AR compressor, if I remember correctly now. And it is not enough for the renesis.
No, you were talking about lag. You can bring as many theoretical examples as your imagination permits, but if the turbo spools up to 10PSI by 4K, it spools up, and does so quickly. So what lag are you talking about?
Yes, maybe if... it would sooner, or maybe if something else... it would differently, but you were talking lag, and I am giving a real life example.
Other reasons why I like it back there, (or soon at the "G" spot) is because everything runs cooler, so if i am loosing pressure due to the drop, I gain it back through colder charge, and cooler running engine, cooler oil, and just because having it there gives people something to talk about, discuss and every time i bring the car somewhere and pop the hood, it gathers a crowd. It is fun to watch people get down on their knees (hot young chicks do too, by the way , I should take a picture next time) climb under the car after they hopelessly tried to locate the turbo in the engine bay.
Now answer me this: how many of you have a car that's fast and makes people kneel and drop on their four behind it?
Could be an issue with the waist gate letting go due to excessive pressure, could be cooked and wobbling bearings, could be all together. It is a .51 AR compressor, if I remember correctly now. And it is not enough for the renesis.
No, you were talking about lag. You can bring as many theoretical examples as your imagination permits, but if the turbo spools up to 10PSI by 4K, it spools up, and does so quickly. So what lag are you talking about?
Yes, maybe if... it would sooner, or maybe if something else... it would differently, but you were talking lag, and I am giving a real life example.
Other reasons why I like it back there, (or soon at the "G" spot) is because everything runs cooler, so if i am loosing pressure due to the drop, I gain it back through colder charge, and cooler running engine, cooler oil, and just because having it there gives people something to talk about, discuss and every time i bring the car somewhere and pop the hood, it gathers a crowd
. It is fun to watch people get down on their knees (hot young chicks do too, by the way , I should take a picture next time) climb under the car after they hopelessly tried to locate the turbo in the engine bay. Now answer me this: how many of you have a car that's fast and makes people kneel and drop on their four behind it?
According to your theory, my turbo is only set at 24psi on pump gas. So anything above 24psi is out of my turbo efficiency range?
No, in fact, my turbo doesn't shine until 30+ psi.
Now, why do you think people ceramic coat their manifold inside and out?
Just to keep the ambient inlet temp low? Just like the other guy said, more heat means more pressure and you will get a faster spool.
I said that specifically in my previous post. Faster spool means less lag. simple as that.
P.S. your exhaust housing A/R is what creates backpressure. Not your compressor housing.
Typically compressor housing A/R is irrelavant. only the actual blade size is.
Last edited by evilbada; 02-07-2008 at 02:46 PM.
02-07-2008, 02:53 PM
#46
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If you place your turbo at the manifold, it WILL have a faster spool then a turbo placed before the muffler ( which I think is idiotic in the first place ).
02-07-2008, 02:58 PM
#47
I think we all agree the turbo on the manifold will spool faster than the other locations.
Rotorrocks is saying that his turbo placement is good enough for him.
There's always `good enough`, and for some just being good isn't enough.
Rotorrocks is saying that his turbo placement is good enough for him.
There's always `good enough`, and for some just being good isn't enough.
02-07-2008, 03:04 PM
#48
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The guy says the T3-T04E is out of efficiency range by 12psi and his " .51 A/R compressor " is what is limiting him.
If my set up was half-assed like his, I wouldn't be able to sleep at night.
I'm not gonna be happy at some half-assed set up just because some chicks bend down to find my turbo..If I wanted a visible turbo, I would've opted for a top mount mani anyway.
02-07-2008, 03:14 PM
#49
The Professor