Turbo vs Supercharger

Technical Disscusion Forum will be used for in depth threads that are moved here by a mod/admin member.... everyone is welcome to add their input, but only on topic replys
hsvgem
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Post by hsvgem »

rotors aren't that bad, but in standard form they are a 17-18 sec. engine
with the fuel economy of a small V8...
Just like any other engine they can go hard with the right amount of money spent on them... i think they sound mad when they are boosted...
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Post by tx240 »

Any engine has problems with desighn, the rotory engine is one such engine that had a fair few flaws straight from the factory. However, with the right amount of brainpower and engineering know how, it is possible to eliminate alot of the underlying problems. say for instance, someone said that rotors and rebuild go hand in hand. that may have been the case 10 years ago, but i see on a daily basis, street driven 400hp+ rotors that were built 2 years ago (by dyson's) and havnt missed a beat since.

i guess what im trying to get at is that with the right amount of work and know how, any engine can go from an archaic piece of junk to a ball tearin bad boy. And the age old debate of "my engine is better than yours" can only be solved by pulling your head out of your ass, and running some numbers on a dyno or quarter mile to prove to the other person that your engine is superior.


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Post by F3ARED »

tx240 wrote:Any engine has problems with desighn, the rotory engine is one such engine that had a fair few flaws straight from the factory. However, with the right amount of brainpower and engineering know how, it is possible to eliminate alot of the underlying problems. say for instance, someone said that rotors and rebuild go hand in hand. that may have been the case 10 years ago, but i see on a daily basis, street driven 400hp+ rotors that were built 2 years ago (by dyson's) and havnt missed a beat since.

i guess what im trying to get at is that with the right amount of work and know how, any engine can go from an archaic piece of junk to a ball tearin bad boy. And the age old debate of "my engine is better than yours" can only be solved by pulling your head out of your ass, and running some numbers on a dyno or quarter mile to prove to the other person that your engine is superior.
Sums it up nicely.

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Crumz
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Post by Crumz »

tx240 wrote:i guess what im trying to get at is that with the right amount of work and know how, any engine can go from an archaic piece of junk to a ball tearin bad boy.
And if that isn't the G-series in a nutshell, I dunno what is.
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Post by Blue Bullet »

Cool....all this info is gold.... what about the sound that each charger makes? What do you guyz prefer? Does the whining of a supercharger turn you on :wink: or does the whooshing of a turbocharger tickle your fancy :P (Also I don't think you get as much, if any, intercooler "dose" with a supercharged setup. I think the reason there is "fluttering" in a turbocharged setup has something to do with the turbine blades spinning backwards as air passes through the intercooler when the throttle is released.... can someone elaborate on this.....)
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Post by F3ARED »

The blades of a turbo, contrary to popular beleif, DO NOT spin backwards. It would take a HUGE amount of pressure and force to stop the blades spinning at the 15,000+ rpm @ full noise, let alone make them rotate the other way.

The flutter [without blow off valve] is actually sound waves being bounced backwards off the shut throttle body and being chopped up by the blades of the turbo. This is amplified by the intercooler, which is technically a large air reserve.

Blow off vaves, the sound emitted is that excess pressure being vented once the throttle body is closed. The noise produced is dependant on the spring tension, pipe length etc of the bov itself.

As for noise, does it really matter? All i want is an 11sec quarter, who cares wether it goes CH or TU.

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Post by DMONIC TF »

GeminiCoupe wrote: who cares wether it goes CH or TU.
me :)
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tx240
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Post by tx240 »

i can feel the blow off valve debate comin back again, but i agree with Nick (Geminicoupe), and at the end of the day, if your runnin the times that your happy with, who really cares whats under the bonnet. the other thing is that most turbo's spin to the 100,000rpm mark and beyond but the principle is still the same as what Nick stated.

on another note, i love the sound that the good old superchargers make, but i also love the sound of a well setup turbo system at full noise, so the sound thing is an even playing field for me (everyone has thier own thoughts and tastes, but this is mine).

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Post by Crumz »

DISCLAIMER

This is a great topic and I thank everyone for their input. There's been a good share of veiws and no bulls*#t. Because of that, it has been moved to the tech discussion.
I ask that this is kept up, it could become a very handy thread.

Also, the flutter argument, leave it.
If you wish to argue about it, create a thread.
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Post by F3ARED »

Just something i thought id point out [yes i was bored]
Crumz wrote:A turbo creates a s*#t load more heat then a supercharger due to the exhaust gasses been used to run the turbine/compressor. I'm sure anyone who knows anything has seen a glowing turbo.
Due to this fact, the air been compressed absorbs more heat and therefore a turbo engine can be more likely to 'ping' then a charged one.
In saying that however, all forced induction will create 'higher' air temps due to the compression of the air.
This is why compression ratios of the engine must be lowered (although new technology is bringing in high comp-forced engines, however the 'oldschool' rule is low-comp) as high cylinder compression as well as boost can raise air temps so high that the a/f mix will ignite without spark (detonation/pinging).
There are two forms of heat produced by both forms of induction - the heat of the unit itself, and the heat of the compressed air produced by the unit.

The heat produced by the unit is generally lower for the turbocharger. The inlet side of the turbocharger takes air @ ambient temperature from the intake before being compressed by the compressor wheel and sent on its way to the combustion chamber. Having the exhaust housing and compressor housing seperated by the core of the turbocharger means that, generally, the majority of the air in the compressor side is unaffected by the heat of the gas in the exhaust housing. There is some heating of the air due to heatsoak [ie. heat from the exhaust housing increasing the ambient temp under the bonnet] and some increase due to the compression-of-air process.

In the supercharger example, the air is flowed into and out of the system, meaning the air must pass throughout the whole unit and mechanical rotating assembly. Being compressed inside the unit means that its temperature is increased via heatsoak from the mechanical components around it. Think of it like the increase of temperature in the sump of your engine due to the rotation of the crank. As a general rule, the heat produced by the supercharger will be higher as the heat is contained inside the supercharger due to the enclosed nature of its housing.

The second form of heat [and the reference of the "glowing" turbo being hotter] is down to the materials used to produce the units themselves. The exhaust housing and dump pipe of a turbo are produced using cast iron. A property of cast iron is that it contains more heat then it radiates/releases. This causes the heat within the exhaust to increase the exhaust temperature. As the gas gets hotter, it loses density and thus loses pressure, which means less restriction and force required to remove the air. Less restriction = more power/higher efficiency. The glowing/red hot is again down to the properties of cast iron. The colour of the material doesnt necessarily mean the material is hotter then another given material :wink:

In a supercharger, the housing consists of cast alloy]. One of the main advantages of alloy is that it radiates heat alot easier then most other metals. In the case of something like an air conitioner, it means that any heat within the gas is quickly removed, keeping your air colder. In theory, the same applys to the supercharger in that the air temp inside the charger should be kept lower if the alloy housing radiates heat at a good rate. Unfortunately its effectiveness is lowered by the fact that the heat is produced inside the charger an some heating of the air will always occur.

Another downfall of radiating heat is that although the internal air temperature [inside the charger] will be lower as a result, the ambient air under the bonnet is increased substantially causing a greater amount of heatsoak then a turbocharger. As such the initial air temperature fed into the charger is higher then that of a turbo. The heat radiated by the exhaust housing in a turbo setup can be reduced if a heat shield is used - something which would make things worse in a supercharger [think about it. The temp of the charger housing would be increased thus the air within the charger will also be heated at a higher rate].

Just something to think about.

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Post by RIX »

this link is a wonderful mass of info i'd suggest u check it out turbo owners?

http://www.turboclub.com/aturbo.htm

and read all the pages 1-4 really good info!
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Help With Turbo

Post by AnalcausT »

Ahoy All,

Ive recently put a new exhaust system onto my TE with a set of extractors. Im wondering if the gemini bolt on turbo kit would work with the extractors. also. its running a 1.6L, what turbo would be the best to run on it, and at what psi could be the best to run it at?

any help would be muchly appreciated
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Post by F3ARED »

Not to sound rude but for best results/answers, post in the Gemini Chat section next time.

Extractors will not work with the turbo - you will need a turbo manifold which is effectively an exhaust manifold with a flange for the turbo. Like i said, post in Gemini Chat with a few more details and we may be of more help.

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Post by archangel62 »

But nonetheless T28 and no more than 10psi on stock engine ;).

Yeah you're in the wrong place though, do a search then put it in Gemini Chat.
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Post by AnalcausT »

cheers.

yer im new to ozgemini.com. some random guy i met at autobarn one day helped me f*#k round with my tacho and he mentioned this site. thanks yall
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